U.S. patent application number 11/733051 was filed with the patent office on 2007-12-13 for implantable intervertebral disc shearing device.
Invention is credited to Bogomir Gorensek, Sean Kavanaugh.
Application Number | 20070288028 11/733051 |
Document ID | / |
Family ID | 32043202 |
Filed Date | 2007-12-13 |
United States Patent
Application |
20070288028 |
Kind Code |
A1 |
Gorensek; Bogomir ; et
al. |
December 13, 2007 |
IMPLANTABLE INTERVERTEBRAL DISC SHEARING DEVICE
Abstract
An implantable device for stabilizing joints is provided. The
stabilizing device, or implant, includes an elongated body and at
least two bone cutting surfaces. The bone cutting surfaces are
adapted to cut bone upon rotation of the body about its
longitudinal axis between two bones. The device is adapted to
promote bone fusion. In one embodiment, a device to initiate bony
fusion between two adjacent vertebral bodies in the spine is
provided. Methods of stabilizing joints and promoting bone fusion
are also provided.
Inventors: |
Gorensek; Bogomir;
(Ljubljana, SI) ; Kavanaugh; Sean; (Eastham,
MA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
32043202 |
Appl. No.: |
11/733051 |
Filed: |
April 9, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10669951 |
Sep 24, 2003 |
7201775 |
|
|
11733051 |
Apr 9, 2007 |
|
|
|
60413111 |
Sep 24, 2002 |
|
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Current U.S.
Class: |
606/80 ;
606/88 |
Current CPC
Class: |
A61F 2/4611 20130101;
A61B 17/1671 20130101; A61F 2002/30622 20130101; A61F 2002/4649
20130101; A61F 2002/30166 20130101; A61B 17/1637 20130101; A61F
2002/2835 20130101; A61F 2/40 20130101; A61B 17/1642 20130101; A61F
2310/00179 20130101; A61F 2/446 20130101; A61F 2002/3092 20130101;
A61F 2002/30593 20130101; A61F 2002/4681 20130101; A61F 2230/0028
20130101; A61F 2002/30677 20130101; A61F 2310/00023 20130101; A61F
2/42 20130101; A61F 2/30767 20130101; A61F 2002/30784 20130101;
A61F 2002/448 20130101; A61F 2310/00976 20130101; A61F 2002/30772
20130101 |
Class at
Publication: |
606/080 ;
606/088 |
International
Class: |
A61B 7/00 20060101
A61B007/00 |
Claims
1. An implantable stabilizing device for stabilizing a joint in the
human body comprising: an elongate body having an upper surface and
a lower surface, wherein said upper and lower surfaces having a
longitudinal axis and transverse axis; a first pair of opposing
blade-like shearing protrusions extending from said upper surface
of the elongate body; a second pair of opposing blade-like shearing
protrusions extending from said lower surface of the elongate body,
wherein said first pair of blade-like shearing protrusions
comprises a leading edge and a trailing edge, and wherein said
second pair of blade-like shearing protrusions comprises a leading
edge and a trailing edge.
2. The device of claim 1, wherein at least one of said first pair
or second pair of blade-like shearing protrusions extend away from
the elongate body at an angle less than about 90 degrees relative
to the transverse axis of the elongate body to facilitate
containment of a harvested bone material.
3. The device of claim 1, wherein at least one of said first pair
or second pair of blade-like shearing protrusions are curved to
facilitate the containment of harvested bone.
4. The device of claim 1, wherein at least one of said first pair
or second pair of blade-like shearing protrusions comprises
barbs.
5. The device of claim 1, wherein at least one of said first pair
or second pair of blade-like shearing protrusions comprises one or
more perforations, holes, or voids.
6. The device of claim 5, wherein said one or more perforations,
holes, or voids permit bone ingrowth.
7. The device of claim 1, wherein at least one of said first pair
or second pair of blade-like shearing protrusions comprises a
porous portion.
