Note: Descriptions are shown in the official language in which they were submitted.
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ORTHOPEDIC FASTENER APPLICATOR
BACKGROUND OF THE INVENTION
This application is a division of copending Canadian application
Serial No.: 2,124,996, filed June 2, 1994.
1. Field of the Invention
This invention relates to an insertion tool for applying an orthopedic
fastener.
2. Background of the Art
Orthopedic fasteners, i.e., surgical bone fasteners, are known. Also
known are surgical fasteners for anchoring soft tissue such as ligament or
tendon
to bone. Various types of soft tissue anchoring devices are illustrated, for
example, in U.S. Patent Nos. 4,454,875; 4,570,623; 4,927,421; and 4,870,975.
Bone implantable devices such as those mentioned above are
typically made of metal or other hard material. More recently, bone
implantable
devices have been made from bioabsorbable material, which offers the advantage
of gradual transfer of stress back to the bone as the healing proceeds.
Bioabsorbable materials are relatively soft as compared to metals
and cannot be self-drilled or impacted into bone. Generally, it is necessary
to
predrill a hole into the bone and thereafter insert the orthopedic fastener.
In
particular orthopedic fasteners are known which possess a pin which, when
pulled, biases barbed legs radially outward to anchor the fastener securely
within
the hole. Up to now, instruments for applying such an orthopedic fastener have
not been available.
SUMMARY OF THE INVENTION
In accordance with an embodiment of the present invention there is provided a
kit
for endoscopically applying an orthopedic fastener activated by a proximally
moving setting pin, the kit comprising: a) means for drilling into bone;
b) an orthopedic fastener including a rivet portion and a setting pin movably
disposed through the rivet portion, the setting pin having a proximal portion
with
an outer surface; c) applicator means for applying the orthopedic fastener,
the
applicator including means for grasping the outer surface of the proximal
portion
of the setting pin; and d) cannula means for receiving the drilling means and
the
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applicator means.
In accordance with another embodiment of the present invention
there is provided a kit for anchoring soft tissue to bone, which comprises: a)
at
least one surgical fastener which includes a rivet having an axial bore, and a
setting pin having a proximal end portion with an outer surface at least
partially
disposed within the bore and at least a portion of which extends proximally of
the
rivet for being grasped by a grasping means, the surgical fastener being
activated
by proximal movement of the setting pin; b) means for drilling a hole into
bone;
c) means for releasably holding the surgical fastener; d) cannula means
possessing an axial bore for slidably receiving the drilling means and the
fastener
holding means; and, e) means for grasping the outer surface of the proximal
end
portion of the setting pin and proximally moving the fastener setting pin.
An instrument and method for applying a surgical fastener activated
by a setting pin is described herein. The instrument includes a fastener
abutting
means, a grasping means for engaging the setting pin and means for moving the
grasping means relative to the fastener abutting means. In one aspect the
instrument may be used endoscopically. A cannula and drill portion are
included
as part of a kit, the cannula being adapted to receive the drill portion and
the
applicator. In another arrangement the applicator includes pivotally connected
handle members which move the fastener abutment means and the setting pin
grasping means to activate the fastener.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of the cannula of the present invention.
Fig. 2 is a perspective view of the drill assembly of the present
invention.
Fig. 3 is a perspective view of the fastener manipulator assembly of
the present invention.
Fig. 4 is a perspective view of the fastener grasping means of the
fastener manipulator assembly.
Fig. 5 is a perspective view of an alternative embodiment of the
fastener manipulator assembly.
Fig. 6 is a perspective view of a fastener.
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Fig. 7 to 10 are partly sectional views illustrating the fastener
applicator of the present invention in use for implanting an orthopedic
fastener.
Fig. 11 is a sectional view of an alternative embodiment of the
setting pin and the grasping means.
Fig. 12 is a perspective view of an alternative embodiment of
applicator of
20
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the present invention.
