Note: Descriptions are shown in the official language in which they were submitted.
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METHODS AND DEVICES FOR UTILIZING THERMAL ENERGY
TO BOND, STAKE AND/OR REMOVE IMPLANTS
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Application No.
60/968,969,
filed August 30, 2007, the entire contents of which are hereby expressly
incorporated by
reference into this disclosure as if set forth fully herein. This application
is also a
continuation-in-part application of: U.S. Patent Application No. 11/416,618
filed May 3,
2006; U.S. Patent Application No. 11/689,670, filed March 22, 2007; and U.S.
Patent
Application No. 11/671,556, filed February 6, 2007. The `556 Application
claimed the
benefit of the following U.S. Provisional Applications: 60/765,857 filed
February 7, 2006;
60/784,186 filed March 21, 2006; and 60/810,080 filed June 1, 2006. The entire
contents of
each of the aforementioned applications are hereby expressly incorporated by
reference into
this disclosure as if set forth fully herein.
FIELD OF THE INVENTION
[0002] The invention relates to fixation or fastening of tissues and implants
within the
body, such as the fastening of two different tissue types, the fastening of an
implant to tissue,
or the fastening of an implant to another implant. This may involve using an
energy source to
bond and/or mechanically interlock biocompatible materials intracorporeally to
stabilize
tissue within a patient's body, such as a fractured bone. The present
invention also relates to
the use of an energy source to remove an implant.
BACKGROUND OF THE INVENTION
[0003] Body tissue often requires repair and stabilization following trauma
such as a
fractured bone, torn ligament or tendon, ripped muscle, or the separation of
soft tissue from
bone. For example, trauma to the rotator cuff usually results in a portion, if
not all, of the
ligament being torn away from bone. To repair such an injury, the rotator cuff
must be
repositioned to its anatomically correct location and secured to the bone.
[0004] One method of repairing a damaged rotator cuff is through the use of a
bone
anchor and a suture. A hole is drilled in the bone near where the rotator cuff
will be
reattached to the bone. Then, an instrument is used to place a mattress stitch
with a suture in
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the detached portion of the rotator cuff. The suture is slideably positioned
through the anchor,
and the anchor is placed in the bone hole using an insertion instrument. This
instrument
includes an anvil and mandrel placed in contact with the anchor so that when
the anvil and
mandrel are moved in opposite directions relative to each other, the anchor is
deformed. The
deformation locks the anchor within the bone. Thereafter, the suture is
tensioned drawing the
rotator cuff toward the anchor. A suture lock is then activated by the
insertion instrument to
thereby pinch the suture between the anchor and suture lock.
[0005] In another example, fractured bones are a common injury seen in trauma
centers.
Sports activities, vehicle accidents, industrial-type incidents, and slip and
fall cases are just a
few examples of how bones may become fractured. Surgeons in trauma centers
frequently
encounter many different types of fractures with a variety of different bones.
Each bone and
each fracture type may require unique procedures and devices for repairing the
bone.
Currently, a one-solution-fixes-all device is not available to repair
fractured bones. Instead,
surgeons may use a combination of bone screws, bone plates, and intramedullary
rods.
[0006] Bone plates may be positioned internal to the skin, i.e. positioned
against the
fractured bone, or may be positioned external to the skin with rods connecting
the bone and
plate. Conventional bone plates are particularly well-suited to promote
healing of the fracture
by compressing the fracture ends together and drawing the bone into close
apposition with
other fragments and the bone plate. However, one drawback with plates and
screws is that
with the dynamic loading placed on the plate, loosening of the screws and loss
of stored
compression can result.
[0007] To reduce the potential of loosening, locking screws and a locking bone
plate
may be used. U.S. Patent No. 5,085,660 to Lin discloses a locking plate
system. The system
has multiple locking pins, each with one end formed as a screw to lock in the
pending
fastening bones or vertebral tubercles, with another end defining rectangular
or similarly
shaped locking post having a threaded locking end. Near the locking post end,
there is formed
a stopping protrusion. A plate defines multiple locking bores disposed at one
side to be
placed over the locking post end until the plate reaches the stopping
protrusion on the locking
pin. The plate defines multiple threaded screwing bores near the other side to
receive locking
pin screw. Multiple locking devices fix the side of the plate having locking
bores to the
locking post end of its locking pins. Multiple screwing pins each have one end
formed as a
pin to be used for penetrating the threaded screwing bore to lock into the
bone or the
vertebral tubercle. Another end which forms a head is for holding against the
threaded
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screwing bore of the plate. Threads are provided near the head for the
screwing pins to be
screwed within the threaded screwing bore of the plate.
[0008] An example of an external bone plate system is disclosed in U.S. Patent
No.
6,171,307 to Orlich. Orlich teaches an apparatus and procedure for the
external unilateral
fracture fastening, fracture compression or enlargement of osseous tissue with
a metal or
equivalent material slotted forked stick to hold and position the threaded
pins in its length,
inserted in the bone with multiple fastening slidable screws and their bolts
to attach the pins
to the slotted forked stick, a solid slidable cube to hold and position the
slotted forked stick, a
supporting axial bar, and an axial threaded bar. A preferred embodiment
includes at least
three slotted forked sticks that hold and fix, with the use of compression
screws and their
bolts, threaded pins that penetrate the proximal and distal fragments of the
bone through both
corticals. Another preferred embodiment includes slotted forked sticks that
adapt to the
threaded pins, introduced in the bone, at any degree of inclination or
orientation that these
pins might have with respect to the bone.
[0009] In addition to internal or external bone plates, surgeons sometimes use
intramedullary rods to repair long bone fractures, such as fractures of the
femur, radius, ulna,
humerus, fibula, and tibia. The rod or nail is inserted into the medullary
canal of the bone and
affixed therein by screws or bolts. After complete healing of the bone at the
fracture site, the
rod may be removed through a hole drilled in the end of the bone. One problem
associated
with the use of today's intramedullary rods is that it is often difficult to
treat fractures at the
end of the long bone. Fastener members, such as bolts, are positioned through
the cortical
bone and into threaded openings in the rod. However, the number and
positioning of the bolt/
screw openings are limited at the tip of the rod because of the decreased
surface area of the
rod and the reduced strength at the tip of the rod. Therefore, fractured bone
sections at the
distal end of a femur, for example, may not be properly fastened to the
intramedullary rod.
Various inventions have been disclosed to repair tissue and fasten implants to
tissue. U.S.
Patent No. 5,120,175 to Arbegast et al. discloses a fastener having an
elongated shank formed
of a shape memory alloy, a head at the upper end of the shank, and an annular
segment at the
lower end of said shank having a deformed cross-sectional shape suitable for
insertion into an
opening extending through adjacent workpieces. The annular segment has a
frusto-conical
trained shape that is larger than this opening. The annular segment radially
flares from the
deformed shape to an approximation of the trained shape when heated above a
critical
transformation temperature, thereby securing the fastener in place with
respect to the
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workpieces. Alternatively, a sleeve made of a different material (e.g.
aluminum) extending
over a portion or the entire length of the fastener can be added for improved
deformational
characteristics, by providing the same frusto-conical shape through axial
contraction of the
shank.
[0010] U.S. Patent No. 5,290,281 to Tschakaloff teaches a surgical system
including a
thermoplastic, body absorbable, bodily tissue fixation plate having a
plurality of formations
and a plurality of through-bores arranged in alternating relation along with
plate. The body
absorbable fasteners are adapted for insertion into the through-bores to
secure the plate to
underlying bodily tissue. The heating apparatus includes a wand having a
heating tip of a
configuration adapted to substantially matingly cooperate with the formations
to facilitate
heating and bending of the plate into conformance with the underlying bodily
tissue.
[0011] U.S. Patent No. 5,941,901 to Egan discloses an expandable soft tissue
fastening
assembly for use in anchoring soft tissue to bone. The assembly includes a tab
connected to
an anchor, a sleeve adapted to surround the anchor, and a flange adapted to
hold a soft tissue
segment next to a bone. The sleeve is inserted into a blind hole in a bone,
and a section of soft
tissue is placed over the hole next to the bone. Energy is applied to the
flange while a
predetermined axial tension is applied to the tab to compress a flared portion
of the anchor
against the sleeve. An upper tube portion of the anchor and the flange are
bonded together,
and the applied axial force on the tab separates it from the anchor, leaving
the assembly
anchored in the bone and the soft tissue section anchored in place between the
flange and the
bone.
U.S. Patent No. 7,018,380 to Cole discloses a femoral intramedullary rod
system. The rod
system is capable of treating a variety of femoral bone fractures using a
uniform
intramedullary rod design. The system generally comprises an intramedullary
rod defining an
opening having an upper surface and a transverse member including a bone
engaging portion
and a connection portion defining a thru-hole with the nail sized to pass
therethrough. A pin
is selectively coupled to the transverse member to rigidly assemble the
transverse member to
the nail when the nail is passed through the thru-hole and the pin is received
within the
opening. In an alternative design, an epiphyseal stabilizer is joined to the
nail by a locking
member.
[0012] Also, U.S. Patent No. 6,228,086 to Wahl et al. discloses a modular
intramedullary nail. The intramedullary nail apparatus comprises a nail having
a proximal
portion, a middle portion and a distal portion. The proximal portion has a
longitudinal slot
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adapted to receive at least one fixing element and the distal portion has at
least one transverse
bore. The proximal portion has a longitudinal axial bore. The apparatus
further includes a set
of inserts, each of which is adapted to be inserted in the longitudinal bore.
Each insert has at
least one guiding bore, the orientation and position of which is different for
each of the
inserts.
[0013] Another assembly and method to fasten tissue is disclosed in U.S.
Patent
6,056,751 to Fenton et al. Fenton teaches a soft tissue fastening assembly
comprising an
anchor element which is installed in a bone or other tissue, and a joiner
element which mates
with the anchor element to define a tissue capture region between them. A
section of soft
tissue is held within the tissue capture region, and energy is transmitted
into the joiner
element to cause relative vibratory motion between the respective components
and localized
melting of the contacting portions of the respective components to establish a
welded joint.
The soft tissue segment is thus fixed to the bone without sutures or other
fasteners.
[0014] U.S. Patent No. 6,080,161 to Eaves, III et al. teaches a fastener for
securing an
osteosynthesis plate to a plurality of bone segments is provided. The fastener
in the form of a
fastener blank includes an elongated shank adapted for insertion through an
opening in the
plate and into a hole formed in the bone. The upper end of the shank forms a
head that serves
to secure the plate to the bone. The elongated shank is constructed of a
material which when
heated will deform to form a tight fit within the hole drilled in the bone.
The fastener is
preferably made of a resorbable material. The invention also provides a method
for securing a
plate to a bone using the fasteners of the invention. A fastener blank is
positioned into the
hole so that a portion of the blank extends into the hole provided in the bone
and another
portion overlies the plate. The blank is heated to raise the temperature of
the blank above the
transition temperature of the material from which it is made and deform the
blank into a tight
fit within the hole.
[0015] U.S. Patent No. 6,605,090 to Trieu et al. discloses orthopedic implants
and
methods of treating bone defects. More specifically, but not exclusively, the
present invention
is directed to non-metallic implants and to methods for intra-operative
assembly and
fastening of orthopedic implants to facilitate medical treatment. The non-
metallic implant
assembly can be secured to underlying tissue by a fastener, such as a bone
screw, that is
capable of swelling on contact with fluid in the underlying tissue.
Alternatively, the non-
metallic implant assembly can be assembled intra-operatively using a fastener
that is
adhesively bonded to a bone plate or the bone plate can be deformed using
heat, force or
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solvents to inhibit withdrawal of the fastener. In preferred embodiments, both
the fastener
and the bone plate are formed of biodegradable material.
[0016] Also, U.S. Patent Publication No. 2004/0030341 to Aeschlimann et al.
teaches
implants at least partially consist of a material that can be liquefied by
means of mechanical
energy. Particularly suitable materials of this type are thermoplastics (e.g.
resorbable
thermoplastics) or thixotropic materials. The implants are brought into
contact with the tissue
part, are subjected to the action of vibratory energy and are simultaneously
pressed against
the tissue part. The liquefiable material then liquefies and is pressed into
openings or surface
asperities of the tissue part so that, once solidified, it is positively
joined thereto. The
implantation involves the use of an implantation device comprising a
generator, an oscillating
element and a resonator, whereby the generator causes the oscillating element
to
mechanically oscillate, and the element transmits the oscillations to the
resonator. The
resonator is used to press the implant against the tissue part whereby causing
oscillations to
be transmitted to the implant. The implants are, for example, pin-shaped or
dowel-shaped and
are used in lieu of screws for forming connections with bone tissue, whereby
the bone tissue
is optionally pre-bored for positioning the implant. By virtue of the fact
that it is unnecessary
to transmit any torsional forces to the implants, these implants can be
provided with a design
that is weaker, i.e. slimmer than that of known screws made of the same
material, and they
can be implanted more quickly.
[0017] Existing systems and techniques for repairing tissue, like the ones
previously
described, can be complex, time consuming, lack the characteristic of being
employed with
precision, be damaging to tissue, and/or fail to provide a robust fastening of
tissue. Therefore,
there is a need for an apparatus and method for the fastening of tissue that
involves reduced
technical ability, fewer medical instruments, less time to complete, greater
strength and
precision, and preservation of living tissue. There is a need for a system
that involves the
precise application of energy to thermoplastic material to affix tissue and
implants within the
body. There also exists a need to be able to remove previously joined
thermoplastic materials
should the clinical situation dictate this.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] A more complete understanding of the present invention, and the
attendant
advantages and features thereof, will be more readily understood by reference
to the
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following detailed description when considered in conjunction with the
accompanying
drawings wherein:
[0019] Fig. 1 is a perspective view of an exemplary vibratory bonding device;
[0020] Fig's. 2A and 2B illustrate exemplary cartridge heaters of the present
invention;
[0021] Fig's. 3A-3K show exemplary embodiments of a bonding horn;
[0022] Fig's. 4A-4C illustrate a three-function bonding horn;
[0023] Fig. 5 shows the input parameters of a bonding control unit;
[0024] Fig. 6 illustrates a manual bonding control box;
[0025] Fig. 7 shows a control box having pre-set bonding parameters;
[0026] Fig. 8A is an illustration of another embodiment of a bonding control
unit;
[0027] Fig. 8B is an illustration of another embodiment of bonding control
unit;
[0028] Fig. 8C is a graph showing a bonding profile having varying wattage;
[0029] Fig. 9 is a flowchart showing the steps for adjusting the bonding
device;
[0030] Fig. 10 is a diagram showing an electrical circuit for checking the
bonding
device;
[0031] Fig's. 1 lA and 1 lB illustrate a physical positive feedback device;
[0032] Fig. 12 shows an embodiment of a thermoplastic fastener;
[0033] Fig's. 13 and 14 illustrate the fastener of Fig. 12 fixed to a spinal
cage;
[0034] Fig. 15 shows an end effector used for implant removal;
[0035] Fig. 16 shows the end effector of Fig. 15 contacted to a T handle;
[0036] Fig's. 17 and 18 show the end effector of Fig. 15 in use to remove an
implant;
[0037] Fig. 19 shows a knotless suture fastening system;
[0038] Fig. 20 shows a suture secured to the knotless suture fastening system
of Fig. 19;
[0039] Fig. 21 shows a first staking application involving the joining of two
porous
materials;
[0040] Fig. 22 shows a second staking application involving the fastening of
soft tissue
to bone with a polymeric anchor;
[0041 ] Fig. 23 shows a third staking application involving fracture fastening
with a
plate and bone screws;
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[0042] Fig. 24 shows a fourth staking application involving near field staking
and far
field bonding;
[0043] Fig's. 25A-25C show another staking application involving a bone screw
and
plate;
[0044] Fig's. 26A-26C show a staking application for a slotted plate and bone
screw;
[0045] Fig's. 27A-27C show a PEEK pin used to prevent loosening of a polyaxial
pedicle screw/rod construct;
[0046] Fig's. 28A-28C show bone screws and plates that can be angulated;
[0047] Fig. 29 shows a dome shaped end effector;
[0048] Fig. 30 shows an end effector with a removal metallic pin that can be
implanted;
[0049] Fig. 31 illustrates an exemplary process for vibratory staking;
[0050] Fig. 32 illustrates a fastener and end effector of the invention,
wherein the
fastener is embedded within bondable material;
[0051 ] Fig. 32A illustrates an alternative welding horn or fastener of the
invention, with
a chiseled end profile;
[0052] Fig. 33 illlustrates an alternative view of the fastener and end
effector of Fig. 32;
[0053] Fig. 34 shows the fastener of Fig. 32 embedded within bondable
material;
[0054] Fig. 35 illustrates a cross section through the center of a long axis
of the fastener
of Fig. 36;
[0055] Fig. 36 illustrates a fastener of the invention, engageable with the
fastener of
Fig. 32;
[0056] Fig. 37 illustrates the fastener of Fig. 32 embedded, with the fastener
of Fig. 36
engaged;
[0057] Fig. 38 illlustrates a method of locking a position of the fastener of
Fig. 36, in
accordance with the invention, within the embedded fastener of Fig. 32;
[0058] Fig. 39 is a cross section through the center of the long axis of
fastener of Fig.
38, after the locking step of Fig. 38;
[0059] Fig. 39A is a cross section through the locking aperture of the
fastener of Fig.
38, after locking;
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[0060] Fig. 40 illustrates an embedded fastener in accordance with Fig. 32,
embedded
within bondable material adjacent to an implant within the body, taken in
cross section
through the center of the long axis of the implant and embedded fastener;
[0061 ] Fig. 40A is an enlarged view of the embedded fastener of Fig. 40;
[0062] Fig. 41 is a cross section through the center of a long axis of a
femur, illustrating
an embeddable end effector of the invention;
[0063] Fig. 42 illustrates the end effector of Fig. 41, secured within the
femur;
[0064] Fig. 43 illustrates a condylar replacement implant secured at least in
part by the
end effector of Fig. 41;
[0065] Fig. 44 illustrates fasteners and methods of fastening in accordance
with the
invention, including far field fastening, mid-field fastening, and near field
fastening;
[0066] Fig. 45 illustrates a longitudinal cross section through the center of
an end
effector in accordance with the invention, and the fastener of Fig. 45A,
illustrating the
relationship therebetween for forming a cap;
[0067] Fig. 45A illustrates a cross section through the center of a
longitudinal axis of a
fastener in accordance with the invention, adapted to secure a plate, and form
a cap;
[0068] Fig. 45B illustrates the fastener of Fig. 45A, together with a plate or
load
spreading device to be fastened;
[0069] Fig. 45C illustrates a fastener of the invention formed of two
dissimilar materials
at least mechanically interlocked to each other to form the fastener;
[0070] Fig. 46 illustrates a cross section through the center of a
longitudinal axis of a
femur, hip implant, and end effector of the invention;
[0071 ] Fig. 46A illustrates an enlarged view of a portion of Fig. 46,
illustrating methods
of repairing loosened bondable material within the body;
[0072] Fig. 46B illustrates an end effector and projections of the invention,
for
introducing bondable material within the body;
[0073] Fig. 46C illustrates the end effector and projections of Fig. 46B,
positioned
within the body, illustrated in a cross section through the center of a
longitudinal axis of a
bone within the body;
[0074] Fig. 46D-H illustrates various fasteners in accordance with the
invention;
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[0075] Fig. 47A illlustrates a cross section through a longitudinal axis of a
tibial implant
and tibia, illustrating the use of fasteners in accordance with the invention;
[0076] Fig. 47B illustrates fastening in accordance with the prior art;
[0077] Fig. 47C illustrates fastening of a graft or augment in conjunction
with the tibial
insert of Fig. 47A, as well as alternative fasteners and fastening methods in
accordance with
the invention;
[0078] Fig. 47D illustrates the use of a clamp in conjunction with fasteners
in
accordance with the invention, and further illustrates the use of a spacer in
accordance with
the invention;
[0079] Fig. 47E illustrates the spacer of Fig. 47D, in position after
fastening, as well as
a fastener securing a formerly clamped region;
[0080] Fig. 48 illustrates an end effector coated over a portion of its
exterior surface
with bondable material, in accordance with the invention;
[0081] Fig. 49 illustrates the end effector of Fig. 48, deployed within the
body in a
partial longitudinal cross section through the center of the end effector and
the bone, and
further illustrates securing of a joint replacement component in accordance
with the
invention;
[0082] Fig. 50 illustrates bonding to a roughened or porous surface, in
accordance with
the invention;
[0083] Fig. 51 illustrates a fastener having two prongs, in accordance with
the
invention, fastened to a roughened or porous surface, or a surface having at
least one cavity
or projection into or upon which bondable material may become connected;
[0084] Fig. 52A and 52B illustrate a device and method in accordance with the
invention of securing a layer using heat meltable flanges;
[0085] Fig. 53 illustrates a method of securing an implant through fastening
into a
porous or roughened surface, or a surface with a cavity or projection, using a
fastener of the
invention inserted through a retrograde approach;
[0086] Fig. 53A illustrates the fastener and methods of Fig. 53, after
fastening;
[0087] Fig. 54 illustrates an implant positioned and secured within an offset
location
using fasteners in accodance with the invention
[0088] Fig. 54A illustrates a wedge shaped fastener in accordance with the
invention;
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[0089] Fig. 54B illustrates an enlarged view of a cone shaped fastener
illustrated in Fig.
54;
[0090] Fig. 54C illustrates a cone shaped fastener provided with an expansion
member
that may be provided in an attached form;
[0091] Fig. 55 illustrates a cross section through a vertebra and fixation
device in
accordance with the invention, illustrating spinal fixation through embedding
into bondable
material, and additionally illustrates positioning of a sack containing
therapeutic material in
conjunction with the device of the invention;
[0092] Fig. 56 illustrates a partial cross section through a series of
vertebrae, illustrating
the embedded fastener of Fig. 55, and further illustrating a strap stabilizing
successive
vertebrae, fastened in accordance with the invention;
[0093] Fig. 57 illustrates a cross section through a vertebra stabilized with
bondable
material, the material having a fastener in accordance with the invention
embedded therein, to
stabilize a fracture, and further illustrating a strap secured to fasteners in
accordance with the
invention;
[0094] Fig. 58 illustrates vibratory mixing in accordance with the invention,
and further
illustrates coating an implant using vibratory energy;
[0095] Fig. 58A illustrates the use of vibratory energy in accordance with the
invention,
in association with an injection molding apparatus;
[0096] Fig. 59 illustrates vibratory energy in accordance with the invention
used to
distribute bondable material for bonding an implant within the body;
[0097] Fig. 60 illustrates a hand held device which controls production of
vibratory
energy based upon pressure applied to the handle of the hand held device;
[0098] Fig. 61 illustrates a vibratory horn optimized to distribute vibratory
energy
throughout an area bonded by bondable material;
[0099] Fig. 62 illustrates a circuit operative to produce a signal suitable
for generating
vibratory energy, based upon a DC source provided by one or more batteries;
[0100] Fig. 63 illustrates a generator system in accordance with the
invention, including
human interface elements, and control logic;
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[0101 ] Fig. 64 is a perspective view of internal elements of a handpiece in
accordance
with the invention which includes an element for generating therapeutic
vibratory energy, and
an array of vibratory elements for diagnostic use;
[0102] Fig. 65 is a side view of the handpiece of Fig. 64;
[0103] Fig. 66 is an end view of the handpiece of Fig. 64;
[0104] Fig. 67 is a graph illustrating a phase shift between voltage and
current,
generated during a bonding process in accordance with the invention;
[0105] Fig. 68 illustrates a substantial change in phase shift that occurs
within a
particular frequency range during a bonding process in accordance with the
invention;
[0106] Fig. 69 illustrates end effector displacement as a function of stack
drive signal,
modifiable through the use of a booster or attenuator;
[0107] Fig. 70 is a graph illustrating sampling at node points, or data
collection points
useful for calculating phase shift;
[0108] Fig. 71 is a graph illustrating a substantial change in impedance,
which may be
associated with an error in the bonding process;
[0109] Fig. 72 illustrates an example of a sequence of steps indicated by an
output
screen associated with a vibratory generator in accordance with the invention;
[0110] Fig. 73 illustrates a spinal cage of the invention, inserted between
vertebrae, and
fastened in accordance with the invention;
[0111 ] Fig. 74 illustrates a stabilizing strap fastened to vertebrae with
fasteners of the
invention;
[0112] Fig. 74B illustrates a vertebral stabilizing plate having an elongated
slot
engagable by a fastener of the invention;
[0113] Fig. 75 illustrates a stranded suture bound within an anchor using
vibratory
energy in accordance with the invention;
[0114] Fig. 76 illustrates a device and method in accordance with the
invention for
securing one or more suture strands within an anchor which binds the strands
upon the
application of vibratory energy and or compression;
[0115] Fig. 77 illustrates an anchor in accordance with the invention,
operable to secure
one or more suture strands through the use of vibratory energy applied by a
horn within an
interior space of the anchor;
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[0116] Fig. 78 illustrates a shaped end effector applying vibratory energy to
a
therapeutic component, with the introduction of bondable material;
[0117] Fig. 79 illustrates the bondable material of Fig. 78 applied to the
union of two
therapeutic components to secure their relative positions;
[0118] Fig. 80 illustrates two layers secured in relative apposition through
the
application of vibratory energy in accordance with the invention;
[0119] Fig. 81 illustrates an end effector and one or more tubes in accordance
with the
invention, the tubes operative to introduce or remove material proximate a
bonding site;
[0120] Fig. 82 illustrates an alternative to the device of Fig. 81, wherein
the tubes are
located within the end effector;
[0121] Fig. 83 illustrates an alternative to the device of Fig. 82, wherein
two tubes are
internally located;
[0122] Fig. 84 illustrates an end effector in accordance with the invention,
provided
with a radio frequency transmitter at an end proximate a bonding site;
[0123] Fig. 85 illustrates, in accordance with the invention, an end effector
of the
invention within a cannula, operative to provide a working space, and to
introduce and
remove materials proximate a bonding site, including tissue to be removed;
[0124] Fig. 86 illustrates a vibratory energy generating handpiece in
accordance with
the invention, incorporating power circuitry, logic circuitry, a piezo stack
or other source of
vibratory motion, a vibratory energy booster, an end effector, and a horn;
[0125] Fig. 87 illustrates the handpiece of Fig. 86, modified to incorporate a
battery and
signal generating circuit for converting battery power, and further
illustrating a housing
additionally incorporating the booster;
[0126] Fig. 88 illustrates a cross section through the center of a
longitudinal axis of an
expanding anchor in accordance with the invention;
[0127] Fig. 89 illustrates the anchor of Fig. 88 expanded;
[0128] Fig. 90 illustrates the anchor of Fig. 89, fastened in an expanded
state;
[0129] Fig. 91 illustrates a mesh in accordance with the invention, fastened
within the
body using fasteners of the invention, the mesh operative, for example, to
promote tissue
ingrowth;
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[0130] Fig. 92 illustrates vibratory fastening within a tubular structure
within the body,
vibratory fastening of at least one stent, and further illustrating an end
effector disposed upon
the end of a catheter or laparoscopic instrument;
[0131 ] Fig. 93 illustrates various methods of the invention for fastening
stents or
implants together within the body;
[0132] Fig. 94 illustrates a method of the invention for fastening two tubular
body
structures together;
[0133] Fig. 95 illustrates an alternative method of the invention for
fastening tubular
body structures together;
[0134] Fig. 96 illustrates fasteners of the invention fastening into an anchor
of bondable
material disposed within a space within the body, and further illustrates a
focal defect
repaired in accordance with the invention by an implant fastened with bondable
material
softened or melted by vibratory energy; and
[0135] Fig. 96B illustrates a focal defect repaired in accordance with the
invention
using bondable material melted or softened by vibratory energy provided by a
conforming
horn in accordance with the invention.
SUMMARY OF THE INVENTION
[0136] For the convenience of the reader, text is organized generally into the
following
headings and order, although it should be understood that content within a
heading does not
necessarily stand on its own, and all of the content is intended to be
understood and
interpreted as a whole. Thus, headings or captions are not intended, and
should not be
construed, to limit or modify the scope of the accompanying text.
Fastenins4 Materials
Sulfonation
Metals
Therapeutic Substances
Naturally Occurring Materials
Polymethylmethacz ylate
Vibratory Mixing
Manufacturing with Vibratory Energy
Bonding Parts
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Tissue Harvesting
Fasteners
Staking Fasteners
Embedded Bone Cement Fastener
Ported Embedded Fastener
Offset Shaft Collar
Knotless Suture Fastening
Bonded Flange Fastener
Headless Fastener
Spacer
End Effector with Cartridge Heater
Configurable End Effector Face
Coated Fastening Base
Expanding Fastener
Parameters and Additives
Additives
Energy Type
Pressure
Collapse
Instrumentation and Controls
Microprocessor Control
User Interface
Frequency Sweep Tuning
Impedance Feedback
Controlled Pressure Handpiece
Battery Powered Vibratory Energy Generator
SONAR Measurement of Collapse
Booster /Attenuator
Thermal Staking
Color Change
Combined Therapeutic/Diagnostic Vibratory Generator
Irrigation/Suction End Effector
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Radio Frequency End Effector
Testins4
Fastenins4 Procedures
Staking
Fastening into Existing Cement/Adhesives
End Effectorfor Fastening into Adhesives
Fastening into Implanted Device
Distal Fastening /Retrograde Approach
Spinal Fixation
Locking Screw Fastening
Resecuring or Removing an Implant
Fastening Dissimilar Materials
Fastening Combinations and Applications
Focal Defect Correction
Chain of Fastening
[0137] As indicated above, the invention relates to devices and methods that
help
stabilize tissue or implanted materials in a patient's body, including the
fastening of two
different tissue types, the fastening of an implant to tissue, or the
fastening of an implant to
another implant. The invention additionally relates to removing and anchoring
implants into
bone cement, anchoring implants using previously implanted and hardened bone
cement and
adhesives, locking implants to body tissue, for example cartilage grafts, or
other implants
using vibratory energy, connecting implants to porous surfaces using vibratory
energy,
devices for generating and controlling delivery of vibratory energy, and
mixing materials
using vibratory energy.
[0138] The methods and devices disclosed herein may be used in conjunction
with any
surgical procedure of the body. In this specification, bonding or welding
refers to the joining
of parts wherein at least one part includes a bondable material, as defined
herein. Welding
herein generally indicates joining two similar materials, whereas bonding
herein generally
indicates they may or may not be the same material. Thus, the invention may be
utilized as a
trauma bonding system for the stabilization of damaged tissue, such as
fractured bones. In
this application, the system may include devices and methods for
intracorporeal thermal
bonding or mechanically interlocking of thermoplastic material. An energy
source can be
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used to bond or lock the material in place. The energy source may be resistive
heating,
radiofrequency, ultrasound (vibratory), microwave, laser, electromagnetic,
electro shockwave
therapy, plasma energy (hot or cold), and other suitable sources. Likewise,
the energy source
may enable a portion of material to be foamed or expanded such that two
components of the
system are secured together. Other energy sources, surgical procedures, and
medical
instruments which may be used with the present invention are disclosed in U.S.
Provisional
Patent Application No. 60/968,969, filed August 30, 2007, U.S. Patent
Application No.
11/689,670, filed March 22, 2007, U.S. Patent Application No. 11/671,556,
filed February 6,
2007, U.S. Provisional Patent Applications Nos. 60/765,857 filed February 7,
2006;
60/784,186 filed March 21, 2006; and 60/810,080 filed June 1, 2006, as well as
U.S. Patent
Application Nos. 11/416,618 filed May 3, 2006; 11/689,670, filed March 22,
2007; and
11/671,556, filed February 6, 2007. The contents of these documents are
incorporated by
reference herein in their entirety.
Fastening Materials
[0139] The trauma bonding and staking system and other embodiments of the
present
invention contemplates the use of any biocompatible material bondable and/or
stakable
within the human body. Preferably, this material can melt with the application
of energy,
becoming gel-like, tacky, or soft. The energy source and the technique used to
bond and/or
stake the material within the body can be selected to minimize or avoid damage
to
surrounding body tissue. Exemplary materials that may be used may include
polymers,
ceramics, composites, and metals, although other materials may also be
suitable for use with
the invention. Generally, there are two types of polymers: thermoset and
thermoplastic.
Thermoplastics may be used with the present invention because they can be
softened,
reheated, molded and remolded.
[0140] Some semi crystalline materials have an amorphous structure or an
amorphous
region within them. These materials are particularly suitable for surgical
bonding and/or
staking, especially vibratory bonding and staking. Examples of such materials
include PAEK
(polyaryletherketone), including PEEK (polyetheretherketone) and PEKK
(polyetherketoneketone). With these special semi crystalline materials, the
amorphous
content of the polymer makes the material more conducive to vibratory energy,
and therefore
a better bond or mechanical interlock is achieved. Also, a lower amount of
energy is needed
for these materials.
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[0141 ] The semi crystalline materials without an amorphous structure or
region have a
rigid or fixed melting point. A high level of energy is required to breakdown
the crystalline
structure before the melting occurs. Once the melting starts, the material
very rapidly moves
through the transition area from a solid to a flowable substance, i.e. a
liquid. Also, the
molecular structure of semi crystalline materials absorbs vibrational energy
making it more
difficult to transmit the vibrational energy from an energy-producing
instrument to the
interface of the parts being joined. When this material is used in surgical
screws, plates, rods,
etc., care must be taken to avoid over melting and weakening of the implant.
The
temperature, time, and pressure must be closely monitored and controlled with
semi
crystalline materials or the implant will fail.
[0142] The polymers used in the present invention, such as PEEK and PLLA, have
randomly arranged molecules allowing vibrational energy to pass through the
material with
little attenuation. As such, the material requires relatively little vibratory
energy to make the
material soften and become tacky. This small amount of energy or heat needed
to bond or
stake PEEK and PLLA helps avoid or minimize the likelihood of tissue necrosis.
[0143] Dissimilar materials can also be mechanically interlocked. Staking is
defined
herein as the process of melting and reforming a piece, such as a stud, to
mechanically lock a
material in place. It provides an alternative to bonding when two parts to be
joined are made
of dissimilar materials that cannot be bonded, or when simple mechanical
retention of one
part relative to another is adequate.
[0144] In this application, the term "bondable" or "bondable material" is used
to refer to
the materials discussed above, as well as any material, suitable for use in in
vivo applications,
which can be softened and made flowable by the application of heat (such as
heat produced
with vibratory energy such as ultrasonic energy), and which, when softened,
may become
tacky and will bond to other materials and will flow to fill available space.
Thus, the material
may be thermoplastic, but it may also exhibit tackiness or bonding ability
when in its plastic
form. Many materials suitable for in vivo applications are made of or
incorporate such
bondable materials. Generally speaking, the amount of heat needed to softened
and make
flowable should be within a temperature range that does not produce
substantial thermal
tissue necrosis. Alternatively stated, the amount of heat required to soften
the bondable
material during vibratory bonding is substantially confinable, due to the
thermal properties of
the bondable material, to an area of contact between two objects which are
being bonded,
thereby protecting living body tissue near the contact between the two objects
from
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substantial thermal tissue necrosis. Selection of such material is within the
ordinary skill of
the art.
Sulfonation
[0145] Polymers used in methods and devices of the invention may be sulfonated
to be
wettable, or hydrophilic, using any of a variety of known methods, including a
method of
exposure to sulfur dioxide, an oxygen donating gas, and a free radical
producing energy, as
described in U.S. Patent 6,066,286, the contents of which are hereby
incorporated by
reference. A hydrophilic surface presents the opportunity for improved bio-
integration of
implanted devices, including an enhanced surface structure for tissue
ingrowth, should that be
an objective. Moreover, therapeutic substances may be readily incorporated
into the
sulfonated surface layer, and may more readily transfer a target therapeutic
dose into the
body. Through sulfonation of bioabsorbable polymers, fasteners may be formed
to elute
therapeutic substances, with the aforementioned desirable benefits.
[0146] Further, a wettable surface may be used to reduce friction on one or
more
bearing surfaces, such as articulating bearing surfaces in joints, creating a
more optimal and
longer lasting replacement or repair. The wettable surface can be inlaid into
the bone surface,
including an inlaid articular surface. One mechanism of operation for the
implant containing
hydrophilic materials is the formation of a molecular linkage with body fluid,
thereby
promoting lubrication, tissue ingrowth, and biocompatibility.
