U.S. patent application number 11/327298 was filed with the patent office on 2006-09-21 for intervertebral spacer.
Invention is credited to James W. Ogilvie, Peter Pal Varga.
Application Number | 20060212119 11/327298 |
Document ID | / |
Family ID | 24369156 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060212119 |
Kind Code |
A1 |
Varga; Peter Pal ; et
al. |
September 21, 2006 |
Intervertebral spacer
Abstract
An intervertebral spacer adapted for implanting between adjacent
vertebral bodies of a human spine as a load-bearing replacement for
a spinal disc. The spacing member may include an external,
non-porous, concavo-convex contour with respect to one dimension of
the spacing member. The spacing member may be constructed from a
rigid, non-resilient load-bearing material that is incapable of
elastic deformation. The spacing member may be inserted with the
aid of a sheathed trocar device that is releasably attached to the
spacer, to enable implantation and selective positioning of the
spacer by the surgeon from the posterior side of the spine, without
the need to retract the dural nerve or the posterior longitudinal
ligament.
Inventors: |
Varga; Peter Pal; (Budapest,
HU) ; Ogilvie; James W.; (Brighton, UT) |
Correspondence
Address: |
KARL R CANNON
PO BOX 1909
SANDY
UT
84091
US
|
Family ID: |
24369156 |
Appl. No.: |
11/327298 |
Filed: |
January 6, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11205284 |
Aug 15, 2005 |
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11327298 |
Jan 6, 2006 |
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11081824 |
Mar 15, 2005 |
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11205284 |
Aug 15, 2005 |
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10957328 |
Oct 1, 2004 |
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11081824 |
Mar 15, 2005 |
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10800418 |
Mar 12, 2004 |
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10957328 |
Oct 1, 2004 |
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10643779 |
Aug 18, 2003 |
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10800418 |
Mar 12, 2004 |
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10358103 |
Feb 3, 2003 |
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10643779 |
Aug 18, 2003 |
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10188281 |
Jul 1, 2002 |
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10358103 |
Feb 3, 2003 |
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09592072 |
Jun 12, 2000 |
6579318 |
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10188281 |
Jul 1, 2002 |
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Current U.S.
Class: |
623/17.11 ;
606/247; 606/279; 606/907; 606/909 |
Current CPC
Class: |
A61F 2/442 20130101;
A61F 2310/00023 20130101; A61F 2/28 20130101; A61F 2310/00179
20130101; A61F 2002/2835 20130101; A61F 2/4465 20130101; A61F
2230/0015 20130101; A61F 2002/30828 20130101; A61F 2002/30133
20130101; A61F 2002/4627 20130101; Y10S 623/908 20130101; A61F
2/4611 20130101; A61F 2/4684 20130101; A61F 2002/30774
20130101 |
Class at
Publication: |
623/017.11 ;
606/061 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61B 17/70 20060101 A61B017/70 |
Claims
1. An intervertebral spacing implant comprising: a spacing member
adapted for implanting between adjacent vertebral bodies of a human
spine as a load-bearing replacement for a spinal disc, said spacing
member further comprising an external, concavo-convex contour with
respect to one dimension of said spacing member; wherein the
spacing member comprises a solid body; wherein the spacing member
comprises an upper surface and a lower surface and a free insertion
end, and wherein at least one of said upper surface and said lower
surface comprises a male corner line, and wherein said spacing
member includes a tapered portion between said male corner line and
said free insertion end of said spacing member such that said
spacing member becomes progressively thinner from said male corner
line toward said free insertion end of said spacing member, wherein
said tapered portion is characterized by at least one smooth
surface that is a part of either said upper surface or said lower
surface and extends from said male corner line to said free
insertion end, said smooth surface having an absence of corners,
points or other abrupt edges; and wherein said spacing member
comprises a sidewall around a perimeter of said spacing member,
said sidewall having a smooth contour characterized by an absence
of corners extending from said upper surface to said lower
surface.
2. The intervertebral spacing implant of claim 1, wherein the
spacing member is either inherently non-porous or is otherwise
rendered non-porous.