DETAILED DESCRIPT10N OF PREFERRED EMBODIMENTS
Refernng to Figs. 1, 2 and 3, the orthopedic fastener applicator kit of the
present invention includes a cannula 10, a drill assembly 15, and a fastener
manipulator
assembly 40. The fasteners intended to be manipulated and applied by the
present invention
are shown for example in Fig. 6.
Briefly, fastener 60 is activated by a proximally moving setting pin and
includes a proximal head portion 61 with distally pointing barbs 62 for
securing soft tissue
(e.g. ligament, tendon, etc). A base portion 63 includes distally projecting
and radially
expandable legs 64 having radially outward pointing barbs 64a. A setting pin
66 is slidably
disposed through aperture 65 which extends axially through the fastener 60.
Setting pin 66
has a flared distal end 67, preferably a circumferential break away notch 69,
and optionally
a relatively wider diameter head 68 to facilitate the grasping and pulling of
the pin 66 by an
instrument. When the setting pin 66 is pulled
30
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proximally, flared end 67 biases Legs 64 radially outward to anchor base 63 of
the
fastener in a hole predrilled into bone. The setting pin 66 snaps apart at
notch 69,
which is located proximally of legs 24 when the setting pin is pulled to its
maximum
extent, so as not to leave any portion of the pin projecting therefrom.
Fastener 60 is
preferably fabricated from a bioabsorbable material such as homopolymers and
copolymers of glycolide, lactide, p-dioxanone, and caprolactone.
This instrument of the present invention may be used endoscopically.
An endoscopic operation is one in which a surgical procedure is carried out in
the
interior of a human (or animal) body by means of instrumentation for operating
or
l0 viewing deployed through one or more tubes, the functional portion of the
instrumentation being manipulated or controlled from outside the body. The
initial
opening in the body tissue to allow passage of the endoscopic tube to the
interior of
the body can be a natural passageway of the body (e.g. bronchial tubes), or it
can be a
puncture produced by an instrument such as a trocar. Because the endoscopic
tubes,
instrumentation, and any required puncture are relatively narrow, endoscopic
surgery
is less invasive and causes much less trauma to the patient as compared with
surgery
in which the surgeon is required to cut open large areas of body tissue.
Referring to Figs. 1, 2, and 3, cannula 10 provides a tubular guideway
and supports the operating instrumentation described below. It is preferably
made of
2 0 a surgically suitable metal, such as stainless steel. Distally pointing
barbs 11 are
located at the distal end of the cannula 10, and they facilitate the grasping,
temporary
holding and placement of the soft tissue intended to be secured to bone. Angle
A of
the point of the barb 11 is preferable from about 10 degrees to about 30
degrees, and
more preferably from about 15 degrees to about 25 degrees. The outer diameter
of
2 5 the cannula 10 preferably ranges from about 0.28 inches to about 0.42
inches. The
inner diameter of the cannula preferably ranges from about 0.27 inches to
about 0.39
inches. Clearly, cannulas of other dimensions can be utilized with the present
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invention. The cannula preferably can be from about 2 to about 6 inches in
length.
The proximal end of cannula 10 includes notches 12 for receiving corresponding
projections 43 of the end cap 42, described below.
Fig. 2 illustrates a drill assembly 1 S which includes a guide tube
portion 20 and a drill portion 30. The guide tube portion 20 includes hollow
cylinder
21 having end plugs 22a and 22b, each having an axial bore 23 of substantially
the
same diameter. Drill portion 30 includes axial drill shaft 33 extending
longitudinally
through the axial bores 23 so as to be centrally aligned through the guide
tube 20.
End plugs 22a and 22b serve as bearings for shaft 33. The shaft is rotatable
and
to longitudinally movable with respect to the guide tube 20. The outer
diameter of the
drill shaft 33 is substantially equal to the diameter of the bores 23 so as to
reduce
deviation of the drill shaft 23 from precise alignment along the central
longitudinal
axis of the instrument. At its distal end, shaft 23 possesses a drill bit 31
and, at
positions respectively distal and proximal to the guide tube portion 20, the
drill
portion 30 possesses stops 32a and 32b fixedly attached to shaft 33 to limit
the degree
of longitudinal movement of the drill portion 30 relative to the guide
assembly 20.