8. The device of claim 7, wherein said porous portion permits bone
ingrowth.
9. The device of claim 1, wherein at least a portion at least one
of said first pair or second pair of blade-like shearing
protrusions is coated with a bone growth facilitator.
10. The device of claim 1, wherein said first pair and second pair
of shearing protrusions extend along said upper and lower surface
of the elongate body at an angle parallel to the transverse axis of
the elongate body.
11. The device of claim 1, wherein said wherein said first pair and
second pair of shearing protrusions are oriented along said upper
and lower surface of the elongate body such that said shearing
protrusions pairs form a wedge.
12. The device of claim 1, wherein the elongate body comprises a
hollow portion.
13. The device of claim 12, wherein the hollow portion is adapted
to accept bone that is sheared by at least one of said first pair
or second pair of blade-like shearing protrusions.
14. The device of claim 1, wherein the elongate body comprises one
or more perforations, holes, or voids.
15. The device of claim 14, wherein said one or more perforations,
holes, or voids permit bone ingrowth.
16. The device of claim 1, wherein the elongate body comprises a
porous portion.
17. The device of claim 16, wherein said porous portion permits
bone ingrowth.
18. The device of claim 1, wherein at least a portion of the
elongate body is coated with a bone growth facilitator.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 10/669,951, which was filed on Sep. 24, 2003,
which claims the benefit of U.S. Provisional Patent Application No.
60/413,111, which was filed on Sep. 24, 2002, and which are all
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention pertains to surgical stabilizing devices and
procedures for stabilizing joints within the spine, and other
joints. More particularly, this invention pertains to a novel
stabilizing device that utilizes one or more local bone autografts
harvested during the implantation procedure.
[0004] 2. Description of the Related Art
[0005] The treatment of back pain can be relieved by preventing
relative motion between spinal vertebrae. Intervertebral
stabilization achieved by the use of spine cages, intervertebral
spacers, and bone grafts for insertion into the space formerly
occupied by a degenerated disc are known in the art. These devices
may involve mechanically coupling the adjacent vertebrae or by
promoting fusion between them. Accordingly, such techniques are
used to stabilize the spine and reduce pain by rigidly joining two
adjacent vertebrae that oppose a degenerated disc or degenerated
posterior elements of the vertebrae (e.g. facet joints).
SUMMARY OF THE INVENTION
[0006] In one embodiment of the current invention, an implantable
stabilizing device for stabilizing two adjacent vertebral bodies in
the human spine is provided. The stabilizing device, or implant,
comprises an elongated body, having a longitudinal axis and a
transverse axis, and at least two bone cutting surfaces. In one
embodiment, the elongated body has a first bone cutting surface and
a second bone cutting surface that are offset from the longitudinal
axis of the body. The first bone cutting surface faces in a first
direction, and the second bone cutting surface faces in a second
direction. The first bone cutting surface and/or the second bone
cutting surface is adapted to cut bone upon rotation of the body
about its longitudinal axis between two adjacent vertebral
bodies.
[0007] In several embodiments, the bone cutting surfaces are blades
or blade-like surfaces. In one embodiment, the first bone cutting
surface, the second bone cutting surface and/or the elongated body
has one or more perforations, holes, or voids. In another
embodiment, the first bone cutting surface, the second bone cutting
surface and/or the elongated body is made of a material that is at
least partially porous.
[0008] In one embodiment, at least a portion of the elongated body
is hollow. In some embodiments, the elongated body is a support
member that serves to connect two bone cutting blades.
[0009] In one embodiment, at least one bone cutting surface
comprises one or more teeth. In another embodiment, at least one
bone cutting surface is curved inward relative to the elongated
body. In one embodiment, at least one bone cutting surface is
sharpened. In another embodiment, at least one bone cutting surface
is blunt.