Metals
[0147] In accordance with the invention, metals are advantageously connected
with
fasteners incorporating polymeric materials. Any of a variety of metals may be
used, either
smooth or formed with at least portions of foam metal, or a roughened or
porous surface, or
formed with cavities or other shapes upon which polymeric material may mold,
enter, adhere,
or otherwise affix. The polymer is softened in accordance with the invention
through the
application of heat, including heat created using vibratory energy, to become
tacky, or
sufficiently softened in order to bond on a microscopic level, or a
macroscopic level through
adaptation to the surface structure of the metal. For use in vivo,
biocompatible metals are
used, including stainless steel, nitinol or other SMA (shape metal alloy),
tantalum, porous
tantalum, titanium, cobalt-chrome alloys, and other metals such as are known
to those skilled
in the art. Additional related information, including bonding polymers and
metals, and
polymer to polymer bonding of implant materials, may be found in U.S. Patents
5,163,960
entitled "Surgical devices assembled using bondable materials", and 7,104,996
entitled
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"Method of performing surgery", the contents of each of which being
incorporated herein by
reference.
Therapeutic Substances
[0148] The fastening device of the present invention may include therapeutic
substances
to promote healing. These therapeutic substances may be combined with the
materials used to
make the device. Alternatively, the therapeutic substances may be impregnated
or coated on
the device. Time-released therapeutic substances and drugs may also be
incorporated into or
coated on the surface of the device. The therapeutic substances may also be
placed in a
bioabsorbable, degradable, or biodegradable polymer layer or layers, or in
cavities disposed
in a fastening device of the present invention.
Naturally Occurring Materials
[0149] In addition to PEEK and the other polymers described herein, the
implants,
devices, and methods of the present invention may use keratin, a naturally
occurring polymer.
Keratin may be vibratory bonded or staked to itself, to other implants, or
within tissue. This
may be performed in the operating room or intracorporeally. Keratin may be
bonded to
collagen or to other known polymers.
[0150] Another polymer that can be used with the present invention is a class
of natural
materials, called polyhydroxyalkanoates- or PHA polymers.
Polymethylmethacrylate
[0151 ] Fasteners of the invention may be coated with polymethylmethacrylate
(PMMA), in order to promote bonding with PMMA used in the body, or PMMA could
be
incorporated into polymer of the fastener, or deposited within cavities or
shapes formed in the
fastener surface, including threaded, roughened, porous, or nano textures. A
fastener may be
thus coated with PMMA, or formed entirely of PMMA, and may be heat bonded,
advantageously using ultrasound, to another PMMA surface or an adhesive
surface,
otherwise as described herein with respect to bone cement.
Vibratory Mixing
[0152] In accordance with the invention, vibratory energy, for example
ultrasound, is
used to mix materials to be used in formulating implants of the invention, for
mixing
adhesives and cements, and for admixing therapeutic substances into implants
and
substances. Materials may be mixed in a production or laboratory setting, or
in the operating
room immediately before implantation. Vibratory energy is applied to the
mixing bowl or
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chamber, to promote even distribution of materials, and the release of gases,
gaps and voids,
resulting in a denser, more even mixture. In addition, the temperature or
pressure, as well as
other parameters, may be applied along with vibratory energy, to produce an
optimal result
for the mixture.
[0153] To improve mixing, the energy level and frequency may be tailored to
the
particular mix constituents. For example, low energy or longer wavelengths may
be used for
polymeric materials mixing, particularly amorphous polymers, and shorter
wavelengths may
be advantageously used for metallic materials and denser polymers, and PMMA.
Other
frequencies may be used, both lower and higher than the frequencies commonly
used in
ultrasonics, for example within the audible range, or in the megahertz range.
[0154] Polymer, adhesive, binding material or grouting agents, including bone
cement,
may be maintained or converted to a liquid or viscous form within the mixer,
therapeutic
substances, including pharmaceuticals, may optionally be admixed, and an
implant may be
dipped into the mixture for coating. The dipped implant can include any
material to be
implanted, including metals and polymers. It is advantageous for the dipped
implant to
maintain its shape until the coated polymer cools and hardens. In this manner,
an implant
such as a stent or arthroplasty component may be coated to elute a therapeutic
substance,
while maintaining appropriate physical dimensions and properties. Further, the
coated
implant may then be fastened within the body using the methods and devices
described in this
specification, the coating forming a substrate for proximal and or distal heat
fastening,
including ultrasonic fastening. Vibratory energy imparted to the mixing
chamber during
coating further serves to improve interdigitation and a close, conforming
coating of the
implant.
[0155] Vibratory mixing as described, advantageously combined with changes in
mixing parameters, such as temperature and pressure, may be used to alter the
polymerization
characteristics of polymers within the mixing chamber. Accordingly, the
resultant polymer
may have properties best suited to the procedure contemplated. Properties
affected may vary,
but may include changes in density, porosity, flexibility, hardness, color,
and smoothness.
Manufacturing with Vibratory Energy
[0156] In addition to mixing, as described herein, vibratory energy may be
advantageously employed in manufacturing requiring a mixing step. Operating
parameters
such as temperature and pressure may be varied, in combination with the
application of
vibratory energy to mixing or staging apparatus. With respect to injection
molding, in
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particular, vibratory energy is applied to the injection molding equipment, to
improve
performance of the injection molding process, as well as to potentially
improving the
resulting injection molded parts.
[0157] Vibratory mixing and packing of the invention is particularly useful in
mold
filling and fabrication of precision parts requiring a tortuous fill path,
having delicate
structures, or having features on the nanometer scale.
[0158] A biologic matrix including fibers, such as collagen fibers, can be
more
uniformly mixed and formed into a polymer or biologic collagen scaffold in
combination
with vibratory energy as described. The matrix may include cells or
pharmaceutical agents,
including chemotherapeutic agents, antibiotics, cell growth agents, growth
inducing factors,
and proteins. Moreover, manufactured or harvesting tissue, cells, or cell
products may be
integrated into a mixture that is molded to conform to a body surface or
cavity, including
epithelial surfaces, or to an implant.
Bonding Parts
[0159] When bonding parts with adhesive, it can be a challenge to evenly
distribute
adhesive between the parts to be fastened. In accordance with the invention,
vibratory energy,
for example ultrasonic energy, is applied to either or both parts, and or the
adhesive or
grouting layer, to promote movement of the adhesive throughout the
interstitial space
between the parts, whereby a more uniform, reliable and predictable bond is
formed.
[0160] In a medical context, it is often necessary to use an adhesive, binding
material or
grouting agent, for example PMMA or bone cement, to secure an implant,
particularly an
arthroplasty component, within the body. The implant may have a projection
which enters a
space within the body, for example the medullary canal of a bone, or may lie
upon the surface
of body tissue. In either application, it is advantageous to create uniform
contact between the
implant, adhesive, and body tissue, in order to avoid the formation of gaps or
voids,
appearing as lucencies in radiography.
[0161 ] In accordance with the invention, vibratory energy, advantageously
ultrasonic
energy, is applied to the implant, body tissue, adhesive layer, or a
combination of same, to
improve movement of the adhesive throughout the interface between the implant
and the
body tissue to be adhered. This is particularly effective when combined with
pressure,
applied to the interface, as by applying pressure to push the implant against
a bone surface.
An example includes the implantation of a tibial insert, including insertion
of an implant stem
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into the tibial medullary canal. Vibratory energy is applied to the upper
portion of the tibial
implant, near or on the bearing surface, or along the sides of the implant, as
the stem is
inserted into the canal. Vibratory energy may be continued for a period of
time thereafter,
until an even distribution of adhesive is achieved. In this example, adhesive
enters the small
cancellous bone interstices, as well as surface formations of the implant, to
improve the bond
between the implant and the body.
Tissue Harvesting
[0162] In accordance with the invention, tissue is harvested by placing a
harvesting tool
with a holding area or chamber, such as a hollow coring drill, upon or within
body tissue and
applying vibratory energy to the harvesting tool, tissue, or both. Vibration,
such as ultrasonic
vibration, is applied to cause cells to become dislodged, freely mobile, or
movable,
whereupon they may be collected in the holding area. Cells may be further
removed by
applying lavage, pressure, suction, or abrasion. In a reverse process,
vibratory energy aids in
the implantation of cells, through modification of the body tissue surface,
rendering the
surface more conducive to implantation, and improves transfer of cells from
the holding area
to the implantation site. The use of vibratory energy is advantageously
applied in the
harvesting or implantation of fetal cells, for example.
[0163] The application of heat or other environmental change, or the addition
of
therapeutic elements, may be used to improve performance of harvesting or
implantation. For
example, including injectible polymers may improve bonding, the addition of
nutrients may
improve cell viability, or the addition of pharmaceutical agents may improve
compatibility.
Fasteners
[0164] Fasteners of the invention may be configured to matingly engage other
implants,
being urged or locked into an advantageous orientation through a molded or
otherwise
formed three dimensional configuration. Alternatively, fasteners of the
invention may be
formed to maximize bonding surface, or to modify strength in designated
locations.
Staking Fasteners
[0165] In another embodiment of the invention, a tackable fastener is sized to
be
insertable through a stab wound, drilled portal, or other focused aperture.
The body of the
fastener may be provided with an aperture or passageway through which another
fastener
may pass, for example a suture, cable, or another similar fastener. The
fastener may further
be provided with a ramped or angled face which advantageously is provided with
a pointed or
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constricted end, operative to pierce material to be held thereon. The distal,
or non-pointed end
of the fastener may be secure using the distal fastening method described in
this specification,
or alternatively by any known means, including a press fit into a bore, or
attachment using the
aperture described above. If materials are to be held on the fastener, they
are passed over the
pointed end of the fastener, pierced by the fastener if needed, and are
optionally followed by
a load spreading device, such as a washer. When all materials have are held, a
cap is placed
upon or formed on the pointed end of the fastener. In one embodiment, and end
effector is
placed upon the pointed end, the pointed end advantageously formed with an
alignment bore
or other surface which mates and aligns with the end effector. Vibratory
energy, such as
ultrasonic energy, is then used to melt the tip and form the melted material
into a cap which
retains and thus stake the held materials.
Embedded Bone Cement Fastener
[0166] As is described in further detail, below, fasteners may be embedded
within
previously solidified bone cement, for example PMMA or other acrylic based
material. In an
embodiment in accordance with the invention, an anchor is connected to an end
effector of a
vibratory energy generator. The anchor is adapted to enter and engage cement
or adhesive
that has been locally melted by vibratory energy, and to be securely retained
therein once the
cement has cooled and hardened.
[0167] The end effector may be provided in any of a variety of shapes, one
example
being an elongated rod or shaft, connectable to a hand piece at a proximal
end, and operative
to transmit vibratory energy at a distal end. The fastener is adapted to
connect to the distal
end of the end effector by mechanical interlocking, as by a bore on either
device sized to
receive a post on the other, optionally with threading. Other mechanical
connections are
contemplated, including twist lock configurations, friction fitting, or
adhesive attachment.
The mechanical connection must be operative, however, to communicate the
vibratory energy
from the end effector to the fastener.
[0168] The fastener is adapted to be securely retained within the grouting
agent or
adhesive, in one embodiment, by being provided with a shaped or contoured
surface upon
which the adhesive may grip once hardened. A roughened or porous surface may
be provided
alone or in combination with a shaped surface, the adhesive obtaining purchase
thereupon.
[0169] The fastener may further be provided with a taper at a leading end
which first
enters the adhesive. The taper improves performance, at least, by promoting
accurate tracking
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and movement of the fastener into the adhesive, piercing tissue, and
facilitating initial
melting by concentrating vibratory energy over a smaller surface region.
[0170] Once anchored, the end effector and embedded fastener may remain
connected,
or the end effector may be removed and another fastener may be connected to
the embedded
fastener, connecting by mechanical means as described, including threading. In
a further
embodiment, a fastener such as described in the related references cited in
paragraph [0001 ]
may be fastened to the embedded fastener of the instant invention, then
secured in its
respective manner. For example, a pointed polymeric fastener may pierce tissue
and enter the
embedded fastener, then connecting by, for example, press fitting or threading
into a bore
within the embedded fastener. The fastener may be distally fastened into the
bore using
vibratory energy as detailed in this specification. Once secured within the
embedded fastener,
a head portion of the polymeric fastener may then be formed to cap and secure
the tissue,
using a vibratory end effector, including an ultrasonic end effector.
Ported Embedded Fastener
[0171 ] In a further embodiment of the invention, the embedded bone cement
fastener
described above is provided with one or more radial gaps, chambers, or ports,
extending from
a central bore. A polymeric fastener is inserted within the central bore, and
vibratory energy
is applied to the polymeric fastener, whereby polymer at the interface between
the embedded
fastener and the polymeric fastener melts. When the polymer melts, and
particularly as
pressure is applied to the polymeric fastener in the direction of insertion,
polymer enters the
ports, flowing in a direction away from the central bore. When vibratory
energy is
discontinued, the polymer solidifies, and the polymer faster is thereafter
secured within the
embedded fastener.
Offset Shaft Collar
[0172] In one embodiment, a fastener has a shaft, which may or may not be
threaded,
which terminates in a tip, and a head that is provided with a recess into
which a pin of an end
effector may be matingly engaged. The head and or shaft has a lip or flange or
collar
extending partially around the circumference of shaft. This flange corresponds
with a channel
formed in a typical spinal implant. In this manner, fasteners of the present
invention may be
adapted to be used in applications where traditional bone screws are used.
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Knotless Suture Fastening
[0173] Although the present invention includes fastener concepts that
eliminate the
need for sutures (so-called "sutureless fastening"). The present invention
also includes
fastener concepts that use suture, but without the need for knots (so-called
"knotless
fastening"). In one embodiment, a system includes an anchor, having a bore
configured and
dimensioned to receive a shaft of the tack. A channel created by the forked
end of the shaft
extends through the tack such that one or more sutures can extend through both
the anchor
and tack. When the tack is partially inserted in the anchor, the suture can
freely move;
however, as the tack is further inserted in the anchor, channels misalign and
trap the suture.
When bonding of the anchor and tack occur, knotless fastening of the suture is
achieved.
[0174] In a further embodiment, a suture is passed through body tissue, and
one or more
strands pass through a gap or aperture in an anchor comprising bondable
material. An end
effector of the invention is applied to the anchor to cause melting of the
bondable material,
trapping the suture strands therein. If the anchor and sutures are of the same
material, the
anchor and sutures may become welded. Alternatively, the anchor may be
provided with a
tortuous pathway for the strands, such that as vibratory energy is applied to
the anchor, the
anchor is deformed and the suture strands are mechanically locked within the
anchor.
[0175] Further, the end effector may be driven into the anchor with vibratory
energy,
thus displacing material of the anchor to cause compression of the suture
strands, binding the
suture strands within the anchor. The end effector is thus advantageously
shaped to penetrate
and displace material along a predetermined path and direction. For example,
fastener 826 of
Fig. 30 is well adapted to penetrate a monolithic anchor, particularly where
there is no
established entry portal.
[0176] In an additional embodiment, more than one end effector may be applied
to an
anchor from opposing sides, whereupon vibratory energy and pressure caused by
pinching of
the anchor between the end effectors operates to compress the anchor and
thereby bind one or
more suture strands within the anchor. The end effectors may further be shaped
to have
contact the anchor along an increased surface area, improving the transmission
of vibratory
energy in the anchor.
Bonded Flange Fastener
[0177] In a further embodiment of the invention, a fastener is provided
adapted to bond
an implant to body tissue, the fastener having the form of one or more flanges
or tabs
projecting from the implant, and being formed of a heat softenable and
bondable material.
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This fastener is advantageously used where the implant has the form of a
liner, surface layer,
or shell, and thus is advantageously formed without projecting mounting posts,
or holes
through which a fastener may pass. Examples include replacements for
articulating surfaces
of a joint, including the acetabular and condylar surfaces.
[0178] In one embodiment, a first implant component is fastened to body tissue
at a
location beneath or adjacent to the intended implantation site for the liner
implant. The first
implant may be attached to body tissue in accordance with any known manner, or
in a
manner disclosed herein. The first implant has mounting projections positioned
to cooperate
with the flanges of the liner. After the first implant is secured, the liner
is positioned in the
body, and the flanges are attached to the mounting projections using vibratory
energy. The
flanges and mounting projections may be provided in the form of mating
flanges, flange and
posts, mating posts, or any other cooperating projections which may be heat
bonded together
upon the application of vibratory energy. When heated the cooperating flanges
and
projections soften and bond together, and are further driven before hardening
to lie in a
position which will not interfere with proper functioning of the body.
[0179] In another embodiment, the flange is fastened directly to bone or body
tissue
adjacent to the site of implantation.
[0180] To further secure the liner, adhesive may be applied to an inner
surface of the
liner before mounting and attachment.
Headless Fastener
[0181 ] In another embodiment of the invention, a fastener is fastened in a
manner
described herein, the fastener passing, for example, through an aperture or
bore; however, the
fastener is not provided with a head or widened portion operative to prevent
the fastener from
passing completely through the aperture. For distally secured fasteners,
described herein,
there is a reduced possibility for the fastener to pass completely through the
aperture, as the
distal end of the fastener is securely fixed. Where the point of fastening is
fixed relative to the
location of the entry of the bore, a fastener head can be avoided. In this
manner, the fastener
may have an excess length, and be trimmed flush after being secured.
Alternatively, the
fastener may be provided with a length predetermined to lie flush with a
surface through
which the fastener is passed.
[0182] In a further alternative, a head portion may be bonded using vibratory
energy, as
described herein, after the fastener has been distally secured and trimmed.
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Spacer
[0183] Implants may be positioned and secured in a precise location, in
accordance with
the invention, through the use of a progressively widening spacer, such as a
spacer having a
conical, ramp or wedge shape, affixed in a predetermined location, through the
use of
vibratory energy, for example ultrasonic energy. The implants include a
bondable material as
described herein, or alternatively, fasten to a surface including bondable
material. One or
both of the surfaces may be provided with a roughened, porous, or shaped
surface, to which
melted material may enter or surround, thereby becoming affixed after cooling.
[0184] Due to the ramped shape of the implant, a progressive insertion of the
device
produces a concomitant displacement of the implant to be affixed, relative to
the body tissue
proximate the implantation site. Spacers may be placed at different locations,
so that they
may cooperatively displace the implant, and offer greater strength when
affixed.
End Effector with Cartridge Heater
[0185] A small cartridge heater may be used to deliver thermal energy,
disposed within
the end effector. To prevent heat build up on the outside shaft, an insulating
region may be
formed between the heater and the shaft.
Configurable End Effector Face
[0186] Further in accordance with the invention, an instrument may include
different
horn or end effector configurations within one design, retractable to alter
the surface
configuration of the tool. The instrument can be configured to have a bonding-
surface face, a
bonding face, and a contouring face.
Coated Fastening Base
[0187] In accordance with the invention, an implant is coated with a bondable
material,
and placed in the body as a point of attachment for other implants. The coated
implant is
advantageously shaped to provide a surface for attachment of numerous
fasteners, or one or
more fasteners at a variety of possible locations. Fasteners may be bonded to
the coated
implant using proximal or distal vibratory fastening, as described herein, or
a combination of
vibratory and mechanical fastening.
Expanding Fastener
[0188] In accordance with a further embodiment of the invention, an expanding
anchor
is provided, adapted to pass through an opening into a hollow space, and
expand within the
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hollow space thereby resisting withdrawal through the opening. The anchor is
fastened using
vibratory fastening in accordance with the invention.
Parameters and Additives
[0189] Monitoring and controlling bonding parameters ensures proper bonding of
thermoplastics. Parameters include, but are not limited to, the type of energy
to emit, type of
thermoplastic material, the size and configuration of the implant, the
thickness of the implant,
implant surface geometry, the aqueous environment, energy time, energy power,
and
frequency of the energy, amount of pressure applied to the implant during and
after
application of the energy, the geometry of the horn, the boost or attenuation
of the end
effector, the density of the implant, the amount of collapse of the
thermoplastic material, the
depth into tissue the implant is to be inserted, and the type and amount of
any therapeutic
agent that may be delivered.
[0190] There are several factors commonly encountered in vivo that effect
bonding or
staking of thermoplastic materials. One is how hydrophilic a material is, or
the tendency of a
material to absorb moisture. If too much fluid gets between the parts it can
decrease the bond
or create foam which prevents proper bonding of the materials. Therefore, the
bonding of
thermoplastics may be performed under vacuum/suction, or a hermetic seal may
be placed
around the thermoplastic during the bonding process.
Additives
[0191 ] In addition to or in place of reducing moisture from the bonding area,
certain
agents can be used to aid in the bonding process. Such agents may include
filler material,
glass filler, glass fiber, talc, and carbon. The agents may be placed at the
bond site as a
temporary bonding enhancement means or may be a permanent agent to enhance the
bonding.
[0192] In addition to avoiding release agents, pigments, and moisture, the
staking
and/or bonding of thermoplastic materials may be further enhanced by adding
minute
metallic material to the polymer. The metallic material may be metal flakes or
metal dust.
Examples of such metal include iron particles, chromium, cobalt, or other
suitable metals.
The metal may be embedded within the polymeric material to enhance the thermal
properties.
Alternatively, or in addition, the metal may be applied to the surfaces of the
polymeric
material. Energy applied to the polymer would heat both the polymeric and
metallic material
providing a faster and more uniform thermal profile. It is contemplated that
glass fillers,
carbon fillers, talc, or combination thereof may also be used in addition to
or in lieu of the
metallic material.
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Energy Type
[0193] Other factors affecting the thermal characteristics of thermoplastics
include size,
thickness, surface geometry, material properties of the thermoplastic, and the
type of host
tissue involved in the bond or staking, i.e. soft, hard, dry, wet, or moist
tissue.
[0194] Furthermore, how the thermoplastic is staked, welded or bonded is an
important
characteristic of obtaining a robust mechanical interlock or thermal bond. The
type of energy
used is one way to control the process. As previously mentioned, various
energy sources may
be used to bond and/or stake polymers. In an exemplary embodiment, two or more
different
types of energy may also be used. For example, vibratory energy may be used to
bond a
polymeric component to another component, while resistive heating may be used
to contour
the surface or change the geometry of the materials. The surface of the
component may be
smoothed out or sculpted using resistive heating.
[0195] The intensity and duration of the energy source impacts the quality of
the bond
or mechanical interlock. For instance, the amount of energy used affects the
thermal
properties. Therefore, the energy may be controlled by the operator depending
on the
component to be bonded or staked. A switch, dial, or other control may be
placed in
connection with the energy source to vary the intensity of the energy applied.
For example,
the amount of current supplied to the instrument may be varied or controlled.
It is also
contemplated that the amount of time that energy is applied may be controlled
not only by the
operator but also via radiofrequency, optical, radiowave, etc. A computer or
other
microprocessor may send signals to the energy emitter to turn the energy on
and off.
Pressure
[0196] Controlling the pressure applied to the thermoplastic material also may
be used
to affect the process. During bonding or staking, a handpiece, an anvil, a
horn, end effector,
or combinations thereof may be used to apply controlled force against the
component. After
completion, while the material is cooling, the force may continue to be
applied to ensure
proper bonding and/or mechanical interlock of the materials.
Collapse
[0197] Controlling collapse is another factor in achieving an effective
thermoplastic
bond or staking. For instance, the time and material collapse may be monitored
to ensure a
proper effect. A measurement of the change of the material being bonded or
staked may be
made to determine when complete. This may be accomplished by using micro-
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provide precise, binary control of the mold. Also, by using a linear variable
displacement
transducer (LVDT), the control system can monitor the bond more precisely.
[0198] Furthermore, collapse may be controlled or monitored through the use of
a
mechanical stop on the fastening device itself or on the instrumentation. The
mechanical stop
would prevent collapse after a predetermined point. It is also contemplated
that the collapse
could be monitored by other methods such as optics, laser, or even a hall-
effect sensor. All of
the above-mentioned parameters may be monitored and controlled by a computer.
Instrumentation and Controls
[0199] Any known energy emitting instrument may be used with the surgical
system of
the present invention. The instrument may produce energy such as resistive
heating,
radiofrequency, ultrasound, microwave, laser, electromagnetic, electro
shockwave therapy,
plasma energy (hot or cold), and other suitable energy. The instrument may be
a vibratory
energy handpiece with a sheath to cover and protect an end effector and hold a
fastener. The
sheath may have a small counter bore at its tip to cover a portion of the cap.
The tip of the
end effector may have a small post protruding from the bonding face, operative
to press into a
bore in the cap of the fastener, to align the fastener post into the anchor
bore and keep the cap
tight against the end effector face.
Microprocessor Control
[0200] In accordance with the invention, a digital signal processor (DSP)
simplifies
additional modes for fastening control. Whether or not analysis is performed
by a DSP, other
processor type, mechanical means, or by the practitioner, modes may include
any or all of the
following:
[0201 ] monitoring the phase angle differential between voltage and current
during use,
and making changes to the signal, including the frequency, to maintain a
resonant frequency;
[0202] varying the output voltage while monitoring the bond power;
[0203] monitoring the stroke using a sensor in the handpiece or end effector;
[0204] varying the drive voltage while monitoring the current and voltage, in
order to
calculate the minimum impedance;
[0205] calculating the total power/energy applied to the bond; and
[0206] monitoring the Eddy or Foucault currents created by movement of the end
effector, wherein as the end effector vibrates, a magnetic field is changed,
whereby the
movement of the end effector can be tracked, the movement indicative of
melting activity;
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[0207] calculating the amount to which the fastener has collapsed or shrunk.
[0208] The methods may be combined, and further, the total time during which
vibratory energy has been applied may be monitored, with a set minimum or
maximum time
being applied. The methods enable adjustment of the signal for variations in
the environment
and loading during a surgical procedure.
[0209] The control modes described above may be combined with input or
measured
parameters automatically by processor control, or at the election of the
surgical practitioner.
In this manner a matrix for overall control is created by the selected
parameters, and selected
control modality.
User Interface
[0210] The surgeon may manually control the parameters, or the parameters may
be
controlled using automation, including using a microprocessor or computer. In
accordance
with the invention, a generator control unit is provided having connections
for grounding and
a signal. The generator advantageously includes a user interface comprising
gauges or
indicators, and in one embodiment an LCD or similar output screen. A user
keypad is
provided to move a cursor or indicator on the output screen, whereby
parameters can be
selected and entered. A footswitch may be provided to enable the surgical
practitioner to
more easily activate the generator.
[0211 ] A staking or fastening process of the invention begins by either
pushing the
generator footswitch or by using a control on the hand piece, or by operating
two or more
controls together, if it is desired to render inadvertent activation less
likely. Upon starting, the
generator may first perform a system check. The software may also check for
proper
grounding, ground offset issues, as well as other vital circuits. If there are
errors with the
system or the grounding, the generator can give a visual or audible indication
that an error
has occurred, and the vibratory signal generator may be disabled to prevent
inadvertent use.
[0212] In accordance with a further embodiment of the invention, the surgical
practitioner enters information pertaining to the surgical procedure through
interaction with
the user interface, which includes a cursor keypad and output screen on the
generator. It
should be understood that an alternative and potentially more sophisticated
and complete
interface may be obtained by connecting a computer (not shown) to the
generator, via a
known method including USB, Bluetooth or network connection. Moreover, the
generator
interface may be programmed for the various types of surgeries and surgical
operating
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parameters expected to be encountered, and the generator may thereafter be
disconnected
from the computer during the procedure.
[0213] Once programmed, the output screen contains menus offering the surgical
practitioner options relevant to the procedure to be performed, including the
type of
procedure, and any or all of the parameters described in this specification.
In this manner, the
practitioner has the ability to input the correct procedure and real-time
parameters, in order to
enable precise control in the use of the generator. Further, the generator can
perform a
sophisticated analysis in order to determine the correct operating parameters,
including for
example frequency, wattage, and pulsing, and the generator may further
independently vary
one or more parameters over time. Accordingly, the practitioner need not make
the complex
calculations necessary in order to achieve a secure and reliable fastening,
and thus time is
saved, and the potential for error is reduced.
Frequency Sweep Tuning
[0214] If no errors are detected, the system may then sweep a frequency range,
such as
from about 38.5 kHz to about 43.5 kHz, to tune the circuit. Current
measurements may be
used to find the resonate frequency of the system, which in some embodiments
may be close
to 41 kHz. The ultrasonic signal is then sent to the hand piece where a
resonator turns the
waveform into linear movement.
Impedance Feedback
[0215] To help ensure a properly executed bond or staking, the instrument of
the
present invention may provide a positive feedback system. One way to provide
user feedback
is by measuring and controlling the impedance of the vibratory generator. This
feedback
system is based on the fact that the load placed on the end effector affects
the impedance of
the system. That is, the pressure put on the end effector by the object to be
bonded or staked
changes the impedance in the handpiece, and more particularly, of the piezo
stack and
associated electronic circuit.
[0216] By first transmitting a low power vibratory signal through the end
effector, the
impedance of the handpiece can be measured with no pressure. This establishes
a baseline
impedance. Then, the end effector may be subjected to known pressures, and the
voltage and
current may be measured to calculate the impedance for each pressure.
Therefore, when a
surgeon or other operator applies pressure from the end effector to a
thermoplastic implant to
be bonded or staked, the actual amount of pressure can be fed back to the
operator because
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the pressure can be correlated to a known impedance. The pressure and
impedance of the
handpiece may be monitored throughout the thermal profile.
[0217] Alternatively, or in addition to the signal, the microprocessor can
stop energy
emission until the correct pressure and impedance is achieved, then the
bonding may be
resumed either automatically by the microprocessor or manually by the surgeon.
If
inadequate pressure is being exerted, the bonding instrument may operate in a
pulse mode to
maintain material in a near-bond state. This may allow the bonding to more
rapidly continue
when adequate pressure is once again being applied.
[0218] By monitoring handpiece impedance, changes to the environment, such as
moisture, ambient temperature, aqueous conditions, etc., may be automatically
compensated
for by adjusting the drive waveform of the vibratory energy. As the impedance,
Z, of the
handpiece changes, the total power delivered also changes. By increasing or
decreasing the
drive voltage to compensate for the change in the impedance, a constant power
can be
delivered.
Controlled Pressure Handpiece
[0219] In accordance with the invention, a tool for producing vibratory energy
is
provided with a gauge positioned to respond to a differential between a
pressure created by
applying a force to the handle, and the physical resistance presented at the
end effector. When
excessive force is applied, a response is generated, operative to warn the
operator and or
reduce power of the vibratory signal. When insufficient force is applied, the
operator is
likewise warned, and or power is not yet applied to produce vibration.
[0220] In one embodiment of the invention, a series of electrical contacts are
interposed
between the handle grip and the end effector. Springs respond to relative
movement of the
handle and the end effector, to position the contacts with respect to each
other, in order to
open or close electrical circuits. These circuits may be connected directly to
a power
generator, or may pass to mechanical or electronic circuits which initiate a
warning or a
change in power level.
Battery Powered Vibratory Energy Generator
[0221 ] A handheld or portable vibratory generator has a requirement for a
substantial
amount of current, at high voltage. In accordance with the invention, an
inverter is provided
to convert a DC battery signal into a suitable sine wave signal, and a step-up
transformer is
provided to increase the voltage to an effective level. In one embodiment,
multiple mosfet
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devices are used in parallel, advantageously provided in pair arrays, to
provide for an
adequate amount of current. A microprocessor controls power to the mosfet
array pairs,
alternately switching power between them, in order to produce an alternating
current within a
transformer. Additional control circuitry modifies the signal parameters to
enable precise
bonding, as described herein.
SONAR Measurement of Collapse
[0222] In another exemplary method, collapse of the fastener may be monitored,
such
as by the use of SONAR. Collapse is the distance a thermoplastic fastener or
implant shrinks
in height when vibratory energy is applied. For example, some thermoplastic
fasteners have
been found to shrink about 20 percent in height and increase 30 percent in
width when
bonded. For fasteners having two pieces, such as a cap and an anchor, the
attenuation of the
reflected vibratory waves changes as the two piece fastener becomes one piece.
This change
in attenuation may be monitored to alert the surgeon or operator when the bond
or staking is
complete. Furthermore, a vibratory transducer could be used in conjunction
with the end
effector to detect the change in acoustic impedance/attenuation of the site.
This signal may be
monitored by a microprocessor/controller or data signal processor (DSP) and
data may be
automatically interpreted to indicate whether the bond was successful.
Booster /Attenuator
[0223] In another embodiment in accordance with the invention, peak to peak
motion,
or amplitude of the vibratory horn is controlled using a booster or attenuator
after the piezo
stack. Control is further achieved by the generator through modulating the
power, or
amplitude, of the high frequency signal.
Thermal Staking
[0224] Staking or fastening of fastening devices of the present invention
could also be
performed using thermal energy. The process for thermal staking is similar to
the one used
for vibratory, except that it may not be necessary to tune the system. The
energy signal sent
to the stake can be either AC or DC. To allow for longer heater life, a pulse
width modulated
(PWM) signal could be used. The PWM signal allows for the energy to be rapidly
switched
on and off with a varying duty cycle proportional to the total system energy
needed for the
staking environment.
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Color Change
[0225] It is also contemplated that the material being bonded or staked may
change
color or visible appearance as heat, vibrations, or vibratory energy is
applied for a
predetermined time and a predetermined frequency and wattage.
Combined Therapeutic/Diagnostic Vibratory Generator
[0226] In accordance with the invention, a vibratory generator includes
circuitry and is
otherwise adapted to perform diagnostic as well as therapeutic tasks.
Diagnostic tasks include
mapping or visualization of a target location. Information gathered during the
diagnostic
phase can be used by the surgical practitioner to determine optimal settings
for a subsequent
therapeutic use of the device, or the information may be directed to a
microprocessor, which
may include a DSP, which will then carry out or suggest optimal settings to
the practitioner.
[0227] Diagnostic information may include the size of implant needed, as well
information pertaining to the microclimate within the intended therapeutic
field.
[0228] In one embodiment, diagnostic ultrasound is produced by an array of low
power
crystals, and therapeutic ultrasound is produced by a stack of crystals. In
this manner, both
structures can be packaged within a single handheld device. Accordingly, a
single
microprocessor may advantageously be used to control both crystal
configurations based on
separate algorithms for each.
Irrigation/Suction End Effector
[0229] During vibratory or ultrasonic bonding, the presence of liquid or
moisture can
impact the performance and quality of the bond. One approach to ensuring a
consistent and
reliable bond, as described in this specification, is to adjust the bonding
parameters according
to the amount of observed or measured moisture within the zone or area of
bonding. Another
approach in accordance with the invention is to remove moisture from the
bonding area, by
introducing an input stream of gas or liquid, or by applying
suction/aspiration proximate the
bonding site. In one embodiment, a tube is attached to a vibratory end
effector, wherein the
inlet for aspiration, or conversely the outlet for a gas or liquid stream, is
positioned at a
location near where bonding is to take place.
[0230] In a further embodiment, a first tube introduces an input stream of gas
or liquid,
and a second tube is placed proximate thereto, operative to form an output
stream to collect
the gas or liquid via suction, together with any debris collected and carried
therein.
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[0231 ] An advantage of the aforedescribed embodiments is the removal of
debris
generated during the bonding process, which may include flash formed at the
bonding
periphery, as well as any other material or body tissue that has vibrated
loose or otherwise
become loose within or near the bonding area.
[0232] The first or second tube may be fastened to the outside of the
vibratory end
effector, or may alternatively be formed as one or more channels or pathways
within the end
effector. In either embodiment, switches or controls for activating an input
or output stream
may be provided on the handpiece connected to the end effector, or on a foot
switch or hand
operated remote, or may be activated by voice control.
Radio Frequency End Effector
[0233] In another embodiment, a radio frequency transmitter is provided
proximate the
end effector, operative to break down or destroy contaminants within the
bonding area,
including moisture or particulates. Shielding is appropriately placed in order
to safeguard any
nearby body tissue or material which might be vulnerable to stray
transmissions.
Testing
[0234] Once a fastener or other implant is vibratory bonded or staked, the
surgeon can
apply a quick tug on the assembly to verify the bond or staking was completed
as intended.
An end effector in accordance with the invention includes a post which emits
vibratory
energy, and which enters a bore or receptacle in a fastener. After bonding,
the surgeon may
actuate biasing prongs which dig slightly into the material of the fastener,
so that the surgeon
may now pull or tug on the instrument proximally to verify that the fastener
is securely
bonded or staked in place. A strain gauge may be used to measure and display
to the surgeon
how many pounds of pull strength is being put on the fastener.
