Note: Descriptions are shown in the official language in which they were submitted.
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DISTRACTOR FOR USE IN SPINAL SURGERY
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates generally to intervertebral
spinal surgery, and more particularly to surgical
instrumentation and to a method for creating one or more
spaces between adjacent vertebral bodies in which the space
has a shape and vertebral surfaces adapted in size to
receive an implant or implants to be implanted in the space,
and the method of implanting those implants.
Background of the Related Art
The spinal disc that resides between adjacent
vertebral bodies maintains the spacing between those
vertebral bodies and, in a healthy spine, allows for
relative motion between the vertebrae. With disease and/or
degeneration a disc may become painful and/or mechanically
insufficient warranting surgical fusion across the affected
disc. Where fusion is intended to occur between adjacent
vertebral bodies of a patient's spine, the surgeon typically
prepares an opening at the site of the intended fusion by
removing some or all of the disc material that exists
between the adjacent vertebral bodies to be fused. Because
the outermost layers of bone of the vertebral endplate are
relatively inert to new bone growth, the surgeon must work
on the endplate to remove at least the outermost cell layers
of bone to gain access to the blood-rich, vascular bone
tissue within the vertebral body. In this manner, the
vertebrae are prepared in a way that encourages new bone to
grow onto or through an implant that is placed between the
vertebrae. An implant or insert may or may not promote
fusion of the adjacent vertebral bodies, may be an
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artificial spinal disc, may permit surface ingrowth, and may
be made of bone or inert material, such as titanium. All of
these examples and more are implants.
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Present methods of forming this space between adjacent vertebrae generally
include the use of one or more of the following: hand held biting and grasping
instruments known as rongeurs; drills and drill guides; rotating burrs driven
by a
motor; and osteotomes, chisels, and scraping implements. Surgeons often prefer
a drilling technique due to its being ease, quick, and accurate. Sometimes the
vertebral endplate must be sacrificed as occurs when a drill is used to drill
across
the disc space and deeper into the vertebrae than the thickness of the
endplate.
Such a surgical procedure is typically used to prepare a space in the spine
for an
implant having a circular cross section and necessarily results in the loss of
the
hardest and strongest bone tissue of the vertebrae, the endplate, and thereby
robs
the vertebrae of that portion of its structure best suited to absorbing and
supporting the loads placed on the spine by everyday activity. Where the
surgeon
chooses to forego drilling a large bore across the disc space in an attempt to
preserve that good bone he must nevertheless use one of the above instruments
to
work upon the endplates of the adjacent vertebrae to access the vascular,
cancellous bone that is capable of participating in the fusion and causing
active
bone growth, and also to attempt to obtain an appropriately shaped surface in
the
vertebral bodies to receive the implant, which means and method are unreliable
for that purpose.
There exists therefore a need for an improved surgical instrumentation and
a related method for providing a space that is non-circular in cross section,
and
preferably a substantially quadrilateral space across the height of a disc
space and
into the adjacent surfaces of the adjacent vertebral bodies while taking
advantage
of the safe, easy, and -accurate technique of boring or drilling into the
spine to
form a space and to shape the adjacent endplates to receive implants not
typically
associated with boring techniques.
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SUMMARY OF THE INVENTION
It is an aspect of the present invention to permit
the formation of a substantially quadrilateral space in a
spine for inserting a spinal implant into a disc space
between adjacent vertebral bodies.
Yet another aspect is to provide surgical
instrumentation for preparing an interbody space to receive
a spinal implant and a related method for working upon
vertebral body endplates adjacent a disc space useful in any
region of the human spine, specifically, the cervical,
dorsal, or lumbar regions.
Additional aspects and advantages of the invention
will be set forth in part in the description which follows,
and in part will be obvious from the description, or may be
learned by practice of the invention. The aspects and
advantages of the invention will be realized and attained by
means of the elements and combinations particularly pointed
out in the appended claims.
According to a broad aspect of the invention,
there is provided a distractor for use in spinal surgery,
comprising: a body having a disc penetrating extension
extending from said body for insertion into the disc space
between the adjacent vertebral bodies and for bearing
against the adjacent vertebral endplates of the adjacent
vertebral bodies, said disc penetrating extension being
hollow and with an open leading end to facilitate insertion
of said extension into the disc space and for containing
disc material within said extension.
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The invention comprises a surgical instrument set
for use in spinal surgery for forming a substantially
quadrilateral space in the spine for implanting a spinal
implant into a disc space between adjacent vertebral bodies
and the methods for doing so.
An embodiment of the present invention includes an
instrument set including a spinal marker for marking a
location on the spine. The marker has a shaft and a disc
penetrating extension extending from the shaft for insertion
into the disc space between adjacent vertebral bodies. The
shaft may have any number of cross sections including
rectangular and circular. The marker preferably includes a
shoulder for abutting against the exterior of the adjacent
vertebral bodies. The disc penetrating extension of the
marker preferably is tapered to facilitate insertion into
the disc space. The shaft of the marker has a proximal end
and an opposite distal end oriented toward the spine. The
shaft of the marker preferably includes a passage having a
dye receiver at the proximal end of the shaft
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WO 00%42898 PCTIUSOO/01821 of the marker and at least one dye exit hole at the
distal end of the shaft of the
marker for marking the spine. The marker preferably includes means for
coupling
to a syringe.
The instrument set includes a guard having an opening for providing
protected access to the disc space and the adjacent surfaces of the vertebral
bodies
adjacent the disc space and having a disc penetrating extension extending from
the
guard for insertion into the disc space between the adjacent vertebral bodies
and
for bearing against the adjacent vertebral endplates of the adjacent vertebral
bodies.
The guard may have two disc penetrating extensions extending from the guard
and
diametrically opposed ta each other. The disc penetrating extensions
preferably
has a leading-edge that may include either of a pointed, tapered, radiused,
chamfered, or wedge tipped shape to ease .msertion of the extensions into the
disc
space. The guard preferably is adapted to conform at least in part to the
exterior
of the adjacent vertebral bodies. The guard may include a shoulder that
conforms
at least in part to the exterior of the adjacent vertebral bodies. The
shoulder
preferably curves to correspond to the external curvature of the adjacent
vertebral
bodies. The guard may further include means for engaging the adjacent
vertebral
bodies when in use. The guard includes a hollow shaft adapted to allow access
through the hollow shaft to the disc space.
The instrument set further includes a guide for guiding a bone removal
device. The guide has a shaft adapted for insertion into the guard. The guide
includes means for guiding the formation of the substantially quadrilateral
space
across the height of the disc space and into the adjacent surfaces of the
adjacent
~ vertebral bodies. The guiding means preferably includes a plurality of guide
bores.
The plurality of guide bores may overlap one another. The plurality of guide
bores may include three guide bores, and in particular may include a main
guide
bore and two secondary guide bores located to a side of the main guide bore.
The
main guide bore and the two secondary guide bores preferably are oriented such
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that the bores formed in the spine through the main guide bore and the two
secondary guide bores form a first hole pattern, which when the guide is
rotated
180 degrees and used to form a second hole pattern, the overlapping first and
second hole patterns form the substantially quadrilateral space.
Another embodiment of the present invention further includes a secondary
guide having a shaft adapted to be inserted into the guard. The secondary
guide
preferably includes means for guiding the formation of a bore centrally
oriented
within the space to be formed. The centrally oriented bore preferably contacts
opposite sides of the substantially quadrilateral space to be formed.