[0010] In several embodiments, a portion of a bone cutting surface
and/or the elongated body includes at least one shearing means or
protrusions. Protrusions include, but are not limited to, barbs,
spikes and wedges. In some embodiments, a portion of a bone cutting
surface and/or the elongated body is treated with a surface
treatment. The surface treatment includes, but is not limited to,
bone growth facilitator (e.g., bone morphogenic protein) and/or
adhesives (e.g., cyanoacrylate). In one embodiment, the implantable
stabilizing device further includes a source or supply of bone
growth facilitator.
[0011] In several embodiments, a portion of a bone cutting surface
and/or the elongated body is constructed from a biocompatible
material, including but not limited to titanium, steel, plastic,
and ceramic.
[0012] In one embodiment of the present invention, an implantable
device for stabilizing a joint is provided. In one embodiment, the
joint is a spinal joint. In other embodiments, the joint is in the
shoulder, wrist, ankle, knee, hip, or digits. In several
embodiments, the implantable device, or implant, comprises a first
bone cutting surface and a second bone cutting surface that are
connected by a support member.
[0013] In one embodiment, the bone cutting surfaces include a first
leading edge, a first trailing edge, a first top edge and a first
bottom edge. The support member comprises a length that is mounted
perpendicular to the first bone cutting surface and the second bone
cutting surface and is spaced from said first bone cutting surface
and second bone cutting surface by a distance in the range of about
1 cm to about 5 cm. At least one of the bone cutting surfaces is
adapted to accept a local bone autograft.
[0014] In one embodiment, at least one of bone cutting surface is a
blade. In another embodiment, at least one of bone cutting surface
is a blade is curved inward relative to the support member.
[0015] In some embodiments, at least one edge of at least one bone
cutting surface is sharpened. In some embodiments, at least one
edge of at least one bone cutting surface is blunt. In one
embodiment, the leading edges of both bone cutting surfaces is
sharp.
[0016] In one embodiment, an implantable stabilizing device for
stabilizing two adjacent vertebral bodies in the human spine is
provided. In one embodiment, the stabilizing device, or implant,
comprises an elongated body having a longitudinal axis and a
transverse axis, a first shearing means on the elongated body
offset from the longitudinal axis and a second shearing means on
the elongated body offset from the longitudinal axis. The first
shearing means faces in a first direction, and the second shearing
means faces in a second direction. At least one of the shearing
means is adapted to shear bone upon rotation of the body about its
longitudinal axis between two adjacent vertebral bodies.
[0017] In one embodiment of the present invention, a method of
initiating bony fusion between a first bone and a second bone is
provided. In one embodiment, an implant having a body with a
longitudinal axis, and at least a first bone cutter and a second
bone cutter offset in opposite transverse directions from the
longitudinal axis is provided. The implant is introduced between
the first and second bones and rotated about its longitudinal axis
so that the first and second bone cutters cut fragments from the
first and second bones. The implant is left in position between the
first and second bones. In one embodiment, a bone growth
facilitator is infused through at least a portion of the implant.
In some embodiments, a second implant is inserted in between the
first and second bones.
[0018] In one embodiment, bony fusion is initiated between adjacent
vertebral bodies. In one embodiment, at least one of the first and
second vertebral bodies is in the sacral spine, lumbar spine or
cervical spine.
[0019] In one embodiment, the implant is rotated through no more
than one revolution. In another embodiment, the implant is rotated
through no more than about 120 degrees. In another embodiment,
rotation is stopped at a point where the first bone cutter is in
contact with the first bone and the second bone cutter is in
contact with the second bone.
[0020] In one embodiment of the current invention, a method of
stabilizing two adjacent vertebral bodies is provided. In one
embodiment, a stabilizing device having a first bone cutting
surface and a second bone cutting surface connected by a support
member is provided. The bone cutting surfaces comprise a leading
edge, a trailing edge, a top horizontal edge and a bottom
horizontal edge. The stabilizing device is oriented such that the
bone cutting surface are perpendicular to the endplates of said
vertebral bodies and the support member is parallel to said
endplates. The stabilizing device is inserted into and across the
endplates such that at least a portion of at least one of the
endplates is lodged between the bone cutting surface. The
stabilizing device is rotated such that at least one of the
endplates is translocated perpendicular to its original
location.