[0235] In accordance with an embodiment of the invention, a frame is provided
with an
aperture through which a fastener body may pass, sized to prevent passage of a
fastener head.
The device may thus test the holding strength of a distally bonded connection,
as well as
proximal bond including a head formed with vibratory energy. A strain gauge,
spring scale,
or other suitable measuring device is connected to the frame, and a force is
applied in a
direction away from the fastened connection. The results are observed and
recorded, together
with the parameters under which the connection was formed and tested.
[0236] To aid in determining the exact conditions under which fastening was
accomplished, an electronic circuit separately measures the power consumed in
tuning the
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vibratory instrument, and performing the bond itself. This data is used,
together with other
parameters, to enable the production of a secure and reproducible bond.
Fastenins4 Procedures
Staking
[0237] Although the above-discussion emphasizes bonding or welding, the
present
invention also contemplates staking in most situations as an alternative or
supplement.
Staking generally involves the mechanical interlock of dissimilar materials.
Staking is the
process of melting and reforming a piece, such as a stud, to mechanically lock
a material in
place. It provides an alternative to bonding when two parts to be joined are
made of
dissimilar materials that cannot be bonded, or simple mechanical retention of
one part relative
to another is adequate.
[0238] The advantages of staking include short cycle time, and the ability to
perform
multiple staking with one end effector. The most common staking application
attaches metal
to plastic. A hole in a metal part is designed to receive a plastic stud. An
end effector with a
contoured tip contacts the proximal end of the stud and creates localized
frictional heat. As
the stud melts, light pressure from the end effector reforms the head to the
configuration of
the end effector. When the end effector stops vibrating, the plastic
solidifies and the metal
and plastic parts are fastened together.
[0239] For example, a PEEK (or other polymer) anchor/fastener, or tack may be
used to
couple two materials together, in this case two porous metals. After staking,
a proximal end
assumes the shape of the end of the end effector. Additionally, the distal end
of the tack is
fastened to porous metal, such as may be found on an interior face of an
implant, secured
using vibratory energy.
[0240] Initially, the anchor is threaded or otherwise secured to the bone. A
post
projecting away from the bone on the proximal end of the anchor can be used to
pierce soft
tissue to be attached, holding it in position relative to the bone. The tip is
then formed into a
cap by staking, with or without an interposing element between the soft tissue
and the cap
formed at the proximal end of the post. If needed, the post can be trimmed
(either
mechanically or by shearing off with vibratory energy) before staking. In this
manner, a plate
or other structure can be attached using two or more tacks.
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Fastening into Existing Cement/Adhesives
[0241 ] In an additional embodiment in accordance with the invention, a
fastener is
formed to embed within, and thereby become securely fastened to, previously
hardened bone
cement, in vivo. This method is advantageously employed, for example, to
repair bone
fractures, secure and resecure implants, repair periprosthetic fractures, and
to secure or repair
dental devices and implants. For example, a medical practitioner may observe a
lucent line
progressively developing as an implant loosens, indicating a separation
between body tissue
and the implant. In the prior art, revision surgery would be required in order
to remove and or
re-cement the implant. In accordance with the invention, a tack, pin, bar,
rod, plate or other
fastener may be inserted into the body, and fastened to cement implanted
earlier, through the
application of vibratory energy, said energy advantageously including
ultrasonic energy. As
discussed elsewhere, herein, the distal portion of the fastener is caused to
resonate and vibrate
in contact with the bone cement, locally heating the latter to enable adhesion
to the fastener.
The fastener thus may serve as an anchor point in subsequent steps to re-
secure the implant.
[0242] As an anchor point, a fastener thus affixed may alternatively be used
to secure
soft tissue, such as a rotator cuff, collateral ligament, or joint capsule.
[0243] Fasteners securable to implanted bone cement include the materials
described in
this specification, including as examples PMMA, metal, metal at least
partially coated with
PMMA or acrylic, PEEK (polyetheretherketone), and acrylic, or can be a
composite
including resin, and or carbon fibers. A thin coating of PMMA or acrylic, as
small as several
microns, contributes to forming a secure bond with bone cement within the
body. Bonds may
additionally be formed between dissimilar adhesives.
[0244] An initial bore may be made in the bone cement to aid alignment, to
temporarily
retain the fastener, or to increase the surface area for fastening. The
fastener may be placed in
an intended location through, for example, intramedullary, percutaneous, or
retrograde
approaches.
End Effectorfor Fastening Into Adhesives
[0245] Further, the end effector can be used as the implant itself.
Specifically, in one
embodiment of the invention, a metal pin, screw, or other engagement shape is
inserted into a
thermoplastic (e.g. PEEK) rod, the pin itself attached to an end effector. The
metal pin must
be firmly attached, or formed integrally with the end effector, to avoid
creating arcing and
sparks due to metal on metal contact between the pin and effector. For
removable pins, a
release mechanism is provided.
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[0246] In accordance with the invention, an end effector having a distal tip
formed or
attached thereto is inserted into a medullary canal in a long bone, and
affixed into adhesive
through the use of vibratory energy, as described in this specification. The
end effector is
then removed from the remainder of the vibratory energy generating device,
whereby
connection means at a proximal end may be used to secure the end effector
within the bone,
or to body tissue to be attached, or to another implant.
Fastening into Implanted Device
[0247] Implants, including fastener implants, may be bonded to cement
previously
implanted within the body. Previously implanted intramedullary devices,
secured with a
substantial amount of adhesive, provided numerous points at which tacks, pins,
rods or other
fastener may be attached through the application of vibratory energy, as
described herein.
These fasteners may then serve as anchoring points for a variety of additional
devices, for
example plates or bands. In particular, where fasteners are affixed on
opposing sides of a
fracture, a plate may be used to stabilize the fracture, without a requirement
for implanting
screws within the bone. In this manner, more invasive or complex conventional
means of
repair, including cerclage, may be used to a lesser extent, or avoided.
[0248] An additional embodiment, similar to implantation of an end effector as
described above, includes the implantation of a device coated over at least a
portion of its
surface with adhesive, or having a roughened or porous surface, or a surface
with shaped
regions, into or onto which a fastener may be affixed as described herein.
Once the device is
implanted, it may then serve as a convenient fastening point as described.
Distal Fastening /Retrograde Approach
[0249] In accordance with a further embodiment of the invention, vibratory
energy is
applied to cause thermal deformation distal to the site of application of the
end effector. In
this application, the mechanical deformation, especially in dissimilar
materials, occurs at a
site away from the vibratory horn or end effector. The staking or bonding can
occur not at the
trailing edge of the implant, but along the implant surface or at the far end
of the implant
where the implant can be mechanically bonded to body tissue, implanted cement,
or another
implant, particularly if it is a dissimilar implant. In accordance with the
invention, a rough or
irregular surface, or at least one surface cavity into which the fastener may
deform, may be
used to promote secure bonding.
[0250] Distal fastening in accordance with the invention is advantageously
employed
where a retrograde approach is safer or easier than direct access to a
fastening site. In this
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manner, a fastener may be inserted at a remote location to contact a distant
object, the distal
end of the fastener being bonded in accordance with the invention, and the
proximal end of
the fastener being secured by means of the invention, or other known means, to
secure the
distant object within the body. An example would include bonding a fastener
having distal
polymeric material to an implant having a roughened or porous surface, or a
surface with a
gap or opening forming a shape into which the polymeric material may flow, to
harden upon
cooling, thereby affixing the fastener to the implant surface. In this manner,
a surface of the
implant positioned in fixed contact with body tissue may be fastened, while an
articulating
surface may remain free of fasteners.
[0251 ] In one embodiment, the retrograde or distally fastened fastener is
additionally
connected to an implanted bone augment, or bone graft, thereby providing
primary and or
secondary stabilization for the augment. The augment may be implanted, for
example, to
replace diseased or damaged bone. In this manner, an articulating surface as
well as an
adjoining area of bone may be secured by a single fastener, or a series of
fasteners. The
fastener may be distally bonded to both the augment and the device bearing the
articulating
surface. The fastener may also pass through the augment, as through a bore.
The augment
may be composed of any material or combination of materials suitable for its
intended
function, including metal, plastic, ceramic, alloys, moldable material
including adhesives, as
well as porous forms of these materials.
[0252] This retrograde approach may be facilitated through the use of a
cannula, or an
expanding cannula, such as is disclosed in U.S. Patent 6,814,715, incorporated
herein by
reference, and related patents cited therein. Retrograde examples include
fastening an
acetabular replacement from behind the cup, fastening a tibial bearing surface
replacement
from a point below the bearing surface, and fastening a hip replacement
implant from the
femur body or distal end of the femur. Like examples are contemplated for the
smaller
analogs of the arm. Retrograde approaches may also be used in fastening or
repairing bones
of the hands, feet, skull, and spine.
[0253] It should be understood that in the case of distal fastening, as well
as proximal
fastening, the fastener body can be advantageously caused to enlargen. The
enlargened
portion may prevent staked material from separating from the fastener.
Alternatively, the
enlarged portion may prevent the fastener from dislocating from a target
location. For
example, the enlargened portion may be too large to pass through the portal or
opening
through which the fastener entered.
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[0254] The fasteners and fastening methods of the invention are advantageously
utilized
for use in-vivo, reducing or avoiding tissue necrosis by minimizing exposure
of tissue to heat,
and may be implemented through reduced size incisions, including keyhole
incisions, as may
be employed in laparoscopic procedures. Fasteners may additionally be formed
and fastened
in accordance with the invention in the operating room, at the convenience of
the surgical
practitioner, when the exact configuration and dimensions needed are best
understood, and
thereafter implanted.
Spinal Fixation
[0255] Staking in accordance with the invention can be advantageously applied
to a
variety of angulated screws, typically used in spinal applications.
Specifically, screws that
can be placed at an angle through the plate and then staked in place. The
screw and plate have
a rounded mating surface, which allows some adjustability in direction. In
accordance with
the invention, an end effector is provided sized to matingly engage an
angulated screw head,
regardless of the angle of the screw head relative to a supporting structure
adjacent the head.
The end effector applies vibratory energy to bond bondable material of the
supporting
structure and or screw head to a mating surface on the supporting structure or
screw head,
respectively.
Locking Screw Fastening
[0256] In another embodiment of the invention, a metallic polyaxial screw/rod
system,
of the type typically used in spinal surgery, is modified to include holes
intersecting both the
saddle that holds the rod and pedicle screw head, and the locking screw used
to maintain the
desired angle of the pedicle screw. Into these holes, a tack is staked or
bonded such that the
material of the tack flows into the threads between the saddle and locking
screw, effectively
preventing loosening of the system.
Resecuring or Removing an Implant
[0257] As described above, vibratory energy, such as ultrasonic energy, is
used to melt
or liquify adhesives, including bone cement. In accordance with the invention,
bone cement is
melted in situ, whereupon melted cement flows to bridge or fill voids and
gaps, the cement
thereafter being allowed to cool in order to thus re-secure a loosened
implant.
[0258] In one embodiment, a vibratory end effector is provided with a wedge or
conically shaped tip, shaped to melt and displace implanted adhesive. In this
manner, the
adhesive is made flowable by the application of vibratory energy, and is
driven by the tip into
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nearby bone, or the interstices between body tissue, filling voids or gaps,
reengaging the bone
to stabilize an attached implant. The end effector and tip could then be
withdrawn, or
alternatively, either or both devices may be left within the body. If the end
effector is to be
removed, it is decoupled from the tip, as by threading or other mechanical
interlock.
[0259] In another embodiment, a rod having at least one shaped projection, for
example
in the form of a blade or leaf, is passed to a distal portion of a hip implant
through a
retrograde entry from the distal portion of the femur. The rod is passed
through a space in the
body, in this example through an intramedullary canal. To faciliate passage, a
boring may be
formed beforehand, or the rod may be hollow, for example in the form of a
coring drill. As
the rod and blade pass through the intramedullary canal, the blade is
resiliently or
mechanically maintained in a direction substantially parallel to the passage.
Once the
implanted adhesive is encountered, vibratory energy is transmitted through the
rod to cause
the blade to vibrate, and thereby melt adhesive proximate the implant. When
sufficient
adhesive is melted or liquified, the blade may be advanced, until a desired
length of blade has
been admitted. Subsequently, the rod bearing the blade may be rotated, thereby
liquefying a
perimeter of adhesive.
[0260] If it is desired to re-secure the implant, the blade may be withdrawn
once the
implant has been repositioned, if desired, and the void or gap of concern has
been re-filled
with melted adhesive. Alternatively, if it is desired to remove the implant,
removal is
accomplished before the adhesive resolidifies, such as by lifting the implant
away from the
adhesive, out of its current location. Multiple blades may be employed to
reduce the time
required to complete the removal or resecuring process.
[0261] Alternative shaped projections include cups, cones, wires, or other
shapes which
may pass through the body to the area where the adhesive is located, and which
are
advantageously formed to best fit the geometry of the adhered interface, to
carry out the
functions previously described.
[0262] In an alternative embodiment, the rod and blades are left within the
body,
embedded in the resolidified cement, to operate as a reinforcement and or
attachment point
for further fasteners or implants, including arthroplasty components and
prosthetics, or
testing or reporting apparatus attached to or embedded within the device. As
an attachment
point, the rod may be provided with bores or apertures, which may be threaded,
into which
other fasteners may be inserted, and optionally further fastened in accordance
with the
methods disclosed herein.
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[0263] In an alternative embodiment, the shaped projection is formed of, or
coated with,
a bondable material, for example a polymer, which is then bonded to a
roughened or porous
surface, either in the operating room, or in the body. Within the body, the
surface may be that
of existing or implanted bone, or that of a previously or recently positioned
implant. When
the shaped surface is positioned in contact with the roughened surface, for
example an
intramedullary rod having a porous metal surface, vibratory energy is passed
to the shaped
projection to cause the projection to melt and bond to the roughened surface.
[0264] The issue of implant removal after bonding or staking of one or more
implants is
one that needs to be addressed if the clinical situation dictates. In
accordance with one
embodiment of the invention, a modified end effector for use with vibratory
energy forms an
implant removal tool. One end engages alternately a vibratory generator, and
subsequently a
t-handle. The other end of the end effector is provided with surface
asperities, or is otherwise
roughened to enhance engagement to the implant or material to be removed. In
use, vibratory
energy is activated to drive end effector around an implant to be removed,
firmly bonding the
end effector to the implant. The t-handle is then connected, and through a
repeated rocking or
oscillating motion of the t-handle, the bond or weld is broken and the implant
may be
removed.
Fastening Dissimilar Materials
[0265] It should be understood that a proximal or distal polymer to polymer
connection
may be made through the application of heat or vibratory energy, such as
ultrasonic energy,
as described herein. In this manner, fastener containing polymer may be
connected to a
roughened, porous or shaped surface, or to another polymeric fastener, or
polymeric coating
on an implant or implanted fastener. For example, an arthroplasty or
prosthetic component
may be at least partly covered with polymer, the polymeric surface exposed to
an intended
site for fastening. Moreover, a plurality of arthroplasty components may
include polymeric or
heat softenable material, the components being thus fastenable together in
accordance with
the invention.
[0266] An advantage to a polymeric containing, or polymeric coated fastener or
implant
is the ability to incorporate one or more therapeutic substances within the
coating, whereupon
the therapeutic substance may elute, or release the therapeutic substance in-
vivo over time, in
a predictable and useful manner. U.S. Provisional Patent Application No.
60/728,206, entitled
"Drug Eluting Implant" and incorporated herein by reference, provides examples
of means
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for delivering therapeutic agents, although those skilled in the art will
appreciate that other
known methods may be advantageously employed in combination with the
invention.
Fastening Combinations and Applications
[0267] The fastening devices of this and other embodiments of the invention
may be
used in combination with fasteners in the prior art. The fastening and repair
of tissue or an
implant may be performed in connection with surgery of a joint, bone, muscle,
ligament,
tendon, cartilage, capsule, organ, skin, nerve, vessel, or other body parts.
For example, tissue
may be repaired during intervertebral disc surgery, knee surgery, hip surgery,
organ
transplant surgery, bariatric surgery, spinal surgery, anterior cruciate
ligament (ACL) surgery,
tendon-ligament surgery, rotator cuff surgery, capsule repair surgery,
fractured bone surgery,
pelvic fracture surgery, avulsion fragment surgery, shoulder surgery, hernia
repair surgery,
and surgery of an intrasubstance ligament tear, annulus fibrosis, fascia lata,
flexor tendons,
etc.
Focal Defect Correction
[0268] In accordance with the invention, areas of disease or trauma are
replaced with an
implant or graft, secured in situ using vibratory energy. In this manner,
healthy tissue may
remain undisturbed, and a focal defect corrected. Examples include replacing a
portion of an
articulating surface, such as a condyle, the acetabulum, or glenoid fossa, or
replacing portions
of bone or soft tissue that have been damaged by injury or disease.
[0269] The diseased area may be replaced by implanted tissue, including bone
fragments or compressed living tissue, fabricated non-living material such as
polymers or
metal, or any other material a medical practitioner deems best. An interface
is created
between the graft and the body, and includes a quantity of bondable material
there between.
Advantageously, if the implant is not made entirely from bondable material, a
surface of the
implant contacting the bondable material of the interface is provided with a
roughened or
porous surface, or a surface with one or more cavities into or onto which heat
softened or
melted material may flow and thereby lock onto once cooled, hereafter an
irregular surface.
Further, the body tissue may be treated to have an irregular surface for the
same purpose. In
addition, an implant may be attached to the body tissue using methods or
devices of the
invention, or alternatively screws, adhesives, or any other known means, the
implant
provided with an irregular surface.
[0270] Thus, once the implanted material is in place, an interface defines a
strata that
includes body tissue having an irregular surface, or an implant attached to
the body tissue, the
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implant having an irregular surface, bondable material, and implant material
having an
irregular surface, unless the implant is provided with bondable material at
the interface.
[0271 ] Vibratory energy is applied proximate the interface, operative to
cause the
bondable material within the interface to soften or melt, thereby locking onto
the irregular
surface of both the body tissue or intervening implant on one side, and the
implanted material
on another side, whereby the implanted material is firmly attached to the body
once the
bondable material has cooled.
Chain of Fastening
[0272] The invention specifically contemplates a chain of fastening from bone
to
implant to tissue. For example, bone cement is fastened to bone, an implant is
fastened to the
bone cement as described herein, tissue is staked or fastened to the implant,
and the end of
the implant is capped or secured as described herein and in the incorporated
references.
Fasteners may alternatively be bonded to bone using methods described and
illustrated herein
and described in the incorporated references, and implants or tissue are
fastened to the
fastener bonded to bone, using the methods and devices of the invention.
[0273] It is contemplated that the devices and methods of the present
invention be
applied using minimally invasive incisions and techniques to fasten, for
example, muscles,
tendons, ligaments, bones, nerves, and blood vessels. A small incision(s) may
be made
adjacent the damaged tissue area to be repaired, and a tube, delivery
catheter, sheath, cannula,
or expandable cannula may be used to perform the methods of the present
invention. In
addition to using a cannula with the present invention, an introducer may be
utilized to
position implants at a specific location within the body.
[0274] The methods of the present invention may further be performed under
indirect
visualization, such as endoscopic guidance, computer assisted navigation,
magnetic
resonance imaging, CT scan, ultrasound, fluoroscopy, X-ray, or other suitable
visualization
technique. The implants, fasteners, fastener assemblies, and sutures of the
present invention
may include a radiopaque material for enhancing indirect visualization. The
use of these
visualization means along with minimally invasive surgery techniques permits
physicians to
accurately and rapidly repair, reconstruct, augment, and secure tissue or an
implant within the
body.
DETAILED DESCRIPTION OF THE INVENTION
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[0275] As detailed below, the invention provides for stabilization of implants
or body
structures, including fastening of a chain of implants. The invention
additionally relates to
removing implants fastened with bondable materials using vibratory energy,
including for
example ultrasonic energy. The invention further provides for locking similar
or dissimilar
materials together in the body by providing a surface between elements that is
roughened or
porous, or which has one or more cavities or projections upon which melted
material may
form and lock to once cooled. Additionally disclosed are devices for
generating and
controlling vibratory delivery, and mixing materials using vibratory energy.
[0276] The methods and devices disclosed herein may be used in conjunction
with any
surgical procedure of the body. The fastening and repair of tissue or an
implant may be
performed in connection with surgery of a joint, bone, muscle, ligament,
tendon, cartilage,
capsule, organ, skin, nerve, vessel, or other body parts. For example, tissue
may be repaired
during intervertebral disc surgery, knee surgery, hip surgery, organ
transplant surgery,
bariatric surgery, spinal surgery, anterior cruciate ligament (ACL) surgery,
tendon-ligament
surgery, rotator cuff surgery, capsule repair surgery, fractured bone surgery,
pelvic fracture
surgery, avulsion fragment surgery, shoulder surgery, hernia repair surgery,
and surgery of an
intrasubstance ligament tear, annulus fibrosis, fascia lata, flexor tendons,
etc.
[0277] Also, an implant may be inserted within the body and fastened to tissue
with the
present invention. Such implant insertion procedures include, but are not
limited to, partial or
total knee replacement surgery, hip replacement surgery, shoulder replacement
surgery, bone
fastening surgery, etc. The implant may be an organ, partial organ grafts,
tissue graft material
(autogenic, allogenic, xenogenic, or synthetic), collagen, a malleable implant
like a sponge,
mesh, bag/sac/pouch, collagen, or gelatin, or a rigid implant made of metal,
polymer,
composite, or ceramic. Other implants include breast implants, biodegradable
plates, porcine
or bovine patches, metallic fasteners, compliant bearing for medial
compartment of the knee,
nucleus pulposus prosthetic, stent, suture, suture anchor, tissue graft,
tissue scaffold,
biodegradable collagen scaffold, and polymeric or other biocompatible
scaffold. The scaffold
may include fetal cells, stem cells, embryonic cells, enzymes, and proteins.
Fastening Materials
[0278] The trauma bonding and staking system and other embodiments of the
present
invention contemplates the use of any biocompatible material bondable and/or
stakable
within the human body. The materials used may include, but are not limited to,
degradable,
biodegradable, bioerodible, bioabsorbable, mechanically expandable,
hydrophilic, bendable,
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deformable, malleable, riveting, threaded, toggling, barded, bubbled,
laminated, coated,
blocking, pneumatic, one-piece, multi-component, solid, hollow, polygon-
shaped, pointed,
self-introducing, and combinations thereof. Also, the devices may include, but
are not limited
to, metallic material, polymeric material, ceramic material, composite
material, body tissue,
synthetic tissue, hydrophilic material, expandable material, compressible
material, bondable
material, and combinations thereof.
[0279] Preferably, this material can melt with the application of energy,
becoming gel-
like, tacky, or soft. The energy source and the technique used to bond and/or
stake the
material within the body can be selected to minimize or avoid damage to
surrounding body
tissue. Exemplary materials that may be used may include polymers, ceramics,
composites,
and metals, although other materials may also be suitable for use with the
invention. While
the present invention contemplates the use of any of these materials in any of
the following
embodiments, polymeric material is used in the following examples and
description simply to
illustrate how the invention may be used.
[0280] Generally, there are two types of polymers: thermoset and
thermoplastic.
Thermoplastics may be used with the present invention because they can be
softened,
reheated, molded and remolded. Thermoplastics are generally classified as
either amorphous
or semi crystalline. Some semi crystalline polymers have some amorphous
structure while
other semi crystalline polymers may be more crystalline than others. Examples
of amorphous
polymers are poly carbonate (LEXAN), polystyrene, polysulfone (ULDALL), and
acrylics
polycarbonate (ABS and styrenes). Examples of semi crystalline polymers
include acetyl
(DELRIN), nylon, polyester, polyethylene, polyether ether ketone, poly
propylene,
polyvinylchloride (PVC), and Caprolactam. Biodegradable semi crystalline
polymers may
include polylactic acid and polyglycolic acid. Copolymers of PGA and PLA may
also be
used. These copolymers may vibratory bond or stake better than pure PGA and
PLA. Other
polymers which may be used with the present invention, either as a
thermoplastic or non-
thermoplastic, are polyethylene glycol (PEG)-copolymers and D,L-lactide-co-
glycolide
polyesters.
[0281] Some semi crystalline materials have an amorphous structure or an
amorphous
region within them. These materials are particularly suitable for surgical
bonding and/or
staking, especially vibratory bonding and staking. Examples of such materials
include PAEK
(polyaryletherketone), including PEEK (polyetheretherketone) and PEKK
(polyetherketoneketone). With these special semi crystalline materials, the
amorphous
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content of the polymer makes the material more conducive to vibratory energy,
and therefore
a better bond or mechanical interlock is achieved. Also, a lower amount of
energy is needed
for these materials.
[0282] The semi crystalline materials without an amorphous structure or region
have a
rigid or fixed melting point. A high level of energy is required to breakdown
the crystalline
structure before the melting occurs. Once the melting starts, the material
very rapidly moves
through the transition area from a solid to a flowable substance, i.e. a
liquid. Also, the
molecular structure of semi crystalline materials absorbs vibrational energy
making it more
difficult to transmit the vibrational energy from an energy-producing
instrument to the
interface of the parts being joined. For example, polylactic acid reaches its
melting point and
goes through its transition region rapidly which causes it to flow in the
tissue. This rapid
heating and complete, or nearly complete, melting of the material weakens the
overall
structure and causes tissue necrosis. When this material is used in surgical
screws, plates,
rods, etc., care must be taken to avoid over melting and weakening of the
implant. The
temperature, time, and pressure must be closely monitored and controlled with
semi
crystalline materials or the implant will fail.
[0283] The polymers used in the present invention, such as PEEK and PLLA, have
randomly arranged molecules allowing vibrational energy to pass through the
material with
little attenuation. As such, the material requires relatively little vibratory
energy to make the
material soften and become tacky. This small amount of energy or heat needed
to bond or
stake PEEK and PLLA helps avoid or minimize the likelihood of tissue necrosis.
In fact,
temperature measurements with PEEK show that the surface of the material, a
distance away
from the immediate bonding interface, does not exceed 37 C, and that the
temperature
profile trails back to ambient within 30 seconds or less, suggesting quick
energy dissipation.
With PLLA, temperature elevation of the surface is limited to 33 C. With
these materials,
the transition period is longer in duration and therefore, when applying
energy, the material
gradually softens, passing from a rigid state through a transition state to a
rubbery state and
then to a flowable gel-like state. The amorphous features of these materials
make them
vibratory bondable and stakable with lower temperature and better bonding
points. To bond
or stake these materials, the true melting point does not need to be reached
or exceeded
except at a limited area at the immediate bonding interface, so there is less
risk to
surrounding body tissue. PEEK and PLLA are also useful with the system of the
present
invention because it has a modulus of elasticity very close to bone.
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[0284] The temperature, time, pressure, and other parameters of the energy
process may
be closely monitored and controlled to achieve an effective bond or staking.
Also, because
the material does not substantially melt (only a limited region softens and
becomes tacky) the
holding strength of the thermoplastic during and after application of the
energy is not
jeopardized. That is, a fastener made of a thermoplastic which melts, like
those in the prior
art, cannot maintain a compressive force against a component or implant during
the bonding
or staking process. This is because the material of the fastener becomes
liquefied, and a
fastener in liquid form cannot maintain a compressive or tension force. The
present invention
contemplates implants made of PHA, PEEK or PLLA which bond by softening or
making
tacky the polymer material at the bonding region. The remaining PHA, PEEK or
PLLA
material does not flow and therefore retains its ability to maintain a
compression or tension
force.
[0285] When bonding two thermoplastic components together, it is optimal that
the
components be chemically compatible to create a molecular bond. Similar
thermoplastics
may be compatible if their melt temperature is within about 6 degrees Celsius
or if they have
similar molecular structures. Generally, amorphous polymers may be bonded to
each other.
In the present invention, PEEK may be bonded to PEEK. Biodegradable polymers
may be
bonded to biodegradable polymers. Biostable polymers may be bonded to
biostable polymers.
Biodegradable polymers may be bonded to biostable polymers.
Sulfonation
[0286] Polymers used in methods and devices of the invention may be sulfonated
to be
wettable, or hydrophilic, using any of a variety of known methods, including a
method of
exposure to sulfur dioxide, an oxygen donating gas, and a free radical
producing energy, as
described in U.S. Patent 6,066,286, the contents of which are hereby
incorporated herein by
reference. A hydrophilic surface presents the opportunity for improved
biointegration of
implanted devices, including an enhanced surface structure for tissue
ingrowth, should that be
an objective. Moreover, therapeutic substances may be readily incorporated
into the
sulfonated surface layer, and may more readily transfer a target therapeutic
dose into the
body. Through sulfonation of bioabsorbable polymers, fasteners may be formed
to elute
therapeutic substances, with the aforementioned desirable benefits.
[0287] Further, a wettable surface may be used to reduce friction on one or
more
bearing surfaces, such as articulating bearing surfaces in joints, creating a
more optimal and
longer lasting replacement or repair. The wettable surface can be inlaid into
the bone surface,
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including an inlaid articular surface. One mechanism of operation for the
implant containing
hydrophilic materials is the formation of a molecular linkage with body fluid,
thereby
promoting lubrication, tissue ingrowth, and biocompatibility. It is further
possible to make a
device surface hydrophobic using sulfonation.
[0288] In one embodiment of the invention, a sulfonated surface improves
bonding and
tissue ingrowth with biological tissue introduced after the surface has been
sulfonated.
[0289] Sulfonation may be used to alter an inherent characteristic of a
material, for
example making a non-wettable surface wettable, useful, for example, with
certain polymers,
including but not limited to polyurethane, polyethylene, polyglactic acid, or
polylactic acid.
[0290] In another embodiment in accordance with the invention, any of the
devices of
the invention may be provided with a sulfonated surface, or fabricated using
sulfonation,
thereby conferring additional beneficial properties to the device. For
example, the stents of
Fig's. 91-92, or the mesh of Fig. 93, may be constructed using sulfonation,
rendering the
device less likely to cause thrombosis. Sulfonation may be used in a variety
of ways to
produce this benefit. In particular, the surface may be made more wettable,
and thus smoother
or more slippery. Alternatively, the surface may be treated with sulfonation
to promote
incorporation of antithrombotic therapeutic substances, for example Heparin,
which may be
released upon implantation, or gradually over time. In another alternative,
the implanted
device may be fabricated from two materials, for example a polymer and a
metal, which are
bonded together using sulfonation.
[0291 ] Specifically, sulfonation may be used to cause the deposition of a
thin layer of
metal upon a polymeric core or form. This form of metal plating may render the
device
harder, smoother, more biocompatible, more durable, magnetic, more receptive
to wave
energy, and thus heatable, or may be used to impart any other property for
which metal is
employed within the body. A harder, smoother surface is particularly
advantageous for an
articulating or load bearing surface, such as a joint. For example, a coating
of cobalt chrome
is plated only to the condylar surface areas of a polymeric femoral implant,
thus reducing
both weight and cost.
[0292] Conversely, sulfonation may be used to improve bonding of a polymer to
a
metallic core or form, in order to confer the metallic form with the
properties of a polymer, as
described further herein, and in the incorporated references.
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[0293] Sulfonation is particularly advantageous for combining therapeutic
substances
and devices, because significant quantities may be associated with the surface
of the device
without the use of heat, pressure, and or time, which could have an adverse
effect on the
device, or on the therapeutic substance.
Metals
[0294] In accordance with the invention, metals are advantageously connected
with
fasteners incorporating polymeric materials. Any of a variety of metals may be
used, either
smooth or formed with at least portions of foam metal, or a roughened or
porous surface, or
formed with cavities or other shapes upon which polymeric material may mold,
enter, adhere,
or otherwise affix. The polymer is softened in accordance with the invention
through the
application of heat, including heat created using vibratory energy, to become
tacky, or
sufficiently softened in order to bond on a microscopic level, or a
macroscopic level through
adaptation to the surface structure of the metal. For use in vivo,
biocompatible metals are
used, including stainless steel, nitinol or other SMA (shape metal alloy),
tantalum, porous
tantalum, titanium, cobalt-chrome alloys, and other metals such as are known
to those skilled
in the art. Additional related information, including bonding polymers and
metals, and
polymer to polymer bonding of implant materials, may be found in U.S. Patents
5,163,960
entitled "Surgical devices assembled using bondable materials", and 7,104,996
entitled
"Method of performing surgery", the contents of each of which being
incorporated herein by
reference.
[0295] Therapeutic Substances
[0296] The fastening device of the present invention may include therapeutic
substances
to promote healing. These substances could include antibiotics, hydroxypatite,
anti-
inflammatory agents, steroids, antibiotics, analgesic agents, chemotherapeutic
agents, bone
morphogenetic protein (BMP), demineralized bone matrix, collagen, growth
factors,
autogenetic bone marrow, progenitor cells, calcium sulfate, immo suppressants,
fibrin,
osteoinductive materials, apatite compositions, germicides, fetal cells, stem
cells, enzymes,
proteins, hormones, cell therapy substances, gene therapy substances, and
combinations
thereof. These therapeutic substances may be combined with the materials used
to make the
device. Alternatively, the therapeutic substances may be impregnated or coated
on the device.
Time-released therapeutic substances and drugs may also be incorporated into
or coated on
the surface of the device. The therapeutic substances may also be placed in a
bioabsorbable,
degradable, or biodegradable polymer layer or layers.
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[0297] The therapeutic agents may also be placed within one or more cavities
disposed
in a fastening device of the present invention. Different agents may be
disposed in different
cavities of the device to specifically tailor the implant for a particular
patient. Dosages of the
therapeutic agent may be the same or different within each of cavities as
well. The cavities
may include a cover which may release the agent in a controlled or timed
manner. The cover
may be biodegradable or bioerodible to allow the agent to release to
surrounding tissue.
Examples of suitable therapeutic agents include bone growth inducing material,
bone
morphogenic proteins, osteoinductive materials, apatite compositions with
collagen,
demineralized bone powder, or any agent previously listed. U.S. Provisional
Patent
Application No. 60/728,206 entitled "Drug Eluting Implant" discloses means for
delivering
therapeutic agents. The above-mentioned provisional application is
incorporated by reference
herein in its entirety.
[0298] The fastening devices of this and other embodiments of the invention
may be
used in combination with fasteners in the prior art. Examples of fasteners,
implants, and their
methods of employment may be found in U.S. Patent Nos. 5,163,960; 5,403,348;
5,441,538;
5,464,426; 5,549,630; 5,593,425; 5,713,921; 5,718,717; 5,782,862; 5,814,072;
5,814,073;
5,845,645; 5,921,986; 5,948,002; 6,010,525; 6,045,551; 6,086,593; 6,099,531;
6,159,234;
6,368,343; 6,447,516; 6,475,230; 6,592,609; 6,635,073; and 6,719,765. Other
fastener types
are disclosed in U.S. Patent Application Nos. 10/102,413; 10/228,855;
10/779,978;
10/780,444; and 10/797,685. The above cited patents and patent applications
are hereby
incorporated by reference in their entirety.
Naturally Occurring Materials
[0299] In addition to PEEK and the other polymers described herein, the
implants,
devices, and methods of the present invention may use keratin, a naturally
occurring polymer.
Keratin may be vibratory bonded or staked to itself, to other implants, or
within tissue. This
may be performed in the operating room or intracorporeally. Keratin may be
bonded to
collagen or to other known polymers. In an exemplary application, keratin may
be used to
fasten tissue to bone since keratin has BMP and tissue scaffold properties. It
is contemplated
that any of devices and methods disclosed herein may utilize keratin alone or
in combination
with PEEK, polylactic acid, or other polymer. Keratin may be used to make
fasteners, disc
replacements, joint replacement components, stents, cell scaffolds, drug
reservoirs, etc. Also,
joint bearing surfaces may include keratin with or without collagen or
chondrocytes. The
bearing surfaces may be fastened to a joint component using PEEK or PLA
fasteners.
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[0300] Another polymer that can be used with the present invention is a class
of natural
materials, called polyhydroxyalkanoates- or PHA polymers. These polymers are
synthesized
in nature by numerous microorganisms, and they have been recently recognized
as the fifth
class of naturally occurring biopolymers (along with the polyamino acids,
polynucleic acids,
polysaccharides, and polyisoprenoids). Unlike the other naturally occurring
biological
polymers, however, the PHA polymers are thermoplastic, i.e. they can be
repeatedly softened
with heat and hardened with cooling. As such, these polymers can be processed
much like the
plastics we use today. A specific example of a PHA polymer that could be used
is poly-4-
hydroxybutyrate material. Such PHA polymers are available from Tepha Inc of
Lexington,
MA.