The instrument set may also include a bone compactor having a shaft
adapted for insertion into the guard. The shaft terminates in a compaction
end.
The compaction end preferably has an upper surface and a lower surface that
presses upon the adjacent vertebral endplates of the adjacent vertebral
bodies. The
compaction end preferably has either a rectangular, trapezoid, or
quadrilateral
cross-section, or any other shape corresponding to the desired cross-section
of the
space to be formed in the spine. The compaction end may be any of beveled,
radiused, or tapered to ease introduction of the bone compactor into the
space.
The bone compactor may have a trailing end having a dimension greater than the
shaft to prevent over penetration of the bone compactor into the guard.
Alternatively, the instrument set may include a tool having a sharpened
leading
end so as to formalize the flattening of the vertebral surfaces.
An embodiment of the invention also comprises a method for creating a
substantially quadrilateral space in a spine for inserting a spinal implant
into a disc
space between adjacent vertebral bodies, comprising the steps of: positioning
a
guard into contact with the adjacent vertebral bodies for protecting access to
the
disc space and the adjacent vertebral bodies; and boring, through the guard, a
plurality of bores across the disc space to form the substantially
quadrilateral space
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into the adjacent surfaces of the
adjacent vertebral bodies, rather than deep into the vertebral bodies
themselves.
An embodiment of the present invention may include the step of marking
the spine for guiding, by reference marks, the proper location of the guard.
The
step of marking preferably includes inserting a penetrating extension of a
spinal
marker into a central point of the disc space between the adjacent vertebral
bodies.
An embodiment of the present invention includes the step of placing dye spots
on
the spine by nJ'ecting the dye through openings in a shaft of the spinal
marker.
i
The depth of penetration of the marker into the disc space is controlled.
An embodiment of the method of the present invention includes the step
of distracting the disc space between adjacent vertebral bodies, and in
particular,
the distracting step may include the step of inserting a distractor having a
disc
penetrating extension into the disc space between adjacent vertebral bodies
and
against endplates of the adjacent vertebral bodies. The depth of penetration
of the
distractor into the disc space is preferably controlled. The method may
further
include the step of changing disc penetrating extensions of the distractor in
accordance with a desired distractor distance between adjacent vertebral
bodies.
The guard may be inserted over the distractor in the disc space, and then the
distractor may be removed from within the guard.
The positioning step may include inserting at least one disc penetrating
extension extending. from the guard into the disc space between the adjacent
vertebral bodies for bearing against endplates of the adjacent vertebral
bodies. The
insertion of the disc penetrating extension into the disc space in one
embodiment
of the preferred invention distracts the adjacent vertebral bodies. Another
method
of the present invention further includes the step of controlling a depth of
penetration of the extension into the disc space. Another embodiment of the
present mvention includes the step of engaging the guard with the adjacent
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vertebral bodies through prongs extending from the guard and into the adjacent
vertebral bodies.
The boring step may include the sub-step of using a template in association
with the guard. The template may be rotated 180 degrees along its longitudinal
axis. The boring step may include the sub-step of using either of a drill,
mill, laser,
burr, grinder, or other means to bore the plurality of bores. The plurality of
bores
may overlap. The boring step may include forming at least three bores in the
spine to form a first bore pattern, and in particular may include forming at
least
a main bore and at least two secondary bores located to a side of the main
bore.
The main bore has a diameter that is preferably greater than a diameter of
each of
the two secondary bores. The main bore in the spine is preferably positioned
to
form a portion of three sides of the substantially quadrilateral space formed
in the
spine. Each of the two secondary bores are preferably positioned to form a
portion of two adjacent sides of the substantially quadrilateral space formed
in the
spine. A second bore pattern having at least three bores in the spine may be
formed such that the first and second bore patterns defined the substantially
,a
quadrilateral space. The substantially quadrilateral space may be one of a
substantially rectangular shape and a substantially trapezoidal shape. Further
a
central bore can be utilized to increase the width of the space formed. The
described "quadrilateral space" is defined to cover a space that is actually a
generally flat upper and flat lower surface having a height therebetween that
is
symmetrical from side to side and that may be uniform from front to back or
may
be such that these opposed surfaces are in angular relationship to each other
from
front to back; to the extent that the sides of the space are located within
the disc
space and not the bone of the vertebral bodies their specific shape is not
important, and need not be planar.
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Further the invention may comprise the step of inserting a multiple passage
drill guide into the guard to guide the formation of those bores. The guide
may
be inserted into the guard for guiding the forming of the first bore pattern.
The
invention may further include the steps of removing the guide from the guard,
rotating the guide 180 degrees along its longitudinal axis, reinserting the
guide into
the guard, and forming, through the plurality of openings in the guide, a
second
bore pattern, the first and second bore patterns defining the substantially
quadrilateral space. The invention may further include the step of controlling
the
depth of penetration of the guide into the guard.
Yet another embodiment of the present invention includes the step of
compressing outer edges of the substantially quadrilateral space. The step of
compressing preferably includes inserting a compactor having a compaction end
through the guard and into the substantially quadrilateral space formed in the
spine. The step of compressing may also include inserting a bone chisel
compactor having a sharpened cutting edge for cutting bone. The depth of
penetration of the compactor into the disc space is preferably controlled. The
step
of compressing may include the sub step of inserting a spinal implant through
the
guard and into the substantially quadrilateral space formed in the spine to
compress the outer edges on the substantially quadrilateral space.
Another embodiment of the present invention includes a surgical method
to prepare a segment of a human spine having a disc and two vertebrae adjacent
the disc to receive an implant that, by way of example and not limitation, may
be
for fusion between body portions of the adjacent vertebrae and through the
space
previously occupied by the disc, each of the adjacent vertebrae to be fused
including a vertebral body having an endplate outer surface adjacent the disc
space,
and a subchondral zone immediately internal to each endplate, the method
comprising: positioning a guard into contact with the adjacent vertebral
bodies for
protecting access to the disc space and the adjacent vertebral bodies; and
forming,
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through the guard, a plurality of bores to form a
substantially quadrilateral space in the spine across the
height of the disc space and into the adjacent endplates of
the vertebrae adjacent the disc space, the quadrilateral
space being formed by the removal of at least bone from at
least the adjacent endplates as deep as with, and generally
not deeper than, the subchondral zone of each of the
adjacent endplates.
In one broad aspect of the invention, there is
provided a distractor for use in urging adjacent vertebral
endplates of two adjacent vertebral bodies apart,
comprising: a body; and a disc penetrating extension
extending from said body for insertion between the adjacent
vertebral bodies, said extension having upper and lower
portions adapted to bear against the adjacent vertebral
endplates of the adjacent vertebral bodies and opposed side
portions between said upper and lower portions, said disc
penetrating extension having a leading end with an opening
into a hollow adapted to contain disc material within said
extension, said opening of said leading end having a maximum
height between said upper and lower portions that is greater
than a combined thickness of said upper and lower portions,
said body having a portion configured to limit the insertion
of said extension between the adjacent vertebral bodies.
In another broad aspect of the invention, there is
provided a distractor for use in urging adjacent vertebral
endplates of two adjacent vertebral bodies apart,
comprising: a body; and a disc penetrating extension
extending from said body for insertion between the adjacent
vertebral bodies, said extension having upper and lower
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portions adapted to bear against the adjacent vertebral
endplates of the adjacent vertebral bodies and opposed side
portions between said upper and lower portions, said upper
and lower portions being angled relative to one another to
induce lordosis between the adjacent vertebral bodies, said
disc penetrating extension having a leading end with an
opening into a hollow adapted to contain disc material
within said extension, said opening of said leading end
having a maximum height between said upper and lower
portions that is greater than a combined thickness of said
upper and lower portions.