[0021] In one embodiment of the invention, a method of promoting
bony fusion between a first bone and a second bone is provided. One
or more implants having a body with a longitudinal axis, and at
least a first shearing means and a second shearing means offset in
opposite transverse directions from the longitudinal axis is
provided. The implants are introduced in between the first and
second bones. At least one of the implants is rotated about its
longitudinal axis so that the first and second shearing means shear
one or more fragments from the first and second bones. At least one
or more implants in left in position between the first and second
bones.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 shows a sagittal view of functional spinal unit.
[0023] FIG. 2 shows a sagittal view of functional spinal unit with
a herniated disc.
[0024] FIG. 3 shows a front cross-sectional view of a functional
spinal unit.
[0025] FIG. 4A, which presents an isometric view of an embodiment
of the invention, FIGS. 4B and C show front view of different
cross-sections of an embodiment of the invention.
[0026] FIG. 5 is an isometric view of an alternative embodiment of
the invention.
[0027] FIG. 6 is an isometric view of an alternative embodiment of
the invention.
[0028] FIG. 7 is an isometric view of an alternative embodiment of
the invention.
[0029] FIG. 8 is an isometric view of an alternative embodiment of
the invention.
[0030] FIG. 9 is a side view of a driver device coupled to the
stabilizing device.
[0031] FIG. 10 is an isometric view of a functional spinal unit
with the posterior elements removed.
[0032] FIGS. 11A, 11B, and 11C show the rotation of a stabilizing
device and translocation of local bone from the endplates of
adjacent vertebral bodies.
[0033] FIG. 12A shows a spinal unit with pre-delivery horizontal
cuts.
[0034] FIG. 12B shows an implanted stabilizing device prior to
rotation.
[0035] FIG. 13 shows alternative delivery method utilizing
cylindrical boring device.
[0036] FIG. 14 is a sagittal view of an ankle joint.
[0037] FIG. 15 is a posterior view of an ankle with an implanted
stabilizing device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0038] Several embodiments of present invention involve stabilizing
devices and methods that immobilize adjacent vertebral bodies or
other selected joints. One or more of the embodiments, a
stabilizing device, or implant, is provided to re-establish and
maintain proper alignment and distance between the adjacent
vertebrae and to serve as a spacer or fusion cage. The shape of the
stabilizing device offers sufficient surface area to offer initial
resistance to axial compression between the adjacent endplates and
over time, as fusion progresses, even greater resistance. Several
embodiments of the present invention are particularly advantageous
because they offer pain relief. In one embodiment, pain caused by
spinal stenosis or by degenerated or herniated disc tissue is
ameliorated or eliminated via discectomy and reestablishment of
proper vertebral spacing. In another embodiment, pain caused by
degenerated facet joints and pathological increased range of motion
is reduced.
[0039] In one embodiment, the methods of autograft bone harvest and
implantation are combined. Here large hunks or plates (as compared
to small chips) are cleaved from a proximal bony surface as the
stabilizing device is inserted between the vertebral bodies. Large
chunks of bone with sufficient surface area and structural
integrity are harvested. The site in which one or more of the
grafts are harvested are also "prepared" in that the bone surface
is scraped, or otherwise manipulated, to stimulate a healing
response and promote fusion. By selecting local bone (and not bone
from, for example the hip which requires addition incisions and
site preparation and closing) and combing the harvesting step with
the implantation step, several embodiments of the invention provide
several benefits. These benefits include, but are not limited to,
decreased operation time, increased surgical efficiency, patient
acceptance of the stabilizing device, and effectiveness of the
fusion. Although, in a preferred embodiment large portions of local
bone are cleaved, one of skill in the art will understand that
smaller bone fragments and/or non-local bone from other sites can
be used in accordance with several embodiments of the present
invention.