3. The intervertebral spacing implant of claim 1, wherein the
spacing member is constructed from a rigid, non-resilient
load-bearing material.
4. The intervertebral spacing implant of claim 1, wherein the
spacing member defines an imaginary arcuate centerline residing
between opposing sides of the external concavo-convex contour of
said spacing member, said arcuate centerline forming less than half
a circle.
5. The intervertebral spacing implant of claim 1, wherein said
spacing member has a cashew shape having a uniform width along a
majority length of the spacing member.
6. The intervertebral spacing implant of claim 1, wherein the
spacing member comprises a bone material.
7. The intervertebral spacing implant of claim 1, wherein the
spacing member comprises metal.
8. The intervertebral spacing implant of claim 1, wherein the
spacing member comprises titanium.
9. The intervertebral spacing implant of claim 1, wherein the
spacing member comprises ceramic.
10. The intervertebral spacing implant of claim 1, wherein the
spacing member includes an anterior wall and a posterior wall, and
wherein the external concavo-convex contour of the spacer is
defined by the posterior wall being concave in a horizontal
dimension and by the anterior wall being convex in a horizontal
dimension.
11. The intervertebral spacing implant of claim 10, wherein the
anterior wall and the posterior wall of the spacing member are each
linear in a vertical dimension.
12. The intervertebral spacing implant of claim 1, wherein the
concavo-convex contour comprises a concave posterior side, and a
convex anterior side disposed in a substantially parallel
orientation with respect to the concave posterior side.
13. The intervertebral spacing implant of claim 1, wherein the
spacing member further comprises a disc-like member having a
thickness at a thickest part of the spacing member, and a length
that is greater in length than said thickness at said thickest
part, and a width that is greater in width than said thickness at
said thickest part.
14. The intervertebral spacing implant of claim 13, wherein the
width of the spacing member is defined by a perimeter wall that
constitutes the concave side and the convex side of the external
concavo-convex contour of said spacing member.
15. The intervertebral spacing implant of claim 1, wherein the
spacing member further comprises a plurality of spaced-apart
recesses formed in said upper surface.
16. The intervertebral spacing implant of claim 15, wherein the
recesses are elongate and are disposed in a substantially parallel
orientation with respect to each other.
17. The intervertebral spacing implant of claim 16, wherein the
recesses extend in an anterior-to-posterior direction.
18. The intervertebral spacing implant of claim 15, wherein the
spaced-apart recesses comprise opposing sidewalls disposed at a
non-parallel angle with respect to each other.
19. The intervertebral spacing implant of claim 18, wherein said
angle is within a range of between approximately 45 degrees and 75
degrees.
20. The intervertebral spacing implant of claim 19, wherein said
angle is approximately 60 degrees.
21. The intervertebral spacing implant of claim 1, wherein said
spacing member further comprises attachment means for releasably
attaching positioning means to said spacing member.
22. The intervertebral spacing implant of claim 21, wherein said
attachment means are positioned on an end of said spacing member
opposite said free insertion end.
23. The intervertebral spacing implant of claim 21, wherein said
attachment means for releasably attaching positioning means to said
spacing member comprises a recess in said spacing member.
24. The intervertebral spacing implant of claim 23, wherein said
attachment means for releasably attaching positioning means to said
spacing member comprises a threaded bore.
25. An intervertebral spacing implant comprising: a spacing member
adapted for implanting between adjacent vertebral bodies of a human
spine as a load-bearing replacement for a spinal disc, said spacing
member further comprising an external, concavo-convex contour with
respect to one dimension of said spacing member; wherein the
spacing member defines an imaginary arcuate centerline residing
between opposing sides of the external concavo-convex contour of
said spacing member; wherein the spacing member comprises a first
end, a second end, and a length between said first end and said
second end; wherein said spacing member includes a tapered portion
at said second end such that said spacing member becomes
progressively thinner toward said second end of said spacing
member; wherein said tapered portion extends along only a portion
of said length; and wherein said spacing member comprises a
sidewall around a perimeter of said spacing member, said sidewall
having a smooth contour characterized by an absence of corners
extending from said upper surface to said lower surface.