It is understood that both the foregoing general
description and the following detailed description are
exemplary and exemplary only, and are not restrictive of the
invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated
in and constitute a part of the specification, illustrate
preferred embodiments of the invention. Together with the
description, they serve to explain the objects, advantages
and principles of the invention. In the drawings:
Fig. 1 is a leading end side perspective view of a
midline spinal marker of the present invention;
Fig. 2 is a leading end view of the midline spinal
marker of Fig. 1;
Fig. 2A is a cross-sectional view along
lines X-X of Fig. 2;
Fig. 2B is a cross-sectional view along
lines Y-Y of Fig. 2;
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Fig. 3 is a trailing end side perspective view of
the midline spinal marker of the present invention being
inserted at the anterior vertebral midline into the disc
space between adjacent vertebral bodies of a segment of the
spine;
Fig. 4 is a cross-sectional view along
lines 4-4 of Fig. 3 illustrating the spinal marker inserted
into the disc space between two adjacent vertebral bodies
along the vertebral midline;
Fig. 5 is a leading end side perspective view of a
spinal distractor of the present invention;
Fig. 5A is a cross-sectional view along
line 5A-5A of Fig. 5;
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Fig. 6 is a trailing end side perspective view of the distractor of Figure 5
with an impaction cap for driving the distractor into the disc space lateral
to the
midline (identified by reference mark) between the adjacent vertebral bodies
of the
spine;
Fig. 7 is a cross-sectional view along line 7--7 of Figure 6 showing the
distractor inserted in the disc space between the adjacent vertebral bodies on
one
side of the vertebral midline;
Fig. 8 is an exploded trailing end side perspective view of a guard providing
protected access to the disc space and the adjacent surfaces of the vertebral
bodies
and an impaction cap of the present invention;
Fig. 9 is a leading end side perspective view of the guard of Figure 8;
Fig. 10 is an exploded trailing end side perspective view of the guard of
Figure 8 for insertion over the distractor of Figure 5 shown inserted in the
disc
space between two adjacent vertebral bodies and a corresponding impaction cap
for seating the guard into the disc space;
Fig. 11 is a cross-sectional view along lines 11-11 of Figure 10 showing the
guard inserted over 'the distractor in the disc space between the adjacent
vertebral
bodies on one side of the vertebral midline;
Fig. 12 is a trailing end side perspective view of a guard positioned over the
distractor and seated after impaction to the distractor by the impaction cap
into
the disc space and adjacent vertebral bodies on one side of the vertebral
midline;
Fig. 12A is a longitudinal cross-sectional view along 12A-12A of Fig. 12
illustrating the guard positioned over-the distractor and seated after
impaction to
the distractor by the impaction cap into the disc space and adjacent vertebral
bodies on one side of the vertebral midline;
Fig. 13 is a trailing end side perspective view of an extraction instrument to
remove the distractor from within the guard;
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Fig. 14 is an exploded trailing end side perspective view of a drill guide
(template) of the present invention for guiding a drill for insertion into the
guard;
Fig. 15 is a cross-sectional view along lines 15-15 of Figure 14 illustrating
the guard of the present invention on one side of the vertebral midline;
Fig. 16 is an exploded trailing end side perspective view of the guard with
the giuide and with a large drill bit and a small drill bit used to remove
bone from
the adjacent vertebral bodies;
Fig. 17 is a cross-sectional view along lines 17-17 of Figure 16 illustrating
the guard, the large drill bit placed within the guide and extending into the
disc
space on one side of the vertebral midline;
Fig. 17A is a cross-sectional view through the leading end of the drill
assembly in the spine along lines 17A-17A of Figure 16 illustrating the guard,
the
large drill bit placed within the guide and extending into the disc space on
one side
of the vertebral midline;
Fig. 18 is a diagrammatic representation of the hole pattern formed with the
guide and large and small drill bits of the present invention after a first
drilling,
then rotating the guide 180E and performing a second drilling;
Fig. 19 is a leading end side perspective view of a bone compactor of the
present invention;
Fig. 20 is an exploded trailing end side perspective view of the compactor
of Figure 19 for insertion within the guard shown engaging the spine and
inserted
in the disc space between two adjacent vertebral bodies with an. impaction cap
for
advancing the compactor into the disc space;
Fig. 21 is a cross-sectional view along lines 21-21 of Figure 20 illustrating
the compactor placed within the guard inserted into the disc space on one side
of
the vertebral midline;
Fig. 22A is a trailing end perspective view of a universal handle assembly of
the present invention;
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Fig. 22B is a leading end perspective view of the engagement mechanism of
the handle of Figure 22A shown in the locked position;
Fig. 22C is a leading end perspective view of the engagement mechanism of
the handle of Figure 22A shown in the unlocked position;
Fig. 23 is an exploded trailing end side perspective view of the guard in
place
with a handle for an implant driver and an implant for implanting through the
guard and into the space between the two adjacent vertebral bodies created by
the
instrumentation and method of the present invention;
Fig. 24 is a fragmentary leading end view of the implant driver instrument
of Figure 23;
Fig. 25 is a cross-sectional view along lines 25-25 of Figure 23 illustrating
the implant driver instrument and implant inserted through the guard and into
the
space created between the two adjacent vertebral bodies on one side of the
vertebral midline;
Fig. 26 is an exploded side perspective view of the guard , an extraction
adapter for engaging the guard and, and an extraction instrument for engaging
the
adapter and for extracting the guard;
Fig. 27 is a side perspective view of the operated segment of the spine with
the guard removed having a first implant inserted on one side of the midline
and
between and in part into the adjacent vertebral bodies in the space created by
the
instrumentation and method of the present invention and with the guard
inserted
on the opposite side of the vertebral midline next to the implant;
Fig. 28 is a cross-sectional view along lines 28-28 of Figure 27 illustrating
the implant positioned on one side of the vertebral midline in the space
created by
the instrumentation and method the of the present invention and the guard
inserted in the disc space on the opposite side of the vertebral midline and
next to
the implant;
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Fig. 29 is an exploded side perspective view of a segment of the spine
prepared to receive two implants with the instrumentation and method of the
present invention;
Fig. 29A is a top perspective view of the lower vertebral body of the
segment of the spine of Fig. 29;
Fig. 30 is a trailing end perspective view of a spacer of the present
invention;
Fig. 31 is a leading end perspective view of a spacer of the present
invention;
Fig. 32 is a side elevational view of two adjacent vertebral bodies in
lordosis
with an implant inserted into a space created between two adjacent vertebral
bodies in which the created space has a lordotic configuration with an implant
having parallel upper and lower surfaces maintaining the angular relationship
of
the adjacent vertebral bodies;
Fig. 33 is a side elevational view of two adjacent vertebral bodies in
lordosis
with a lordotic implant placed between the two adjacent vertebral bodies in a
space
created between the two adjacent vertebral bodies;
Fig. 34 is an exploded trailing end side perspective view of a second
embodiment of the guard of the present invention for placement into a segment
of the spine having a removable insertion end and an adapter and a handle
assembly;
Fig. 35 is a side elevational view of the removable insertion end having
extended portions with an anatomical configuration;
Fig. 35A is a side elevational view of an alternative embodiment of a
removable insertion end;
Fig. 35B is a side elevational view of yet another alternative embodiment of
a removable insertion end;
Fig. 36 is a fragmentary view of the leading end of the guard of Figure 34;
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Fig. 37 is an exploded trailing end side perspective view of the guard of
Figure 34 inserted in the disc space between two adjacent vertebral bodies for
receiving a drill (template) guide of the present invention;
Fig. 38 is a cross-sectional view along lines 38-38 of Figure 37 illustrating
the guard inserted into the disc space between two adjacent vertebral bodies
on
one side of the vertebral midline;
Fig. 39 is a trailing end side perspective view of the guard with the drill
guide inserted into the guard and with a large drill bit and a small drill bit
of the
present invention used wremove bone from the adjacent vertebral bodies;
Fig. 40 is a trailing end side perspective view of the guard inserted on one
side of the vertebral midline and into the disc space between two adjacent
vertebral
bodies and a central bore guide of the present invention for insertion
therein;
Fig. 41 is a trailing end side perspective view of the central bore guide
inserted in the guard and the large drill and a handle assembly of the present
invention;
Fig. 42 is a diagrammatic illustration of the hole pattern formed with the
guide and the large' and small drill bits of the present invention;
Fig. 43 is a diagrammatic illustration of the hole pattern formed after the
drill guide instrument is flipped 180 degrees and additional holes are drilled
with
the large and small drill bits of the present invention;
Fig. 44 is a diagrammatic illustration of the space created with the drill
guide method of Fig. 43, but where the space to be prepared is wider than in
Fig.