[0040] Reference is now directed at FIG. 1, which is a sagittal
view of a functional spinal unit 100 comprising a superior
vertebral body 1, an anulus fibrosus 3 connected to an adjacent
inferior vertebral body 2. Posterior elements of the vertebral
bodies include a spinous process 4, transverse process 4 and facet
joint 6. Each vertebral body has an inferior 7 and superior
endplate 8 which along with the anulus fibrosus 3 bounds the
nucleus pulposus.
[0041] FIG. 2 shows the functional spinal unit of FIG. 1, with a
herniated disc 200. Here the collagenous fibers of the anulus
fibrosus 3 have broken and nucleus pulposus and anulus fibers have
entered the space normally occupied by the nerves of the spinal
canal.
[0042] FIG. 3 shows a front cross-sectional view of a functional
spinal unit 100. The endplates 7, 8, 9, 10 are comprised of dense
cortical bone near the periphery of the endplates and more porous
and flexible cancellous bone towards the center. Within each
vertebral body 1, 2 is marrow 12. The anulus 3 and nucleus pulposus
11 are also shown.
[0043] FIG. 4A represents an isometric view of one embodiment of
the invention. FIG. 4A shows a stabilizing device, or implant,
comprising an elongated body 14 and first 16 and second 18 opposing
bone cutting surfaces separated by the width of the elongated body
14. Alternatively the bone cutting surfaces could simply be
connected by one or more struts or support members instead of the
elongated body. Each bone cutting surface can have four sharpened
edges or portions sharpened thereof such on or more of the leading,
trailing, and horizontal edges of the bone cutting surfaces. In
several embodiments, the first bone cutting surfaces 14 and/or the
second bone cutting surfaces 16 is comprised of a plurality of bone
cutting surfaces. In one embodiment, the first bone cutting surface
14 and second bone cutting surface 16 are each configured of two
separate bone cutting surfaces, e.g., an upper bone cutting surface
and a lower bone cutting surface. In one embodiment, the bone
cutting surfaces are blades or blade-like surfaces. As shown in
FIG. 4A, the elongated body 14 has a first bone cutting surface 16
and a second bone cutting surface 18 that are offset from the
longitudinal axis of the body 14. The first bone cutting surface 16
faces in a first direction, and the second bone cutting surface 18
faces in a second direction. The first bone cutting surface 16
and/or the second bone cutting surface 18 is adapted to cut bone
upon rotation of the body 14 about its longitudinal axis between
two adjacent bones.
[0044] FIG. 4B and FIG. 4C show front views of different
cross-sections of one embodiment of the device. FIG. 4B shows an
"H"-like cross-section with straight bone cutting surfaces 20, 22,
comprising bards or roughened surface to fix bone grafts. FIG. 4C
shows curved bone cutting surfaces 24, 26 to trap and/or fix bone
graft material. In one embodiment, a "T"-like cross-section is
provided.
[0045] FIG. 5 is an isometric view of one embodiment of the
invention showing an elongated body with a first bone cutting
surface 116 and second bone cutting surface 118. The body 114 is at
least partially hollow. In one embodiment, the hollowed portion is
adapted to accept graft material or other biocompatible material.
In one embodiment, the hollow body facilitates rotation of the
stabilizing device. In embodiments where the body is not hollow, a
hex-shaped insert may be cut-out of the body to facilitate rotation
with compatible rods and tools. In some embodiments, the elongated
body is a support member that serves to connect two bone cutting
surfaces.