26. The intervertebral spacing implant of claim 25, wherein the
spacing member is solid and is either inherently non-porous or is
otherwise rendered non-porous.
27. The intervertebral spacing implant of claim 25, wherein the
spacing member is constructed from a rigid, non-resilient
load-bearing material.
28. The intervertebral spacing implant of claim 25, wherein said
arcuate centerline forms less than half a circle.
29. The intervertebral spacing implant of claim 25, wherein said
spacing member has a cashew shape having a uniform width along a
majority length of the spacing member.
30. The intervertebral spacing implant of claim 25, wherein the
spacing member comprises a bone material.
31. The intervertebral spacing implant of claim 25, wherein the
spacing member includes an anterior wall and a posterior wall, and
wherein the external concavo-convex contour of the spacer is
defined by the posterior wall being concave in a horizontal
dimension and by the anterior wall being convex in a horizontal
dimension.
32. The intervertebral spacing implant of claim 31, wherein the
anterior wall and the posterior wall of the spacing member are each
linear in a vertical dimension.
33. The intervertebral spacing implant of claim 25, wherein the
concavo-convex contour comprises a concave posterior side, and a
convex anterior side disposed in a substantially parallel
orientation with respect to the concave posterior side.
34. The intervertebral spacing implant of claim 25, wherein the
spacing member further comprises a disc-like member having a
thickness at a thickest part of the spacing member, and a length
that is greater in length than said thickness at said thickest
part, and a width that is greater in width than said thickness at
said thickest part.
35. The intervertebral spacing implant of claim 34, wherein the
width of the spacing member is defined by a perimeter wall that
constitutes the concave side and the convex side of the external
concavo-convex contour of said spacing member.
36. The intervertebral spacing implant of claim 25, wherein the
spacing member further comprises a plurality of spaced-apart
recesses formed in said upper surface.
37. The intervertebral spacing implant of claim 36, wherein the
recesses are elongate and are disposed in a substantially parallel
orientation with respect to each other.
38. The intervertebral spacing implant of claim 37, wherein the
recesses extend in an anterior-to-posterior direction.
39. The intervertebral spacing implant of claim 36, wherein the
spaced-apart recesses comprise opposing sidewalls disposed at a
non-parallel angle with respect to each other.
40. The intervertebral spacing implant of claim 39, wherein said
angle is within a range of between approximately 45 degrees and 75
degrees.
41. The intervertebral spacing implant of claim 40, wherein said
angle is approximately 60 degrees.
42. The intervertebral spacing implant of claim 25, wherein said
spacing member further comprises attachment means for releasably
attaching positioning means to said spacing member.
43. The intervertebral spacing implant of claim 42, wherein said
attachment means are positioned on an end of said spacing member
opposite said free insertion end.
44. The intervertebral spacing implant of claim 42,. wherein said
attachment means for releasably attaching positioning means to said
spacing member comprises a recess in said spacing member.
45. The intervertebral spacing implant of claim 42, wherein said
attachment means for releasably attaching positioning means to said
spacing member comprises a threaded bore.
46. An intervertebral spacing implant comprising: a spacing member
adapted for implanting between adjacent vertebral bodies of a human
spine as a load-bearing replacement for a spinal disc, said spacing
member further comprising an external, concavo-convex contour with
respect to one dimension of said spacing member; wherein the
spacing member defines an imaginary arcuate centerline residing
between opposing sides of the external concavo-convex contour of
said spacing member, said arcuate centerline forming less than half
a circle, said spacing member further comprising an upper surface,
a lower surface, and a sidewall extending around a perimeter of
said spacing member between said upper surface and said lower
surface, and wherein said sidewall has a smooth contour
characterized by an absence of corners extending from said upper
surface to said lower surface; wherein the spacing member comprises
a bone material.
47. The intervertebral spacing implant of claim 46, wherein the
spacing member is solid and is either inherently non-porous or is
otherwise rendered non-porous.
48. The intervertebral spacing implant of claim 46, wherein the
spacing member is constructed from a rigid, non-resilient
load-bearing material.