43;
Fig. 45 is the configuration of the space created with the drill guide
instrument and the holes drilled as shown in Fig. 44;
Fig. 46 is a diagrammatic illustration of a hole drilled with a central bore
drill guide into the space of Fig. 45 of the present invention;
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Fig. 47 is the configuration of the space created with the drill guide
instrument and central bore drill guide instrument of Fig. 46 of the present
invention;
Fig. 48 is another diagrammatic illustration of a space created with multiple
holes drilled with a central bore drill guide in accordance with the present
invention to prepare a still wider space;
Fig. 49 is a perspective view of a spinal fusion implant oriented in an
initial
insertion position and configured for clockwise rotation within the disc
space, the
top and bottom walls thereof being tapered relative to one another for
inducing
angulation of the adjacent vertebral bodies;
Fig 50 is a side perspective view of a vise adapted to hold the implant of
Fig.
49 for loading the implant with fusion promoting substances; and
Fig. 51 is a side perspective view of the vise of Fig. 50 holding the implant
of Fig. 49.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Reference will now be made in detail to the present preferred embodiment
of the invention, as illustrated in the accompanying drawings.
Figs. 1-28 are generally directed to an embodiment of an instrument set
having a rectangular cross-section for use in spinal surgery for forming a
substantially quadrilateral space in the spine. Figs. 34-41 are generally
directed to
another embodiment of the present invention surgical instrument set having a
circular cross-section for forming a substantially quadrilateral space in the-
spine.
Figs. 29, 29A, 32, 33, and 42-48 generally show the space formed in the spine
by
the instrument sets of Figs. 1-28 and 34-41 with implants for placement in the
created space. Figs. 49-51 generally show an implant and vise adapted to hold
the
implant for loading the implant with fusion promoting substances. An
instrument
set for use in spinal surgery is used to form a substantially quadrilateral
space in
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the spine for implanting a spinal implant into a disc space between adjacent
vertebral bodies.
The anterior aspect (front) of the spine may be exposed either by opening
a surgical incision large enough to allow direct visualization or
laproscopically
with a small opening to allow instruments to be placed through the body from
outside the body for visualization through an endoscope. The vertebral
midline,
which bisects the vertebral bodies along the longitudinal axis of the spinal
column
separating left from right is identified by the surgeon. As shown in Figs. 1-
4, an
exemplary embodiment of a midline marker 100 of the present invention
preferably is used to create reference marks at the vertebral midline on the
disc
material and on the adjacent vertebral bodies in a segment of the spine.
Marker
100 has a shaft 102 terminating in an insertion tip 104 having a tapered
leading
edge 106 allowing it to be placed into a multitude of discs having various
heights.
Tapered leading edge 106 facilitates the insertion of marker 100 into the disc
material contained in the disc space between two adjacent vertebral bodies.
The
juncture of shaft 102 and insertion tip 104 of marker 100 forms a shoulder 108
for
butting against the anterior aspect of the adjacent vertebral bodies and thus
prevents unwanted over penetration of insertion tip 104 into the disc space.
Also
located at shoulder 108 at the anterior aspect of shaft 102 are a plurality of
dye exit
holes 110. Dye exit holes 110 are in communication via a passage 112 with a
syringe engaging well 1141ocated at a trailing end or proximal end 116 of
shaft
102. We11114 is adapted to receive the tip of a syringe (not shown), or any
other
well-known device for containing and injecting a dye into marker 100. A
preferred marker 100 has advantages over a needle due at least in part to
having a
shoulder for preventing over penetration of the disc space or having the
ability to
provide multiple marks on the spine via multiple dye exit holes.
After marker 100 is inserted into the disc space, it may have its position
confirmed radiographically to make sure that insertion tip 104 is accurately
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positioned at the vertebral midline and to assess the depth of the disc space
relative
to the known length of insertion tip 104. After marker 100 is correctly placed
at
the vertebral midline, a dye such as indigo carmine dye preferably is attached
to
marker 100 at well 114 at proximal end 116 of shaft 102. With irijection, the
dye
flows through passage 112 within shaft 102 of marker 100 and exits dye exit
holes
110 to create reference marks 118 at the vertebral midline on the adjacent
vertebral
bodies and on the disc material. The position of reference marks 118
corresponds
to dye exit holes 110 at the leading end or distal end 120 of shaft 102 of
marker
100. Marker 100 is then removed from the disc space and reference marks 118
remain on the vertebral bodies and disc material. Reference marks 118 are
visible
to the surgeon and are used as alignment reference points in guiding
instruments
into the spine.
As embodied herein, and as shown in Figs. 5-7, an instrument set of the
present invention may include a distractor 130 that urges two adjacent
vertebral
bodies apart and maintains the vertebral bodies in a selected spacial
relationship
to each other. Distractor 130 comprises a shaft 132 capable of receiving a
graduated series of removable, partially hollow tips 134. The junction of
shaft 132
and tip 134 forms a shoulder 136 that abuts against the two adjacent vertebral
bodies when tip 134 is inserted between the two adjacent vertebral bodies.
Shoulder 136 of shaft 132 preferably curves to correspond to the external
curvature of the vertebral bodies adjacent the disc space in which distractor
130 is
inserted. Tip 134 is preferably, but not requisitely, hollow to facilitate
insertion
into the disc material and to avoid displacing its own volume that might cause
disc
protrusion. Tip 134 has a height at its distal end of approximately 4-16 mm
that
increases to approximately 7-20mm at the junction of tip 134 with shoulder 136
of shaft 132 to facilitate insertion of tip 134 into the disc space. When used
= anteriorly, tip 134 is generally of a lesser height at the leading end. A
length of
approximately 15-30mm is preferred for use from anterior to posterior. The
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length of tip 134 is preferably 15-42mm for use translaterally. The increase
in
height along tip 134 also may be used to position the two adjacent vertebral
bodies
in an angular spacial relationship, such as to create lordosis. Shaft 132 is
preferably
hollow to reduce the overall weight of distractor 130.