Polymethylmethacrylate
[0301] Fasteners of the invention may be coated with polymethylmethacrylate
(PMMA), in order to promote bonding with PMMA used in the body, or PMMA could
be
incorporated into polymer of the fastener, or deposited within cavities or
shapes formed in the
fastener surface, including threaded, roughened, porous, or nano textures. A
fastener may be
thus coated with PMMA, or formed entirely of PMMA, and may be heat bonded,
advantageously using ultrasound, to another PMMA surface or other adhesive
surface,
otherwise as described herein with respect to bone cement.
[0302] Although PMMA, known generally as bone cement, and other polymers may
function more as a grouting agent than a cement or adhesive, only the term
"adhesive" is used
throughout the specification for simplicity.
Vibratory Mixing
[0303] With reference to Fig. 58, vibratory energy is used to mix materials
2104, for
example materials to be used in formulating implants of the invention,
adhesives and
cements, therapeutic materials and other substances to be incorporated into
implants,
materials to be implanted within the body, or materials to be used during a
medical
procedure.
[0304] Materials 2104 may be mixed in a production or laboratory setting, or
in the
operating room immediately before implantation. A mixer 2108 applies vibratory
energy to
materials 2104, and includes a horn 2100, a mixing bowl or chamber 2102, and
optionally a
supporting member 2106. Vibratory energy may be applied directly to chamber
2102, or may
be applied to supporting member 2104, as illustrated, in order to promote even
distribution of
materials 2104, possibly including the release of gases, gaps and voids, and
resulting in a
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denser and or more even mixture. In addition, the temperature or pressure of
chamber 2102 or
mixture 2104, as well as other parameters, may be controlled by means known in
the art,
along with the application of vibratory energy, including for example
ultrasonic energy, to
produce an optimal resulting mixture 2104 after processing.
[0305] To improve mixing, the energy level and frequency may be tailored to
the
particular mix constituents. For example, low energy or longer wavelengths may
be used for
polymeric materials mixing, particularly amorphous polymers, and shorter
wavelengths may
be advantageously used for metallic materials and denser polymers, and PMMA.
Other
frequencies may be used, both lower and higher than the frequencies commonly
used in
ultrasonics, for example within the audible range, or in the megahertz range.
[0306] Polymer or adhesive, including bone cement, may be maintained or
converted to
a liquid or viscous form within mixer 2108. Additionally, therapeutic
substances, including
pharmaceuticals, may optionally be admixed. Further, an implant 2110 may be
dipped into
the materia12104 within chamber 2102 in order to be coated by materia12104.
The dipped
implant 2110 can include any material to be implanted, including metals and
polymers,
including porous metal or material with pores, cavities or a roughened
surface, wherein
materia12104 enters the pores or cavities in order to produce a stronger bond,
and to increase
the amount of material of the coating. It is advantageous for the dipped
implant to maintain
its shape until the coated polymer cools and hardens, if the polymer is
heated.
[0307] In this manner, an implant such as a stent or arthroplasty component,
for
example implant 2110, may be coated to elute a therapeutic substance, while
maintaining
appropriate physical dimensions and properties. Further or alternatively, the
coated implant
may then be fastened within the body using the methods and devices described
herein, the
coating forming a substrate for proximal and or distal heat fastening,
including vibratory
fastening. Vibratory energy imparted to the mixing chamber during coating
further serves to
improve interdigitation and a close, conforming coating of the implant.
[0308] Vibratory mixing as described, advantageously combined with changes in
mixing parameters, such as temperature and pressure, may be used to alter the
polymerization
characteristics of materia12104, for example, polymers within mixing chamber
2102.
Accordingly, the resultant polymer may have properties best suited to the
procedure
contemplated. Properties affected may vary, but may include changes in
density, porosity,
flexibility, hardness, color, and smoothness.
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Manufacturing with Vibratory Energy
[0309] With reference to Fig. 58A, in addition to mixing, as described herein,
vibratory
energy may be advantageously employed in manufacturing requiring a mixing
step.
Operating parameters such as temperature and pressure may be varied, in
combination with
the application of vibratory energy to mixing or staging apparatus. With
respect to injection
molding, in particular, vibratory energy is applied to any or all of the
hoppers 2122, rams
2124, ejectors 2126, gates, sprues or runners 2128, and cavities and cores
2130 during the
injection process. Vibratory horns 2100 are illustrated, connected to a source
of vibratory
energy (not shown) as known in the art, of sufficient power to achieve a
desired affect, which
may include for example improved mixing, improved flow, more uniform filling,
more
efficient ejection, faster injection, preheating of injected material, and
increased compaction
of molded material. With respect to injection molding, in particular,
vibratory energy is
applied to any or all of the gates, sprues, runners, cavities and cores during
the injection
process. In this manner, it is possible to increase the density and uniformity
of the molded
product, as well as to improve fracture resistance and performance of the part
both during the
fabrication process, and after fabrication.
[0310] Vibratory mixing and packing of the invention is particularly useful in
mold
filling and fabrication of precision parts requiring a tortuous fill path,
having delicate
structures, or having features on the nanometer scale.
[0311] In an additional manufacturing application, a biologic matrix including
fibers,
such as collagen fibers, can be more uniformly mixed and formed into a polymer
or biologic
collagen scaffold in combination with vibratory energy as described. The
matrix may include
cells or pharmaceutical agents, including chemotherapeutic agents,
antibiotics, cell growth
agents, growth inducing factors, and proteins. Moreover, manufactured or
harvesting tissue,
cells, or cell products may be integrated into a mixture that is molded to
conform to a body
surface or cavity, including epithelial surfaces, or to an implant.
Manufacturing may take
place, for example, in a factory, laboratory, operating room, outpatient
facility, or medical
office.
[0312] It should be understood that vibratory energy selected from a wide
range of
frequencies may be used to improve injection molding, for example vibration
within the
audible range, including vibratory energy of lower than 1 kHz, for example 0.3
kHz.
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Bonding Parts
[0313] Referring now to Fig. 59, when bonding parts with adhesive, it can be a
challenge to evenly distribute grouting agent or adhesive between the parts to
be fastened. In
accordance with the invention, vibratory energy, for example vibratory energy,
is applied to
either or both parts, and or the adhesive layer, to promote movement of the
adhesive
throughout the interstitial space 2142 between the parts, whereby a more
uniform, reliable
and predictable bond is formed.
[0314] With further reference to Fig. 59, in a medical context, it is often
necessary to
use an adhesive or grouting agent, for example PMMA or bone cement 2140, to
secure an
implant, particularly an arthroplasty component, such as tibial arthroplasty
component
1400A, within the body. Implant 1400A has a projection or keel portion 1422A
which enters
a space within the body, for example the medullary canal of a bone 1402, or
implant 1400A
may simply lie upon the surface of body tissue. In either application, it is
advantageous to
create uniform contact in interstices 2140 between the implant, adhesive, and
body tissue, in
order to avoid the formation of gaps or voids, which may appear as lucencies
in radiography.
[0315] In accordance with the invention, vibratory energy, advantageously
vibratory
energy, is applied to an implant, body tissue, or adhesive layer, for example
implant 1400A,
bone 1402, and adhesive layer 2140, or a combination of same, to improve
movement of
adhesive 2410 throughout the interface between the implant and the body tissue
to be
adhered. In Fig. 59, horn 2100 contacts component 1400A, connected to a
vibratory energy
generator (not shown). Alternatively, horn 2100 may contact the bone, or
another portion of
the implant 1400A. Vibratory energy is advantageously combined with pressure,
applied to
the interface, as by applying pressure to push the implant against a bone
surface. An example
includes application of force to an upper surface 2144 of tibial insert 1400A
in the direction
of Arrow "A", which includes insertion of an implant stem 1422A into the
tibial medullary
canal of bone 1402. Vibratory energy is applied to the upper portion of the
tibial implant, for
example near or on the bearing surface, or along the sides of the implant, as
the stem is
inserted into the canal. Vibratory energy may be continued for a period of
time thereafter,
until an even distribution of adhesive 2140 is achieved. In this example,
adhesive enters the
small cancellous bone interstices, as well as surface formations, including a
roughened or
porous implant surface, or an implant surface with one or more cavities, to
improve the bond
between the implant and the body.
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Tissue Harvesting
[0316] In accordance with the invention, tissue is harvested by placing a
harvesting tool
with a holding area or chamber, such as a hollow coring drill, upon or within
body tissue and
applying vibratory energy to the harvesting tool, tissue, or both. Vibration,
such as vibratory
vibration, is applied to cause cells to become dislodged, freely mobile, or
movable,
whereupon they may be collected in the holding area. Cells may be further
removed by
applying lavage, pressure, suction, or abrasion. In a reverse process,
vibratory energy aids in
the implantation of cells, through modification of the body tissue surface,
rendering the
surface more conducive to implantation, and improves transfer of cells from
the holding area
to the implantation site. The use of vibratory energy is advantageously
applied in the
harvesting or implantation of fetal cells, for example.
[0317] The application of heat or other environmental change, or the addition
of
therapeutic elements, may be used to improve performance of harvesting or
implantation. For
example, including injectible polymers may improve bonding, the addition of
nutrients may
improve cell viability, or the addition of pharmaceutical agents may improve
compatibility.
Fasteners
[0318] Fasteners of the invention may be configured to matingly engage other
implants,
being urged or locked into an advantageous orientation through a molded or
otherwise
formed three dimensional configuration. Alternatively, fasteners of the
invention may be
formed to maximize bonding surface, or to modify strength in designated
locations.
Staking Fasteners
[0319] With reference to Fig. 45 and 45A-C, in another embodiment of the
invention, a
tackable fastener 1100 is sized to be insertable through a stab wound, drilled
portal, or other
focused aperture. The body 1102 of the fastener is provided with a passageway
or aperture
1104 through which another fastener may pass, for example a suture, cable, or
another similar
fastener. Fastener 1100 is further provided with a ramped or angled face 1106
which
advantageously is provided with a constricted or pointed proximal end 1108,
operative to
pierce material to be held 1118 thereon. The distal end 1110 of the fastener
may be secure
using the distal fastening method described in this specification, or
alternatively by any
known means, including a press fit into a bore, attachment using the aperture
described
above, or adhesive. Distal end 1110 may be provided with a roughened or porous
surface to
promote secure attachment by adhesive. If materials are to be held on the
fastener, they are
passed over proximal end 1108, being pierced by the fastener if needed, and
are optionally
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followed by a load spreading member, such as a plate or washer 1112. When all
materials are
held, a cap 1114 is formed on or placed upon the proximal end of the fastener,
as described in
this specification, and the materials are staked. In Fig. 45, an end effector
or horn, for
example end effector 104 and horn 120D, are applied to fastener 1102 at
proximal end 1108,
and upon the application of vibratory energy, melt and curl over sides 1116,
thus forming cap
1114. In the example shown, pin 106 of end effector 104 enters bore or
aperture 1118 at
proximal end 1108, thus establishing and maintaining alignment with horn 120D
at least
before and during the application of vibratory energy.
[0320] Referring now to Fig. 45C, fastener 1120 is formed of at least two
dissimilar
materials, for example two materials 1122 and 1124 having different melting
points. In the
example shown, a proximal end 1108 is advantageously formed of a bondable
material 1124
that may be formed using the proximal application of vibratory energy, as
described above.
[0321 ] Distal end 1110 is advantageously fabricated with a material 1122
having a
higher melting point than material 1124, and may include, for example, metal,
ceramic, or a
high molecular weight polymer with a higher melting point than material 1122,
and may be
driven into adhesive or polymer in vivo using a distal fastening method of the
invention, or
using other means of attachment. For example, first end 1122 may be press fit,
adhered, or
threaded onto another fastener.
[0322] The dissimilar materials are joined through any known means, such as
extrusion,
molding, press fit, threading, and adhesion. Mating segments 1126 and 1128 may
be provided
to promote a strong bond between the proximal and distal ends 1108 and 1110.
Embedded Bone Cement Fastener
[0323] With reference to Figures 32-34 , anchors or embedding fasteners 800
may be
embedded within previously solidified bone bondable materia1802, for example
PMMA or
other acrylic based adhesive. In an embodiment in accordance with the
invention, embedding
fastener 800 is connected to end effector 804 of a vibratory energy generator
100, such as the
type shown in Fig. 1. Embedding fastener 800 is adapted to enter and engage
adhesive or
bondable material 802 that has been locally melted by vibratory energy,
through contact
between embedding fastener 800 and bondable materia1802 during operation of
generator
100. Embedding fastener 800 is securely retained by bondable material 802 once
the latter
has cooled and hardened.
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[0324] End effector 804 may be provided in any of a variety of shapes, one
example
being an elongated rod or shaft such as is shown in Fig's. 32-34, connectable
to a hand piece
at a proximal end 806, and operative to transmit vibratory vibratory energy at
a distal end
808. While a rod shape is shown and selected for reduced manufacturing cost,
end effector
804 may have the form of box or hex channel, oval or other shape, provided it
communicates
vibratory energy to a distal end portion, or to an attached fastener.
Embedding fastener 800 is
adapted to connect to distal end 808 of end effector 804 by mechanical
interlocking, as by a
bore 810 in embedding fastener 800, sized to receive a post 812 on end
effector 804,
optionally provided with internal or external threading (not shown), wherein
post 812 has
mating threads. Similarly, a bore or aperture may be provided in end effector
804, matable
with a post or projection on embedding fastener 800. Other mechanical
connections are
contemplated, including twist lock configurations, friction fitting, or
adhesive attachment.
The mechanical connection must be operative, however, to communicate vibratory
energy
from end effector 804 to embedding fastener 800, as by a firm mechanical
connection.
[0325] Embedding fastener 800 is adapted to be securely retained within
adhesive 802,
in one embodiment, by being provided with a shaped or contoured surface 814
upon which
the adhesive may grip, once hardened. A roughened or porous surface (not
shown) may be
provided alone or in combination with shaped surface 814, the adhesive
obtaining improved
purchase thereupon.
[0326] Embedding fastener 800 may further be provided with a taper 816 at a
leading
end 818, which first enters the adhesive, as shown in Fig. 32A. Taper 816 may
improves
performance, for example, by promoting accurate tracking and movement of
embedding
fastener 800 into bondable materia1802, piercing body tissue, and facilitating
initial melting
by concentrating vibratory energy over a smaller surface region.
[0327] Embedding fastener 800 may be provided with channels 820 operative to
provide a path for molten cement 822 to be displaced, providing room for entry
of embedding
fastener 800. Where embedding fastener 800 is to displace a substantial amount
of material,
channels may be extended along the entire length of embedding fastener 800,
and may further
extend along end effector 804, as shown for channel 824 in Fig. 34. Channels
820 are further
operative to reduce the possibility of rotation of fastener 800 within
bondable materia1802.
Channels 820 are thus disposed to extend into bondable material 802 after
insertion, and may
extend to the face of embedding fastener 800. Channels 820 are additionally
illustrated on
embeddable end effector 3054 in Fig. 84.
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[0328] Once anchored, end effector 804 and embedding fastener 800, embedded in
bondable materia1802, may remain connected. Alternatively, end effector 804
may be
removed and another fastener of a similar or different design may be connected
to an
implanted embedding fastener 800, connecting by mechanical means as described,
for
example, by threading. In a further embodiment, a fastener such as described
in the
incorporated related prior patents and applications may be fastened to an
implanted or
installed embedding fastener 800, then secured in its respective manner. For
example, a
pointed polymeric fastener may pierce body tissue and enter secured embedding
fastener 800,
connecting by, for example, press fitting, or threading into a bore within
embedding fastener
800. The additional fastener may be distally fastened into the bore using
vibratory energy as
detailed in this specification. Once secured within embedding fastener 800, a
head portion of
the polymeric fastener may then be formed to cap and secure the tissue, using
a vibratory end
effector, such as is described with respect to Figures 3C or 22, for example.
[0329] An alternative method of attaching a removable embedded fastener is
illustrated
in Fig. 30, wherein releasable fastener 826, in this embodiment a pointed
structure, is
connected to end effector 104 through push and turn engagement 828 comprising
a pin 832
associated with fastener 826, and an L-shaped slot 830, associated with end
effector 104. Pin
832 travels through slot 830 until it rests at the end of slot 830, whereupon
fastener 826 is
retained upon end effector 104. To further promote retention of fastener 826,
a resilient
member, such as spring 834, is provided within end effector 104 to maintain
tension between
pin 832 and slot 830. Slot 830 may further be angled to enhance retention of
pin 832. Further,
it should be understood that slot 830 may be provided within fastener 826, and
pin 832 may
extend from end effector 104. This embodiment has the additional advantage of
providing a
current conducting metal to metal contact surface between end effector 104 and
fastener 826,
thus preventing arcing or sparking during use.
Ported Embedded Fastener
[0330] With reference to Fig's. 35-39, a locking fastener 840 is provided with
one or
more channels 844, accessible when locking fastener 840 is installed. A
channe1844 is
communicative with one or more ports 842 extending to a surface of fastener
840. In the
example shown, a central bore forms channel 844, and connects with two ports
842, which
emerges to the surface 846 of fastener 840, for example at threads 848. When
locking
fastener 840 is threaded into embedding fastener 800, described above, a heat
meltable
fastener 850 may be inserted within channe1844. Subsequently, vibratory energy
is applied to
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meltable fastener 850, to soften and at least partially melt material from
meltable fastener
850, at a point distally located from end effector 804. When material of the
meltable fastener
850 melts, and particularly as pressure is applied to meltable fastener 850 in
the direction of
insertion, melted material enters one or more ports 842, flowing in a
direction away from
channel 844. When locking fastener 840 is installed in embedded fastener 800,
an interface
between both fasteners is created within bore 810 and at surface 846. Melted
material of
meltable fastener 850 thus flows into this interface, and adheres therein,
particularly when
cooled and hardened, to further secure fasteners 800 and 840. Where the
interface includes
shapes, such as threads 848 and mating threads 856 within bore 810, cooled
material of
meltable fastener 850 further forms a mechanical lock 858, in addition to or
as an alternative
to an adhesive lock as described.
[0331] A guide port 852 may be provided within meltable fastener 850,
operative to set
and maintain alignment of meltable fastener 850 with post 106, the latter
disposed at the
distal end of end effector 804. Meltable fastener 850 may further be provided
with a tapered
or pointed end 854, operative to promote initial melting of meltable fastener
850 through
vibratory energy, by concentrating vibratory forces within a smaller surface
area. Pointed end
854 may further serve to pierce body tissue or other materials, should that be
advantageous.
[0332] With reference to Fig. 39A, in another embodiment, fastener pin 860 is
sized to
fit through port 842 in threads 848 or surface 846 of locking fastener 840, as
previously
described. Embedded fastener 800 is further provided with port 862, sized to
admit passage
of pin 860. When fasteners 800 and 840 are fastened, ports 842 and 862 are
aligned to permit
passage of pin 860 in one or both of directions "A" or "B", as convenient for
the practitioner.
Pin 860 may be sized to be retained with ports 842, 862 by being press fit.
Alternatively,
fastener pin 860 may include bondable material, heat softenable with the
application of
vibratory energy, whereupon pin 860 becomes tacky and or conforms to gaps or a
roughened
surface within ports 842 and 862, thereby locking fasteners 800 and 840 in
respective
fastened alignment. Alternatively, pin 860 may be retained by threading,
adhesive, or other
known means for retaining a pin within an aperture. Pin 860 may further be
sufficiently long
to pass entirely through locking fastener 840 and at least a portion of
embedded fastener 800.
Offset Shaft Collar
[0333] Fig. 12 shows an embodiment of a fastener 200 of the present invention.
Although fastener 200 is particularly well-suited for used with a spinal cage
implant, it can be
used for other clinical situations as well. Fastener 200 has a shaft 202,
which can be threaded
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(not shown) or not threaded (shown). At a distal end, shaft 202 terminates in
a tip 204 and at
a proximal end, shaft 202 includes a head 206 that is provided with a recess
208 (Fig. 13) into
which a pin of an end effector can matingly engage. Head 206 has a lip 210
that only partially
extends around the circumference of shaft 202. As show, lip 210 extends about
half (180 ) of
the circumference, but any angle can be used.
[0334] Fig's. 13 and 14 show fastener 200 fixed to a spinal cage 212. As is
typical for
these types of implants, spinal cage 212 includes a recessed area 214
configured and designed
such that an inserter (which can also mate with the centrally located threaded
screw hole 216)
can be used to facilitate implantation. Spinal cage 212 includes a plurality
of fastener holes
218 that under the prior art a traditional bone screw would be used to secure
cage 212.
Fastener holes 218 are located along the periphery of recessed area 214,
creating a step. In
order to accommodate for this step, lip 210 extends about half of the
circumference. The
geometry of lip 210 also facilitates the bond. With other fastener designs,
the bonding occurs
with the far tip of the fastener. In contrast, fastener 200 uses a shear joint
with the diameter
of head 206 slightly larger than hole 218. Fig. 73 illustrates fastener 212
within the spine
2000, between vertebrae 2002.
[0335] Fastener 200 and cage 212 can be made of the same material (such as
PEEK) or
different materials. In this regard, cage 212 can be made of a different
thermoplastic material
than that of fastener 200. Alternatively, cage 212 need not be made of a
thermoplastic
material. Where dissimilar materials are used, bonding occurs through an
interlocking of
bondable material between fastener 200 and cage 212, or interlocking of
bondable material
and the physical structure of the object to be bonded.
Knotless Suture Fastening
[0336] Although the present invention includes fastener concepts that
eliminate the
need for sutures (so-called "sutureless fastening"). The present invention
also includes
fastener concepts that use suture, but without the need for knots (so-called
"knotless
fastening"). Fig's. 19 and 20 show a knotless fastening system 300. System 300
includes an
anchor 302 that is similar to the anchors of the inventors' prior applications
and a fastener cap
or tack 304 that is also similar to the fastener cap of the prior
applications. In this regard,
anchor 302 is shown threaded, but could be otherwise provided with protrusions
or other
surface features for engaging the tissue into which it is inserted.
Alternatively, it could be
smooth.
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[0337] Anchor bore 306 is configured and dimensioned to receive shaft 308 of
tack 304.
Bore 306 can be substantially cylindrical or can be configured for holding an
allen-type
wrench. The figures illustrate an anchor bore that is square-shaped with
rounded corners,
although other allen-wrench shapes such as hexagonal shaped, star-shaped,
pentagonal
shaped, or the like may likewise be suitable to allow torque to be imparted to
the anchor in
order to help drive the anchor into bone, tissue, or implant material. An
anchor channe1310
extends through anchor 302 and anchor 302 is also provided with slits 311 so
that a suture
does not become tangled during insertion and can slide when tightening.
[0338] Various methods are disclosed in U.S. Patent publication 2007/0208378
for
securing sutures. With reference to Fig's. 75-77, several such methods are
illustrated.
However, anchors 3900, 3900A and 3900B are contacted by end effector 104 and
or horns
adapted to fit and communicate vibratory energy to the anchor, as shown and
described for
example with respect to fastener 826 of Fig. 30, and horns 2100 of Fig. 59 and
2310 of Fig.
61, whereupon the anchor may be caused to soften, melt or deform to lock
suture 3902 within
the anchor.
[0339] For example, a suture 3902 is passed through body tissue, and one or
more
strands pass through a gap or aperture in an anchor 3900, 3900A, 3900B
comprising
bondable material. An end effector of the invention is applied to the anchor
to cause melting
of the bondable material, trapping the suture strands therein.
[0340] With respect to Fig's. 75 and 76, horns 3908 are caused to contact
anchor 3900
or 3902 and transmit vibratory energy into anchor 3900 or 3900A sufficient to
cause
softening or deformation thereof, and to thereby bind sutures 3902. Pressure
may be applied
in the direction of the heavy arrows within horns 3908, during and or after
application of
vibratory energy, to improve bonding.
[0341] With reference to Fig. 77, end effector 104 is provided with a tip 3904
adapted
to fit within recess 3906 of anchor 3900C, and to transmit vibratory energy to
anchor 3900C
to cause softening and deformation thereof, sufficient to bind sutures 3902
within anchor
3900C. Pressure may be applied in the direction of the heavy arrow within tip
3904, during
and or after application of vibratory energy, to improve bonding.
[0342] If the anchor and sutures are of the same material, the anchor and
sutures may
become welded. Alternatively, the anchor may be provided with a tortuous
pathway for the
strands, such that as vibratory energy is applied to the anchor, the anchor is
deformed and the
suture strands are mechanically locked within the anchor.
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[0343] Further, the end effector may be driven into the anchor with vibratory
energy,
thus displacing material of the anchor to cause compression of the suture
strands, binding the
suture strands within the anchor. The end effector is thus advantageously
shaped to penetrate
and displace material along a predetermined path and direction. For example,
fastener 826 of
Fig. 30 is well adapted to penetrate a monolithic anchor, particularly where
there is no
established entry portal.
[0344] In an additional embodiment, more than one end effector may be applied
to an
anchor from opposing sides, whereupon vibratory energy and pressure caused by
pinching of
the anchor between the end effectors operates to compress the anchor and
thereby bind one or
more suture strands within the anchor. The end effectors may further be shaped
to have
contact the anchor along an increased surface area, improving the transmission
of vibratory
energy in the anchor.
[0345] A tack channe1312 (created by the forked end of shaft 308) extends
through tack
304 such that one or more sutures 314 can extend through both anchor 302 and
tack 304.
When tack 304 is partially inserted in anchor 302, suture 314 can freely move
since anchor
channe1310 is aligned with tack channe1312. However, as tack 304 is further
inserted in
anchor 302, channels 310 and 312 misalign, trapping suture 314. When the
bonding of anchor
302 and 304 occurs, knotless fastening of suture 314 is achieved. Experimental
studies have
shown that with anchor 302 and tack 304 made of PEEK and suture 314 made of
polyethylene, knotless fastening can be achieved without any melting or
degradation of the
suture material. Although a single suture lead is shown in Fig. 20, there
could be two leads
through one side of anchor 302 and a loop of the suture for holding tissue out
the other.
[0346] As discussed in connection with other embodiments, tack shaft 308 may
have a
cross-sectional shape corresponding to the shape of the anchor bore 306. One
potential
advantage of this embodiment of the invention is that it may allow the
physician to apply a
greater amount of torsional force to turn the anchor further into or out of
the bone, tissue or
implant material either before or after the anchor and tack have been bonded
together. This
would allow depth control of insertion and/or further control of the suture
tension. Rotation
of the tack can be achieved in several different ways. For example, an open-
ended wrench
may be used to grip the tack shaft and turned in a clockwise or counter-
clockwise direction.
Similarly, the tack lid 316 may be configured to receive a wrench that allows
the fastener
assembly to be rotated in or out of position. Tack lid 316 may include a
bonding recess 318
that allows a bonding device to be aligned with and impart energy to the
anchor. The bonding
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recess also may be configured to receive a tool either before or after
bonding, or both, that
allows a physician to manipulate the fastener. Thus, the shape of the bonding
recess may be
configured to receive an allen-type wrench, a screwdriver, or the like so that
torsional forces
may be exerted on the fastener. Alternatively, the outer periphery of tack lid
316 may be
shaped to engage a tool, for example, while tack lid 316 is illustrated as
round, it may be
square, or hex shaped.
[0347] Providing features in the fastener that allow a physician to manipulate
the
assembly may be useful in several different ways. For instance, such a
configuration may
allow a physician to bond the assembly together and then rotate it to further
deploy the
assembly into the body. Such a configuration also may facilitate easier
removal of the
assembly at a later time. This configuration also may permit a physician to
make one or more
adjustments in the deployment or positioning of the fastener assembly, either
during the
initial procedure or later in time. While such benefits each have advantages,
it should be
noted that no embodiment of the invention requires these advantages to be
realized in order to
fall within the scope of the invention.
[0348] Bonding of the tack to an inside bore of an anchor may result in a
collapse of the
tack during the bond. As a result of this collapse, the gap distance between
the anchor top
surface and the underside surface of the tack may decrease. This reduction in
the gap may be
beneficial for further ensuring that the material disposed in the gap is more
securely held in
place by the fastener assembly. For instance, the bonding process may cause
the gap to be
reduced 1 mm or more due to bonding. This reduction may therefore cause the
cap lid and top
of the anchor to impinge on the tissue or implant materials disposed in
between these
surfaces.
[0349] In some instances, it may be desirable to fine-tune the security of the
tissue and
compression against the bone. As mentioned above, the fastener may be
configured to receive
a tool that allows manipulation of the assembly. In this manner, the fastener
lid 316 may be
manipulated to drive the anchor 302 and tack 304 further into the bone. This
would decrease
the distance between the cap lid 316 and bone, better securing a thinner
tissue or implant
material disposed therebetween by placing it under more compression.
Alternatively, if it was
thought that tissue was under too much compression the fastener cap could be
turned the
opposite direction increasing the gap between the bone and fastener lid. A
washer may be
disposed between the lower surface of the cap lid 316 and the tissue or
implant material that
is being fastened in place. As the cap lid is rotated or otherwise
manipulated, the washer may
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help reduce damage to the tissue or implant material from shearing forces that
may be
imparted from rotation of the cap lid 316.
[0350] Additionally, such a configuration may allow the anchor placement to be
adjusted even before bonding takes place. For example, the anchor may be
placed in a first
position. Implant material or tissue may be disposed between the anchor and a
fastener. A
portion of the fastener may be inserted through the implant material or tissue
and into the
anchor bore. If the physician then determines that the anchor position needs
adjustment, the
cap may be rotated to move it further into or out of the material in which it
is placed. Once
the anchor is in a desired position, the cap may be bonded or otherwise
secured to the anchor.
As noted above, further adjustments in position of the assembly may be made
even after the
assembly is secured together.
Bonded Flange Fastener
[0351 ] With reference to Fig's. 52A-B, a fastener 1700 is provided, adapted
to bond an
implant 1710 to body tissue 1712. Fastener 1700 includes one or more flanges
1714 or tabs
projecting from implant 1710, and being formed of a bondable material.
Fastener 1700 is
advantageously used where the implant has the form of a shell, surface layer,
or liner 1716,
and where liner 1716 is advantageously formed as a smooth, continuous surface,
without
projecting mounting posts, or holes through which a fastener may pass. Fig's.
52A-B are
cross sectional illustrations through an acetabulum, an area of roughly
hemispheric shaped
body tissue, and an implant 1710, having a corresponding mating shape. The
discussion with
respect to the acetabulum applies equally to other bearing surfaces, such as
condylar surfaces,
or other lined surfaces of the body.
[0352] An implant base 1714 is fastened to body tissue 1712 at a location
beneath or
adjacent to the intended implantation site for liner 1716. Implant base 1720
is attached to
body tissue in accordance with any known manner, or in a manner disclosed
herein. Implant
base 1720 has mounting projections 1718 positioned to cooperate with flanges
1714 of
fastener 1700. After implant base 1720 is secured, liner 1716 is positioned in
the body, and
flanges 1714 are attached to mounting projections 1718 using vibratory energy.
Flanges 1714
and mounting projections 1718 may be provided in the form of mating flanges,
flange and
posts, mating posts, or any other cooperating projections which may be heat
bonded together
upon the application of vibratory energy. Two forms of mounting projection are
illustrated, as
1718 and 1718A. Projection 1718 extends beyond a final position, and
projection 1718A
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terminates at a final position which does not interfere with proper
functioning of the body, or
is potentially useful for proper body functioning.
[0353] With reference to Fig. 52B, it can be seen that projection 1718 and
flange 1714
are bonded and bent to rest at a final position 1722. Bonding may occur either
before or after
bending. Bonding for projection 1718A differs in that only flange 1714 is bent
to contact
flange 1718A, and flange 1714 is then heated using vibratory energy to mold
onto and bond
to flange 1718A.
[0354] While two variations of an implant base projection 1718, 1718A are
shown, it
should be understood that a single style may be advantageously employed around
the entire
circumference of the union between implant base 1720 and liner 1716. However,
if the style
of bonding is to change, a division or seam in flange 1714, or projection
1718, may be
provided to facilitate a transition.
[0355] Bonding may be improved by providing a roughened or porous surface, or
at
least one cavity, on projection 1718, 1718A, or on flange 1714.
[0356] In another embodiment, flange 1714 is fastened directly to bone or body
tissue
adjacent to the site of implantation, using vibratory energy to heat flange
1714, whereupon
flange 1714 may be shaped to conform to existing body tissue structure, and
may bond
thereto, for example, by adhesion or mechanical interlocking. Body tissue may
be provided
with a roughened or shaped surface to promote bonding with flange 1714.
[0357] To further secure the liner, adhesive may be applied to an inner
surface of the
liner before mounting and attachment.
Headless Fastener
[0358] In another embodiment of the invention, illustrated in Fig. 46G, a
fastener 1240
is provided, fastenable in a manner described herein, the fastener passing,
for example,
through an aperture or bore. However, the fastener is not provided with a head
or widened
portion operative to prevent the fastener from passing completely through the
aperture. For
distally secured fasteners, described herein, there is a reduced possibility
for the fastener to
pass completely through the aperture, as the distal end of the fastener is
securely fixed.
Where the point of fastening is fixed relative to the location of the entry of
the bore, a
fastener head can be avoided. In this manner, the fastener may have an excess
length, and be
trimmed flush after being secured. Alternatively, the fastener may be provided
with a length
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predetermined to lie flush with a surface through which the fastener is
passed. Fastener 1240
is described further, below.
[0359] With reference to Fig. 49, in a further alternative, a head portion
provided as a
mountable cap 1516, may be bonded to fastener 1240 using vibratory energy, as
described
herein, after the fastener has been distally secured and trimmed. Reference
may be had to a
further discussion of Fig. 49, below.
Spacer
[0360] With reference to Fig's. 54 and 54A-C, implant 1900 may be positioned
and
secured in a precise location, in accordance with the invention, through the
use of a
progressively widening spacer. Examples include conical spacer 1902, or wedge
spacer 1904.
Spacers 1902, 1904 advantageously include a surface or at least partial
coating of bondable
material as described herein, or alternatively, fasten to one or more surfaces
of implant 1900
that include bondable material. Any of fastener 1902 or 1904, implant 1900, or
implant base
1906 may be provided with a roughened or porous surface, or a surface with at
least one
cavity, into or onto which bondable material may bond.
[0361] Due to the ramped shape of spacer 1902, 1904, a progressive insertion
of the
device produces a concomitant displacement of the implant to be affixed,
relative to the body
tissue proximate the implantation site. Spacers 1904, 1902, and 1906 are
placed at different
locations, so that they may cooperatively displace the implant, and offer
greater strength
when affixed. Spacer 1906 is of a different size than spacer 1902; a range of
sizes is
advantageous where gaps of differing size are required to be formed. A tool
engaging
structure, such as an aperture, groove, or slot 1908 may be formed in a
spacer, as shown in
spacers 1902 and 1906, which may be engaged by a tool to facilitate placement
or removal,
as by twisting.
[0362] Fig. 54C illustrates an alternative form of spacer 1910, having a
spacer core
1912 which may be driven into the interior 1914 of spacer 1910 to drive outer
walls 1916
apart, either before or after spacer 1910 has been implanted within the body,
and then
maintain outer walls at a fixed orientation. An aperture or other tool
engaging structure, such
as hex receiver 1918 may be provided to enable driving core 1912 into spacer
1910, as by
pushing, or engaging mating threads 1920, 1922. Core 1912 may alternatively be
provided as
a cam structure, rotatable to push walls 1916 apart. Core 1912 may be a
separate part, or
attached to spacer 1910, for example by living hinge 1924 or other flexible
structure.
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[0363] Spacers of the invention, including spacer examples 1902 or 1904, are
affixable
in a predetermined location, through the use of vibratory energy. Once in
position, proximal
or distal vibratory fastening, as described herein, is used to bond spacer
1902 or 1904 to
implant 1900, or to body tissue 1924, adjacent implant 1900.