49. The intervertebral spacing implant of claim 46, wherein the
spacing member comprises a first end, a second end, and a length
between said first end and said second end; wherein said spacing
member includes a tapered portion at said second end such that said
spacing member becomes progressively thinner toward said second end
of said spacing member; wherein said tapered portion extends along
a portion of said length such that said tapered portion covers less
than approximately 25% of said length.
50. The intervertebral spacing implant of claim 46, wherein said
spacing member has a cashew shape having a uniform width along a
majority length of the spacing member.
51. The intervertebral spacing implant of claim 46, wherein the
spacing member includes an anterior wall and a posterior wall, and
wherein the external concavo-convex contour of the spacer is
defined by the posterior wall being concave in a horizontal
dimension and by the anterior wall being convex in a horizontal
dimension.
52. The intervertebral spacing implant of claim 51, wherein the
anterior wall and the posterior wall of the spacing member are each
linear in a vertical dimension.
53. The intervertebral spacing implant of claim 46, wherein the
concavo-convex contour comprises a concave posterior side, and a
convex anterior side disposed in a substantially parallel
orientation with respect to the concave posterior side.
54. The intervertebral spacing implant of claim 46, wherein the
spacing member further comprises a disc-like member having a
thickness at a thickest part of the spacing member, and a length
that is greater in length than said thickness at said thickest
part, and a width that is greater in width than said thickness at
said thickest part.
55. The intervertebral spacing implant of claim 54, wherein the
width of the spacing member is defined by a perimeter wall that
constitutes the concave side and the convex side of the external
concavo-convex contour of said spacing member.
56. The intervertebral spacing implant of claim 46, wherein the
spacing member further comprises a plurality of spaced-apart
recesses formed in said upper surface.
57. The intervertebral spacing implant of claim 36, wherein the
recesses are elongate and are disposed in a substantially parallel
orientation with respect to each other.
58. The intervertebral spacing implant of claim 57, wherein the
recesses extend in an anterior-to-posterior direction.
59. The intervertebral spacing implant of claim 56, wherein the
spaced-apart recesses comprise opposing sidewalls disposed at a
non-parallel angle with respect to each other.
60. The intervertebral spacing implant of claim 59, wherein said
angle is within a range of between approximately 45 degrees and 75
degrees.
61. The intervertebral spacing implant of claim 60, wherein said
angle is approximately 60 degrees.
62. The intervertebral spacing implant of claim 46, wherein said
spacing member further comprises attachment means for releasably
attaching positioning means to said spacing member.
63. The intervertebral spacing implant of claim 62, wherein said
attachment means are positioned on an end of said spacing member
opposite a free insertion end.
64. The intervertebral spacing implant of claim 62, wherein said
attachment means for releasably attaching positioning means to said
spacing member comprises a recess in said spacing member.
65. The intervertebral spacing implant of claim 62, wherein said
attachment means for releasably attaching positioning means to said
spacing member comprises a threaded bore.
66. A method of implanting an artificial intervertebral disc
comprising: (a) making an incision in an annulus of a human spinal
column between adjacent vertebral bodies of said spinal column to
thereby expose a space residing between said adjacent vertebral
bodies; (b) inserting a trial spacer through the incision and into
position between the adjacent vertebral bodies, and evaluating a
snugness of fit of said spacer as it resides between said adjacent
vertebral bodies and determining a spacer size thereby; and (c)
inserting a spacing member, with a tapered end of said spacing
member first, through the incision and into position between the
adjacent vertebral bodies, and positioning said spacing member at
an anterior location with respect to the spinal column such that
more intervertebral space resides posteriorly to said spacing
member than anteriorly thereto.
67. The method of claim 66, wherein part (b) further comprises
dislodging any unwanted soft tissue from between the vertebral
bodies with the trial spacer.
68. The method of claim 66, further comprising inserting said trial
spacer through the incision in an arcuate path.
69. The method of claim 66, further comprising applying compression
to posterior portions of the adjacent vertebral bodies.