A proximal end 138 of distractor 130 comprises an extraction head 140 for
coupling to an extraction instrument 150 described in detail below. While a
preferred embodiment is shown, it is appreciated that a variety of
configurations
at proximal end 138 of distractor 130 could be utilized for the intended
purpose,
including but not limited to, threads, key-ways that rotate and lock, male and
female interlocking parts and the like without departing from the present
teaching.
Insertion of distractor 130 into the disc space preferably is guided by
reference
marks 118 created by marker 100. During insertion of distractor 130, shaft 132
of
distractor 130 preferably is positioned to one side of the vertebral midline
marked
by reference marks 118.
Tip 134 of distractor 130 may be driven into the disc space by an impaction
force imparted to distractor 130 through an impaction cap 160 which couples to
proximal end 138 of distractor 130 and prevents damage to end 138 of
distractor
130. In yet another alternative embodiment, an adapter engages distractor
removing engagement means and the adaptor engages at its opposite end to a"T"
handle that can be utilized with or without a mallet to install or remove
distractor
130, or any of the other instruments that at their trailing ends are similarly
configured. The depth of insertion of tip 134 of distractor 130 into the disc
space
is sufficient to achieve the desired distraction and vertebral alignment and
is
;i
limited by shoulder 136 that abuts the two adjacent vertebral bodies to
prevent
1 25 any unwanted movement of tip 134 beyond the disc space.
As embodied herein, and as shown in Figs. 8-11, an instrument set of the
present invention may include a guard 170 having a hollow body 172 that
terminates in an insertion end 174 that preferably curves to correspond to the
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external curvature of the two adjacent vertebral bodies of the spine.
Extending
from insertion end 174 of guard 170 are a pair of disc penetrating extensions
176
that are diametrically opposite one another on the sides of guard 170. Each of
extensions 176 preferably have a wedged tip to facilitate insertion into the
disc
D material between the two adjacent vertebral bodies. Extensions 176 have a
height
that preferably is less than the height of guard 170 such that a shoulder 178
is
formed at the distal end 180 of guard 170 in which shoulder 178 functions as a
depth limiting stop to prevent over penetration of extension 176 into the disc
space.
Preferably, protruding from insertion end 174 of guard 170 also is a pair of
prongs 182 for engaging the bone of the vertebral bodies. Prongs 182 function
to
engage guard 170 to the two adjacent vertebral bodies and to hold the two
adjacent
vertebral bodies in a selected spacial relationship. A proximal end 184 of
guard
170 is open to permit insertion of instruments and implants into guard 170 as
described in detail below. The internal opening of guard 170 is suitably
dimensioned for receiving distractor 130. For laproscopic use, proximal end
184
of guard 170 can be attached to a laproscopic port allowing for the passage of
instruments through the port and guard 170 while effecting a fluid and gas
seal.
As embodied herein, and as shown in Figs. 10 and 11, with distractor 130
inserted between the two adjacent vertebral bodies, guard 170 slidably engages
proximal end 138 of distractor 130 and advances toward the spine with
distractor
130 functioning as a guide post for aligning guard 170. Guard 170 seats into
position with an impaction force imparted onto proximal end 184 of guard 170
via
a large impaction cap 160. As shown in Figure 12, impaction cap 160 has an
internal configuration capable of receiving extraction head 140 of distractor
130
and has a shoulder portion 162 for abutting proximal end 184 of guard 170.
Once
extraction head 140 contacts the internal part of impaction cap 160, guard 170
can
no longer advance and thus serves as a depth limiting stop. Guard 170, like
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distractor 130 and the bone compactor can also be installed and removed by use
of the slap hammer, or an adaptor and mallet.
With particular reference to Figs. 11, 12, and 12A, after guard 170 seats
against and engages the spine, extensions 176 are positioned in the disc space
at
opposite sides of the insertion end of distractor 130. Extensions 176 serve to
create
or maintain a selected spacial relationship of the two adjacent vertebral
bodies and
also serve as guards to keep the surgical procedure within the area between
extensions 176 and to prevent any unwanted movement of an instrument or
implant outside of the area between extensions 176.
In an alternative embodiment of the present invention, guard 170 may be
inserted directly into the spine without recourse to the preliminary use of
distractor 130. In that case, it is preferred that the leading end of
extensions 176
of guard 170 be configured so as to both facilitate the easy introduction of
guard
170 into the disc space, and so as to urge the vertebral bodies apart into a
distracted
state. For this purpose, the most distal end of extensions 176 themselves
would
have a lesser height than the remainder of extensions 176 and preferably a
pointed,
tapered, radiused, or chamfered shape. It should be recognized that while the
.
present instrument set provides means for identifying and achieving the
optimal
intervertebral distraction prior to the removal of any bone, it also provides
for
adjusting it later in the procedure via graduated spacer blocks and graduated
guards
having a variety of heights. While it is believed that the predistraction of
the
intervertebral space prior to bone removal is desirable, it is not requisite
and it is
anticipated that the present instrument set allows for the distraction of the
intervertebral space later in the procedure, and/or by the insertion of the
implant
itself.
As shown in Figure 13, once guard 170 is seated, distractor 130 preferably
is removed with an extraction instrument 150 which couples to extraction head
140 and may be advanced away from the spine with slap-hammer style
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advancement or pulled a,ith a handle which couples to an end of extraction
instrument 150.
As embodied herein, and as shown in Figs. 14-18, an instrument set of the
present invention may include a guide 190 for creating a quadrilateral space,
or
more particularly a rectangular space between the two adjacent vertebral
bodies.
Guide 190 preferably has a large bore 192 and two small bores 194 to one side
of
large bore 192. Guide 190 has a shaft 196 terminating in an insertion end 198
that
is inserted into guard 170. Guide 190 also has a trailing end 200 that
preferably has
a dimension greater than the inside opening of guard 170 that functions as a
depth
limiting stop to prevent further insertion of guide 190 into guard 170.
With particular reference to Figs. 17 and 17A, a large drill bit 210 is shown
having a longitudinal shaft 212 terminating at one end in a cutting portion
214 and
having an engagement head 216 at the other end for engaging a rotating device,
such as a handle or a power driven motor. A trailing end 218 of large drill
bit 210
also includes a stop member 220 for abutting the surface of trailing end 200
of
guide 190 to prevent unwanted over penetration of large drill bit 210 irito
the disc
space. Large drill bit 210 is configured and dimensioned for placement through
large bore 192 of guide 190.
Similarly, a small drill bit 230 terminates in a cutting end 232 and has an
.
engagement head 234 for engaging a rotating handle or rotating motor. A
trailing
'
end 236 of small drill bit 230 also has an enlarged portion 238 for abutting
the
trailing end 200 of guide 190 to prevent unwanted over penetration of small
drill
bit 230 into the disc space.
In use, large drill bit 210 passes through large bore 192 in guide 190 to
position the cutting portion 214 into the disc space and then is rotated to
remove
bone from the endplates of the two adjacent vertebral bodies. Large and small
drill
bits 210, 230 can be turned by a "T" handle or preferably by use of a power
drill.