[0046] In one embodiment, a portion of a bone cutting surface
and/or the elongated body includes at least one shearing means or
protrusion. Protrusions include, but are not limited to, barbs,
spikes and wedges. In some embodiments, a portion of a bone cutting
surface and/or the elongated body is treated with a surface
treatment, such as bone growth facilitator (e.g., bone morphogenic
protein) and/or adhesives (e.g., cyanoacrylate). In one embodiment,
the implantable stabilizing device further includes a source or
supply of bone growth facilitator. Bone growth facilitator aids in
the promotion of bone growth and/or stability and, in some
embodiments, can accelerate bone fusion and decrease patient
recovery times.
[0047] FIG. 6 shows a hollow elongated body 214, comprising one or
more perforations, holes, or voids. The first bone cutting surface
216 and/or the second bone cutting surface 218 also comprises one
or more perforations, holes, or voids. One function of the
perforations, holes, or voids is to permit bone ingrowth and
promote fusions. In one embodiment, at least one of the cutting
surfaces or the body is at least partially porous. The porous
material, and the perforations, holes, or voids, are also
advantageous because they permit the infusion or passage of bone
growth facilitator to the required sites.
[0048] FIG. 7 expands on the concept depicted in FIG. 6 by removing
substantially all of the elongated body to leave a body 314
comprising of a leading support member 328 and trailing support
member 330, shown here with rectangular voids. One of skill in the
art will understand that the voids can be of any shape suitable to
accomplish the desired purpose, including, but not limited to,
rectangular, square, triangular, oval or circular-shaped voids. In
one embodiment, the first bone cutting surface 316 and/or the
second bone cutting surface 318 have sharpened horizontal edges
20', 20'' and can be rotated up to 360 degrees and serve to scoop,
bore or core out an entire graft segment, or portions thereof. In
another method, the device 500 can be rotated in the range of about
90 degrees to about 180 degrees.
[0049] FIG. 8 shows one embodiment of the device with the first
bone cutting surface 416 and second bone cutting surface 418
comprising one or more voids in the body 414 and/or bone cutting
surfaces 416, 418. In one embodiment, two or more voids along the
horizontal edges 20', 20'' create teeth 432, 434. In one
embodiment, each bone cutting surface 416, 418 has a horizontal
edge 20 with leading 432', trailing upper teeth 432'', and leading
434' and trailing 434'' lower teeth. One skilled in the art will
understand that fewer or more teeth can be used in accordance with
several embodiments of the present invention.
[0050] FIG. 9 shows a side view of one embodiment of the
stabilizing device 500 coupled to a driver 550. The stabilizing
device, or implant, comprises a leading edge 510 and a horizontal
edge 520. The coupling, engagement or connection can be a socket
and sleeve, friction fit, clamp, or other connection known in the
art. The driver 550 can be used as a site to apply the force of a
hammer, or other like tool, to cut through the vertebrae of a
herniated spine unit 200 and later as a site to apply rotational
force 510 by hand or machine. According to several embodiments of
the invention, the stabilizing device 500 can be a uni- or
multi-component construct of biocompatible material. For example
the entire stabilizing device 500, or portions thereof, could be
constructed from titanium or steel, or some combination thereof.
Alternatively, other metals and alloys could be employed for the
bone cutting surfaces and coupled to plastic, ceramic, or other
biocompatible material comprising the connection member or
elongated body. Accordingly, various embodiments of the invention
can be constructed from ceramics, metals, plastics, composites or
any suitable biocompatible material and combinations thereof.
[0051] As discussed above, in several embodiments, various
sharpened and blunt protrusions along the length and faces of the
bone cutting surfaces and off of the central body of the
stabilizing device can be used for shearing and cutting. For
example, the sharpened protrusions on the leading edge of the bone
cutting surfaces can be used to facilitate straight shearing or
cutting as the stabilizing device is hammered in place prior to the
rotational shearing by the blunt or sharpened horizontal edge. The
shape of the bone cutting surface and its orientation with respect
to the elongated body or connection members can be adapted to hold
or keep harvested autograft in place by angling the bone cutting
surfaces less than 90 degrees relative to the body or by curving
them in ward. Barbs or surface roughness along the bone cutting
surfaces and body may also be used to fix the graft to the
stabilizing device.