70. A method of implanting an artificial intervertebral disc
comprising: (a) making an incision in an annulus of a human spinal
column between adjacent vertebral bodies of said spinal column to
thereby expose a space residing between said adjacent vertebral
bodies; (b) selecting a spacing member comprising an external
concavo-convex contour with respect to one dimension of said
spacing member, wherein said spacing member comprises a solid body,
wherein said spacing member comprises an upper surface, a lower
surface and a free insertion end, and wherein said spacing member
includes a tapered portion such that said spacing member becomes
progressively thinner toward said free insertion end of said
spacing member; and (c) inserting said spacing member, with said
tapered portion of said spacing member first, through the incision
and into position between the adjacent vertebral bodies, and
positioning said spacing member at an anterior location with
respect to the spinal column such that more intervertebral space
resides posteriorly to said spacing member than anteriorly
thereto.
71. The method of claim 70, further comprising applying compression
to posterior portions of the adjacent vertebral bodies.
72. The method of claim 70, further comprising removing a natural
human disc from the space.
73. The method of claim 70, further comprising attaching an
insertion instrument to said spacing member.
74. The method of claim 73, wherein attaching an insertion
instrument to said spacing member comprises threading a trocar on
said spacing member.
75. The method of claim 71, further comprising compressing the
posterior portions of the adjacent vertebral bodies toward each
other to a degree sufficient to move said adjacent vertebral bodies
into a sagittal alignment.
76. The method of claim 75, further comprising attaching a holding
means to the adjacent vertebral bodies for holding said adjacent
vertebral bodies in the sagittal alignment to thereby inhibit said
vertebral bodies from moving out of sagittal alignment.
77. The method of claim 76, wherein attaching holding means further
comprises affixing pedicle screws to posterior pedicle portions of
the vertebral bodies, and interconnecting rods with the pedicle
screws.
78. The method of claim 70, further comprising removing a posterior
portion of one of the vertebral bodies for autogenous bone
grafting.
79. The method of claim 70, further comprising placing a lamina
spreader between spinous processes to spread adjacent vertebral
bodies apart.
80. The method of claim 70, further comprising preparing a bone
graft from autogenous bone graft material.
81. The method of claim 80, further comprising harvesting
autogenous bone and passing said autogenous bone through a mill to
form said autogenous bone graft material.
82. The method of claim 70, further comprising bringing the
adjacent vertebral bodies closer together on a posterior side than
on an anterior side.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of co-pending
U.S. patent application Ser. No. 11/205,284, filed Aug. 15, 2005,
entitled "Intervertebral Spacer," which is a continuation of U.S.
patent application Ser. No. 11/081,824, filed Mar. 15, 2005,
entitled "Intervertebral Spacer," which is continuation-in-part of
U.S. patent application Ser. No. 10/957,328, filed Oct. 1, 2004
entitled "Intervertebral Spacer," which is a continuation of U.S.
patent application Ser. No. 10/800,418, filed Mar. 12, 2004,
entitled "Intervertebral Spacer," which is a continuation of U.S.
patent application Ser. No. 10/643,779, filed Aug. 18, 2003,
entitled "Intervertebral Spacer," which is a continuation of U.S.
patent application Ser. No. 10/358,103, filed Feb. 3, 2003,
entitled "Intervertebral Spacer," which is a continuation of U.S.
patent application Ser. No. 10/188,281, filed Jul. 1, 2002,
entitled "Intervertebral Spacer," which is a continuation of U.S.
patent application Ser. No. 09/592,072, filed Jun. 12, 2000, now
U.S. Pat. No. 6,579,318, entitled "Intervertebral Spacer," which
applications are hereby incorporated by reference herein in their
entireties, including but not limited to those portions that
specifically appear hereinafter, the incorporation by reference
being made with the following exception: In the event that any
portion of the above-referenced applications is inconsistent with
this application, this application supercedes said above-referenced
applications.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND
[0003] 1. The Field of the Invention.
[0004] The present disclosure relates generally to an
intervertebral spacer, and more particularly, but not necessarily
entirely, to a interbody spacing system for accomplishing enhanced
intervertebral fusion between adjacent vertebral bodies of a human
spine.
[0005] 2. Description of Related Art.