Similarly, small drill bit 230 passes through small bores 194 of guide 190 to
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position cutting end 232 into the disc space and then rotates to remove bone
from
the endplates of the adjacent vertebral bodies. As shown in Fig. 17,
extensions 176
of guard 170 protect the unwanted movement of large and small drill bits 210,
230
in a lateral or transverse direction and confine the drilling products so that
they
are evacuated by drill bits 210, 230.
As shown in Fig. 18, the holes created with large drill bit 210 and small
drill
bit 230 form a pattern as indicated in solid lines in the drawing.
After the first three holes have been drilled, guide 190 is removed from
within guard 170. Guide 190 then is rotated 180 degrees and reinserted into
guard
170. Guide 190 now is oriented such that large bore 192 is positioned over the
area in which the small holes were previously drilled and small bores 194 are
positioned over the area in which the large bore was previously drilled. The
drilling procedure with large drill bit 210 and small drill bit 230 is
repeated to
create a pattern of holes as indicated by the dotted lines in Figure 18. The
result
of this drilling procedure, is the removal of a portion of bone from the
endplates
of the adjacent vertebral bodies creating a space approximating the
configuration
of a rectangle.
Although the drilling of the bone of the endplates creates a space with a
configuration that approximates the shape of a rectangle, if desired a perfect
rectangle may be obtained by use of a rectangular bone compactor.
As shown in Figs. 19-21, a box-shaped bone compactor 240 has a shaft 242
terminating in a compaction end 244. Compaction end 244 of shaft 242 may
include beveled, radiused, or thinned edges to ease introduction. Compactor
end
244 compresses any remaining boney protuberances into the vertebral bodies
achieving a perfectly rectangular space. A trailing end 246 of shaft 242 may
include an extraction head 248 for coupling to an extraction instrument 150.
In a preferred embodiment, there is no fixed stop until approximately 32-36
mm, so that a slotted and calibrated impaction cap 260 can be used to
predictably
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and adjustably insert compaction end 244 into the intervertebral space to the
desired optimal depth. Alternatively, compactor 240 can have a fixed depth
limiting means. As a further alternative, leading edges 250 of compactor 240
can
be sharpened so that it functions wholly or in part as a chisel to cut rather
than
compact the bone. This is considered less desirable, though still workable,
than
the preferred compaction end 244 by which the density of the bone at the
prepared recipient site is actually increased by the compaction process.
Compactor 240 is inserted into guard 170 and advanced by an impaction
force imparted to the trailing end 246 of compactor 240 by an impaction cap
260
similar to the impaction cap previously described above. The advancement of
compaction end 244 of compactor 240 impacts the remaining portions of the bone
that were not removed in the drilling step previously described into the
vertebral
bodies themselves.
As an alternative to compactor 240, trial size spacers 291 resembling
implants 290 with either smooth or abraiding surfaces may be impacted into the
space to complete the flattening of the opposed bone surfaces.
As show in Figs. 22A-C, a handle assembly 270 is shown for coupling to the
drilling instrumentation and other instruments of the present invention.
Compactor 240 is removed from within guard 170 by coupling to extraction
instrument 150 a nd advanced outside of guard 170 with extraction instrument
150
shown in Figs. 13 and 26.
Figs. 23-25 show a driver 280 for inserting an intervertebral implant 290
into the created space between the two adjacent vertebral bodies. Driver 280
has
a leading end 282 configured to cooperatively engage an implant 290. As shown
in Figure 24, driver 280 has a threaded portion 284 and a non-threaded pin 286
extending from the leading end 282 for insertion into corresponding openings
in
the trailing end of the implant 290. Threaded portion 284 is rotatable by a
knob
288 at the opposite end of driver 280 so as to threadably couple driver 280 to
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implant 290. Driver 280 has a handle coupling means 289 for coupling to handle
assembly 270 for controlling driver 280.
After implant 290 is coupled to driver 280, implant 290 and leading end 282
of driver 280 are inserted into guard 170 and advanced towards and into the
created space between the two adjacent vertebral bodies. After implant 290 has
been placed within the created space by use of the "T" handle with or without
impaction of the slap hammer, or an adaptor and a mallet, knob 288 of driver
280
is rotated to uncouple implant 290 from driver 280. Driver 280 then is removed
from within guard 170 leaving implant 290 inserted in the created space.
It is clearly anticipated that while the specific configuration of the
preferred
ends has been described, that a variety of threaded and non-threaded means for
coupling implants 290 to driver 280 could in the alternative be employed
without
departing from the present inventive concept.
Fig. 26 shows guard 170 being removed from the disc space and from the
adjacent vertebral bodies with extraction assembly 150 which couples to an
extraction adapter 152 configured to fit within the proximal-end 184 of guard
170.
Extraction adapter 152 is locked into place by a spring-biased butterfly
member
that fits into corresponding notches at the proximal end 184 of guard 170.
After
extraction assembly 150 is coupled to guard 170, extraction assembly 150 is
advanced away from the spine with a slap-hammer style motion or any other
suitable means to remove guard 170 from the spine. After guard 170 is removed,
implant 290 remains in place in the created space between the endplates of the
two
adjacent vertebral bodies.
Figs. 27 and 28 show that the procedure being repeated on the opposite side
of the vertebral midline. Distractor 130 and guard 170 are rotated 180 degrees
to
conform to the curvature of the vertebral bodies on the second side of the
vertebral midline. The above steps for the present invention are repeated for
inserting guard 170 into position on the opposite side of the vertebral
midline. As
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shown in Fig. 28, first implant 290 is positioned and remains arithin the
created
space between the adjacent vertebral bodies and guard 170 is positioned on the
opposite side of the vertebral midline to first implant 290.
As shown with implant 290 in Fig. 29 and a spacer block 291 in Fig. 31,
either of implant 290 or spacer block 291 may be inserted in the space created
in
the spine. As shown in Figs. 30 and 31, spacer block 291 may have an external
configuration similar to that of the implant, except that it may be more or
less
solid. It is appreciated that spacer blocks 291 and implants 290 may be wedged-
shaped or rectangular so as to adjust the angular relationship of the
vertebral
bodies to each other.
As shown in Figs. 32 and 33, the instrumentation and method of the present
invention may be used to create or maintain lordosis of the spine in at least
two
ways and to accept both generally rectangular and trapezoidal implants. As
shown
in Fig. 32, the created space may be formed at an angle to the vertebral
endplates,
such that the planes of the top and bottom surface of the created space are in
an
angular relationship to each other. The two adjacent vertebral bodies are
positioned in angular relationship to each other with the insertion of implant
290
having parallel upper and lower surfaces within the created space. The
insertion
of implant 290 into the angular space causes the vertebral bodies to be placed
in
an angular relationship.
Figs. 32 and 33 show two adjacent vertebral bodies in a desired lordotic
angular relationship. In Fig. 32, the space was created by means of the shape
of
extensions 176 on guard 170 during the drilling and compaction procedure. A
rectangular space was formed with more bone removed posteriorly than
anteriorly
in anticipation of receiving a generally rectangular implant 290. This is a
preferred
stable configuration as the compressive loads of the spine onto implant 290
are
received generally perpendicular to the surface (rather than on an angle that
might
urge the implant forward or backwards). Additionally, once installed implant
290
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is blocked from further penetration by the wall of bone created by the removal
of
the bone before it, and is blocked from backing out because the implant upper
and
lower surfaces would need to move against the inclined slanted surfaces of the
vertebral bodies in order to move and that would require significantly more
energy than remaining in the more stable position of being fully installed.