Dimensions and Size Range
[0052] In several embodiments, the stabilizing device can be
properly sized from precise dimensions of the intervertebral disc
geometry of the individual selected for treatment. One skilled in
the art will understand that these dimensions can be culled from
CAT scan data or similar data from another modality. For example,
scans can be used to determine the proper or normal distance
between adjacent vertebral bodies and this distance can be used to
approximate the height of the stabilizing device. Similarly, data
from scans depicting the internal dimensions of the anulus and
endplates (in a neutral position) can be used to design the outer
shape of the device so that after harvesting bone along the
endplates and rotating the stabilizing device, a precise fit is
achieved. In one embodiment, the device has a width in the range of
about 0.25 cm to about 7 cm, preferably between about 0.5 cm to
about 6 cm, more preferably between about 1 cm to about 5 cm. In
one embodiment, the device has a length in the range of about 0.25
cm to about 5 cm, preferably between about 0.5 cm to about 4 cm,
more preferably between about 1 cm to about 3 cm. In one
embodiment, multiple stabilizing devices are stacked between the
same two vertebral bodies. Such stacking, in some embodiments, aid
in stability and allow for the use of smaller stabilizing
devices.
Delivery Method
[0053] In one embodiment of the present invention, a method of
initiating bony fusion between a first bone and a second bone is
provided. In one embodiment, an implant having a body with a
longitudinal axis, and at least a first bone cutter and a second
bone cutter offset in opposite transverse directions from the
longitudinal axis is provided. The implant is introduced between
the first and second bones and rotated about its longitudinal axis
so that the first and second bone cutters cut fragments from the
first and second bones. The implant is left in position between the
first and second bones. In some embodiments, a second implant is
inserted in between the first and second bones. In one embodiment,
bony fusion is initiated between adjacent vertebral bodies. In one
embodiment, at least one of the first and second vertebral bodies
is in the sacral spine, lumbar spine or cervical spine. In one
embodiment, the implant is rotated through no more than one
revolution. In another embodiment, the implant is rotated through
no more than about 120 degrees. In another embodiment, rotation is
stopped at a point where the first bone cutter is in contact with
the first bone and the second bone cutter is in contact with the
second bone.
[0054] In one embodiment, bone growth facilitator is infused
through at least a portion of the implant. Bone growth facilitator
can be introduced via one or more lumens in the boring instrument
or rods, described below, or can be introduced using a separate
insertion device. In one embodiment, bone growth facilitator is an
integral part of the stabilizing device. In some embodiments, the
stabilizing device, or implant, is coupled to a source of bone
growth facilitator. In alternative embodiments, the implant is
pre-treated with bone growth facilitator.
[0055] In several embodiments, more than one stabilizing device is
used. In one embodiment, two stabilizing devices are used. In
another embodiment, three stabilizing devices are used. In one
embodiment, a stabilizing device as described herein is used in
connection with one or more structural devices, such as screws,
that are used to stabilize the space between two bones by
restricting movement.
[0056] In one embodiment, insertion of the stabilizing device is
performed using an anterior approach, though a lateral approach can
also be used. FIG. 10 shows an isometric view of the posterior of a
functional spinal unit 100 comprising a superior vertebral body 1,
inferior vertebral body 2, an anulus 3, a transverse process 4, and
portion of a facet joint 6. The other posterior elements have been
surgically removed. In this embodiment, a posterior approach can be
used.
[0057] In one embodiment, arthroscopic equipment known in the art
may be used to perform a partial or complete discectomy to provide
an initial implantation site. A distraction device can then be used
to provide access to the intervertebral space and allow for precise
delivery. Alternatively, the stabilizing device itself can be
designed with a wedge profile and forcibly inserted across the
endplates thereby distracting them. An insertion rod can engage or
be placed against the distal or trailing side if the device and
used to push the device or as a site to apply the force of a
hammer.