End Effector with Cartridge Heater
[0364] Another exemplary instrument 110 is illustrated in Fig's. 2A and 2B. A
small
cartridge heater 116 may be used to deliver thermal energy. Heater 116 may be
a SUNROD
1/8 inch cartridge heater, for example. To prevent heat build up upon the
outside shaft 112,
an insulating region 114 may be formed between heater 116 and shaft 112. In
Fig. 2A, four
set screws 118 are used to create the insulating region 114, which in this
example is an air
barrier, while in Fig. 2B, a single set screw 118 is used.
Configurable End Effector Face
[0365] Referring to Fig's. 3A-3K, energy emitting instruments may include
various
horn or end effector configurations. It has been discovered that for a fixed
set of parameters
(energy, power, time, etc.), the bonding or bond characteristics can be varied
depending on
the configurations of the horn or end effector. For example, if extension 122
is made longer
or the angle of the tip is changed, the stake or bond created can be adjusted.
In Fig. 3A, the
horn 120A emits energy to the top surface of the implant as well as the
central core via an
elongate extension 122A. The horn 120B of Fig. 3B is recessed to hold the
thermoplastic
implant during bonding or staking. In Fig. 3C, the horn 120C is concave to
provide a rounded
surface to the implant after bonding. As discussed below, horn 120C has been
found to be
particularly suitable for staking. The horn 120D of Fig. 3D is concave and
includes a central
extension 122D to deliver energy throughout the implant. In Fig. 3E, the horn
120E includes
a spike 124E which may be disposed within an implant. The horn 120F of Fig. 3F
includes a
threaded pin 126F which may be received by a bore in the implant. In Fig. 3G,
the horn 120G
includes dual spikes 124G. The distal portion of the horn 120H of Fig. 3H may
be
dimensioned to fit within the thermoplastic implant. In Fig. 31, a sleeve 1281
is disposed
about the horn 1201 and implant. A side-bond horn 120J is shown in Fig. 3J,
wherein the horn
or engaging portion 128J is disposed along a side surface 130J. In Fig. 3K, a
dual horn
bonder 120K is used to simultaneously bond two fasteners 130. It should be
noted that
generation of heat through an extension such as 122A, 122D, 124E, 126F, 124G
and 128J
will vary with respect to that generated through the broader direct contacting
surface 124D,
and may be diminished.
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[0366] In Fig's. 4A-4C, an instrument 140 is shown which includes three
different horn
or end effector configurations in one design. The instrument 140 can be
configured to
produce a roughened or complex surface (Fig. 4A), for producing an aperture
(Fig. 4B), and
for flattening or contouring a surface (Fig. 4C). In Fig. 4A, a center shaft
142 is extended
distally from the instrument 140, and outer shaft 144, which slides over
center shaft 142, is
also extended distally. This produces an outer circle and an inner circle on a
surface when
vibratory energy is applied to end effector 104. It should be understood that
a variety of
patterns could be produced in this manner, by changing the shape and relative
extension of
shafts 142, 144, or by adding additional shafts. In Fig. 4B the outer shaft
144 has been
retracted into the bonding instrument, leaving only the center shaft 142
extended. In this
position, the instrument 140 will form an aperture in bondable material, for
example in
preparation for adding cap 1010 (not shown), detailed elsewhere herein.
Finally, Fig. 4C
shows both the center and outer shafts 142 and 144 retracted into the
instrument. Sheath 146,
which surrounds instrument 140, has also been retracted. In this position, the
instrument 140
is in a contouring horn configuration. The distal surface 148 of the
contouring horn may be
used to reshape a thermoplastic implant, such as the head of a fastener. A
flat surface is
shown, however surface 148 may be curved to produce a rounded, smooth surface
after
application of vibratory energy.
[0367] In use, the instrument of Fig's. 4A-4C may be reconfigured quickly by
the
operator as required during the procedure. In each configuration, the
instrument is configured
with the appropriate shafts 142, 144 and sheath 146 (if present) extended or
contracted.
Extended shafts 142 and or 144 may thereby come in contact with bondable
material to be
affected. Energy, such as vibratory energy, may be emitted from the center and
outer shafts to
create a roughened surface on the implant, to create an indentation or blind
hole in the
implant, or to create a through hole in the implant. The type of fastening
desired and the
intended fastener to be used will determine how deep the bonding-surface horn
should be
moved into the implant. With the staking/bonding surface formed, the outer
shaft 144 is
retracted into the instrument (Fig. 4B).
[0368] The distal portion of a fastener may be placed in or on the bonding
surface of the
implant, and the end effector may be placed on the fastener with the center
shaft extending
into a bore in the fastener. Using the desired parameters, the operator emits
vibratory energy
from the end effector to bond and/or mechanically interlock the fastener to
the implant. Once
bonded or staked, the fastener may be contoured or reshaped or resized with
the contouring-
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horn of the instrument by retracting the center shaft and optionally
retracting the sheath
around the instrument (Fig. 4C).
[0369] Movement of shafts 142, 144 and or sheath 146 may be accomplished by
known
methods of mechanical action, for example guide shafts extending through end
effector 104,
or electromechanical or pneumatic actuators within the distal portion of end
effector 104.
[0370] Hollow tubular outer shaft 144 may additionally be used for removing
bonded
implants. When used without center shaft 142, it may be used to surround an
implant bonded
to body tissue or another implant with a heat meltable bond, as described
herein. In this
application, vibratory energy is transmitted through hollow shaft 144 and the
shaft is placed
in contact with the melted bond. As bondable material is softened, shaft 144
is advanced,
until a sufficient amount of the bond is severed by shaft 144. Combined with
mechanical
action applied to the handpiece, as needed, a bonded part now housed within
shaft 144 may
be thus loosened and removed.
[0371] Shaft 144 may be used when extended alone in the configuration shown in
Fig.
4A, or may be provided in a fixed or dedicated end effector or end effector
endpiece
containing only shaft 144. Further, it should be understood that shaft 144 may
be provided in
configurations adapted to the shape and depth of the bond of specific parts to
be removed.
[0372] Additionally, shaft 144 or 142 may be used to core or drill,
respectively, in
bondable material. In this manner, apertures may be formed for inserting or
attaching
additional implants, which may optionally be secured in place with vibratory
energy, as
described herein.
Coated Fastening Base
[0373] With reference to Fig. 48, a coated implant 1500, shown bisected along
a
longitudinal axis, includes a core 1502 and a coating 1504 of bondable
material. In the
embodiment shown, core 1502 is metallic, and coating 1504 is bone cement.
However, the
coating may be any bondable material as described herein, and core 1502 may be
the same
material as the coating, or any other material of suitable strength to which
the coating may be
securely attached, as by adhesion or mechanical attachment. The form of coated
implant 1500
shown is that of a rod, sized and shaped to enter an intramedullary canal;
however, a different
shape may be selected to advantageously serve as a base for fastening at least
one other
fastener, depending upon the application and location. The coating is applied
over at least a
portion of the exterior surface of the core.
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[0374] Coated implant 1500 is placed in the body as a point of attachment for
other
implants, for example any of the fasteners of the invention. The coated
implant is
advantageously shaped to provide a surface for attachment of numerous
fasteners, or one or
more fasteners at a variety of possible locations. Fasteners may be bonded to
the coated
implant using proximal or distal vibratory fastening, as described herein, or
a combination of
vibratory and mechanical fastening.
[0375] Core 1502 may be attached within the body using any means known in the
art.
In the embodiment shown, the distal end 1506 of core 1502 is provided with
threads 1508,
which may connect to mating threads of an implant previously implanted and
affixed within
the body, for example embedded fastener 800. In this manner, core 1502
functions as
described for end effector 804.
[0376] Once secured, coated implant 1500 forms a base for fastening other
fasteners,
for example the fasteners illustrated in Fig's. 46D-H. With reference to Fig.
49, an elongate
fastener 1240 may be seen attached to coated implant 1500 at a distal end.
Coated implant
1500, in the example shown, may be attached as described with respect to
fastener 900, of
Fig. 43. Other means of attachment to secure coated implant 1500, as detailed
herein, may
alternatively be used. For example, fastener 1240 is distally bonded to
coating 1504, and has
been trimmed at a proximal end at the surface of bone 882. As such, fastener
1240 stabilizes
coated implant 1500 by restricting motion of coated implant 1500 within
intramedullary canal
1222, and particularly in a longitudinal direction.
[0377] Fastener 1240 is shown without a cap 1010, however fastener 1240A is
additionally, shown, provided with a mountable cap 1516, shown both separated
and
attached. An optional aperture 1512 may be provided in fastener 1240,
operative to receive a
post 1514 projecting from mountable cap 1516. Post 1514 aligns cap 1516, and
provides
greater surface area for bonding of cap 1516 and fastener 1240 upon the
application of
vibratory energy, as described herein. It should be understood that post 1514
and aperture
1512 may be eliminated, and vibratory fastening may still be accomplished.
Mountable cap
1516 prevents fastener 1240A from moving inwardly with respect to the center
of the bone,
and falling out of the opening in cortical bone through which it resides.
[0378] With further reference to Fig. 49, one or more fasteners 1518, 1520, of
the
invention are distally fastened to coated implant 1500. In this manner, the
distal ends of
fasteners 1518, 1520 which are embedded in coating 1504 are fixed in position
relative to
each other. However, the proximal ends, projecting through the outer cortical
bone of bone
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882, are movable with respect to each other due to a fracture 918 in bone 882.
To stabilize
fasteners 1518, 1520, and to secure fracture 918 in a closed configuration,
plate 1522 is
provided, passing over fasteners 1518, 1520, before caps 1010, 1516 are formed
and attached,
respectively. In this manner, both proximal and distal ends of fasteners 1518,
1520 are fixed,
and thus fracture 918 is stabilized, and proper healing is facilitated.
Expanding Fastener
[0379] With reference to Fig's. 88-90, an expanding fastener 3300 is provided,
adapted
to pass through an opening 3304 in a wa113302 into a hollow space 3306, and
expand within
hollow space 3306 thereby resisting withdrawal through opening 3304. Fastener
3300 is
fastened using vibratory fastening in accordance with the invention.
[0380] In particular, fastener 3300 is provided with one or more wings 3308,
which are
attached to a flange 3312. Wings 3308 are passed through opening 3304, the
latter sized
smaller than flange 3312. In this manner, fastener 3300 is prevented from
passing completely
through opening 3304. Wings 3308 are adapted to fold at living hinge 3310, or
alternatively,
wing 3308 may resiliently bend, whereby wings 3308 expand away from opening
3304 when
folded or bent, thereby creating a profile that is too large to pass through
opening 3304. In the
embodiment shown, a post 3314, connected to wings 3308 at a distal end 3316
thereof, passes
through opening 3304, together with wings 3308. After wings 3308 and post 3314
are passed
through opening 3304, post 3314 may be pulled in a direction away from hollow
space 3306,
thereby causing wings 3308 to expand as described, as illustrated in Fig. 89.
[0381] Fastener 3300 may be fabricated entirely from a bondable material, for
example
a polymer; however, in the embodiment shown, at least flange 3312 and post
3314 are coated
with, or made entirely from a bondable material. In Fig. 90, post 3314 and
flange 3312 have
had vibratory energy applied at an area 3318, whereby material of post 3314
becomes bonded
to material of flange 3312, thereby securing wings 3308 in an expanded
position. Post 3314
may be cut to a desired length after fastening.
[0382] Flange 3314 may be adapted to enable attachment of body tissue or other
implants, by being provided with one or more apertures 3320, operative to
retain a suture
3322, or other material to be secured. Alternatively, flange 3314 may be
provided with a
threaded bore 3324, or other structure useful for attachment as known in the
art.
Alternatively, post 3314 may be provided with one or more apertures 3326, or
may be
provided with a central bore 3328, which may be threaded, or may be self
tapped by a screw
driven therein.
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[0383] Fastener 3300 enables fastening through an aperture or opening 3304
where the
medical practitioner does not have access to hollow space 3306 beyond opening
3304. It
should be understood that hollow space 3306 may be cancellous bone or other
tissue which is
sufficiently soft to be displaced when wings 3308 are bent. Vibratory energy
enables a
fastener 3300 of simple and reliable construction, as there is no need for a
threaded post and a
threaded aperture at distal end 3316, as is required in prior art fasteners.
Parameters and Additives
[0384] Monitoring and controlling the parameters ensures proper bonding of
thermoplastics. Fig. 5 illustrates the various parameters that may be
monitored and controlled
for the system of the present invention. The parameters include, but are not
limited to, the
type of energy to emit, type of thermoplastic material, the size and
configuration of the
implant, the thickness of the implant, implant surface geometry, the aqueous
environment,
energy time, energy power, and frequency of the energy, amount of pressure
applied to the
implant during and after application of the energy, the geometry of the horn,
the boost or
attenuation of the end effector, the density of the implant, the amount of
collapse of the
thermoplastic material, the depth into tissue the implant is to be inserted,
and the type and
amount of any therapeutic agent that may be delivered.
[0385] There are several factors that effect bonding or staking of
thermoplastic
materials. One is hydroscopicity, the tendency of a material to absorb
moisture. If too much
fluid gets between the parts it can decrease the bond or create a foam which
prevents proper
bonding of the materials. Therefore, the bonding of thermoplastics may be
performed under
vacuum/suction, or a hermetic seal may be placed around the thermoplastic
during the
bonding process. Also, the bonding may be performed using a cannula which
prevents fluid
from entering the bonding area. Furthermore, pressure, such as air pressure or
compression
force, may be applied during bonding to prevent entry of moisture or liquid.
Additives
[0386] In addition to or in place of reducing moisture from the bonding area,
certain
agents can be used to aid in the bonding process. Such agents may include
filler material,
glass filler, glass fiber, talc, and carbon. The agents may be placed at the
bond site as a
temporary bonding enhancement means or may be a permanent agent to enhance the
bonding.
For example, the agent may be placed within the bonding region of PHA, PEEK or
PLLA.
The agent may be left in place to bond or could be removed. It is contemplated
that any
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amount of agent may be used to enhance the bond strength of the
thermoplastics. In an
exemplary embodiment, the amount of agent may be about 10 to 20 percent.
[0387] Moisture may further be eliminated or prevented from entering the
thermoplastic
material through the use of desiccants. Desiccants may be added prior to or
during the staking
or bonding process. Also, the thermoplastic material may be stored using
desiccant material
to prevent change in thermal properties. It is contemplated that this moisture
reducing means
may be applied to any polymeric material.
[0388] Another factor which may affect bonding or staking of thermoplastic
material is
pigments, particularly white or black coloring. In many materials used in
medical
applications, white pigment is added to the polymer to make it appear sterile.
Some pigments
may negatively affect the bonding and staking characteristics of the material.
Accordingly,
pigment-free thermoplastics, such as PEEK, are advantageously used for
fastening.
[0389] Mold release agents also affect the thermal properties of
thermoplastics.
Polymeric components are usually formed in a mold to create a desired
configuration. The
component is easily removed from the mold because a release agent is placed
between the
mold and polymer. These agents, lubricants, plasticizers, and flame retardants
can negatively
affect the bonding ability of the polymer. Thus, it is preferred in the
present invention that
PHA, PEEK, PLLA, and other thermoplastics used for bonding or staking are
substantially
free of these substances.
[0390] In addition to avoiding release agents, pigments, and moisture, the
staking
and/or bonding of thermoplastic materials may be further enhanced by adding
minute
metallic material to the polymer. The metallic material may be metal flakes or
metal dust.
Examples of such metal include iron particles, chromium, cobalt, or other
suitable metals.
The metal may be embedded within the polymeric material to enhance the thermal
properties.
Alternatively, or in addition, the metal may be applied to the surfaces of the
polymeric
material. Energy applied to the polymer would heat both the polymeric and
metallic material
providing a faster and more uniform thermal profile. It is contemplated that
glass fillers,
carbon fillers, talc, or combination thereof may also be used in addition with
or in lieu of the
metallic material, although some materials, while conferring desired
properties, may
adversely affect bonding, at least depending on the concentration used.
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Energy Type
[0391] Other factors affecting the thermal characteristics of thermoplastics
include size,
thickness, surface geometry, material properties of the thermoplastic, and the
type of host
tissue involved in the bonding or staking, i.e. soft, hard, dry, wet, or moist
tissue. These and
other factors are explained in more detail with reference to Fig. 5.
[0392] Furthermore, how the thermoplastic is staked or bonded is an important
characteristic of obtaining a robust mechanical interlock or thermal bond. The
type of energy
used is one way to control the process. As previously mentioned, various
energy sources may
be used to bond and/or stake polymers. In an exemplary embodiment and as used
primarily
throughout the invention, ultrasound energy is used to create vibrations
within the polymeric
material thereby exciting and heating the molecules to transition to a tacky
state. Two or
more different types of energy may also be used. For example, ultrasound may
be used to
bond a polymeric component to another component, while resistive heating may
be used to
contour the surface or change the geometry of the materials. The surface of
the component
may be smoothed out or sculpted using resistive heating.
[0393] The intensity and duration of the energy source impacts the quality of
the bond
or mechanical interlock. For instance, the amount of energy used affects the
thermal
properties. Therefore, the energy may be controlled by the operator depending
on the
component to be bonded or staked. A switch, dial, or other control may be
placed in
connection with the energy source to vary the intensity of the energy applied.
For example,
the amount of current supplied to the instrument may be varied or controlled.
In an exemplary
embodiment, the ultrasound power may be varied, for example, between 80 and
100 Watts.
The amount of time the energy is applied affects the bond or staking as well.
The time may
be varied from milliseconds to hundredths of seconds to actual seconds
depending on the
desired end result. Thus, controlling the time of exposure to the energy
source can be used to
limit the amount and the degree of thermoplastic material which softens and
becomes tacky.
In an exemplary embodiment, energy may be applied from 0.1 seconds to 3
seconds, such as
approximately 0.3 seconds. In case of RF and ultrasonic energy, the frequency
of the energy
may be varied to affect the softening or melting of the thermoplastic. It is
also contemplated
that the amount of time that energy is applied may be controlled not only by
the operator but
also via radiofrequency, optical, radiowave, etc. A computer or other
microprocessor may
send signals to the energy emitter to turn the energy on and off.
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[0394] Pulsing of the energy source may likewise be used to intermittently
apply energy
to the site or to vary characteristics of the energy source over time, such as
the power,
frequency, or pressure, to enhance bonding or mechanical interlock and avoid
tissue necrosis.
That is, the energy may be emitted, then relaxed, then emitted, etc.
Pressure
[0395] Controlling the pressure applied to the thermoplastic material also may
be used
to affect the process. During bonding or staking, a handpiece, an anvil, a
horn, end effector,
or combinations thereof may be used to apply controlled force against the
component. After
completion, while the material is cooling, the force may continue to be
applied to ensure
proper bonding and/or mechanical interlock of the materials. The handpiece,
anvil, horn, and
end effector may be made of aluminum, titanium, or other suitable material.
Also, the
pressure may be varied, increased or decreased, during the process. In an
exemplary
embodiment, the pressure may be applied by the operator or may be applied with
a spring. A
sensor, spring, and/or piezoelectric device may be used to monitor and control
the amount of
pressure applied. In another exemplary embodiment, the bonding horn may apply
ultrasound
energy and pressure to a polymeric implant being attached to bone. The bone
may act as the
anvil eliminating the need for an anvil instrument. Also, a hard implant or
another polymeric
material may function as the anvil.
[0396] Furthermore, the placement of the energy source on the thermoplastic
affects the
bond or staking. The energy may be applied to one side of the polymer, through
the center of
the polymer, to two or more sides of the polymer, or to generally the outer
surface of the
polymer.
Collapse
[0397] Controlling collapse is another factor in achieving an effective
thermoplastic
bond or staking. For instance, the time and material collapse may be monitored
to ensure a
proper effect. A measurement of the change of the material being bonded or
staked may be
made to determine when complete. This may be accomplished by using micro-
switches to
provide precise, binary control of the mold. Also, by using a linear variable
displacement
transducer (LVDT), the control system can monitor the bond more precisely.
Because a
LVDT translates position to voltage, the bond and/or staking profile can be
dynamically
controlled. For example, the initial energy delivered can be a higher wattage,
then when the
material starts to collapse the amplitude of the wave can be decreased.
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[0398] By being able to monitor the position of the collapse, different bond
or staking
profiles can be programmed into the system. In addition, to control how far
the material
collapses, a combination of current and time preset in the generator control
system could be
used. This can also be coupled with a defined force applied during the bond or
staking.
Furthermore, collapse may be controlled or monitored through the use of a
mechanical stop
on the fastening device itself or on the instrumentation. The mechanical stop
would prevent
collapse after a predetermined point. It is also contemplated that the
collapse could be
monitored by other methods such as optics, laser, or even a hall-effect
sensor.
[0399] All of the above-mentioned parameters may be monitored and controlled
by a
computer. The discussion relating to Fig's. 5-8, among others, illustrate
instruments that may
be used for controlling the parameters. Feedback may be provided by the
computer to vary,
start, and stop the various parameters. The feedback and control of the
computer may be
programmed based on the type of polymer being bonded and/or staked and the
type of
material the polymer is being bonded or interlocked to. For example, for PEEK
to PEEK
bonds, the computer may apply a set of parameters (time, power, pressure,
frequency, etc.) to
achieve an desired or effective bond. Other parameters may be established or
preset for other
polymers, other bond materials, or for staking dissimilar materials.
[0400] Without being bound by any particular theory, it is generally thought
that the
surgical system (either bonding or staking) of the present invention causes
primarily radial
deformation of the fastener. This was discussed above in the context of
collapse. Because the
primary deformation is collapse so that radial expansion occurs, there is
little, if any,
elongation in the longitudinal direction. Detailed analysis has shown that for
a fastener or
tack made of PEEK and having typical dimensions (head 0.180 inch; and tip
0.109 inch),
there is a bond collapse of 0.050 inch for set bond parameters (111 Watts; 500
millisecond
bond time; and 5-81bs force applied). As previously discussed, this collapse
can be increased
or decreased by changing the bond parameters, the geometry of the end effector
and tack,
and/or material of the fastener.
Instrumentation and Controls
[0401 ] Any known energy emitting instrument may be used with the surgical
system of
the present invention. The instrument may produce energy such as resistive
heating,
radiofrequency, ultrasound (vibratory), microwave, laser, electromagnetic,
electro shockwave
therapy, plasma energy (hot or cold), and other suitable energy. FIG 1
illustrates an
exemplary handpiece or instrument 100 that may be used with the present
invention. The
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instrument 100 may be a vibratory handpiece with a sheath 102 to cover and
protect the end
effector 104 and hold a fastener. As will be discussed in greater detail
below, the instrument
may be used to bond or mechanical interlock a cap of an implanted device to an
anchor, or
likewise may be used to bond or mechanically interlock other components
together.
[0402] The sheath 102 may have a small counter bore at its tip to cover a
portion of the
cap. There also may be a bushing at a nodal point of the vibratory signal to
prevent the end
effector 104 from contacting the sheath 102. The tip of the end effector 104
has a small post
106 sticking out of the bonding face which presses into a bore in the cap of
the fastener. This
can help align the fastener post into the anchor bore and keep the cap tight
against the end
effector face. The end effector 104 may be removable to allow it to be
replaced or cleaned
after use.
[0403] The post 106 on the end effector 104 may be threaded or have a Morse
taper to
mate with the cap. Alternatively, the end effector 104 has a bore that the top
of the cap mates
into. The mating of the components could also be by threads or a Morse taper
along with a
straight post. Furthermore, the post could be roughened on the outside surface
for better
adhesion.
Microprocessor Control
[0404] In accordance with the invention, A DSP simplifies additional modes for
fastening control. Whether an analysis is performed by a DSP, other processor
type,
mechanical means, or by the practitioner, processing modes for fastening in
accordance with
the invention include the modes described as follows.
[0405] The phase angle differential between voltage and current is monitored
during
use, and changes are made to the signal to maintain a resonant frequency. For
example, the
drive frequency could be varied to maintain a particular phase angle
differential. An optimal
or target phase angle may be determined by a frequency tuning sweep,
calculation, empirical
means, or a combination of these methods. This is discussed further with
respect to Fig. 67,
below.
[0406] The output voltage may be varied while while monitoring power
consumption
during bonding. A device using this method must adapt to the typically large
variations in
loading during the bonding step.
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[0407] The stroke of the handpiece is measured by a sensor disposed within the
handpiece or end effector. This method provides the advantage of a robust and
accurate
measurement of the physical displacement of the end effector.
[0408] The drive voltage is varied while monitoring the current and voltage
during
bonding. The minimum impedance is then calculated in real time, to adapt to
variations in the
environment, particularly a medical environment, during bonding.
[0409] The total power/energy applied to the bond may be calculated during
bonding,
and when a total predetermined amount of energy has been delivered the bonding
step is
terminated.
[0410] The total time during which power is applied during bonding is tracked
and
when power has been applied for a predetermined amount of time, bonding is
complete and is
stopped.
[0411 ] The Eddy or Foucault currents created by movement of the end effector
are
tracked, the movements being indicative of melting activity. As the end
effector vibrates, a
magnetic field is changed, creating measurable current which may be analyzed
during
bonding.
[0412] Collapse of the fastener is measured by a sensor within the end
effector or
handpiece, indicative of an amount of melting corresponding to preset levels
established for
correct bonding of a particular configuration.
[0413] The control methods of the invention may be combined. The methods
enable
adjustment of the signal for variations in the environment and loading during
a surgical
procedure.
[0414] The control modes described above may be combined with input or
measured
parameters automatically by processor control, or at the election of the
surgical practitioner.
In this manner a matrix for overall control is created by the selected
parameters, and the
selected control modality. Reference may be had to the following example
parameters:
Implant Type 1 1 2 3
Environment Dry/Moist Wet All All
Control Method Phase Angle Min Impedance Min Impedance Stroke
Term Power Energy Energy Collapse
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[0415] In each of the four examples above, selection of an implant triggers
loading of
the optimal phase angle, impedance, and or energy values. Environment values
may be input
by the practitioner, or measured by the system. The system may determine the
type of
implant based on either input from the practitioner, or by sensors or switches
associated with
the handpiece, whereby. For example, the particular type end effector
currently connected
triggers a signal to the processor regarding the appropriate type and size of
fastener that will
be used. Alternatively, the fastener itself indicates its presence, either by
physically triggering
a switch, or by other known means of signaling, for example an embedded RFID
tag.
User Interface
[0416] Fig. 6 shows a manual control box 150. A surgeon determines the optimum
or
desired parameters and may then enter them into the control box 150 prior to
or during
bonding or staking. In Fig. 7, an automatic control box 152 may be provided
with pre-set
parameters. For example, preset 1 may be for implant A which has a known
material, size,
etc. to be bonded in a dry environment. Preset 2 may be for implant A in a
moist
environment. Preset 3 may be for implant A in a wet environment. Preset 4 may
be for
implant B using energy source X. Preset 5 may be for implant C using energy
source Y.
Preset 6 may be implant D using energy source Z. It is contemplated that any
combination of
bond parameters may be pre-set into the control box.
[0417] The control box 154 of Fig. 8A is automatic. A sensor on the end
effecter 156
determines the parameters when the horn is placed adjacent the thermoplastic
material. The
sensor 156 picks up material type, humidity of the environment, and any other
parameter,
then sends the data to the control box. The control box 154 automatically
selects the time,
wattage, and any other parameters. Fig. 8B illustrates a vibratory energy
control box which
may be used with the surgical systems of the present invention. Control box
154 includes a
handpiece connector 154A, and interface controls 154B for changing bonding
parameters.
[0418] The exemplary energy control units described herein may be used to
select and
vary any of the parameters. In Fig. 8C for example, the power or wattage of
the horn is varied
over time. During a first period of bonding, a large amount of energy is
delivered to
overcome heat sink. In the second period, the energy is reduced. In a
subsequent period, the
energy is maintained at an appropriate level to thermal bond or stake an
implant.
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[0419] Other variations of the use of a control box may likewise be used. For
instance, a
computer may be used to query or receive data about the surgical procedure.
The physician
may enter an implant manufacturer, for instance, and then select or enter an
implant model,
size, etc. Based on the entered information, the computer may assist the
physician by
instructing which energy source(s), horns, or other parameters may be
recommended for the
procedure. While the control box or computer may automatically select and
apply a thermal
profile based on expected input parameters, the control box or computer may
also allow a
physician to alter or override the expected input or otherwise select a
different thermal
profile. The ability to allow varying degrees of manual control of the
instrument may also be
provided.
[0420] The exemplary energy control units previously described may be used to
select
and vary any of the parameters. For example, the power or wattage of the horn
may be varied
over time. During a first period of bonding, a large amount of energy may be
delivered to
overcome heat sink. In the second period, the energy may be reduced. In a
subsequent period,
the energy may be maintained at an appropriate level to thermal bond an
implant.
[0421 ] With reference to Fig. 63, the surgeon may manually control the
parameters, or
the parameters may be controlled using automation, including using a
microprocessor or
computer. In accordance with the invention, a generator control unit 2500 is
provided having
connections for grounding and a signa12502, 2504, 2506. The generator
advantageously
includes a user interface comprising gauges or indicators, and in one
embodiment an LCD or
similar output screen 2510. A user keypad 2516 is provided to move a cursor or
indicator on
the output screen, whereby parameters can be selected and entered. A
footswitch, not shown,
may be provided to enable the surgical practitioner to more easily activate
the generator.
[0422] With further reference to Fig. 63, in accordance with a further
embodiment of
the invention, the surgical practitioner enters information pertaining to the
surgical procedure
through interaction with the user interface, which includes a cursor keypad
2516 and output
screen 2510 on the generator 2500. It should be understood that an alternative
and potentially
more sophisticated and complete interface may be obtained by connecting a
computer (not
shown) to the generator, via a known method including USB, Bluetooth or
network
connection. Moreover, the generator interface may be programmed for the
various types of
surgeries and surgical operating parameters expected to be encountered, and
the generator
may thereafter be disconnected from the computer during the procedure.
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[0423] Once programmed, output screen 2510 contains menus offering the
surgical
practitioner options relevant to the procedure to be performed, including the
type of
procedure, and any or all of the parameters described in this specification.
An example of a
menu is found in Fig. 72. In this example, a first screen 4200 indicates an
initialization phase,
after which the system performs self-tests 4202, which if unsuccessful, error
codes are
indicated at 4204. If self tests 4202 are passed, the practitioner is prompted
at 4206 to select
the type of fastener to be bonded. The practitioner makes a selection, as by
pressing a button
2516 on the generator, pressing buttons 3124 (Fig's. 86-87) on the handpiece,
pressing a
footswitch, clicking a mouse, through voice activation, or other human
interface method, and
the system advances through additional parameters, in this example prompting
for the
material of the fastener in "PEEK PLLA" at 4208, fastener size at 4210,
environmental
conditions at 4212, and finally indicating a "ready" status at 4214, whereupon
when ready the
practitioner may start bonding.
[0424] In this manner, the practitioner has the ability to input the correct
procedure and
real-time parameters, in order to enable precise control in the use of the
generator. Further,
the generator can perform a sophisticated analysis in order to determine the
correct operating
parameters, including for example frequency, wattage, and pulsing, and the
generator may
further independently vary one or more parameters over time. Accordingly, the
practitioner
need not make the complex calculations necessary in order to achieve a secure
and reliable
fastening, and thus time is saved, and the potential for error is reduced.
Frequency Sweep Tuning
[0425] An exemplary process for vibratory staking is illustrated in Fig. 31.
The staking
process begins at "start stake" 2700 by either pushing the generator
footswitch or using the
control on the hand piece. Upon starting, the generator may first perform a
"system check"
2702. The software may also check for proper grounding, ground offset issues,
as well as
other vital circuits. If there are errors with the system or the grounding,
the generator can give
a visual or audible indication that an error has occurred, at "error: shutdown
system" 2708,
and the vibratory signal generator may be disabled to prevent inadvertent use.
[0426] If no errors are detected, the system may then sweep a frequency range,
such as
from about 38.5 kHz to about 43.5 kHz, to tune the system, and particularly to
"tune stake to
system resonate frequency" 2704. Current measurements may be used to find the
resonate
frequency of the system, which in some embodiments may be close to 41 kHz.
Next at "start
bond" 2706 the vibratory or ultrasonic signal is then sent to the hand piece
where a resonator
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turns the waveform into linear movement. A maximum bonding time is determined
by the
user, or by microprocessor control of the system. If an excess time is
reached, a "timeout"
2710 is signaled and the system shuts down at error 2708. When bonding is
complete at
"staking complete" 2712, as determined by the user or by microprocessor
control of the
system, the generator is shut down at "stop ultrasonic generator" 2714,
whereupon "staking
complete" 2716 indicates bonding has been accomplished.
Impedance Feedback
[0427] To help ensure a properly executed bond or staking, the instrument of
the
present invention may provide a positive feedback system. One way to provide
user feedback
is by measuring and controlling the impedance of the vibratory generator. This
feedback
system is based on the fact that the load placed on the end effector affects
the impedance of
the system. That is, the pressure put on the end effector by the object to be
bonded or staked
changes the impedance within the handpiece, and specifically the piezo stack
and electronics
controlling the end effector. To determine the handpiece impedance, the drive
voltage and
current through handpiece may be monitored during the thermal process. By
using Ohm's
Law V = IR, the impedance, Z, may be calculated from the voltage, V, and
current, I.
[0428] Fig. 9 illustrates one method of ensuring a consistent or desired bond
or stake.
The medical practitioner initiates a process in accordance with the invention
by first
transmitting a low power vibratory signal through the end effector, whereupon
the impedance
of the handpiece is measured with no pressure applied to the end effector.
This establishes a
baseline impedance. Then, the end effector may be subjected to known
pressures, and the
voltage and current may be measured to calculate the impedance for each
pressure. Thus a set
of values is known, and may be stored within a device in accordance with the
invention, to be
used in a subsequent bonding process, as follows.
[0429] When a surgeon or other operator applies pressure from the end effector
to a
thermoplastic implant to be bonded or staked, the actual amount of pressure
can be fed back
to the operator because the pressure can be correlated to a known impedance.
Thus, "Start"
2600 corresponds to contacting the fastener in preparation for fastening, and
"Send Signal"
2602 corresponds to indicating to the system that bonding should begin.
[0430] The surgeon may increase or decrease the pressure on the end effector
until the
desired pressure is achieved. In one embodiment, the instrument may provide
audible and/or
visual signals at "In Range" 2604 that tests when a surgeon is applying too
much or too little
pressure, whereupon a signal may be indicated at "Error! Correct" 2608, or an
adequate
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amount of pressure is applied at "Perform Weld" 2606, whereupon the surgeon
may activate
the handpiece, whereupon vibratory energy is emitted in accordance with the
calculated
thermal profile established above. When fastening is completed, the
practitioner or the system
stops application of power at "Stop" 2610.
[0431 ] In another exemplary embodiment for providing positive feedback, the
pressure
and impedance of the handpiece, and more particularly the piezo stack and
associated
electronic circuit, may be monitored throughout the thermal profile. In the
previously
described method, the proper pressure based on impedance was achieved by the
surgeon
using a low power signal, and then the vibratory energy was emitted for
bonding when an
amount of pressure within a range was applied to the fastener. In this method,
the pressure
and impedance is measured during the bond. When pressure on the end effector
is applied
and the bond is started, for example by a hand control or footswitch, the
current may be
measured and the impedance calculated by a microprocessor. When the impedance
is too
high or too low or outside an acceptable range indicating an incorrect applied
pressure, the
microprocessor may send an audible or visual signal to the surgeon, or may
alter the signal to
maintain correct bonding parameters.
[0432] Alternatively, or in addition to the signal, the microprocessor can
stop energy
emission until the correct pressure and impedance is achieved, then the
bonding may be
resumed either automatically by the microprocessor or manually by the surgeon.
If
inadequate pressure is being exerted, the bonding instrument may operate in a
pulse mode to
maintain material in a near-bond state. This may allow the bonding to more
rapidly continue
when adequate pressure is once again being applied.
[0433] Referring Fig. 10, circuit 2620 may be used to monitor power used by
the
handpiece. Because the drive signal for vibratory energy is sinusoidal,
"V(monitor)" and
"V(current)" are sampled at a rate that is advantageously at least twice the
frequency of the
vibratory waveform to be produced at the end effector. Reference may be had to
Fig. 70, for
example, where nodes, representatively illustrated by reference 2640,
represent sample
points. For example, if the waveform is a 41 kHz sinusoid, then samples are
taken at least at
82 kHz. Further, if the resistances in circuit 2620 are known, and
"V(current)" and
"V(monitor)" are known, the impedance of the handpiece 100 may be calculated
in a manner
known in the art.