For the space shown in Fig. 33, extensions 176 of guard 170 were positioned
between the vertebral bodies so that the adjacent vertebral surfaces were
generally
parallel during the creation of the recipient space. This was done in
anticipation
that the desirable lordosis would be achieved by the use of an implant at
least in
part generally trapezoidal in shape, or having upper and lower surfaces for
engaging the adjacent vertebral bodies, which surfaces are in a non-parallel
angular
relationship to each other.
While this is theoretically a less stable configuration than that previously
described, it offers the advantage that the amount of bone removal is minimal
but
sufficient for its intended purpose and the thickness of the bone removed is
more
uniform in thickness.
As shown in Fig. 33 instead of creating an angular space, the created space
may have parallel upper and lower surfaces. The two adjacent vertebral bodies
are
positioned in an angular relationship to each other with the insertion of an
implant having upper and lower surfaces that are angled toward each other.
Figs. 34-41 show a second set of instrumentation similar to the first in that
it provides both for the creation of a generally rectangular or trapezoidal
space in
a non-traumatic way and for the insertion of an implant through the same
instrumentation, but differs in that the guard is generally cylindrical while
the
prior guard was generally rectangular. A rectangular shape has less volume and
space than a cylindrical shape, which has no corners and is less expensive to
manufacture.
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Figs. 34-36 show a second embodiment of a guard of the present invention.
Guard 370 has a hollow body 372 that terminates in an insertion end 374, which
is removably coupled to body 372. The distal end 380 of guard 370 is curved to
correspond to the external curvature of the two adjacent vertebral bodies the
spine. Extending from the insertion end 374 are a pair of extensions 376 in a
diametrically opposite position on the sides of the insertion end 374. Each of
the
two extensions 376 have a suitable configuration to facilitate insertion into
the disc
material between the two adjacent vertebral bodies. As shown in Figure 35,
extensions 376 may have an "anatomic" configuration to conform to the contours
of the vertebral endplates adjacent to the disc space in which guard 370 is to
be
inserted. Preferably, but not requisite, also protruding from the insertion
end 374
are a pair of prongs 382 for engaging the bone of the adjacent vertebral
bodies.
Prongs 382 function cooperatively with extensions 376 to engage guard 370 to
the
adjacent vertebral bodies and to hold the two adjacent vertebral bodies in a
selected spacial relationship. The proximate portion of insertion end 374 may
include a threaded portion for threadably coupling to body 372 of guard 370.
It
is appreciated that other coupling means are anticipated without departing
from
the scope of the present invention.
Fig. 36 shows body 372 having a collar 404 which has a thread to engage
the threaded portion of the removable insertion end 374. Guard 370 provides
the
added advantage of having interchangeable removable insertion ends 374 with
different shaped extensions depending on the surgical procedure being
employed.
For example, instead of having an anatomical configuration, the extensions may
have a parallel configuration as shown in Fig. 35A or may have a wedged
configuration as shown in Fig. 35B, so as to allow the surgeon to achieve the
desired angular relationship of the vertebral bodies to be fused.
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Proximal end 384 of hollow guard 370 is open to permit the insertion of
other instruments and implants into the guard as described herein. As with the
previously described guard, a closeable part may be connected to the proximal
end
384 of this guard for laproscopic use allowing for the passing of instruments
through guard 370 while providing for a gas and fluid seal.
Guard 370 is seated into the disc space and engaged to the spine by being
manually advanced or by imparting an impaction force onto the proximal end 384
of guard 370. As shown in Fig. 34, an insertion and extraction handle assembly
270 is shown with a coupling member for engagement to proximal end 384 of
guard 370.
As shown in Fig. 38, after guard 370 is properly seated and engaged to the
spine, extensions 376 are positioned in the disc space between the two
adjacent
vertebral bodies on one side of the vertebral midline. Extensions 376 serve to
maintain the spacial relationship of the two adjacent vertebral bodies and
also
serve as guards to maintain an instrument or implant within the area between
extensions 376 and to prevent any unwanted movement of an instrument or
implant outside of the area between extensions 376.
Fig. 37 shows a guide 390 for creating a rectangular space between the two
adjacent vertebral bodies. Guide 390 comprises a large bore 392 and two small
bores 394 to one side of large bore 392. Guide 390 has a shaft 396 terminating
in
an insertion end 398 that is capable of being inserted into guard 370 and has
a
trailing end 400 having a dimension greater than the inside opening of guard
370
so as to act as a depth limiting stop to prevent further insertion of 390
guide into
guard 370. Moreover, guide 390 is prevented from rotating within guard 370 by
pins 402, which fit into the corresponding grooves at the proximal end 384 of
the
guard 370.
Fig. 39 shows a large drill bit 410 and a small drill bit 430 configured
similarly to large and small drill bits 210, 230 described above with specific
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reference to Fig. 16. In use large drill bit 410 is passed through large bore
392 in
guide 390 to position cutting end 414 into the disc space and is then rotated
to
remove bone from the endplates of the two adjacent vertebral bodies.
Similarly,
small drill bit 430 is passed through the small bores 394 of guide 390 to
position
cutting end 432 into the disc space and then rotated to remove bone from the
endplates of the adjacent vertebral bodies.
As shown in Fig. 42, the holes created with large drill bit 410 and small
drill
bit 430 form a pattern as indicated in the dotted lines. After the first three
holes
have been drilled to provide a large hole L and two small holes S, guide 390
is
removed from within guard 370 and guide 390 is rotated a 180 degrees and
reinserted into guard 370. Guide 390 is now oriented such that large bore 392
is
positioned over the area in which the small holes S were drilled and small
bores
394 are positioned over the area in which the large hole L was drilled. The
drilling
procedure with large drill bit 410 and small drill bit 430 is repeated to
create a
pattern of holes as indicated by the dotted lines in Fig. 43. As a result of
this
drilling procedure, a substantial portion of bone is removed from the
endplates of
the adjacent vertebral bodies creating a space approximating the configuration
of
a rectangle.
As shown in Fig. 40, as the central portion of the space created may not
have all of the bone removed from the drilling procedure through guide 390, a
central bore guide 500 may be inserted into guard 370. Central bore guide 500
has
a large bore 502 that is centrally placed, such that when large drill bit 410
is passed
through central bore guide 500, the portion of bone remaining in the central
portion of the space being created can be removed. As shown in Fig. 44, the
use
of central bore guide 500 may be of particular value in removing remaining
bone
where guide 390 has a hole pattern that when reversed provides for a lesser
amount
of overlap of bores formed through large bore 392. Fig. 45 shows the space
created
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with the drilling procedure through Fig. 44. Central hole C
created with central bore guide 500 is shown in dotted line
in Fig. 46.
As shown in Fig. 47, the space created with the
drilling procedure with the present invention results in a
substantial portion of bone being removed from the endplates
of the adjacent vertebral bodies creating a space that more
closely approximates the configuration of a rectangle.
Fig. 48 shows a space created with the drilling
procedure of the present invention to prepare a still wider
space with a template pattern for the guide having a hole
pattern that uses an offset central drill guide to drill two
additional large bores to remove additional bone to form the
space.
By way of example only, impacted implant 290 has
been illustrated as one type of implant that could be
inserted into the opening formed in the spine by the various
embodiments of instrumentation and methods of the present
invention. By way of another example, without limitation to
use of any other type of implant, a self-broaching,
rotatable impacted implant such as disclosed in U.S. Patent
serial number 6,537,320 could also be inserted into the
opening formed in the spine by the instrumentation and
methods disclosed herein.