Precise alignment of the drill along the central longitudinal axis of the
instrument is
facilitated by close tolerances between the respective parts of the
instrument. Thus,
the outer diameter of guide tube 20 as well as the outer diameters of stops
32a and
32b are substantially equal to the inner diameter of the cannula 10. The end
plugs 22a
and 22b, and stops 32a and 32b support the drill shaft 33 and maintain the
drill 30 in
axial alignment within drill assembly 15 and also help to suppress bending of
the drill
30, thereby maintaining its rectilinearity.
The cylindrical tube 21 is preferably fabricated from a surgically
suitable metal such as stainless steel. The end plugs 22a and 22b, which serve
as
bearings, are preferably fabricated from polymeric material having suitable
strength,
abrasion and wear resistance, and non-stick characteristics. For example, a
material
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suitable for use in fabricating such bearings is Delrin~ AF, available from E.
I.
DuPont de Nemours, & Co., Inc. of Parkersburg, W. Va., which comprises an
acetal
polymeric resin containing fibers of polytetrafluoroethylene. The drill
portion can be
fabricated from any metal alloy suitable for drilling in surgical
applications.
Referring now to Fig. 3, fastener manipulator assembly 40 includes
cylindrical member 41 having an axial bore 41 a through which manipulator rod
50 is
movably disposed and a distal surface 41b for abutting the proximal end
surface of the
fastener head. An end cap 42 is located at the proximal end of member 41 and
possesses distally extending projections 43 for engaging corresponding notches
12 of
the cannula. Cylindrical member 41 is adapted to slide into cannula 10 and
possesses
an outer diameter substantially equal to the inner diameter of the cannula 10.
Manipulator rod 50 possesses a setting pin grasping means 51 at its
distal end, and optionally a threaded portion 55 adapted to screw into a
corresponding
tapped portion 44 in the inside surface of the bore 41 a. An embodiment of the
setting
pin grasping means 51 is illustrated in Fig. 4 and includes an opening 51 a
adapted to
allow entry and positioning of the head 68 of setting pin 66. Grasping means
51 also
includes a wedge shaped slot 51 d, longitudinally extending aperture 51 c, and
shelf
51b. The head 68 of pin 66 is inserted by sliding pin 66 through slot 51 d
such that the
shaft of pin 66 extends through aperture 51 c and the head 68 is located
inside opening
5la and rests on shelf Slb. When the manipulator rod 50 is moved proximally
the pin
is thereby pulled from the fastener.
Proximal or distal movement of the manipulator rod 50 shown in Fig.
3 is achieved by rotating the rod 50 relative to the cylindrical member 41 so
as to
screw rod 50 into or out of aperture 41 a.
2 5 In another embodiment, as shown in Fig. 5, the manipulator rod 50 has
no threads and slides longitudinally along the axis of the instrument without
the
necessity of rotating. Optionally, a longitudinally oriented elongated slot 45
is
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included in member 41. A peg 56 is attached to rod 50 and projects radially
outward
therefrom into slot 45. The longitudinal motion of the rod SO within member 41
is
thereby limited to the length of the slot.
Referring now to Figs. 7 to 10, operation of the apparatus is carried
out as follows:
The cannula 10 is positioned on the bone 70 at the location where the
surgeon intends to implant the orthopedic fastener. The barbs 11 can be used
to pick
up and move soft tissue 80 to the desired location.
The drill assembly 1 S is inserted into the cannula 10 and advanced
1o distally, as shown in Fig. 7. The drill assembly 30 is rotated by means of
any suitable
type drill motor (not shown) attached to the proximal end of the shaft 33 to
advance
the drill assembly distally. A hole 71 is thereby created in the bone mass 70.