[0434] Also, by monitoring handpiece impedance, changes to the environment,
such as
moisture, ambient temperature, aqueous conditions, etc., may be automatically
compensated
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for by adjusting the drive waveform of the vibratory energy. For example, if
for a certain
material it is determined that 80W of power is required for a 400ms period to
achieve a
consistent bond or staking, then the waveform can be adjusted to ensure that
this amount of
energy is constantly delivered. Power is calculated using P=IV(cos T), where P
is the average
power, measured in watts, I is the RMS value of the sinusoidal alternating
current (AC), V is
the RMS value of the sinusoidal alternating voltage, and T is the phase angle
between the
voltage and the current. Because the signal from the waveform is sinusoidal,
the root mean
square (RMS) voltage as V=(1N2)A must be used.
[0435] As the impedance, Z, of the handpiece changes, the total power
delivered also
changes. By increasing or decreasing the drive voltage to compensate for the
change in the
impedance, a constant power can be delivered.
[0436] With reference to Fig. 71, in an another embodiment of the invention,
impedance during bonding is monitored over time. While bonding is taking
place, during
"Time (bond)", a sudden drop off in impedance, illustrated at reference 2642,
can indicate
that the end effector has slipped off the bond site, or some other error has
occurred. This error
can be communicated to the medical practitioner, and or a controlling
microprocessor, so that
corrective measures may be taken.
[0437] In accordance with the invention, a phase angle differential is
observed together
with, or in place of, an impedance change as described herein. With reference
to Fig. 67, an
alternating current circuit under load is illustrated, demonstrating that the
current and voltage
oscillate sinusoidally. Unless the circuit is purely resistive or in
resonance, the voltage and
the current will be out of phase. This phase angle differential "(D" (phi) is
monitored, where
current "I(t)" trails voltage "V(t)" over time, and changes are made to the
signal based upon
the observed phase angle differential, as well as other parameters, including
the frequency, in
order to maintain a resonant frequency at an area on the end effector where it
is desired for
bonding to take place.
[0438] More particularly, prior to bonding, the end effector is subjected to a
sweep
through a frequency range expected to contain an optimal resonance frequency,
beginning at
a frequency lower than is expected to produce resonance, and either the phase
angle
differential or highest and lowest impedance is observed. The optimal
frequency and other
parameters corresponding to the optimal frequency are recorded, for example by
an electronic
circuit or microprocessor, and when bonding is to be carried out, these
parameters are used as
initial values.
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[0439] This is further illustrated with reference to Fig. 68, wherein a
particular range of
frequencies generates a disproportionate change in phase angle. The change in
phase angle
corresponds to resonance of the end effector or horn, and thus resonance may
be inferred
from the phase angle differential. While resonance may be calculated under
certain
conditions, empirical data may additionally or alternatively be captured and
used to reduce
the time required for determining an optimal frequency range; the phase angle
differential is
one parameter that may be monitored to determine when an optimal frequency has
been
achieved.
[0440] A frequency likely to be close to an optimal frequency during bonding
is thus
determined prior to bonding, with the end effector not in contact with any
other object.
During bonding, an optimal frequency may change. In accordance with the
invention,
changes are made to one or more parameters as needed, for example the
frequency, to
maintain resonance of the end effector. Monitoring a phase angle differential
is one of the
ways in accordance with the invention of maintaining an optimal frequency
during bonding.
Moreover, because an optimal frequency may be maintained during bonding, the
step of first
determining a likely optimal frequency prior to attempting a bond may be
eliminated, which
is advantageous when multiple bonds are to be performed.
[0441 ] The foregoing methods may be used for bonding at an anti-resonant
frequency
as well as at a resonant frequency. An anti-resonant, or non-resonant
frequency, can still be
used to accomplish bonding, although it will generally result in higher
impedance and a
higher voltage requirement. Anti-resonant bonding is thus less efficient;
however, it may
result in a handpiece that is less sensitive to pressure changes, and thus
determining a non-
resonant frequency may be useful at least when this type of bonding is
desired.
Controlled Pressure Handpiece
[0442] In accordance with the invention, a tool for producing vibratory energy
is
provided with a gauge positioned to respond to a differential between a
pressure created by
applying a force to the handle, and the physical resistance presented at the
end effector. When
excessive force is applied, a response is generated, operative to warn the
operator and or
reduce power of the vibratory signal. When insufficient force is applied, the
operator is
likewise warned, and or power is not yet applied to produce vibration.
[0443] In one embodiment of the invention, a series of electrical contacts are
interposed
between the handle grip and the end effector. Springs respond to relative
movement of the
handle and the end effector, to position the contacts with respect to each
other, in order to
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open or close electrical circuits. These circuits may be connected directly to
a power
generator, or may pass to mechanical or electronic circuits which initiate a
warning or a
change in power level.
[0444] With reference to Fig. 60, a handpiece 2200 is provided for
transmitting
vibratory energy, advantageously including ultrasonic energy, in accordance
with the
invention. Handpiece 2200 includes a grip sleeve 2202 sized to be conveniently
held by a
surgical practitioner's hand, or engageable with a haptic or robotic arm. A
core body 2204 is
sized to slide in engagement with sleeve 2202. While core body 2204 is
illustrated to slide
within sleeve 2202, it should be understood that sleeve 2202 may be disposed
to slide within
body 2204 without departing from the spirit and scope of the invention.
Extending from core
body 2204 is an end effector 104, not shown in its entirety, as described
herein. Core body
2204 contains means to produce vibratory energy, as described herein, for
example including
a piezoelectric stack, not shown.
[0445] Extending between sleeve 2202 and body 2204 is resilient member 2206,
which
may have the form of a spring or other collapsible or bendable resilient
element, or magnetic
resitive element. End effector 104 may be pressed against a fastener of the
type described
herein through application of force to sleeve 2202 in the direction of Arrow
"A". The
application of force thus causes resilient member 2206 to compress, and sleeve
2202 to
overlap core body 2204. As the application of force to sleeve 2202 is reduced,
resilient
member 2206 acts to restore an original relative position of sleeve 2202 and
core body 2204.
Resilient member 2206 may be retained within a space formed between sleeve
2202 and core
body 2204, and may be attached to one or both of sleeve 2202 and core body
2204. Other
means may be provided to prevent over extending or separation of sleeve 2202
and core body
2204, as is known in the art.
[0446] Associated with core body 2204 and sleeve 2202 are electrical contacts
2210,
2212, respectively. Disposed between contacts 2210, 2212 is contact 2214,
attached to
resilient support 2216. All contacts 2210, 2212 and 2214 are electrically
connected to
modifying means 2218 for enabling, disabling, or modifying the vibratory
energy generated
by handpiece 2200. Modifying means 2218 may be an electronic circuit contained
within
handpiece 2200, or in core body 2204, or alternatively may be provided
external to the
handpiece, connected by wired or wireless transmission means, not shown, as
known in the
art. Alternatively, modifying means 2218 may merely enable and disable an
energizing
circuit operative to power a vibratory generator within handpiece 2200. In
either an electrical
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or electronic configuration, as sleeve 2202 is urged in a direction "A",
contact 2214 will
ultimately electrically connect with contact 2210, closing a circuit or
sending a signal to
energize a vibratory energy generating circuit. As sleeve 2202 is urged
further in direction
"A", contacts 2210 and 2216 remain electrically connected, contact 2214 moving
in
connection with resilient support 2216, which becomes compressed. As movement
in
direction "A" continues, contact 2212 ultimately electrically connects to
contact 2214,
changing the circuit previously created by contacts 2210 and 2214, opening a
circuit or
sending a signal to deenergize a vibratory energy generating circuit.
[0447] In this manner, if insufficient pressure is applied to a fastener of
the invention by
end effector 104, vibratory energy will not be applied. Moreover, as excess
pressure is
applied to the fastener, vibratory energy will not be applied. Thus, handpiece
2200 may be
operated to reliably apply vibratory energy only while an amount of force
within a
predetermined range is applied. While the circuit formed between contacts
2210, 2212 and
2214 has been described to control or signal a hard limit, that is, too little
or too much force,
it should be understood that it is possible to reduce or increase a vibratory
signal based upon
excess or insufficient pressure, respectively, by using pressure sensing
transducers in place of
one or more of contacts 2210, 2212 or 2214, or by employing additional
contacts.
[0448] It should further be understood that contacts 2210, 2212, or 2214 may
be
positioned along an interface formed between overlapping portions of sleeve
2202 and core
body 2204. An electrical connection may be formed between sleeve 2202 and core
body
2204, to convey one or more signals, and or to convey power to core body 2204,
in a similar
manner, or through the use of a self coiling wire 2208, as shown. Core body
2218 may
alternatively obtain power through the use of an attached battery, as
described further herein.
Additionally, resilient support 2216 may be attached to core body 2204, as
opposed to sleeve
2202, with corresponding changes to the circuit logic to achieve the
aforedescribed circuit
effects.
[0449] In an alternative embodiment of the invention, resilient support 2216
functions
as a strain guage, and transmits pressure information to a microprocessor or
guage. Similarly,
any or all of contacts 2210, 2212 and 2214 may function as strain guages. As
such,
transmitted information may cause the microprocessor to control operation of
the device
based upon the pressure sensed. In this manner, it may not be necessary for
contacts 2210,
2212 and 2214 to establish and break contact with each other, but rather, they
may resiliently
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contact each other throughout all or a portion of their relative movement,
relaying relative
pressure data.
Battery Powered Vibratory Energy Generator
[0450] With reference to Fig. 62, a handheld or portable vibratory generator
has a
requirement for a substantial amount of current, at high voltage. In
accordance with the
invention, an inverter 2400 is provided to convert the signal from a direct
current battery
2424 into a suitable sine wave signal, and a step-up transformer 2402 is
provided to increase
the voltage to an effective level.
[0451 ] In one embodiment multiple mosfet devices 2404, 2406 may be connected
in
parallel, advantageously provided in pair arrays, to provide for an adequate
amount of
current, wherein each pair 2404, 2406 increases the amount of current the
circuit can provide.
A control circuit 2414 includes a microprocessor 2408, which controls a MOSFET
driver
2416, which provides power to the mosfet array pairs 2404, 2406. To convert
from the direct
current of battery 2418 to the alternating current required by a piezo stack
or vibratory energy
transducer, control circuit 2414 alternately switching power between MOSFET
devices 2404
and 2406, in order to produce an alternating current within the primary
windings 2420 of
transformer 2402. This in turn induces an alternating magnetic field, which
induces an
alternating current in secondary winding 2422. Control circuit 2414,
advantageously further
including a digital signal processor (DSP) 2410 for further signal
modification, thus creates a
wave form at the proper frequency and voltage for vibratory bonding of the
invention.
[0452] Additional control circuitry may be employed, as known in the art, to
modify the
signal parameters to enable precise bonding, as described herein, including
circuitry for
voltage regulation, phase control, and voltage and current detection and
measurement.
[0453] Output 2412 of transformer 2402 is ultimately directed to a handpiece
or piezo
stack (not shown), which will transform the electrical signal into vibratory
energy.
[0454] To drive the circuit with adequate power, it is advantageous to use an
efficient
power storage medium, such as lithium ion batteries, which at the current time
are capable of
sourcing up to 80 amperes at a reasonable cost.
[0455] Fig. 87 illustrates a handpiece containing one or more batteries 3110,
and an
electronic circuit 3112 which may correspond to control circuit 2414.
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SONAR Measurement of Collapse
[0456] In another exemplary method, collapse of the fastener may be monitored,
such
as by the use of SONAR. Collapse is the distance a thermoplastic fastener or
implant shrinks
in height when vibratory energy is applied. For example, some thermoplastic
fasteners have
been found to shrink about 20 percent in height and increase 30 percent in
width when
bonded. For fasteners having two pieces, such as a cap and an anchor, the
attenuation of the
reflected vibratory waves changes as the two piece fastener becomes one piece.
This change
in attenuation may be monitored to alert the surgeon or operator when the bond
or staking is
complete. Furthermore, a vibratory transducer could be used in conjunction
with the end
effector to detect the change in acoustic impedance/attenuation of the site.
This signal may be
monitored by a microprocessor/controller or data signal processor (DSP) and
data may be
automatically interpreted to indicate whether the bond was successful.
[0457] Another way of providing feedback of an effective bond is to monitor
the Eddy
currents created by the movement of the end effector. As the end effector
vibrates, the linear
motion creates a change in the magnetic field. By monitoring the travel of the
end effector,
the amount of collapse can be determined.
Booster /Attenuator
[0458] With reference to Fig's. 69 and 86-87, in another embodiment in
accordance
with the invention, peak to peak motion, or amplitude of the vibratory horn or
end effector
104 is controlled using an attenuator or booster 3100, positioned after the
piezo stack 3102.
Fig. 69 illustrates displacement varying in relationship to the stack drive
signal, wherein a
booster or attenuator alters the minimum and maximum displacement of the end
effector.
Booster 3100 comprises an input mass 3104 and an output mass 3106, sized
relative to each
other, with output mass 3106 of a lower mass and smaller dimension, operative
to result in an
increase in vibratory frequency of end effector 104. While a booster 3100 is
shown, it should
be understood that an attenuator, not shown, is likewise adapted as known in
the art to reduce
an output frequency, with an output mass larger and or larger dimension than
an input mass.
[0459] Fig. 86 illustrates a booster 3100 positioned exterior to a housing
3108 of
handpiece 100, whereas in Fig. 87, booster 3100 is positioned internal to
housing 3108. The
invention contemplates that by positioning booster 3100 within housing 3108,
rigidity of
booster 3108 may be reduced, as it is provided with additional support by
housing 3108. In
this manner, the overall weight and cost of handpiece 100 may be reduced. If
the entire cost
of handpiece 100 is sufficiently low, handpiece 100 may be designed for use in
a single
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medical procedure and thereafter discarded, thereby removing a requirement
that the device
be sterilizable (e.g. able to withstand steam and pressure), and further
reduces the potential
for cross contamination between patients.
[0460] Fig. 87 further illustrates a battery powered vibratory device in
accordance with
the invention, containing one or more batteries 3110, and electronic circuit
3112 operative to
produce the signal required for production of vibratory energy in accordance
with the
invention, as described elsewhere herein. Contacts 3114 enable an electrical
connection for
recharging the batteries. Alternatively, the batteries may be provided
precharged in a single
use device, wherein contacts 3114 may be eliminated. Alternatively, an
inductive coil, not
shown, may be used to provide power, using techniques known in the art, for
charging
batteries 3110, or for powering the handheld device 100 whether or not there
are internal
batteries 3110.
[0461] In contrast, the handpiece of Fig. 86 is provided with conductors 3116,
operative
to convey a required signal from a generator or control device, not shown. It
should be
understood that the device of Fig. 86 may also be configured as battery
operated as shown for
Fig. 87; however only one device is shown as such for brevity.
[0462] With reference to Fig's. 86 and 87, logic circuit 3118 is provided to
carry out
computational calculations as described herein, and control circuit 3120 is
provided to change
an input signal as required to generate a correct vibratory output at end
effector 104.
Alternatively, logic and control may be provided entirely by a connected
generator, not
shown.
[0463] In addition to booster 3100, control may further be achieved by the
generator or
logic circuit 3118 and or control circuit 3120 by modulating the power, or
amplitude, of the
high frequency signal, as described elsewhere herein. Buttons 3124 may be
provided to
commence bonding, stop bonding, toggle through options, or otherwise control
actions of the
handpiece.
[0464] Booster 3100 may be replaced, as by a threaded or other mechanical
connection
to end effector 104, and piezo stack output shaft 3122. To facilitate booster
3100 selection,
and to reduce the incidence of error, booster 3100 may be color coded, and may
further be
color coded to match fasteners, handpiece 100, end effector 104, or other
physical device or
instruction document properly associated with the use of booster 3100. Color
coding may be
used elsewhere when carrying out the invention, for example between fasteners
and single
use handpieces, such as handpiece 100 of Fig. 87, and fasteners and end
effectors and horns.
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Thermal Staking
[0465] Staking of the fastening device of the present invention could also be
done using
thermal energy. The process for thermal staking is similar to the one used for
vibratory,
except that it may not be necessary to tune the system. The energy signal sent
to the stake can
be either AC or DC. To allow for longer heater life, a pulse width modulated
(PWM) signal
could be used. The PWM signal allows for the energy to be rapidly switched on
and off with
a varying duty cycle proportional to the total system energy needed for the
staking
environment.
Color Change
[0466] It is also contemplated that the material being bonded or staked may be
translucent or transparent, and a visual indicator within the material could
indicate when the
process is complete. For example, a pigment, dye, or other substance may be
impregnated
into the thermoplastic which when subjected to vibratory energy the pigment or
dye would be
released indicating that the bond or staking is complete. However, as
discussed elsewhere
herein, certain pigments, particularly in high concentration, may adversely
affect bonding;
accordingly, appropriate testing must be carried out for each admixture.
Alternatively, the
material of the thermoplastic may have the characteristic of changing color as
heat or
vibration is applied for a predetermined time or a predetermined frequency and
wattage.
Combined Therapeutic/Diagnostic Vibratory Generator
[0467] With reference to Fig. 63, in accordance with the invention, a
vibratory energy
generator 2500, advantageously a vibratory generator, includes power and logic
circuitry
2522 for generating and controlling a signal which may be used to create
vibratory energy,
and is otherwise adapted to perform diagnostic as well as therapeutic tasks.
Diagnostic tasks
include mapping or visualization of a target location. Information gathered
during the
diagnostic phase can be used by the surgical practitioner to determine optimal
settings for a
subsequent therapeutic use of the device, specifically including vibratory
fastening as
described herein.
[0468] Generator 2500 may include separate connectors 2502, 2504 which are
dedicated to diagnostic or therapeutic purposes, respectively, or a combined
connector 2506
may be used cooperative with combination handpiece 2508, described further
below.
Generator 2500 may further be provided with any one or more of an integrated
output display
2510, external display 2512, mouse 2514, or integrated keypad 2516. It should
be understood,
however, that the range of integrated and external human interface devices
known in the art
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may be employed in combination with the invention. In one embodiment, any of
the mouse
controls, for example buttons 2518, 2520 may be used to switch between
diagnostic or
therapeutic modes, wherein a transducer is caused to output diagnostic or
therapeutic
vibratory energy depending upon the button pressed, advantageously in
combination with a
mode selected with another human input device or the circuitry within
generator 2500.
[0469] The diagnostic information may further be directed to a microprocessor,
either
within circuitry 2522, or external (e.g. within a personal computer) to
generator 2500, either
of which may include a DSP, which will then carry out or suggest optimal
therapeutic
settings to the practitioner, which may then be communicated by output devices
associated
with the external microprocessor, or through human interface output devices
connected to
generator 2500.
[0470] Diagnostic information may include mapping information pertaining to
structures in the body which are not visible, including representative images
of physiological
areas of interest. Additionally, diagnostic information may include
information pertaining to
the environment in which fastening in accordance with the invention is to take
place,
including microclimate information, including temperature, humidity, or
information relevant
to the size of implant needed. This information may be determined using
calculations of the
speed of travel of vibratory energy through various medium, and is
particularly well
understood with respect to vibratory energy.
[0471 ] Referring now to Fig. 64-66, in one embodiment of the invention, a
vibratory
energy generator is provided in a portable or handheld device 2530, which
produces vibratory
energy for diagnostic purposes with an array of crystals 2532, and for
therapeutic purposes by
a stack of crystals 2534, within a housing 2536 incorporating both arrays.
[0472] In one embodiment of the invention, crystals 2532 and 2534 are
piezoelectric
crystals of ceramic with tungsten-bronze structures, but may include any
crystals, or any
other transducer whether or not crystalline, known in the art to generate
vibratory energy
from electricity, and electricity from vibratory energy.
[0473] Accordingly, a single microprocessor may advantageously be used to
control
both crystal configurations 2532, 2534 based on separate algorithms for each,
and a medical
practitioner may switch between diagnostic and therapeutic uses without
switching to a
different tool.
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[0474] Housing 2536, shown, has a simple form, although it should be
understood that
housing 2536 may be ergonomically shaped to best fit the human hand, or may be
shaped in
the manner of a gun, and may further include buttons or other controls, not
shown, useful for
communicating with associated equipment, such as generator 2500. Wire 2538,
extending
from housing 2536 and connected to each crystal array, extends to a generator
of vibratory
energy, such as generator 2500. Alternatively, device 2530 may be provided
with its own
source of battery power, as described elsewhere herein, and may be wirelessly
connected to a
microprocessor or digital signal processor which conveys signal information
relevant to the
medical and bonding procedure undertaken.
[0475] It is advantageous to reduce the time required for most tasks during a
medical
procedure not only to reduce costs and the time required to complete the
procedure, but also
to reduce the time during which the patient is subjected to discomfort or the
risks of surgery,
which include prolonged anesthesia, increased bleeding, and additional
exposure to
microorganisms. The instant invention reduces the time required to complete a
procedure by
enabling rapid generation of accurate data pertaining to the physical
environment, the tissue
or structures to be fastened, the dimensions of a required fastener, and the
bonding
parameters. Once this data is available, the device enables therapeutic use of
vibratory
energy, including the bonding of fasteners as described herein, without a
requirement to
change tools.
Irrigation/Suction End Effector
[0476] With reference to Fig. 81, during vibratory bonding, the presence of
liquid or
moisture can impact the performance and quality of the bond. One approach to
ensuring a
consistent and reliable bond, as described herein, is to adjust the bonding
parameters
according to the amount of observed or measured moisture within the zone or
area of
bonding. Another approach in accordance with the invention is to remove
moisture from the
bonding area, by introducing an input stream of gas or liquid, or by applying
suction/aspiration proximate the bonding site. In one embodiment, a tube 3000
is attached to
a vibratory end effector 104, wherein tube 3000 has a distal opening 3002
which serves as the
inlet for aspiration, or conversely the outlet for a gas or liquid stream,
opening 3002
positioned at a location near where bonding is to take place. A fitting or
coupling 3004 may
be provided at a proximal opening 3008, to releasably attach tube 3000 to a
source of vacuum
or low pressure, not shown. Tube 3000 is attached by any means known in the
art, including
for example adhesive 3006, brazing or welding, or one or more resilient bands
or screws. To
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avoid potentially damping a vibratory signal, however, it may be advantageous
to
alternatively attach tube 3000 to sheath 146, which surrounds end effector
104, but does not
significantly inhibit vibratory motion.
[0477] In a further embodiment, an additional tube 3010 is provided, attached
to end
effector 104, having like components relative to tube 3000, including a
coupling 3012 at
proximal opening 3014, and a distal opening 3016. Tube 3000 or 3010 may be
bent or shaped
to direct opening 3002, 3016, respectively. For example, as illustrated at
3018, tube 3000 is
bent to direct opening 3002 towards a bonding site. In an embodiment having
two or more
tubes, at least one of tube 3000 or 3010 introduces an input stream of gas or
liquid, and a
second tube is operative to form an output stream to collect the gas or liquid
via suction,
together with any debris collected and carried therein. While tube 3010 is
illustrated as being
directly connected to end effector 104, it may alternatively be connected to
sheath 146, as
outline above with respect to tube 3000.
[0478] An advantage of the aforedescribed embodiment is the removal of debris
generated during the bonding process, which may include flash formed at the
bonding
periphery, as well as any other material or body tissue that has vibrated
loose or otherwise
has become loose within or near the bonding area.
[0479] The first or second tube 3000, 3010 may be fastened to the outside of
the
vibratory end effector, as described with respect to Fig. 81, or may
alternatively be formed as
one or more channels or pathways within the end effector, as may be seen in
Fig's. 82-83, or
a combination of internal and external pathways. Fig. 82 illustrates a single
channe13020,
having a proximal opening 3022, a coupling 3024, and a distal opening 3026.
Fig. 83
illustrates two channels, 3020, 3040, channe13040 having analogous elements
including
proximal opening 3042, coupling 3044, and distal opening 3046. It should be
understood,
however, that channels 3020 or 3040 formed within end effector 104 may impact
transmission of vibratory energy, and thus tuning may result in differing
parameters with
respect to an end effector without channels, particularly if the channels are
formed with a
significant length transverse to a longitudinal axis of end effector 104.
[0480] Liquids which may be passed to the body through tube 3000, 3010, 3020
or
3040 (hereafter collectively tube 3000) include, for example, sterile saline,
therapeutic
substances including the substances defined herein, injectable polymer, bio-
graft material,
radioisotope tagged liquid, live cells, or any other material as determined by
a medical
practitioner to be of benefit to the patient. Similarly, gases passable
through tube 3000
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include oxygen, nitrogen, carbon dioxide, or any other gas determined by a
medical
practitioner to be of benefit to the patient. Flowable powders or particulates
may also be
passed through tube 3000, as determined to be of benefit.
[0481] In the embodiments of Fig's. 81-83, switches or controls for activating
an input
or output stream may be provided on a handpiece to which end effector 104 is
connected, for
example handpiece 100, or on a foot switch or hand operated remote, not shown,
or the input
or output stream may be activated by voice control.
[0482] Referring now to Fig. 85, the end effector 104 of Fig. 83 is shown
disposed
within a cannula 3200. In this manner, materials introduced through tube 3020
may be
confined within a specific area defined by cannula 3200. Moreover, additional
materials may
be introduced through cannula 3200, and these materials may also be confined
within cannula
3200. Thus, materials may be introduced to an area of fastening which have a
reduced impact
on surrounding body tissue. Additionally, benefits of a cannula, or expanding
cannula, may
be attained, including the maintenance of potentially intruding tissue at a
distance away from
a fastening site.
[0483] In one embodiment of the invention, a stream introduced through tube
3020, or
alternatively through cannula 3200 (indicated by arrow "A") may dislodge
tissue cells 3202
which are intended to be harvested for subsequent use, or which are harmful
and are intended
to be removed for the health of the patient. For harmful tissues, radio
frequency may be
emitted as described with respect to Fig. 84, to destroy or loosen harmful
cells. Alternatively,
a therapeutic substance may be used to loosen or dislodge harmful cells, the
substance
admitted at "A" or through tube 3000. Further, material may be admitted at "A"
or through
tube 3020 under pressure. In particular, material may be admitted through tube
3020, for
example, at sufficiently high pressure to have a significant mechanical effect
on exposed
tissue, wherein firmly anchored tissue or other matter may effectively be
dislodged.
Moreover, vibratory energy may be applied by end effector 104 to contribute to
a loosening
effect. Loosened material may be removed by suction, as through tube 3040, or
through a
flow upwards in a direction opposite to arrow "A", to a point exterior of
cannula 3200.
Additionally, an aspirator, not shown, may be employed.
[0484] It should be understood that the devices of Fig's. 81 or 82 may
alternately be
used in conjunction with cannula 3200 as described, or alternatively, any of
the other devices
of the invention which may advantageously be admitted to the body through a
cannula.
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Radio Frequency End Effector
[0485] With reference to Fig. 84, in another embodiment, one or more radio
frequency
transmitting antenna 3050 are provided proximate the distal end of end
effector 3054,
operative to break down or destroy contaminants within the bonding area,
including moisture
or particulates. Shielding, not shown, is appropriately placed in order to
safeguard any
nearby body tissue or material which might be vulnerable to stray
transmissions. One or more
wires 3052 connect antenna 3050 to a radio frequency signal generator, not
shown. The RF
embodiment of Fig. 84 may be combined with other end effector types, including
those of
Fig's. 81-83.
Testins4
[0486] The previously described methods for providing positive feedback to the
operator included the use of measurements and/or computers. Another positive
feedback
system is provided which relies on physical force. When two objects are
fastened to each
other, it is common for the technician or mechanic to pull or tug on the
assembly to ensure
the parts are securely fastened. This common technique may apply to the
thermoplastic
system of the present invention. Once a fastener or other implant is vibratory
bonded or
staked, the surgeon can apply a quick tug on the assembly to verify the bond
or staking was
completed as intended.
[0487] In accordance with an embodiment of the invention, a frame is provided
with an
aperture through which a fastener body may pass, sized to prevent passage of a
fastener head.
The device may thus test the holding strength of a distally bonded connection,
as well as
proximal bond including a head formed with vibratory energy. A strain gauge,
spring scale,
or other suitable measuring device is connected to the frame, and a force is
applied in a
direction away from the fastened connection. The results are observed and
recorded, together
with the parameters under which the connection was formed and tested.
[0488] Fig's. 1 lA and 1 lB illustrate a feedback instrument 160 for
performing such a
physical positive feedback check. An end effector 162 includes a post 164
which emits
vibratory energy. A thermoplastic fastener 166 is placed on the end effector
162 with the post
164 in a bore or receptacle 168 of the fastener 166. After emitting vibratory
energy and
bonding or staking the fastener to an implant or tissue, the surgeon may
actuate a biasing
prong or prongs 170 from the post 164 of the end effector while the post 164
is still in the
fastener 166. In a stored configuration, the prongs 170 are positioned within
the post 164. In a
deployed configuration, the prongs 170 extend radially from the post 164 by
the activation of
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a handle, switch, or button. The extended prongs 170 dig slightly into the
material of the
fastener 166 so that the surgeon may now pull or tug on the instrument 160
proximally to
verify that the fastener 166 is securely bonded or staked in place.
Additionally, the prongs
170 and/or post 164 may include a strain gauge or other force measuring device
to measure
and display to the surgeon how many pounds of pull strength is being put on
the fastener.
[0489] To aid in determining the exact conditions under which fastening was
accomplished, an electronic circuit separately measures the power consumed in
tuning the
vibratory instrument, and performing the bond itself. This data is used,
together with other
parameters, to enable the production of a secure and reproducible bond.
Fastenins4 Procedures
[0490] When two dissimilar materials need to be bonded together, the bonding
may be
performed outside the body, such as during the manufacturing process or within
the operating
room. This is done to avoid damage to surrounding tissue caused by the heat
required to bond
the dissimilar materials to each other. Then, once implanted, further bonding
may be done
within the body to bond like thermoplastics creating the desired implant
configuration. For
example, a spacer made of PEEK may be joined to a metallic implant outside the
body. The
spacer and implant may be placed in the body, and the PEEK may be bonded with
another
PEEK element inside the body so that there is a PEEK to PEEK bond. The metal
implant may
be the load bearing surface or the bearing point, while the PEEK to PEEK bond
provides for
the fastening and stabilization of the implant.
Staking
[0491 ] Although the above-discussion emphasizes bonding or welding, the
present
invention also contemplates staking in most situations as an alternative or
supplement.
Staking generally involves the mechanical interlock of dissimilar materials.
Staking is the
process of melting and reforming a piece, such as a stud, to mechanically lock
a material in
place. It provides an alternative to bonding when two parts to be joined are
made of
dissimilar materials that cannot be bonded or simple mechanical retention of
one part relative
to another is adequate.
[0492] The advantages of staking include short cycle time, the ability to
perform
multiple staking with one end effector. The most common staking application
attaches metal
to plastic. A hole in a metal part is designed to receive a plastic stud. An
end effector with a
contoured tip contacts the proximal end and creates localized frictional heat.
As the stud
melts, light pressure from the end effector reforms the head to the
configuration of the end
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effector. When the end effector stops vibrating, the plastic solidifies and
the metal and plastic
parts are fastened together.
[0493] Thus as set forth in the prior art, which is not in the medical field,
staking using
vibratory energy causes thermal deformation at the site of the end effector
and the near end of
a polymer. As the inventors have previously defined for bonding, vibratory
bonding can be
near field (less than ~/4 inch from the end effector) and far field (greater
than ~/4 inch from the
end effector). Staking, as defined in the prior art is all near field. To
date, no one has
performed distal or far field staking. This is where the mechanical
deformation occurs at a
site away from the vibratory horn or end effector. The staking can occur, not
at the trailing
edge of the implant, but along the implant surface, or at the far end of the
implant, where the
implant can be bonded to another implant mechanically, particularly if it is a
dissimilar
implant. The distal staking of the invention causes deforming and melting to
mechanically
interlock into a like or dissimilar material. In accordance with the
invention, the horn does
not necessarily reform or change a surface with which it comes in contact, as
is disclosed in
the prior art.
[0494] Fig's. 21-24 illustrate some uses of vibratory staking for implants and
tissue
fastening. In Fig. 21, a PEEK (or other polymer) tack 4000 having a proximal
end similar to
the anchor in Fig. 22 is used to couple two materials together, in this case
two porous metals
4002, 4004. After staking, the proximal end assumes the shape 4006 of the end
of the end
effector. Additionally, the distal end 4008 of the tack could be secured to
porous metal using
vibratory energy.
[0495] Fig. 22 shows a polymeric anchor 4010 prior to staking with the domed-
shape
end effector. The anchor 4010 is illustrated as threaded, as a means of
securing the base to the
body or other implant. However, the base may be connected to the body or
another implant
using vibratory energy in accordance with the invention, or may otherwise be
secured using
means known in the art. Post 4014 on the proximal end of anchor 4010 can be
used to pierce
one or more objects, in this example soft tissue 4016, holding it in position
relative to 4012.
The objects may alternatively be bound by passing the end of post 4014 through
an aperture
or gap in each of the objects to be staked, or by forming the gap or aperture
with post 4014.
The tip 4018 is then formed by staking using end effector 104. In this
example, end effector
104 is curved or dome shaped, and is operative to form a complementary dome
shape on the
end of post 4014. Generally, however, bondable material on the end of post
4014 will expand
outwards, enlargening the end of post 4014. In this manner, the end of post
4014 becomes
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larger than the gap in the objects. It is desired for the end of post 4014 to
expand to a size at
least larger than the gap in the object closest to the end of post 4014, in
order to at least
secure the top-most object. As such, objects upon post 4014 are secured within
the body,
bounded by secured base on one side, and expanded post 4014 on the other, and
are thus
staked. If needed, the post can be trimmed (either mechanically or by shearing
off with the
vibratory energy) before staking. A load bearing surface 4020 may be added
before tip 4018
is formed, if additional support is deemed beneficial.
[0496] In Fig. 23, a fracture fastening plate 4100 is secured with screws 4102
having
tips 4104 projecting above the top surface of plate 4100. Screws 4102 can be
placed through
holes in plate 4100, and tips 4104 staked to secure plate 4100 to bone 4012.
Screws 4102 can
be inserted through the plate at angles other than ninety degrees. In another
embodiment,
screws 4102 are first threaded into bone 4012 and then plate 4100 is inserted
over the
proximal tip.
[0497] Fig. 24 shows that two implants can be joined with far-field bonds
4014, then
formed at the end effector to seal over bone or implant. The near-field
staking 4016 should
not adversely damage or affect the far-field bond 4014, as each bond is tuned
for the
particular locus of vibration desired.
[0498] Fig's. 25A-C show another embodiment of an anchor 400 particularly well
suited for staking to a plate 402. Anchor 400 has a body 404 with threads 406
for fastening to
bone. As shown in the testing jig, after anchor 400 is secured to bone, the
plate 402 is
inserted over head 408 of anchor 400. If needed, head 408 can be trimmed or
otherwise cut to
size. A staking end effector 410 is placed on head 408. Upon activation of the
vibratory
energy, head 408 deforms to the shape of the tip of end effector 410 (in this
case, domed
shaped) to secure anchor 400 to plate 402.
[0499] Fig's. 26A-C show an alternative anchor 422 configuration analogous to
the
configuration shown in Fig. 23, however plate 402A has an elongated slot 420
enabling a
variety of fastening positions.
[0500] Figs. 27A-27C show another staking application of the invention. In
particular, a
standard metallic polyaxial screw/rod system 4120 has been modified to include
holes 4122
intersecting both the saddle 4124 that holds the rod 4126 and pedicle screw
head 4130 (not
visible) and the locking screw 4128 used to maintain the desired angle of the
pedicle screw
4132. A tack 4134, including bondable material at least on its exterior
surface, is inserted into
holes 4122, and then staked or bonded using vibratory energy in accordance
with the
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invention. In this manner, the material of tack 4134 flows into the threads
4136 between
saddle 4124 and locking screw 4128, effectively preventing loosening.
[0501] Fig's. 28A-28C show that the staking concept can be applied to
angulated
screws, typically used in spinal applications. Specifically, screws that can
be placed at an
angle through the plate and then staked in place. This embodiment is discussed
further within
a discussion of spinal fixation, herein.