With reference to Fig. 49, an interbody spinal
fusion implant is indicated generally as 600. The implant
has a body 602 having an insertion end 604, a trailing end
606, opposed side walls 608, and opposed upper and lower
walls 610. Body 602 has a cross section with side walls 608
intersecting the upper and lower walls 610 at junctions that
are preferably two diametrically opposed corners and two
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diametrically opposed arcs. Fin-like projections 612 extend
outwardly from respective ones of upper and lower walls 610
and are adapted,to penetrate the vertebral endplates of the
adjacent vertebral bodies upon rotation of implant 600 while
the upper and lower walls 610 support the vertebral
endplates of those adjacent vertebral bodies. Body 602 of
implant 600 preferably includes a hollow
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portion that may be accessed through a cap 614 that is preferably located on
an
end of implant 600. The holloaT portion is adapted to contain fusion promoting
material including, but not limited to, bone, in any of its varied forms,
hydroxyapatite, coral, bone morphogenetic proteins, genes coding for the
production of bone, and agents with the ability to induce cells to become
osteoblasts or to make bone.
As shown in Figs. 50 and 51, a vise 700 has surfaces 702 adapted to
cooperatively receive fins 612 and thereby cover the openings between fins
612.
While holding implant 600 in vise 700 with cap 614 removed from implant 600,
fusion promoting material may be compressively loaded into implant 600. Fusion
promoting material may be loaded into implant 600 until the material is
extruded
from openings in side walls 608.
Having described certain preferred embodiments of the surgical instrument
set of the present invention, the method for creating a substantially
quadrilateral
space in a spine will now be described in more detail. A method for creating a
substantially quadrilateral space in a spine for inserting a spinal implant
into a disc
space between adjacent vertebral bodies, comprises the steps of: positioning
guard
170 into contact with the adjacent vertebral bodies for protecting access to
the disc
base and the adjacent vertebral bodies; and boring, through guard 170, a
plurality
of bores across the disc space to form the substantially quadrilateral space
across
the height of the disc space and into the adjacent surfaces of the adjacent
vertebral
bodies.
The present invention may include the step of marking the spine for
guiding, by reference marks, the proper location of guard 170. The step of
marking preferably includes inserting a penetrating extension of a spinal
marker
100 into a central point of the disc space between the adjacent vertebral
bodies.
An embodiment of the present invention includes the step of placing dye spots
on
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the spine by injecting the dye through openings in a shaft 102 of spinal
marker
100. The depth of penetration of marker 100 into the disc space is controlled.
Yet another embodiment of the method of the present invention includes
the step of distracting the disc space between adjacent vertebral bodies, and
in
particular, the distracting step may include the step of inserting a
distractor 130
having a disc penetrating extension into the disc space between adjacent
vertebral
bodies and against endplates of the adjacent vertebral bodies. The depth of
penetration of distractor 130 into the disc space is preferably controlled.
The
method may further include the step of changing disc penetrating extensions of
distractor 130 in accordance with a desired distractor distance between
adjacent
vertebral bodies. Guard 170 may be inserted over distractor 130 and the disc
space, and then distractor 130 may be removed from within guard 170.The
positioning step may include inserting at least one disc penetrating extension
176
extending from guard 170 into the disc space between the adjacent vertebral
bodies
for bearing against endplates of the adjacent vertebral bodies. The insertion
of disc
penetrating extension 176 into the disc space in one embodiment of the
preferred
inverition distracts the adjacent vertebral bodies. Another method of the
present
invention further includes the step of controlling a depth of penetration of
extension 176 into the disc space. Another embodiment of the present invention
includes the step of engaging guard 170 with the adjacent vertebral bodies
through
prongs 182 extending from guard 170 and into the adjacent vertebral bodies.
The boring step may include the sub-step of using a template in association
with guard 170. The template may be rotated 180 degrees along its longitudinal
axis. The boring step may include the sub-step of using either of a drill,
mill, laser,
or grinder to bore the plurality of bores. The plurality of bores may be
overlapping, circular, or both. The boring step may include forming at least
three
bores in the spine to form a first bore pattern, and in particular may include
forming at least a main bore and at least two secondary bores located to a
side of
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the main bore. The main bore has a diameter that is preferably greater than a
diameter of each of the two secondary bores. The main bore in the spine is
preferably positioned to form a portion of three sides of the substantially
quadrilateral space formed in the spine. Each of the two secondary bores are
preferably positioned to form a portion of two adjacent sides of the
substantially
quadrilateral space formed in the spine. A second bore pattern having at least
three bores in the spine may be formed such that the first and second bore
patterns
defined the substantially quadrilateral space. The substantially quadrilateral
space
may be one of a substantially rectangular shape and a substantially
trapezoidal
shape.
Further the invention may comprise the step of inserting a multiple passage
drill guide 190 into guard 170. Guide 190 may be inserted into guard 170 for
guiding the forming of the first bore pattern. The invention may further
include
the steps of removing guide 190 from guard 170, rotating guide190 one hundred-
eighty degrees along its longitudinal axis, reinserting guide 190 into guard
170, and
forming, through the plurality of openings in guide 190, a second bore
pattern, the
first and second bore patterns defining the substantially quadrilateral space.
The
invention may further include the step of controlling the depth of penetration
of
guide 190 into guard 170.
Another embodiment of the present invention includes the step of boring
a centralized bore within the substantially quadrilateral space. The
centralized
bore preferably forms a portion of opposite sides of the substantially
quadrilateral
space. Further the invention may include the step of inserting a secondary
guide
500 into guard 170 and further forming, through an opening in secondary guide
500, a centralized bore within the substantially quadrilateral space.
Yet another embodiment of the present invention includes the step of
compressing outer edges of the substantially quadrilateral space. The step of
compressing preferably includes inserting a compactor 240 having a compaction
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end 244 through guard 170 and into the substantially quadrilateral space
formed
in the spine. The step of compressing preferably includes inserting compactor
240
having compaction end 244 having a sharpened cutting edge for cutting bone.
The
depth of penetration of compactor 240 into the disc space is preferably
controlled.
The step of compressing may include the sub step of inserting a spinal implant
through guard 170 and into.the substantially quadrilateral space formed in the
spine to compress the outer edges on the substantially quadrilateral space.
Another embodiment of the present invention includes a surgical method
to prepare a segment of a human spine having a disc and two vertebral bodies
adjacent the disc for fusion between body portions of the adjacent vertebral
bodies
and through the space previously occupied by the disc, each of the adjacent
vertebral bodies to be fused including a vertebral body having an endplate
outer
surface adjacent the disc space, and a subchondral zone immediately internal
to
each endplate, the method comprising: positioning a guard 170 into contact
with
the adjacent vertebral bodies for protecting access to the disc space and zhe
adjacent vertebral bodies; and forming, through guard 170, a plurality of
bores to
form a substantially quadrilateral space in the spine across the height of the
disc
space and into the adjacent endplates of the vertebral bodies adjacent the
disc
space, the quadrilateral space being formed by the removal of at least bone
from
at least the adjacent endplates as deep as with, and generally not deeper
than, the
subchondral zone of each of the adjacent endplates.
Other embodiments of the invention will be apparent to those skilled in the
art from consideration of the specification and practice of the invention
disclosed
herein. It is intended that the specification be considered as exemplary only,
and
a true scope and spirit of the invention being indicated by the following
claims.
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