[0006] The human spine is a complex, sophisticated mechanical
system. The vertebrate spine operates as a structural member,
providing structural support for the other body parts. A normal
human spine is segmented with seven cervical, twelve thoracic and
five lumbar segments. The lumbar portion of the spine resides on
the sacrum, which is attached to the pelvis. The pelvis is
supported by the hips and leg bones. The bony vertebral bodies of
the spine are separated by intervertebral discs, which reside
sandwiched between the vertebral bodies and operate as joints
allowing known degrees of flexion, extension, lateral bending and
axial rotation.
[0007] The intervertebral disc primarily serves as a mechanical
cushion between adjacent vertebral bodies, and permits controlled
motions within vertebral segments of the axial skeleton. The disc
is a multi-element system, having three basic components: the
nucleus pulposus ("nucleus"), the annulus fibrosus ("annulus") and
two vertebral end plates. The end plates are made of thin cartilage
overlying a thin layer of hard, cortical bone that attaches to the
spongy, richly vascular, cancellous bone of the vertebral body. The
plates thereby operate to attach adjacent vertebrae to the disc. In
other words, a transitional zone is created by the end plates
between the malleable disc and the bony vertebrae.
[0008] The annulus of the disc forms the disc perimeter, and is a
tough, outer fibrous ring that binds adjacent vertebrae together.
The fiber layers of the annulus include fifteen to twenty
overlapping plies, which are inserted into the superior and
inferior vertebral bodies at roughly a 40 degree angle in both
directions. This causes bi-directional torsional resistance, as
about half of the angulated fibers will tighten when the vertebrae
rotate in either direction.
[0009] It is common practice to remove a spinal disc in cases of
spinal disc deterioration, disease or spinal injury. The discs
sometimes become diseased or damaged such that the intervertebral
separation is reduced. Such events cause the height of the disc
nucleus to decrease, which in turn causes the annulus to buckle in
areas where the laminated plies are loosely bonded. As the
overlapping laminated plies of the annulus begin to buckle and
separate, either circumferential or radial annular tears may occur.
Such disruption to the natural intervertebral separation produces
pain, which can be alleviated by removal of the disc and
maintenance of the natural separation distance. In cases of chronic
back pain resulting from a degenerated or herniated disc, removal
of the disc becomes medically necessary.
[0010] In some cases, the damaged disc may be replaced with a disc
prosthesis intended to duplicate the function of the natural spinal
disc. U.S. Pat. No. 4,863,477 (granted Sep. 5, 1989 to Monson)
discloses a resilient spinal disc prosthesis intended to replace
the resiliency of a natural human spinal disc. U.S. Pat. No.
5,192,326 (granted Mar. 9, 1993 to Bao et al.) teaches a prosthetic
nucleus for replacing just the nucleus portion of a human spinal
disc.
[0011] In other cases it is desired to fuse the adjacent vertebrae
together after removal of the disc, sometimes referred to as
"intervertebral fusion" or "interbody fusion."
[0012] In cases of intervertebral fusion, it is known to position a
spacer centrally within the space where the spinal disc once
resided, or to position multiple spacers within that space. Such
practices are characterized by certain disadvantages, including a
disruption in the natural curvature of the spine. For example, the
vertebrae in the lower "lumbar" region of the spine reside in an
arch referred to in the medical field as having a sagittal
alignment. The sagittal alignment is compromised when adjacent
vertebral bodies that were once angled toward each other on their
posterior side become fused in a different, less angled orientation
relative to one another.
[0013] Another disadvantage of known spacing techniques and
intervertebral spacers are the additional surgical complications
that arise in the use of multiple spacers in a single disc space.
In such cases, surgeons will often first perform a posterior
surgery to remove the affected disc and affix posterior
instrumentation to the posterior side of the vertebrae to hold the
posterior portions of the vertebrae in a desired position.
Placement of the multiple spacers is often too difficult to
accomplish from the posterior side of the patient, at least without
causing with undue trauma to the patient, because a surgeon would
need to retract the dura nerve as well as the anterior longitudinal
ligament, thereby increasing damage, pain and morbidity to the
patient. Surgeons have therefore often chosen to turn the patient
over after completing the posterior surgical portion, to perform an
anterior operative procedure, through the patient's belly, in order
to insert multiple spacers between the vertebrae from the anterior
side instead of from the posterior side.