[0502] In a final staking application, Fig. 30 shows that the end effector can
be used as
the implant itself. Specifically, one application would be inserting a metal
pin into a PEEK
(or other thermoplastic material) rod. Typically, using a metal pin would
create arcing and
sparks due to the metal on metal contact. In order to minimize this effect, a
metallic pin is
rigidly attached to an end effector. Although a connection similar to a BNC
connection is
shown, any quick release mechanism could be used.
[0503] For example, a PEEK (or other polymer) anchor/fastener, or tack may be
used to
couple two materials together, in this case two porous metals. After staking,
a proximal end
assumes the shape of the end of the end effector. Additionally, the distal end
of the tack is
fastened to porous metal, such as may be found on an interior face of an
implant, secured
using vibratory energy.
[0504] Initially, the anchor is threaded or otherwise secured to the bone. A
post
projecting away from the bone on the proximal end of the anchor can be used to
pierce soft
tissue to be attached, holding it in position relative to the bone. The tip is
then formed into a
cap by staking, with or without an interposing element between the soft tissue
and the cap
formed at the proximal end of the post. If needed, the post can be trimmed
(either
mechanically or by shearing off with vibratory energy) before staking. In this
manner, a plate
or other structure can be attached using two or more tacks.
Fastening into Existing Cement/Adhesives
[0505] With reference to Fig. 44, in an additional embodiment in accordance
with the
invention, one or more fasteners 1000 are provided to embed within, and
thereby become
securely fastened to, previously hardened bondable materia1802, such as bone
cement, in
vivo. Fastener 1000 may be any of the fasteners which may be connected to
bondable
material with vibratory energy, as described herein. This method is
advantageously
employed, for example, to repair bone fractures, secure and resecure implants,
repair
periprosthetic fractures, and to secure or repair dental devices and implants.
For example, a
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medical practitioner may observe a lucent line progressively developing as an
implant
loosens, indicating a separation between body tissue and the implant. In the
prior art, revision
surgery would be required in order to remove and or re-cement the implant. In
accordance
with the invention, a tack, pin, bar, rod, plate or other fastener 1000 may be
inserted into the
body, and fastened to bondable materia1802, implanted earlier, through the
application of
vibratory energy, said energy advantageously including ultrasonic energy. As
discussed
elsewhere, herein, the distal portion 1002 of the fastener is caused to
resonate and vibrate in
contact with the bondable materia1802, locally heating the latter to enable
adhesion to
fastener 1000. The fastener thus may serve as an anchor point in subsequent
steps to re-secure
the implant.
[0506] With reference to Fig's. 40-41, embedded fastener 800 has been embedded
within bondable material 802 within the body. As is the case with all
illustrations herein,
Fig's. 40-41 are not necessarily to scale, but rather drawn to simplify
understanding of the
invention. In the example shown, bondable materia1802 is found surrounding
acetabular
replacement prosthetic 880, implanted within femur 882, and locking fastener
840 has been
secured to embedded fastener 800. In some procedures, it may be necessary to
first drill a
hole or remove body tissue in order to access the implanted bondable
materia1802 with
embedded fastener 800. Once implanted, embedded fastener 800 may serve as a
convenient
attachment point for further implants or fasteners, or may simply lock the
adhesive and
bonded prosthetic 880 in position relative to bone 882. In the example shown,
locking
fastener 840 attaches unsecured member 884 relative to bone 882. Unsecured
member 884
may be, for example, a prosthetic, a living tendon, an allograft, or any other
object a surgical
practitioner may wish to secure in a specific location.
[0507] Fasteners securable to implanted bone cement include the materials
described in
this specification, including as examples PMMA, metal, metal at least
partially coated with
PMMA or acrylic, PEEK (polyetheretherketone), and acrylic, or can be a
composite
including resin, and or carbon fibers. A thin coating of PMMA or acrylic, as
small as several
microns, contributes to forming a secure bond with bone cement within the
body. Bonds may
additionally be formed between dissimilar adhesives.
[0508] An initial bore may be made in the bone cement to aid alignment, to
temporarily
retain the fastener, or to increase the surface area for fastening. The
fastener may be placed in
an intended location through, for example, intramedullary, percutaneous, or
retrograde
approaches.
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[0509] With further reference to Fig. 44, a brace 1004 is positioned along
bone 882.
Alternatively, brace 1004 may be positioned upon the surface of the skin, or
at any point
between the bone surface and the skin, according to the requirements of the
surgical
procedure. Further, brace 1004 may be placed within the bone, for example in
an
intramedullary canal. Fastener 1000 is secured to bondable material 802, or a
porous surface
of implant 880, in a manner described herein, for example through distal
vibratory fastening.
A cerclage wire 1006 may be employed as known in the art, to provide further
stabilization,
in combination with fasteners 1000. A head portion 1012 may be provided upon
fastener
1000, or may be formed using vibratory energy.
[0510] In an embodiment of the invention, one or more of fastener 1000 passes
through
and stabilizes brace 1004 with respect to bone 882, on a first side of bone
damage 918A.
Brace 1004 extends to a point distal to the first side of bone damage 918A,
for example to a
bone 882 portion on an opposite or second side of damage 918A. Brace 1004 is
further
secured on the second side of damage 918a, and the two sides of damage 918A
are thus
secured relative to each other, enabling healing or repair of damage 918A
during a period of
reduced mechanical disturbance. Fasteners 1000 may be used to stabilize brace
1004 on the
second side of damage 918A if embedded bondable material is present on the
second side of
damage 918A, for example embedding into bondable material at 802A. Capped
fasteners
1008 are shown, passing completely through both sides of bone 882. Caps or
heads 1010 may
be formed using vibratory energy as described in this specification, or capped
fastener 1008
may be passed through 882, as by piercing bone 882 with a pointed end of the
fastener, or by
forming openings in bone 882 before passing the fastener through bone 882.
Alternatively,
capped fastener 1008 may be provided in the form of a drill bit, with caps
formed before or
after implantation using vibratory energy, as described in this specification.
[0511] In yet another embodiment of the invention, a fastener 1008 is passed
through
bone 882, contacting bondable material 802 along at least one area of shaft
1014 of fastener
1008. Through tuning, described in this specification, vibratory parameters
are established
which promote vibration in a contact area between shaft area 1014 and bondable
material
802. Accordingly, fastener 1008 is bonded to bondable materia1802 at shaft
area 1014.
Additional stabilization is optionally provided by passing fastener 1008
through another
cortical layer of bone 882, and in the example shown, an area on an opposite
side of damage
918A.
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[0512] Referring now to Fig. 96, body tissue 3700, in the example shown, a
tendon, is
fastened to body tissue 3702, in the example shown, a bone, using fasteners
1256 (of Fig. 50)
in accordance with the invention. While fastener 1256 is shown, other
fasteners of the
invention may be used, including fastener 800, or the fasteners of Fig's. 46D-
46H, for
example. Fastener 1256 extends through body tissue 3700, and is fastened to
the surface of
tissue 3702, which advantageously has been provided with a roughened or porous
surface, or
a surface with at least one cavity therein, in or upon which softened or
melted material of
fastener 1256 may attach.
[0513] Fastener 1256A penetrates body tissue 3702, either by being driven
through
tissue 3702, or by passing through an aperture formed within tissue 3702 in
advance. Anchor
3704 of bondable material has been injected into, or otherwise been positioned
within body
tissue 3702, so that it is adhered within tissue 3702. Any of the bondable
materials as
described herein may be used, including biocompatible forms of n-butyl
methacrylate, or
poly-butyl-methacrylate (PBMA), of suitable strength. Anchor 3704 may further
be
advantageously of a biodegradable material. Fastener 1256A is thus caused to
pass through
tissue 3702 to contact anchor 3704, whereupon distal fastening in accordance
with the
invention may be carried out. In this manner, anchor 3704 serves to bind a
distal side 3706 of
tissue 3702 to a proximal side 3708, relative to fastener 1256A. In this
manner, fracture 3710
is maintained in a position advantageous for proper healing. In the embodiment
shown,
fastener 1256A serves both to affix tissue 3700 and secure fracture 3710;
however it should
be understood that one or the other purpose may be carried out alone. For
example, fastener
1256A need not pass through tissue 3700 in order to secure fracture 3710, or
alternatively,
may secure tissue 3700 as shown, in the absence of fracture 3710.
End Effectorfor Fastening into Adhesives
[0514] Further, the end effector can be used as the implant itself.
Specifically, in one
embodiment of the invention, a metal pin, screw, or other engagement shape is
inserted into a
thermoplastic (e.g. PEEK) rod, the pin itself attached to an end effector. The
metal pin must
be firmly attached, or formed integrally with the end effector, to avoid
creating arcing and
sparks due to metal on metal contact between the pin and effector. For
removable pins, a
release mechanism is provided.
[0515] In accordance with the invention, an end effector having a distal tip
formed or
attached thereto is inserted into a medullary canal in a long bone, and
affixed into adhesive
through the use of vibratory energy, as described in this specification. The
end effector is
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then removed from the remainder of the vibratory energy generating device,
whereby
connection means at a proximal end may be used to secure the end effector
within the bone,
or to body tissue to be attached, or to another implant.
[0516] With reference to Fig's. 41-43, an end effector 900 operative to
transmit
vibratory energy, for example ultrasonic energy, is passed into the body, to
contact a
bondable material 802 within the body. The end effector may be provided with a
separable
distal end portion operative to transmit vibratory energy to the bondable
material, such as, for
example, fastener 800 of Fig. 32A. Alternatively, the end effector may be
provided with a
shaped distal end 902 operative to enter bondable materia1802. In one
embodiment, end
effector 900 is replaceable and selectable by the practitioner to best pass
through the body or
enter bondable material. End Effector 900 may be removed or replaced, for
example, at a
threaded or other mechanical connection 906 proximate a handpiece 908.
[0517] With reference to Fig. 42, an end effector has been passed into the
intramedullary canal of bone 882 in a body, in the example shown, a femur. It
should be
understood, however, that the dimensions of end effector 900, together with
any attached
fastener or shaped end, is selected to fit within the particular body space
contemplated by the
surgical procedure, which may include for example soft tissue space, or a
location proximate
the spine or skull. Bondable material may include any of the materials
described in this
specification, however in the example shown, materia1802 is bone cement,
previously
implanted to retain hip replacement prosthetic 880.
[0518] Once end effector 900 has been secured to bondable materia1802,
handpiece
908 may be removed, exposing a portion of mechanical connection 906 at a
proximal portion
of the end effector 900. A proximal fastener 910 is then mechanically attached
to mechanical
connection 906, as by threading. Retaining means 912 are provided for affixing
proximal
fastener 910 to the body.
[0519] In the example shown, retaining means 912 comprise a flange in cortical
tissue
of bone 882. Proximal fastener 910 is shaped with a cooperating flange 916,
sized to be
retained by retaining means 912. In this manner, once a mechanical connection
is made
between proximal fastener 910 and mechanical connection 906, a compressive
force is
established between retaining means 912 and embedded shaped distal end 902,
secured
within bondable material 802. If proximal fastener 910 and mechanical
connection 906 are
threaded, the amount of compressive force is adjustable based upon the amount
of threaded
overlap. Retaining means 912 may alternatively include an additional implant,
for example a
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plate or pin (not shown), or an arthroplasty component 920, having an area
sized and
dimensioned to engage proximal fastener 910, and to thereby transmit a force
applied to
fastener 910 to the body.
[0520] Compressive force may be employed, for example, to bring together
portions of
body tissue, such as portions separated by trauma or disease, or that have
been separated in
the normal course of a surgical procedure. For example, in Fig. 41, a region
of bone damage
918, such as a fracture or diseased bone area, is shown prior to application
of a compressive
force as described, and in Fig's. 42 and 43, the fracture has been
approximated by
compressive force.
[0521] With further reference to Fig. 43, arthroplasty component 920, in this
case the
articulating surfaces of the medial and lateral condyles and the trochlear
groove, are retained
upon bone 882 at least by end effector 900. Mechanical connection 906 passes
at least
partially through a portion of component 920, and proximal fastener 910 is
connected thereto
at mating portion 912A to secure component 920 onto end effector 900. In the
example
shown, a portion 922 of component 920 containing a single condylar surface and
the
trochlear groove is fastened directly to end effector 900, and a remaining
condylar surface
portion 924 is attached to portion 922.
Fastening into Implanted Device
[0522] As described elsewhere herein, implants and fasteners in accordance
with the
invention are secured within the body, and then serve as attachment points for
further
implants or fasteners. With reference to Fig. 61, an additional embodiment of
the invention
includes an implant formed in parts, including a base 2300 attached within the
body through
connection to body tissue or another implant, using apparatus and methods of
the invention,
or using means known in the art. Base 2300 includes a surface 2302 that may be
smooth, but
in accordance with the invention, is advantageously provided with an irregular
surface, such
as a porous or roughened surface, or a surface having one or more cavities
2304 into which a
bondable material may enter and thereby lock to the surface.
[0523] Mating portion 2306 engages base 2300 along mating surface 2308. In
accordance with the invention, mating surface 2308 includes bondable material
along at least
a part of the surface which contacts surface 2302. Base 2300 and mating
portion 2306 are
placed in apposition, whereupon vibratory energy, advantageously combined with
pressure,
is applied to form a bond between surface 2302 and mating surface 2308, as
described
elsewhere herein.
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[0524] In the embodiment shown in Fig. 61, however, a vibratory horn 2310 is
shaped
to conform to an inner surface 2312 of mating portion 2306. In one embodiment,
horn 2310
is a portion or the entire implant intended to be left in the body after a
surgical procedure, and
is connected to a source of vibratory energy (not shown) when horn 2310 is
used to bond
mating portion 2306 to base 2300. In this manner, vibratory energy is
uniformly distributed
throughout the region of intended bonding. Moreover, if inner surface 2302 is
additionally
formed with bondable material, or the entire mating portion 2306 is formed of
bondable
material, ideal conformance may be obtained on both sides of mating surface
2308, between
horn 2310 (the implant) and base 2300. This is advantageous for smooth joint
replacement
movement.
[0525] After application of vibratory energy, advantageously ultrasonic
energy, mating
surface 2308 is firmly fixed to irregular surface 2302; however, if horn 2310
and inner
surface 2312 are sufficiently smooth, a gliding interface is created
therebetween. Similarly, if
it is a goal of having mating portion floating between horn 2310 and base
2300, a smooth
surface may be provided for surface 2302. Further, it should be understood
that a heat
meltable surface may be additionally provided upon surface 2302, and mating
surface 2308
may alternatively be provided with the irregular surface described above.
[0526] In the example shown in Fig. 61, base 2300 and mating portion 2306 are
shaped
to function as a replacement for an acetabulum, however it should be
understood that any
implanted shapes may be connected as described herein. For a hip replacement,
vibratory
energy may be applied to a portion of the implant proximate horn 2310, of
sufficient energy
to cause the required melting or softening as described above.
Distal Fastening /Retrograde Approach
[0527] In accordance with a further embodiment of the invention, vibratory
energy is
applied to cause thermal deformation distal to the site of application of the
end effector. In
this application, the mechanical deformation, especially in dissimilar
materials, occurs at a
site away from the vibratory horn or end effector. The staking or bonding can
occur not at the
trailing edge of the implant, but along the implant surface or at the far end
of the implant
where the implant can be mechanically bonded to body tissue, implanted cement,
or another
implant, particularly if it is a dissimilar implant.
[0528] Distal fastening is accomplished by reducing significant vibration at a
proximal
end of a fastener, and tuning for vibration at a distal end of a fastener, or
alternatively, an
intermediate portion of a fastener. The vibratory horn may be releasably
connectable fastened
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to a source of vibratory energy, as by threading or twist lock engagement or
other mechanical
means, thereby damping vibration at a point of connection, and enabling a
transfer or
transmission to a distal end of the horn. The releasable connection is used,
for example,
where it is intended to leave the horn within the body, or simply to discard
the horn after use.
Alternatively, the vibratory horn may simply be in firm contact with the end
effector or
source of vibratory energy, in order to transmit vibratory energy at a distal
end. By
establishing a firm contact, it is possible to prevent generation of large
quantities of heat at
the point of contact. In particular, sufficient heat to substantially soften
the welding horn at a
point of contact can be avoided, should the welding horn contain bondable
material.
[0529] In one embodiment, the end effector itself is fastened. In this
embodiment,
where the end effector is elongated, a point of fastening is inherently distal
from a body
surface, or an entry point of the end effector.
[0530] With reference to Fig. 46G, in an alternative embodiment, assembly 1240
includes an end effector 1242 comprised of or at least partially coated with a
bondable
material 1244. After assembly 1240 is attached using vibratory energy, end
effector 1242
may be cut to a desired length. Fasteners 46D, 46G and 46H are advantageously,
though not
necessarily, elongated, so that they may pass through body tissue with a
minimum of
displacement thereof, to reach a point of fastening.
[0531] In a further embodiment, with reference to Fig. 46H, an attachable
fastener
1250, which includes bondable material 1252 is secured to the end of an end
effector,
wherein vibration at the attachment is discouraged, as by a sufficiently firm,
secure
attachment, for example threading 1254 (shown in cross section), or adhesion.
In this manner,
vibration may be tuned to occur at a distal end 1256 of fastener 1250, and not
at a point of
attachment 1258 between fastener 1250 and end effector 104. Accordingly, the
fastener now
serves as a vibratory horn, whereupon it is used to generate heat at a distal
point of contact. If
the contact surface contains bondable material, that material may be softened.
If the fastener
includes bondable material at the point of contact, that material may also be
softened by heat
produced by vibration at the contact area. If the bondable material of the
fastener and the
contact surface are the same or sufficiently similar, welding may occur,
whereupon the
fastener and contact surface become bonding when the materials cool. If the
materials are
different, the two softened surfaces may mix, or lock to each other
mechanically after
cooling.
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[0532] As the fastener has passed through body tissue, it is frictionally
engages
therewith, or may additionally be affixed using methods of the invention or
prior art methods
of attachment. In this manner, the contact surface is further stabilized
within the body through
being bonded to the fastener.
[0533] Referring now to Fig. 47A, an implant 1400, in this example a tibial
arthroplasty
prosthesis, has a surface 1404 onto which a fastener including bondable
material may deform
and adhere, in order to form a bond therebetween. Fastener 1250 is shown
extending from the
underside of implant 1400, through bone 1402. Prior to forming cap or head
1010, in a
manner described herein, a hole is formed in bone 1402, or fastener 1250 is
driven, pushed,
or drilled into bone 1402, until distal end 1256 is proximate implant 1400. In
the example
shown, cement, adhesive, or bondable material 1206 has been applied to the
underside of
implant 1400, either in a previous procedure, or in the same procedure during
which fastener
1250 is affixed. If bondable material 1206 is present, it may be melted by
distally applied
vibratory energy, as described above, to enable distal end 1256 to reach
implant 1400. Once
distal end 1256 is in contact with implant 1400, vibratory energy is applied
to create heat at a
contact area between fastener 1400 and distal end 1256, whereby distal end
1256 deforms
and flows onto a surface of implant 1400, to which it adheres.
[0534] To improve bonding, at least a portion of the surface of implant 1400
is
advantageously provided with a rough, porous or irregular surface, or at least
one surface
cavity into which softened material of fastener 1250 may flow or be urged, as
by pressure
acting in the direction of the bond. Upon cooling, distal end 1256 is bonded
to implant 1400,
the bond strength improved due to either or both of an increased surface area
of contact, or
mechanical interlock with the irregular surface of fastener 1400.
[0535] Fastener 1250, in one embodiment, is sized so that sufficient material
remains
exposed beyond the surface of bone 1402, wherein cap 1010 may be formed, as
described
herein. Alternatively, fastener 1250 may be cut, as with a knife or saw,
either flush with the
surface of bone 1402, as may be seen for example in Fig. 47C, or may be
provided with
sufficient excess material to form cap 1010, as shown in Fig. 47A.
[0536] Distal fastening in accordance with the invention is advantageously
employed
where a retrograde approach, such as that illustrated for fastener 1250 in
Fig. 47A. A
retrograde approach may be the only feasible or safe approach to a fastening
site, or may
simply be easier than an antegrade approach. A further advantage, as can be
seen in the
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illustration, is that a surface of the implant positioned in fixed contact
with body tissue may
be fastened, while an articulating surface may remain free of fasteners.
[0537] With further reference to Fig. 47A, fastener 1240 extends through bone
1402 at
a downwards angle towards the interior of bone 1402, with respect to the
proximate end of
bone 1402. A distal end 1260 of fastener 1240 has been distally fastened as
described herein.
A proximal end 1262 extends from bone 1402, and may be cut at a level flush
with the
exterior of bone 1402, or at least a part of the extending portion may be
formed into a cap
1010. Alternatively, proximal end 1262 may be used as a stake for fastening
body tissue or
other implants. In Fig. 47A, fastener 1264 is fastened to implant 1400, in
this example
embedded in bondable material 1206. Alternatively, fastener 1264 may be
fastened to implant
1400, as described for fastener 1240, above, or fastener 1264 may be
mechanically connected
to implant 1400. Fastener 1264 is advantageously angled to promote the secure
retention of
staked material. In the example shown, a tendon 1268 is staked, and fastener
1264 is disposed
at a neutral angle with respect to the proximal end of bone 1402. Further, a
reverse angle may
afford additional stability and strength of fastening, wherein fastener 1264
is angled upwards
towards the interior of bone 1402 with respect to the proximal end of bone
1402. Fastener
1264 has a cap 1010 formed using the application of vibratory energy applied
to the proximal
end 1262 of fastener 1264, although other means of securing staked materials
may be
employed, such as by applying a mechanical fastener.
[0538] Fig. 47B illustrates a method of attaching an articulating surface in
the prior art.
Note that prior art implant 1410 must be formed in at least two parts 1412,
1414, due to the
requirement of first installing a fastener 1416 through implant portion 1414
into cortical bone
1418, and then installing implant portion 1412 over fastener 1416.
[0539] In contrast, implant 1400 of the invention may be formed as a single
part, or at
least the articulating surface 1420 may be integrally formed with a portion
1422 which
extends into bone 1402, thus presenting fewer points of potential failure, and
providing a
more stable and durable implant.
[0540] Referring now to Fig. 47C, a retrograde and distally fastened fastener
1440 is
additionally connected to an implanted bone graft, or bone augment 1442,
thereby providing
primary and or secondary stabilization for augment 1442. Augment 1442 may be
implanted,
for example, to replace diseased or damaged bone. In this manner, an
articulating surface
1444 as well as an adjoining bone augment 1442 may be secured by a single
fastener 1440, or
a series of fasteners. Fastener 1440 may be distally bonded to both augment
1442 and the
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device 1446 bearing articulating surface 1444. Fastener 1440 may also pass
through augment
1442, for example through a bore preformed in augment 1442. Augment 1442 may
be
composed of any material or combination of materials suitable for its intended
function,
including metal, plastic, ceramic, alloys, moldable material including
adhesives, as well as
porous forms of these materials. Augment 1442 may additionally comprise
cartilage graft
material.
[0541] The retrograde approach of the invention may be facilitated through the
use of a
cannula, or an expanding cannula, such as is disclosed in U.S. Patent
6,814,715, incorporated
herein by reference, and related patents cited therein. Retrograde examples
include fastening
an acetabular replacement from behind the cup, fastening a tibial bearing
surface replacement
from a point below the bearing surface, and fastening a hip replacement
implant from the
femur body or distal end of the femur. Like examples are contemplated for the
smaller
analogs of the arm. Retrograde approaches may also be used in fastening or
repairing bones
of the hands, feet, skull, and spine.
[0542] With reference to Fig. 47D-E, one or more of clamp 1450 may be used in
accordance with the invention to position and or retain implant 1400 in a
location for
fastening. This is particularly advantageous where a fastener of the invention
is distally
fastened to implant 1400, without the use of an intervening adjustable
mechanical coupling,
such as that described for fastener 840, herein. In the illustration, a c-
clamp type of claim
1450 is shown, however any suitable clamp may be used, provided exposure is
maintained
for installing a fastener of the invention, and for applying vibratory energy
thereto. In Fig.
47E, fastener 1240 has been installed, and clamp 1450 has been removed.
[0543] With further reference to Fig's. 47D-E, a fastener 1460 has been
distally bonded
to implant 1400. Fastener 1460 is formed in a manner illustrated for fastener
1250 in Fig.
46H, however a cap 1468 is formed or attached in advance of installation. In
the use of this
embodiment, it may not be possible to precisely determine the length of a
proximal portion
1462 extending beyond the surface of bone 1402. Accordingly, the invention
provides a
spacer 1464, shaped to fill a portion of a space formed between cap 1468 and
bone 1402.
Spacer 1464 is further formed with an opening, so that a spacer 1464 having a
desired width
may be selected after fastener 1460 is inserted into bone 1402. An amount of
fastener
collapse, described in this specification, is calculated or estimated, and a
spacer 1464 is
selected so that an amount of free space remains between cap 1468 and bone
1402,
corresponding to the expected amount of collapse. Accordingly, after
fastening, fastener 1460
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transmits a force through cap 1468 and spacer 1464 to bone 1402. Further,
fastener 1460 is
stabilized in firm connection to bone 1402. Moreover, body tissue may not
enter a space
between cap 1468 and bone 1402, either through tissue ingrowth or through
tissue movement.
It should be understood that spacer 1464 may be employed in any fastening
application in
accordance with the invention where there is a space to be filled along the
length of the
fastener, and whether the fastener is attached to body tissue or another
implant.
[0544] Fig's. 49 and 50 illustrate distal fastening to secure a femoral
arthroplasty
prosthesis 920A, provided with a non-smooth surface 926, for example a surface
that is
roughened or porous, or has at least one cavity therein. A fastener 1256, or
other fastener of
the invention, for example fastener 1232 of Fig. 46D or 1240 of Fig. 46G, may
be attached
using distal vibratory fastening as described herein. Softened or melted
material of the
fastener enters into surface 926, and upon cooling, is firmly attached due to
the greater
surface area for adhesion presented by the irregularity of surface 926, or by
an interlocking of
the cooled and now hardened material into the shaped or roughened projections
or cavities of
surface 926. Distal fastening in accordance with the invention may be carried
out upon a
smooth surface, however a non-smooth surface offers the advantages described,
including
greater surface area, and an increased potential for mechanical interlocking.
A combination of
known methods, such as posts 1260, affixed by bone cement, and fasteners of
the invention,
may be combined as determined by the practitioner to be optimal.
[0545] With reference to Fig. 51 and 5lA-B, a fastener 1600 has a plurality of
tines
1610. While two tines are illustrated, it should be understood that any number
of tines or
projections may be employed in accordance with the invention. Fastener 1600 is
contacted by
an end effector 104, or may be attached to an end effector of the invention,
for example as
described for fastener 1250 shown if Fig. 46H, and vibratory energy is applied
to produce a
bond between tines 1610 and a surface 1612. Vibratory energy is tuned as
described herein,
to produce heat proximate the end of tines 1610 and surface 1612, whereby
bondable material
of either or both of tines 1610 and surface 1612 becomes softened or
liquefied, whereupon a
bond is formed between tines 1610 and surface 1612.
[0546] Surface 1612 may be body tissue or another implant, and is
advantageously non-
smooth, as described for example with respect to surface 926 of Fig. 50. Where
surface 926 is
body tissue, it may be roughened or otherwise provided with a non-smooth
surface, as by
filing, drilling, or other known means, prior to bonding.
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[0547] Fig. 51A illustrates a cross section of fastener 1600, showing an
aperture
through which an end effector may be attached, and or through which body
tissue or an
additional implant may be affixed. As can be seen in Fig. 51B, a tine 1610 may
be provided
with one or more projections 1616 which may serve to maintain a location of
fastener 1600
prior to bonding, and which may promote bonding by becoming heated and
softened earlier
than the remainder of the tine, thus speeding the heating of tines 1610 for
rapid and reliable
bonding.
[0548] Referring now to Fig's. 53 and 53A, distal fastening is illustrated in
the context
of an acetabular replacement implant 1800. A retrograde approach, as through
illium 1806, is
used to introduce a fastener of the invention. Fasteners 1240 and 1250 are
illustrated,
although other fasteners of the invention may be used. For fastener 1250,
fastening is into a
shaped cavity 1802, formed in the retrograde side of implant 1800. End
effector 104,
connected to fastener 1250, causes vibration at distal end 1256 while applying
force in the
direction indicated by arrow "A". The force urges distal end 1256 into shaped
cavity 1802,
generating heat sufficient to soften distal end 1256, whereby it is urged into
cavity 1802,
enlarging and spreading to at least partially fill cavity 1802, producing a
partial shortening or
collapse of the length of fastener 1250, and forming a mechanical interlock
between fastener
1250 and implant 1800. After vibratory energy is discontinued, the material of
distal end
1256 cools and solidifies, and end effector 104 is removed. Fastener 1250 thus
prevents
rotational movement of implant 1800, though engagement with a bore or aperture
1804
through which fastener 1250 passes. If aperture 1804 is tight fitting,
fastener 1250 may
provide additional stability with respect to a movement of implant 1800 away
from contact
with acetabulum 1808. A cap 1010 may additionally be bonded using vibratory
energy, as
described herein, to provide further stabilization.
[0549] With further reference to Fig's. 53 and 53A, fastener 1240 is
introduced through
a more antegrade approach than that of fastener 1250, but could be introduced
through a
retrograde approach as well. Rather than enter into a relatively large cavity
as shown for
fastener 1250, fastener 1240 bonds to a roughened or porous surface 1810,
formed on the
body contacting side of implant 1800, and is bonded therewith in a manner as
described
herein. It should be understood that while fasteners 1250 and 1240 are
depicted for fastening
into a cavity, and onto a porous surface, respectively, the relative roles of
the fasteners could
be reversed, and other fasteners of the invention could be used as described
for either fastener
1240 or 1250.
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[0550] It can be seen, as illustrated for fasteners 1250 and 1240 in Fig's. 53
and 53A,
that in the case of distal fastening, as well as proximal fastening, the
fastener body can be
advantageously caused to enlarge. The enlarged portion may prevent staked
material from
separating from the fastener, and can prevent the fastener from detaching from
a bonded
location. Further, the enlarged portion may be too large to pass through the
portal or opening
through which the fastener entered. As examples, distal end 1256 cannot be
withdrawn from
cavity 1802 after cooling, and cap 1010, formed onto fastener 1240 by proximal
vibratory
fastening, prevents passage of fastener 1240 inwardly towards acetabulum 1808.
[0551] The fasteners and fastening methods of the invention are advantageously
utilized
for use in-vivo, reducing or avoiding tissue necrosis by minimizing exposure
of tissue to heat,
and may be implemented through reduced size incisions, including keyhole
incisions, as may
be employed in laparoscopic procedures. Fasteners may additionally be formed
and fastened
in accordance with the invention in the operating room, at the convenience of
the surgical
practitioner, when the exact configuration and dimensions needed are best
understood, and
thereafter implanted.
Spinal Fixation
[0552] With reference to Fig's. 55-57, fastening in accordance with the
invention can be
advantageously applied to correction of problems of the spine 2000. In Fig.
55, a vertebra
2002 is shown, the vertebral body 2004 containing a bondable material 1206,
placed using,
for example, vertebroplasty or kyphoplasty. A spinal fastener 2008 has been
driven into
vertebral body 2004, and embedded within bondable material 1206 using
vibratory energy.
[0553] With reference to Fig's. 28A-C, an angulated screw 2016 can be placed
at an
angle through a plate 2018, 2018A and then driven or staked in place. Screws
2016 and plates
2018, 2018A have a rounded mating surface 2020, 2022 respectively, which
allows some
adjustability in direction of screw 2016 relative to plate 2018, 2018A. Screw
2016 can be
inserted, for example, 11 degrees off of a straight line axis through mounting
holes 2024
through which they project.
[0554] With reference to Fig. 29, in accordance with one embodiment of the
invention,
in order to stake screw 2016, an end effector 2026 having a change in diameter
2028 can be
used. An enlarged mating surface 2028 is sized to engage screw 2016 regardless
of its angle
within mating surface 2022. Fig. 28B shows a single hole plate 2018 with the
rounded hole,
and Fig. 28C shows a four hole plate 2018A with angulated screws prior to
staking. In this
embodiment, surface 2022 and or a portion of mating surface 2020 of fastener
2016 contains
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bondable material, whereby application of end effector 2026 can apply
vibratory energy
sufficient to bond surfaces 2020 and 2022, regardless of the angle of fastener
2016. In
addition or alternatively, bondable material may be provided at a distal end
2030 of fastener
2016, and vibratory energy may be applied to bond distal end 2030 as described
herein for
distal fastening.
[0555] Spinal fastener 2008 may be provided with a distal end 2010 that is
separable, or
is otherwise shaped as described for fastener 800; however, any of the other
end forms or
fasteners described herein may be selected in the discretion of the
practitioner. As described
for example with respect to Fig. 28, spinal fastener 2008 may be provided with
a head portion
having a profile 2020 shaped to engage a mating support 2024, whereby spinal
fastener 2008
may be secured at an angle relative to support 2018, 2018A. In this manner, a
fracture may be
stabilized, successive vertebrae may be maintained in a fixed relation
relative to each other,
or a secure fixation point may be established. In Fig. 55, two spinal
fasteners 2008 are
secured together by clamps 2012, which may have the form described with
respect to Fig's.
27A-C. A rod 2014 is secured between clamps 2012. Alternatively, rod 2014 may
be
connected between clamps 2012 on different vertebrae, according to the needs
of the patient.
[0556] As may further be seen in Fig. 55, a mesh pouch or bag 2016 contains a
therapeutic substance, and is placed proximate a surgical site or area needing
treatment over
time. Bag 2016 may contain any of the therapeutic substances described herein
or in the
incorporated references, or other beneficial agent as known in the art,
including for example
antimicrobial agents, or bone healing or ingrowth agents. Formed with a mesh,
bag 2016
enables the inward migration of gaseous or liquid materials from the body, or
body tissue
ingrowth, and the outward migration of therapeutic substances. Bag 2016 may be
attached to
an implanted structure, such as fastener 2008, clamp 2012, or rod 2014, by
attachment means,
for example by one or more sutures (not shown). Bag 2016 or attachment means
may be
biodegradable or bioabsorbable.
[0557] With reference to Fig. 56, in a further embodiment, a connector 2032 is
fastened
to heat melatable material 1206 within vertebral body 2004, using fasteners
2034. Connector
2032 is shown as an elongated bar, strip, or strap that extends between
vertebrae. Fasteners
2034 may be secured to bone, or to bondable material 1206, as shown in cross
section for
vertebra 2036. Any of the fasteners or methods of the invention may be used to
attach
connector 2032 to vertebrae. Connector 2032 may be used to secure vertebrae
with respect to
each other, or to secure a vertebral component to any other object within the
body, including
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other bones, soft tissue, or implant, or to a point external to the body, such
as a brace or other
external fixation device. Fastener 2034 may be selected from any of the
fasteners described
herein, depending upon, at least, the fixation medium, and the needs of the
patient.
[0558] An alternative view may be found in Fig. 74B, wherein a plate 2046 is
provided,
for additional strength, if needed, and to provide for stabilization with
movement permitted
along a limited range of motion. In particular, plate 2046 is limited in
movement relative to a
stabilizing fastener 2050. Elongated slot 2048 enables vertical or
anteroposterior motion of
plate 2046 relative to fastener 2050, however fastener 2050 is secured within
the disc space,
and thus the disc space cannot move dorsoventrally. Elongated slot 2048 may be
formed
along other angles, and plate may be positioned in other locations, enabling
limited range of
motion along other axes, as would be understood by one skilled in the art.
[0559] Referring now to Fig. 57, one or more fasteners 2038 in accordance with
the
invention are embedded within bondable material 1206, disposed within a space
associated
with a vertebra, in this embodiment, the vertebral body 2004. fasteners 2038
may
alternatively be fastened to bondable material disposed on the outside surface
of the vertebra,
ribs, or other bone of the body. In the embodiment shown, a strap 2040 passes
from one
fastener 2038 to another, and is bound to each, as by an aperture through
which a portion of
each fastener 2038 passes. Alternatively, strap 2040 and or fastener 2038 may
include
bondable material, and the elements are bonded together using vibratory energy
as described
herein. While two fasteners 2038 are shown, it should be understood that
additional fasteners
2038 could be used, or a single fastener 2038, wherein strap 2040 passes
completely around
an object to fasten to fastener 2038 at more than one point along its length.