[0058] In an alternative delivery method, the stabilizing device
can be used without performing a discectomy or distracting the
endplates. In this embodiment, the leading edges of the bone
cutting surfaces of the stabilizing device are also sharpened and
used to cut straight into the vertebral bodies (across to the
endplates) as the stabilizing device is driven between and parallel
the adjacent endplates. As the stabilizing device is inserted, a
hollow mid-section of the central body can accept the displaced
disc material in between.
[0059] FIGS. 11A-C show a method of delivery according to one
embodiment of the invention. Following the initial implantation
between the vertebral bodies 7, 8, one or more drivers 550 or
insertion rods are engaged to the device and used to impart axial
rotation (driver is not shown) causing the bladed edges of the
stabilizing device along its length to gouge and shear off portions
of the adjacent endplates 7, 8. These portions are then forced into
the adjacent hollow receiving zones of the stabilizing device.
Barbs or other means, including, but not limited to spikes, wedges,
surface treatments, adhesives (e.g., cyanoacrylate) or some
combination thereof, may be used along the stabilizing device
surface, or portions of the stabilizing device surface, to retain
the harvested bone 600.
[0060] After rotation through approximately 90 degrees, the driver
550 or insertion rod is removed. In this orientation, the harvested
bone 600 contacts the sidewalls and edges of both vertebrae that
now have freshly scraped osteogenic surfaces. The curved and
sharpened edges of the stabilizing device lie substantially
parallel to the endplates and the harvested bone is flush with or
extends beyond their edges to reduce or prevent further cutting or
physical trauma. In one embodiment, a hollow stabilizing device (as
shown in FIG. 7) is used to fully shear through the bone in one or
more partial or complete revolutions.
[0061] FIG. 12A and 12B show an alternative delivery method in
which an initial step is added prior to inserting the stabilizing
device. Here one or more horizontal holes or slots 905 are punched
above each of the endplates as shown. The stabilizing device 500 is
hammered into place through the endplates and across the disc
space. One advantage of this step is that it facilitates rotation
of the stabilizing device 500 (and displacement of the bone
grafts).
[0062] FIG. 13 shows a cylindrical boring instrument 900 and the
cut 910 it makes into the vertebral bodies 1, 2. After the bore 900
has been removed, a device 500 with or without sharpened edges may
be inserted and rotated, as described above.
[0063] In one or more embodiments discussed herein, initial
fixation can be achieved through one or more of vertebral taxis
(caused be the tension of the remaining anulus fibers), wedging
action and friction. Secondary or permanent fixation via fusion
occurs over a period of weeks as the portions of the harvested bone
in the stabilizing device fuse to each other and the adjacent
vertebrae until eventually the stabilizing device is
encapsulated.
[0064] In one embodiment of the invention, stabilizing devices of
varying sizes and geometries are used to fuse other pathological
joints of the body. These joints include, but are not limited to
joints of the shoulder, wrist, ankle, knee, hip, and digits. FIG.
14 shows a sagittal view of an ankle joint, including fibula 980,
tibia 986, talus 988 and calcaneus 982.
[0065] FIG. 15 shows the ankle bone with an implanted stabilizing
device 500. The stabilizing device 500 is used to fuse an ankle
joint. In this embodiment, the stabilizing device is inserted along
the bones and cartilage between the tibia 986, talus 988, calcaneus
982, an/or fibula 980. In one embodiment, the stabilizing device is
implanted between two or more adjacent bones.
[0066] While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
scope of the invention encompassed by the appended claims.
Additionally, it will be recognized that the methods described
herein may be practiced using any device suitable for performing
the recited steps. Such alternative embodiments and/or uses of the
methods and devices described above and obvious modifications and
equivalents thereof are intended to be within the scope of the
present disclosure.
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