After the hole has been completed, the drill assembly 1 S is removed
from the cannula 11. A fastener 60 is connected to the fastener manipulator
assembly
40 by inserting the setting pin head 68 of a fastener into the opening S 1 a
of the
grasping means S 1. Slight retraction of rod 50 will straighten the fastener
60. The
fastener manipulator assembly is then inserted into the cannula 10 and moved
distally
to insert the fastener into the prepared hole 71, as shown in Fig. 8. The
cylindrical
member 41 and fastener manipulator rod SO are adjusted either by turning or
sliding
2 0 rod 50 in accordance with the embodiments as described above so as to
position the
distal end 41 b of the cylindrical member 41 in abutment with the proximal
side of the
fastener head 61, as shown in Fig. 9. After the fastener 60 has been suitably
positioned within hole 71 the manipulator rod 50 is withdrawn proximally
either by
turning or sliding, thereby pulling setting pin 66, as shown in Fig. 10. The
flared
2 5 portion 67 of the pin biases legs 64 outwardly to anchor the pin 66 in
hole 71. With
su~cient pulling force, pin 66 snaps apart at notch 69. The cannula 10 and
manipulator assembly 40 may then be removed.
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An alternative configuration of the setting pin and setting pin grasping
means is illustrated in Fig. 11. As mentioned above, the wider diameter head
portion
68 of the setting pin is optional. Fig. 11 illustrates a setting pin 166 which
possesses
notches 168 instead of a wider diameter head portion. The notches 168 each
include
a proximal abutment surface 168a and preferably one, and more preferably two,
side
abutment surfaces. The manipulator rod 150 has an inner bore 150a adapted to
receive the proximal end of setting pin 166. Detents 151 are adapted to snap
fit into
notches 168 when the setting pin 166 is inserted into the bore 1 SOa of the
manipulator
rod. Proximally facing abutment surfaces 1 S 1 a of the manipulator rod are
adapted to
to abut the proximal abutment surfaces 168a of the notches. Thus, after
engagement of
the manipulator rod 1 SO and the setting pin 166, proximal movement of the
manipulator rod 150 causes proximal movement of the setting pin 166. The
detents
151 each have a sloping distal surface 151b to facilitate entry of the setting
pin. The
detents 1 S 1 can be of integral construction with the manipulator rod 150.
The
manipulator rod should then have sufficient resiliency to open the diameter of
its bore
150a sufficiently to permit entry of the setting pin 166 and snap locking
engagement
of the manipulator rod 150 and the setting pin 166. Side abutment surfaces
168b
facilitate rotation of the setting pin 166 by manipulator rod 1 SO when the
manipulator
rod 1 SO is moved by screw motion, as discussed above.
2 0 The embodiment of the present invention presented above can be used
endoscopically. In some surgical applications, non-endoscopic type applicators
may
be used. Fig. 12 illustrates an alternative, non-endoscopic embodiment of the
present
invention.
Fastener applicator 100 comprises members 110 and 120 pivotally
2 5 connected by pin 130. Each member has a handle portion 111 and 121,
respectively,
and a fastener grasping portion 112 and 122, respectively. Notches 113 and 123
in
fastener grasping portions 112 and 122 allow engagement with an orthopedic
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fastener, the fastener setting pin 66 being disposed in notches 123 and 113 as
illustrated. When the handles 111 and 112 are squeezed, fastener grasping
portions
112 and 122 are splayed further apart. Fastener grasping portion 112 abuts
setting
pin head 68, and fastener grasping portion 122 abuts fastener head 61. Hence,
when
the fastener grasping portions 112 and 122 are splayed further apart, setting
pin 66 is
pulled proximally out of the fastener 60 and the fastener is activated as
described
above.
While the above description contains many specifics, these specifics
should not be construed as limitations on the scope of the invention, but
merely as
l0 exemplifications of preferred embodiments thereof. Those skilled in the art
will
envision many other possible variations that are within the scope and spirit
of the
invention as defined by the claims appended hereto.