To further secure
strap 2040 to one or more fasteners 2038, heads or caps 1010 may be attached
to fasteners
2038 as described herein, or alternatively, to strap 2040. If attachment is to
strap 2040, either
or both of caps 1010 or strap 2040 is fabricated with heat softenable
material, and the
elements are bonded using vibratory energy as described herein. In the partial
cross section
shown in Fig. 57, a fracture 2042 is illustrated, maintained in a position for
healing by
fasteners 2038 and strap 2040.
Locking Screw Fastening
[0560] In another embodiment of the invention, a metallic polyaxial screw/rod
system,
of the type typically used in spinal surgery, is modified to include holes
intersecting both the
saddle that holds the rod and pedicle screw head, and the locking screw used
to maintain the
desired angle of the pedicle screw. Into these holes, a tack is staked or
bonded such that the
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material of the tack flows into the threads between the saddle and locking
screw, effectively
preventing loosening of the system.
Resecuring or Removing an Implant
[0561] As described above, vibratory energy, such as ultrasonic energy, is
used to melt
or liquify adhesives, including bone cement. In accordance with the invention,
and with
reference to Fig's. 46 and 46A, bone cement is melted in situ, whereupon
melted cement
softens or flows to bridge or cross and fill or close voids and gaps 1208
between the implant
and body tissue, the cement thereafter being allowed to cool in order to thus
re-secure or
reduce the loosening of the implant.
[0562] With reference to Fig's. 46-47, assembly 1202 including end effector
104, is
passed into a space within the body, in the example shown, intramedullary
canal 1222 within
bone 882. End effector 104 is provided with at least one shaped projection
1200. Projections
1200 may be threadably or otherwise mechanically connected to end effector
104, whereby
the projections 1200 may be left inside the body for, as examples, future use,
convenience, or
further stabilization. Projections 1200 may have any convenient shape, and
advantageously
has a tip and at least one side edge which has a tapered profile, to
facilitate passage through
bondable material 1206.
[0563] To facilitate passage of end effector 104 and at least one projection
1200, a bore
1204 may be preformed within cancellous bone or tissue of intramedullary canal
1222. For
other body areas, space may be made as needed, for example by retraction,
insufflation, or
other means known in the art. In another alternative, end effector 104 is
formed as a hollow
tube, as in a coring drill, to facilitate passage through body tissue.
[0564] In an alternative embodiment, projections 1200 may be formed as a
continuous
or substantially continuous surface, thus forming the shape of a cone,
cylinder, box or shaped
space, as may be seen for example in Fig's. 46D-46F. If bore 1204 is narrower
than the width
of projections 1200, the latter may be formed of sufficiently flexible
material as to collapse
while within the bore, and expand upon reaching an area of bondable material
1206.
[0565] Upon reaching bondable material, vibratory energy is generated within
projections 1200, through a connection with end effector 104 attached to
generator and
handpiece 908, as described herein. In this manner, bondable material 1206 is
made flowable
by the application of vibratory energy through contact with projections 1200.
Projections
1200 may then be pushed further into bondable material 1206 to a desired
depth. In the
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example shown, projections 1200 are deflected by implant 880 and enter the
interstice
between body tissue and implant 880, filled with bondable material 1206. As
bondable
material 1206 is melted, voids or gaps, such as gap 1208, formed by a
loosening of implant,
may be filled, and upon cooling, the implant is restabilized. It should be
understood that gap
1208 is shown above projection 1200, for clarity; however, projections 1200
are provided
with a length sufficient to reach a gap of concern.
[0566] Once bondable material has been sufficiently softened, end effector 104
may be
rotated to correct further defects along the path of moving projections 1200.
After gaps 1208
have been corrected, end effector 104 and or projections 1200 may then be
withdrawn, or
alternatively, either or both devices may be left within the body. If end
effector 104 is to be
removed, it is first decoupled from projections 1200, for example at
releasable coupling 1210.
[0567] In an alternative embodiment, a fastener 1270 or end effector 104A is
passed to
gap 1208 from a side entry. Fastener 1270 may be of the type shown, for
example, in Fig's.
46D-H, or may be modified with an end portion 1272 having a more blunt
profile, thereby
increasing a contact surface. End effector 104A may similarly be provided with
a widened or
blunt profile 1274. Fastener 1270 or end effector 104A is caused to contact
bondable material
1206 at a gapped portion 1208, either by drilling a hole to access gap 1208,
or by driving or
drilling fastener 1270 or end effector 104A to gap 1208. Vibratory energy may
further be
employed, particularly if passing through bondable material 1206 to reach gap
1208. Upon
reaching gap 1208, vibratory energy is applied to remelt bondable material
1206 to cause
same to soften and flow to cross and fill in gap 1208. In this manner,
fastener 1270 is acting
as a vibratory horn, transmitting vibratory energy from a vibratory energy
generator to
bondable material 1206 proximate gap 1208. In Fig. 46A, a gap 1208 is shown to
extent from
a point indicated at "A" to a point indicated at "B". As can be seen, regions
of gap 1208 have
been closed by the introduction of fastener 1270 and end effector 104A. It
should be
understood that, depending upon the length and width of gap 1208, that a
portion or the entire
gap 1208 may be remelted and corrected, depending upon the size of end portion
1272 or
profile 1274, and the amount and duration of vibratory energy applied. Melting
may further
be caused to occur along a side portion of fastener 1270 or end effector 104A.
[0568] In addition to remelting existing implant binding material or bondable
material
1206, additional material may be introduced that is associated with fastener
1270.
Specifically, fastener 1270 may be fabricated from bondable material 1206, or
a different
bondable material, which is caused to additionally soften upon the application
of vibratory
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energy, and to flow into and further fill gap 1208. Alternatively, fastener
1270 may be
provided with bondable material at least in an area upon fastener 1270 which
is intended to
form a contact proximate gap 1208.
[0569] It may further be seen that, in the example shown, end effector 104A is
angled in
a first direction, and fastener 1272 in a contrary direction. The surgical
practitioner may
select an angle with respect to a vector in a direction of insertion of the
implant, that best
causes remelting, and that provides further stability if end effector 104A or
fastener 1272 is
left in the body. It may be advantageous to affix the vibratory horn, here
further serving as an
implanted fastener, at an obtuse angle, as measured between a line extending
along the
longitudinal axis of the vibratory horn, and a line extending from a point
where the vibratory
horn contacts the binding material 1206, extending in a direction of insertion
of the implant,
as may be seen for fastener 1270.
[0570] End effector 104A or fastener 1274 may be trimmed at a convenient
point, for
example at the surface of bone 822. Alternatively, as illustrated by dotted
lines 1276, end
effector 104A or fastener 1274 may extend to a more distant point, for example
to the surface
of the skin, or to external fixation apparatus.
[0571] With reference to Fig's. 46B-D, projections 1212 are at least partially
coated
with a bondable material 1214. Where the bondable material lacks sufficient
strength for an
intended application, one or more of projections 1200 may be included,
underlying bondable
material 1214. In this embodiment, projections 1212 may enter the body as
described with
respect to Fig's. 46 and 46A, and in particular, projections 1212 may be
squeezed together, to
resiliently expand after passing through a passageway. Assembly 1220 may be
used to soften
bondable material 1206, particularly where bondable material 1206 has the same
or a lower
melting point than bondable material 1204. In this manner, assembly 1220
illustrated in Fig's.
46B-D may be used in a manner similar to that described for assembly 1202 of
Fig's. 46 and
46A. However, because assembly 1220 incorporates bondable material 1214, it
may be used
in application where there is little or no other bondable material available
at a target location.
[0572] Fig. 46C illustrates assembly 1220 inserted within the body, after
having been
softened by the application of vibratory energy. As can be seen in the
illustration, bondable
material 1214 near a proximal area 1224 has flowed upwards to a distal area
1226. Bondable
material 1206, if existing, is mixed with, or displaced by, bondable material
1214. After
cooling, projections 1212 are affixed to bone 882, implant 880, or both. In
this embodiment,
although a connector 1210 may be provided, it is particularly advantageous to
have end
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effector 104 connected, whereby it may be used to not only secure an
additional implant,
such as arthroplasty component 920 as illustrated in Fig. 43, but may serve to
simply anchor
implant 880, as illustrated in Fig. 42.
[0573] With reference to Fig. 46D, in one embodiment, an assembly 1232
includes a
vibratory end effector 104 provided with a heat meltable connector 1230 having
either an
amorphous or defined shape, including a hollow space, for example a blob 1234,
wedge, cone
1236 or tube 1238, as best adapted to the application. Connector 1230 is
advantageously used
where it is not necessary to resecure or separate a large region of bondable
material 1206, but
rather, to connect a first implant and a second implant, or a first implant to
body tissue, for
example to cartilage, tendon, bone, or soft tissue.
[0574] If it is desired to re-secure the implant, the blade may be withdrawn
once the
implant has been repositioned, if desired, and the void or gap of concern has
been re-filled
with melted adhesive. Alternatively, if it is desired to remove the implant,
removal is
accomplished before the adhesive resolidifies, such as by lifting the implant
away from the
adhesive, out of its current location. Multiple blades may be employed to
reduce the time
required to complete the removal or resecuring process.
[0575] Alternative shaped projections include cups, cones, wires, or other
shapes which
may pass through the body to the area where the adhesive is located, and which
are
advantageously formed to best fit the geometry of the adhered interface, to
carry out the
functions previously described.
[0576] In an alternative embodiment, the rod and blades are left within the
body,
embedded in the resolidified cement, to operate as a reinforcement and or
attachment point
for further fasteners or implants, including arthroplasty components and
prosthetics, or
testing or reporting apparatus attached to or embedded within the device. As
an attachment
point, the rod may be provided with bores or apertures, which may be threaded,
into which
other fasteners may be inserted, and optionally further fastened in accordance
with the
methods disclosed herein.
[0577] In an alternative embodiment, the shaped projection is formed of, or
coated with,
a bondable material, for example a polymer, which is then bonded to a
roughened or porous
surface, either in the operating room, or in the body. Within the body, the
surface may be that
of existing or implanted bone, or that of a previously or recently positioned
implant. When
the shaped surface is positioned in contact with the roughened surface, for
example an
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intramedullary rod having a porous metal surface, vibratory energy is passed
to the shaped
projection to cause the projection to melt and bond to the roughened surface.
[0578] The issue of implant removal after bonding or staking of one or more
implants is
one that needs to be addressed as the clinical situation dictates.
[0579] With regard to Fig's. 46, and 46A-46D, it can be seen that while the
bondable
material is liquified or softened by vibratory energy, removal of an adhered
object is
facilitated. This is particularly useful for well fixed implants, and
particularly objects within
the intramedullary canal.
[0580] Referring now to Fig's. 15-18, end effector 250 is shown, which uses
vibratory
energy as part of an implant removal too1252. Implant removal too1252 includes
hollow end
effector 252 and a T handle 254. The proximal end of end effector 250 has an
internal thread
256 that matches the threading on the hand piece of a vibratory generator. The
proximal end
also has an external thread 258 that matches the threading on T handle 254. T
handle 254 can
also be provided with a pin or other projection that extends into end effector
250 for
increasing stability. Although the proximal end is shown and described as
having threads 256
and 258 to mate with the hand piece and T handle, respectively, any suitable
mechanism for
removably connecting the end effector to the hand piece and T handle can be
used.
Additionally, the mechanisms for connecting to the hand piece and T handle
could be
reversed with the external surface used for the hand piece and the internal
surface used for the
end effector.
[0581] The distal end of end effector 250 is provided with surface asperities
260 or
otherwise roughened to help grip the implant or material to be removed. In use
(Fig. 17), end
effector 250 is connected to a vibratory hand piece and is placed over an
implant 262 to be
removed. Head 264 can be removed (using vibratory energy or by simply shearing
off) from
implant 262 to help ensure end effector 250 is centered over implant 262. The
vibratory
energy is activated to drive end effector 250 around implant 262 and into the
rod 266 to
which implant 262 is bonded. In studies conducted to date, an energy level of
80 to 100 Watts
with no time limit is sufficient. Average insertion time is around 2-5
seconds. Upon cooling
of the material of implant 262, the material of implant 262 adheres to end
effector 250.
[0582] Leaving end effector 250 around implant 262, the hand piece is removed
from
end effector 250 and T handle 254 is connected. Repeated rocking or
oscillating motion on T
handle 254 is used to break the bond or weld such that when T handle 254 is
pulled back,
implant 262 is removed.
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[0583] The present invention also contemplates the use of end effector 250 for
removing screws and other implants from bone. End effector 250 could be
disposable (single
use) such that removal of the cored implant would not be necessary.
Alternatively, end
effector 250 could be reusable.
Fastening Dissimilar Materials
[0584] It should be understood that a proximal or distal polymer to polymer
connection
may be made through the application of energy, such as vibratory energy, as
described
herein. In this manner, fastener containing polymer may be connected to a
roughened, porous
or shaped surface, or to another polymeric fastener, or polymeric coating on
an implant or
implanted fastener. For example, an arthroplasty or prosthetic component may
be at least
partly covered with polymer, the polymeric surface exposed to an intended site
for fastening.
Moreover, a plurality of arthroplasty components may include polymeric or heat
softenable
material, the components being thus fastenable together in accordance with the
invention.
[0585] An advantage to a polymeric containing, or polymeric coated fastener or
implant
is the ability to incorporate one or more therapeutic substances within the
coating, whereupon
the therapeutic substance may elute, or release the therapeutic substance in-
vivo over time, in
a predictable and useful manner. U.S. Provisional Patent Application No.
60/728,206, entitled
"Drug Eluting Implant" and incorporated herein by reference, provides examples
of means
for delivering therapeutic agents, although those skilled in the art will
appreciate that other
known methods may be advantageously employed in combination with the
invention.
Fastening Combinations and Applications
[0586] It is contemplated the surgical system of the present invention may be
used with
and integrated with the methods and devices disclosed in published U.S.
Application
Publication No. US 2008-0039845. In the '845 document, various thermoplastic
fastening
devices are disclosed. The fastening devices may be, but are not limited to,
degradable,
biodegradable, bioerodible, bioabsorbable, mechanically expandable,
hydrophilic, bendable,
deformable, malleable, riveting, threaded, toggling, barded, bubbled,
laminated, coated,
blocking, pneumatic, one-piece, multi-component, solid, hollow, polygon-
shaped, pointed,
self-introducing, and combinations thereof. Also, the devices may include, but
are not limited
to, metallic material, polymeric material, ceramic material, composite
material, body tissue,
synthetic tissue, hydrophilic material, expandable material, compressible
material, bondable
material, and combinations thereof.
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[0587] The methods and devices disclosed in the'845 document may be used in
conjunction with any surgical procedure of the body. The fastening and repair
of tissue or an
implant may be performed in connection with surgery of a joint, bone, muscle,
ligament,
tendon, cartilage, capsule, organ, skin, nerve, vessel, or other body parts.
For example, tissue
may be repaired during intervertebral disc surgery, knee surgery, hip surgery,
organ
transplant surgery, bariatric surgery, spinal surgery, anterior cruciate
ligament (ACL) surgery,
tendon-ligament surgery, rotator cuff surgery, capsule repair surgery,
fractured bone surgery,
pelvic fracture surgery, avulsion fragment surgery, shoulder surgery, hernia
repair surgery,
and surgery of an intrasubstance ligament tear, annulus fibrosis, fascia lata,
flexor tendons,
etc.
[0588] It is contemplated that the devices and methods of the present
invention be
applied using minimally invasive incisions and techniques to fasten muscles,
tendons,
ligaments, bones, nerves, and blood vessels. A small incision(s) may be made
adjacent the
damaged tissue area to be repaired, and a tube, delivery catheter, sheath,
cannula, or
expandable cannula may be used to perform the methods of the present
invention. U.S. Patent
No. 5,320,611 entitled "Expandable Cannula Having Longitudinal Wire and Method
of Use"
discloses cannulas for surgical and medical use expandable along their entire
lengths. The
cannulas are inserted through tissue when in an unexpanded condition and with
a small
diameter. The cannulas are then expanded radially outwardly to give a full-
size instrument
passage. Expansion of the cannulas occurs against the viscoelastic resistance
of the
surrounding tissue. The expandable cannulas do not require a full depth
incision, or at most
require only a needle-size entrance opening.
[0589] U.S. Patent Nos. 5,674,240; 5,961,499; and 6,338,730 also disclose
cannulas for
surgical and medical use expandable along their lengths. The cannula can be
provided with a
pointed end portion and can include wires having cores which are enclosed by
jackets. The
jackets are integrally formed as one piece with a sheath of the cannula. The
cannula may be
expanded by inserting members or by fluid pressure. An expandable chamber may
be
provided at the distal end of the cannula. The above mentioned patents are
hereby
incorporated by reference.
[0590] In addition to using a cannula with the present invention, an
introducer may be
utilized to position implants at a specific location within the body. U.S.
Patent No. 5,948,002
entitled "Apparatus and Method for Use in Positioning a Suture Anchor"
discloses devices
for controlling the placement depth of a fastener. Also, U.S. Patent
Application No.
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10/102,413 discloses methods of securing body tissue with a robotic mechanism.
The above-
mentioned patent and application are hereby incorporated by reference. Another
introducer or
cannula which may be used with the present invention is the VersaStep System
by Tyco
Healthcare.
[0591] The present invention may also be utilized with minimally invasive
surgery
techniques disclosed in U.S. Patent Application No. 10/191,751 and U.S. Patent
Nos.
6,702,821 and 6,770,078. These patent documents disclose, inter alia,
apparatus and methods
for minimally invasive joint replacement. The femoral, tibial, and/or patellar
components of a
knee replacement may be fastened or locked to each other and to adjacent
tissue using
fastening devices disclosed herein and incorporated by reference. Furthermore,
the methods
and devices of the present invention may be utilized for repairing,
reconstructing,
augmenting, and securing tissue or implants during and "on the way out" of a
knee
replacement procedure. For example, the anterior cruciate ligament and other
ligaments may
be repaired or reconstructed; quadriceps mechanisms and other muscles may be
repaired; a
damaged rotator cuff may be mended. The patent documents mentioned above are
hereby
incorporated by reference.
[0592] Furthermore, it is contemplated that the present invention may be used
with
bariatric surgery, colorectal surgery, plastic surgery, gastroesophageal
reflex disease (GERD)
surgery, or for repairing hernias. A band, mesh, or cage of synthetic material
or body tissue
may be placed around an intestine or other tubular body member. The band may
seal the
intestine. This method may be performed over a balloon or bladder so that
anastomosis is
maintained. The inner diameter of the tubular body part is maintained by the
balloon. The
outer diameter of the body part is then closed or wrapped with a band, mesh,
or patch. The
inner diameter of the tubular body member may be narrowed or restricted by the
band. The
band may be secured to the tubular body part or surrounding tissue with the
devices and
methods described herein and incorporated by reference.
[0593] It is further contemplated that the present invention may be used in
conjunction
with the devices and methods disclosed in U.S. Patent Nos. 5,329,846 entitled
"Tissue Press
and System" and 5,269,785 entitled "Apparatus and Method for Tissue Removal."
For
example, an implant secured within the body using the present invention may
include tissue
harvested, configured, and implanted as described in the patents. The above-
mentioned
patents are hereby incorporated by reference.
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[0594] Additionally, it is contemplated that the devices and methods of the
present
invention may be used with bondable materials as disclosed in U.S. Patent No.
5,593,425
entitled "Surgical Devices Assembled Using bondable materials." For example,
the implants
of the present invention may include bondable material. The material may be
deformed to
secure tissue or hold a suture or cable. The fasteners made of bondable
material may be
mechanically crimped, plastically crimped, or may be bonded to a suture or
cable with RF
(Bovie devices), laser, ultrasound, electromagnet, ultraviolet, infrared,
electro-shockwave, or
other known energy. The bonding may be performed in an aqueous, dry, or moist
environment. The bonding device may be disposable, sterilizable, single-use,
and/or battery-
operated. The above-mentioned patent is hereby incorporated by reference.
[0595] Furthermore, the methods of the present invention may be performed
under
indirect visualization, such as endoscopic guidance, computer assisted
navigation, magnetic
resonance imaging, CT scan, ultrasound, fluoroscopy, X-ray, or other suitable
visualization
technique. The implants, fasteners, fastener assemblies, and sutures of the
present invention
may include a radiopaque material for enhancing indirect visualization. The
use of these
visualization means along with minimally invasive surgery techniques permits
physicians to
accurately and rapidly repair, reconstruct, augment, and secure tissue or an
implant within the
body. U.S. Patent Nos. 5,329,924; 5,349,956; and 5,542,423 disclose apparatus
and methods
for use in medical imaging. Also, the present invention may be performed using
robotics,
such as haptic arms or similar apparatus. The above-mentioned patents are
hereby
incorporated by reference.
[0596] Moreover, the devices and methods of the present invention may be used
for the
repair and reconstruction of a tubular pathway like a blood vessel, intestine,
urinary tract,
esophagus, or other similar body parts. For example, a blood vessel may be
intentionally
severed during a surgical operation, or the blood vessel may be damaged or
torn as a result of
an injury. Flexible fastening of the vessel would permit the vessel to
function properly and
also compress and stabilize the vessel for enhanced healing. To facilitate the
repair or
reconstruction of a body lumen, a balloon may be inserted into the lumen and
expanded so
the damaged, severed, or torn portion of the vessel is positioned against the
outer surface of
the inflated balloon. In this configuration, the implants and methods
described and
incorporated herein may be used to approximate the damaged portion of the
vessel.
[0597] It should further be understood that vibratory energy, and particularly
ultrasonic
energy, may be created within the body, through a barrier such as skin or
other body tissue.
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This is described more particularly in pending US Application serial
10/945,331 (Publication
2006/0064082), of common inventor P. Bonutti, the contents of which are hereby
incorporated herein by reference.
Focal Defect Correction
[0598] With reference to Fig's. 96-96B, in accordance with the invention,
areas of
disease or trauma representing a focused or focal defect 3800 are replaced
with an implant or
graft 3802, secured in situ using vibratory energy. In this manner, healthy
tissue 3804 may
remain undisturbed, and defect 3800 is corrected. Examples include replacing a
portion of an
articulating surface, such as a condyle 3806, acetabulum, or glenoid fossa, or
replacing
portions of bone or soft tissue that have been damaged by injury or disease.
[0599] The diseased area is replaced by, for example, implanted tissue,
including bone
fragments or compressed living tissue, fabricated non-living material such as
polymers or
metal, or any other material a medical practitioner deems best. An interface
3808 is created
between graft 3802 and body tissue 3804, and includes a quantity of bondable
materia13810
therebetween. Advantageously, if the implant is not made entirely from
bondable material, a
surface 3812 of the implant contacting the bondable material of the interface
is provided with
a roughened or porous surface, or a surface with one or more cavities into or
onto which heat
softened or melted material may flow and thereby lock onto once cooled,
hereafter an
irregular surface. Similarly, the body tissue 3804 may be treated to have an
irregular surface
3814 for purpose of improving a bond between body tissue 3804 and bondable
materia13810.
In addition, an implant 3816 may be attached to body tissue 3804 using methods
or devices
of the invention, or alternatively screws 3818, adhesives, or any other known
means, and the
implant may be provided with an irregular surface 3820 for the purpose of
improving a bond
between implant 3816 and bondable materia13810.
[0600] Thus, once graft 3802 is in place, interface 3808 defines a strata that
includes
body tissue 3804 having an irregular surface 3814, or an implant 3816 attached
to body tissue
3804, implant 3816 having an irregular surface 3820, bondable materia13810,
and graft 3802
having an irregular surface 3812, unless the implant is provided with bondable
material at
interface 3808. If a bond of satisfactory strength may be made without
irregular surface at
3812, 3814 or 3820, the irregular surface need not be formed or provided.
[0601 ] Vibratory energy is applied proximate the interface by an end effector
104, and
horn 3822, operative to cause bondable materia13810 within interface 3808 and
within graft
3802, if present, to soften or melt, thereby locking onto the irregular
surface of both body
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tissue 3804 or intervening implant 3816, if present, and graft 3802, whereby
graft 3802 is
firmly attached to the body once bondable materia13810 has cooled. Horn 3822
is
advantageously provided with a shape which improves transfer of vibratory
energy either
directly to interface 3808, or to graft 3802, which may be caused to vibrate
to heat interface
3808.
[0602] bondable materia13810 may be provided in the form of a wedge 3810A,
which
may be driven into a gap between graft 3802 and body tissue 3804, whereby a
tight and
secure connection is formed, operative to maintain graft 3802 in a desired
position during
bonding, and to improve the transfer of vibratory energy throughout interface
3808.
Chain of Fastening
[0603] The invention specifically contemplates a chain of fastening from bone
to
implant to tissue. For example, bone cement is fastened to bone, an implant is
fastened to the
bone cement as described herein, tissue is staked or fastened to the implant,
and the end of
the implant is capped or secured as described herein and in the incorporated
references.
Fasteners may alternatively be bonded to bone using methods described and
illustrated herein
and described in the incorporated references, and implants or tissue are
fastened to the
fastener bonded to bone, using the methods and devices of the invention.
[0604] Examples of chains of fastening have been provided elsewhere herein,
and Fig.
91 illustrates a further example. Specifically, a mesh 3400 is fastened within
the body by one
or more fasteners 3502 in accordance with the invention. In the example of
Fig. 91, fastener
3502 is selected from fasteners of the invention which enable the formation of
cap 1010.
Further, an embedded fastener 800 (not shown) may be used to secure fastener
3502 within
body tissue 3504. In the example illustrated, mesh 3502 is operative to
promote the growth of
cells, shown symbolically as circles 3506, and may also be used to close,
bridge or secure a
fissure or tissue gap 3508 from further expansion, until tissue growth closes
tissue gap 3508.
Mesh 3500 may incorporate therapeutic substances as described elsewhere
herein, in any of
the manners described elsewhere herein. For example, mesh 3500 may be coated
with a
bondable material incorporating a tissue ingrowth agent. The aperture size of
mesh 3500 may
be selected to promote the type of tissue ingrowth desired; for example, bone
ingrowth is
favored by an aperture size of 100-400 microns, whereas soft tissue growth is
favored by an
aperture size of 50-150 microns.
[0605] Mesh 3500 is advantageously coated with, or fabricated from, a bondable
material. As such, as caps 1010 are formed as described elsewhere herein, caps
and
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associated fasteners 3502 are additionally fastened to bondable material of
mesh 3500 by
vibratory fastening in accordance with the invention. Accordingly, mesh 3500
is secured to
body tissue 3504 with greater strength and reliability.
[0606] The invention further contemplates connecting implants together using
vibratory
energy. Examples have been given elsewhere herein, and additional examples are
provided in
Fig's. 92-93A. Specifically, with reference to Fig. 92, a first stent 3500 is
disposed within a a
tubular body vesse13502, for example a blood vessel, within a patient, and a
second stent
3504 is positioned within a branching blood vesse13506. A connecting fastener
3508 in
accordance with the invention is positioned between stent 3500 and stent 3504,
and is
connected to both stents 3500, 3504, at regions 3510, 3512, respectively.
Connecting fastener
3508 includes a bondable material at least upon its surface, and may be
fabricated entirely of
a bondable material.
[0607] When connecting fastener 3508 is positioned in overlapping contact with
stent
3500, vibratory energy may be applied along a portion or the entire
overlapping region of
connecting fastener 3506, in order to cause bondable material of connecting
fastener to soften
and form around material of stent 3500 and 3504, wherein upon cooling,
connecting fastener
is firmly attached to stent 3500 and 3504.
[0608] In accordance with the invention, vibratory energy may be provided
inside
blood vesse13502 or 3506, or other confined space, by an end effector 104
disposed at the
end of a catheter or laparoscopic shaft 3514. Vibratory energy is generated at
piezo stack
3516, supplied with a suitable signal through wires (not shown) extending
within shaft 3516.
Visualization may be carried out using fluoroscopy or other known method.
Alternatively,
connecting fastener 3508 is fabricated with metal, and is caused to vibrate to
produce heat
using a source of ultrasonic vibration produced outside the body and directed
at connecting
fastener 3508, to cause the latter to vibrate resonantly, as described for
example in copending
U.S. Patent application 10/945,331, the contents of which are incorporated
herein by
reference.
[0609] Stent 3500 and or 3504 (hereafter referred to as stent 3500) may be
fabricated
partially or entirely with bondable material. In this manner, vibratory energy
applied at a
region of overlap between stent 3500 and connecting fastener 3508 may operate
to cause
melting of bondable material of connecting fastener 3508 and stent 3500,
whereby bonding is
potentially improved by integration of bondable material of both connecting
fastener 3508
and stent 3500. Alternatively, or in addition to connecting fastener 3508
containing metal,
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stent 3500 may be fabricated with metal and caused to vibrate and produce heat
sufficient for
softening bondable material of stent 3500, or bonding with bondable material
of connecting
fastener 3508.
[0610] Additionally, vibratory energy may be applied to stent 3500 to soften
same,
facilitating expansion. Stent 3500 is generally transferred to an implantation
site in an
unexpanded state, typically surrounding a balloon catheter, as known in the
art. An
unexpanded stent is illustrated, for example, in Fig. 93. A heated stent 3500
may be easier to
expand, particularly if coated with bondable material, and more particularly
if there are
multiple layers of material, possibly including therapeutic substances.
[0611] It should be understood that stent 3500 and connecting fastener may be
formed
of biodegradable material. It should further be understood that other
expandable devices, or
alternatively filtration devices, or any other such device adapted to reside
within a space in
the body may be adapted as described for stent 3500, and may be bonded within
the body,
operating room, or other setting, in accordance with the invention.
[0612] Referring now to Fig. 93-93A, stent 3500 and 3500B are bonded together
within
tubular body tissue 3502A at connection area 3520, shown at a possibly
enlarged size for
clarity, comprising bondable material of either stent 3500 or 3500B or both,
melted by
vibratory energy applied as described above. In this embodiment, there is no
requirement for
a separate connector, such as connecting fastener 3508.
[0613] With further reference to Fig's. 93-93A, a collapsed or non-expanded
stent
3500A is positioned within the body using known means, positioned to be
overlapped by
another stent 3500 along a portion of its length. Stent 3500A is then
expanded, possibly
softened using vibratory energy as described above, whereby portions of stent
3500A contact
portions of stent 3500B. Bonding may then take place, representatively
illustrated at 3522. In
addition to extending a length of body tissue supported by a stent, this
embodiment enables a
second stent 3500A to be securely fixed with respect to a first stent 3500.
Moreover, if tissue
ingrowth has occurred within the first stent 3500, second stent 3500A may then
be used to
increase an occluded diameter of first stent 3500 by being expanded within
first stent 3500.
[0614] An alternative approach is further illustrated in Fig's. 93-93A,
wherein stent
3500C is bonded to a side surface of stent 3500B, the bonding illustrated at
3524, gaining
access through tubular body tissue 3502B. Stent 3500C may abut stent 3500B, or
alternatively, stent 3500 B may be provided with an aperture into which stent
3500C is sized
to fit. In either event, bonding is accomplished as described above.
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[0615] With reference to Fig. 94, two tubular body tissue members 3604, 3608
are
joined in a surgical anastomosis procedure of the invention. A supporting
frame 3610 is
provided to maintain segments 3604, 3608 in an open, flowing configuration,
should tubular
body tissue 3604, 3608 require additional support. Other methods of supporting
tissue during
anastomosis are disclosed in U.S. Patent 5,254,113 to Wilk, the contents of
which are
incorporated herein by reference. One or more bands 3600 is positioned to
encircle one or
more segments 3604, 3608, overlapping supporting frame 3610. Band 3600
comprises
bondable material along at least one end portion 3602 of an exterior surface.
Where bondable
material is provided on only one end portion, a joining portion 3602A is
advantageously
provided with a roughened or porous surface, or a surface having one or more
cavities
therein. Accordingly, vibratory energy may be applied to one or more end
portions 3602,
3602A, to cause bondable material thereof to soften or melt in accordance with
the invention.
If both ends 3602, 3602A contain bondable material, the respective material
will become
bonded at 3616, and upon cooling, band 3600 will be secured in place. If one
end of 3602 or
3602A contains bondable material, bonding takes place between the ends by
mechanical
interlock, improved by the roughened surface of the other end. Band 3600
advantageously
comprises material which shrinks when warmed, whereby heat imparted by
application of
vibratory energy causes ends 3602, 3602A to not only bond together, but causes
band 3600 to
shrink in order to improve a seal between band 3600, body tissue 3604, 3608,
and supporting
frame 3610.
[0616] With reference to Fig. 95, a band 3612 is provided, sufficiently wide
to overlap
at least a portion of both body tissue 3604 and 3608. Band 3612 is fastened,
and optionally
heat shrunk, as described for bands 3600. If supporting frame 3610 is required
to maintain
body tissue 3604, 3608 open and flowing, it is provided as described with
respect to Fig. 94.
[0617] In a further embodiment of the invention, vibratory energy is applied
to at least a
portion 3614 of band 3612 which is in overlapping contact with supporting
frame 3610. In
this manner, if contacting surfaces of supporting frame 3614 and band 3612
contain bondable
material, they may become bonded, rendering the union of body tissue 3604 and
3608 more
durable, and potentially improving a seal between band 3612, body tissue 3604,
3608, and
supporting frame 3614.
[0618] It should be understood that while various methods of bonding are
illustrated
together in Fig's. 92-94, and throughout the specification, any or all methods
may be
combined as deemed best by the medical practitioner.
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[0619] Referring now to Fig's. 78-80, methods of the invention may be combined
to
construct prostheses or other implants. In Fig. 78, end effector 104 and horn
800 of Fig. 32A
apply vibratory energy to a threaded post 3920 projecting from an upper base
layer 3922. A
supply of bondable materia13924 is introduced proximate a point of heating
caused by the
application of vibratory energy, whereupon bondable materia13924 is caused to
melt and
bond to post 3920 and upper layer 3922, operative to secure post 3920 and
layer 3922 relative
to each other, as may be seen in Fig. 79.
[0620] With further reference to Fig. 79, a horn 3926, connected to an end
effector (not
shown), is applied to upper layer 3922. Lower layer 3928 contains bondable
material, or
alternatively, bondable material is placed between layers 3922 and 3928. Upon
application of
vibratory energy through horn 3926, layers 3922 and 3928 are caused to vibrate
relative to
each other along at least an area underlying horn 3926, causing bondable
materia13930 of
layer 3928 to soften or melt and bond to the underside of layer 3922, as may
be seen in Fig.
80. A variety of permutations are possible for binding layers 3922 and 3928,
including
providing bondable material attached to the underside of layer 3922, and
providing a separate
layer of bondable material between layers 3922 and 3928.
[0621] Fig's. 78-80 thus illustrate several of the many ways in which methods
and
devices of the invention may be used to construct a wide variety of structures
useful for
therapeutic purposes.
[0622] It is contemplated that the devices and methods of the present
invention be
applied using minimally invasive incisions and techniques to fasten, for
example, muscles,
tendons, ligaments, bones, nerves, and blood vessels. A small incision(s) may
be made
adjacent the damaged tissue area to be repaired, and a tube, delivery
catheter, sheath, cannula,
or expandable cannula may be used to perform the methods of the present
invention. In
addition to using a cannula with the present invention, an introducer may be
utilized to
position implants at a specific location within the body.
[0623] The methods of the present invention may further be performed under
indirect
visualization, such as endoscopic guidance, computer assisted navigation,
magnetic
resonance imaging, CT scan, ultrasound, fluoroscopy, X-ray, or other suitable
visualization
technique. The implants, fasteners, fastener assemblies, and sutures of the
present invention
may include a radiopaque material for enhancing indirect visualization. The
use of these
visualization means along with minimally invasive surgery techniques permits
physicians to
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accurately and rapidly repair, reconstruct, augment, and secure tissue or an
implant within the
body.
[0624] All references cited herein are expressly incorporated by reference in
their
entirety. In addition, unless mention was made above to the contrary, it
should be noted that
all of the accompanying drawings are not to scale.
[0625] There are many different features to the present invention and it is
contemplated
that these features may be used together or separately. Thus, the invention
should not be
limited to any particular combination of features or to a particular
application of the
invention. Further, it should be understood that variations and modifications
within the spirit
and scope of the invention might occur to those skilled in the art to which
the invention
pertains. Accordingly, all expedient modifications readily attainable by one
versed in the art
from the disclosure set forth herein that are within the scope and spirit of
the present
invention are to be included as further embodiments of the present invention.
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