[0014] U.S. Pat. No. 5,961,554 (granted Oct. 5, 1999 to Janson et
al.) illustrates a spacer having a high degree of porosity
throughout, for enhanced tissue ingrowth characteristics. This
patent does not address the problem of compromising the sagittal
alignment, or of increased pain and trauma to the patient by
implantation of multiple spacers in a single disk space.
[0015] The prior art is thus characterized by several disadvantages
that are addressed by the present disclosure. The present
disclosure minimizes, and in some aspects eliminates, the
above-mentioned failures, and other problems, by utilizing the
methods and structural features described herein.
[0016] The features and advantages of the disclosure will be set
forth in the description which follows, and in part will be
apparent from the description, or may be learned by the practice of
the disclosure without undue experimentation. The features and
advantages of the disclosure may be realized and obtained by means
of the instruments and combinations particularly pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The above and other objects, features and advantages of the
disclosure will become apparent from a consideration of the
subsequent detailed description presented in connection with the
accompanying drawings in which:
[0018] FIG. 1 is a perspective view of an intervertebral spacer,
made in accordance with the principles of the present
disclosure;
[0019] FIG. 2 is a plan view of the intervertebral spacer of FIG.
1;
[0020] FIG. 3 is a frontal view of the intervertebral spacer of
FIGS. 1 and 2;
[0021] FIG. 4 is a side view of the intervertebral spacer of FIGS.
1, 2 and 3;
[0022] FIG. 5 is side view of a pair of adjacent vertebral bodies
from the lumbar region of a human spine;
[0023] FIG. 6 is a schematic view of a sheathed trocar device
releasably attached to a trial spacer shaped similarly to the
intervertebral spacer of FIG. 1, in accordance with the principles
of the present disclosure;
[0024] FIG. 7 is a schematic view of a sheathed trocar device
releasably attached to the intervertebral spacer of FIG. 1, in
accordance with the principles of the present disclosure;
[0025] FIGS. 8A-8D illustrate a schematic progression of the
placement of the intervertebral spacer of FIG. 1 between vertebral
bodies of a human spine;
[0026] FIG. 9 illustrates posterior instrumentation by which
compression is applied to the posterior sides of a pair of adjacent
vertebral bodies of a human spine;
[0027] FIG. 10 is a side view of an alternative embodiment
intervertebral spacer;
[0028] FIG. 11 is a back view of an alternative embodiment
intervertebral spacer; and
[0029] FIG. 12 is a cross-sectional view of the alternative
embodiment intervertebral spacer of FIG. 11, taken along line
A-A.
DETAILED DESCRIPTION
[0030] For the purposes of promoting an understanding of the
principles in accordance with the disclosure, reference will now be
made to the embodiments illustrated in the drawings and specific
language will be used to describe the same. It will nevertheless be
understood that no limitation of the scope of the disclosure is
thereby intended. Any alterations and further modifications of the
inventive features illustrated herein, and any additional
applications of the principles of the disclosure as illustrated
herein, which would normally occur to one skilled in the relevant
art and having possession of this disclosure, are to be considered
within the scope of the disclosure claimed.
[0031] Before the apparatus and methods of the present disclosure
are described further, it is to be understood that the disclosure
is not limited to the particular configurations, process steps, and
materials disclosed herein as such configurations, process steps,
and materials may vary somewhat. It is also to be understood that
the terminology employed herein is used for the purpose of
describing particular embodiments of the disclosure only, and is
not intended to be limiting since the scope of the present
disclosure will be limited only by the appended claims and
equivalents thereof.
[0032] The publications and other reference materials referred to
herein to describe the background of the disclosure and to provide
additional detail regarding its practice are hereby incorporated by
reference. The references discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as a suggestion or
admission that the inventors are not entitled to antedate such
disclosure by virtue of prior invention.
[0033] In describing and claiming the present disclosure, the
following terminology will be used in accordance with the
definitions set out below.
[0034] As used herein, "comprising," "including," "containing,"
"characterized by," and grammatical equivalents thereof are
inclusive or open-ended terms that do not exclude additional,
unrecited elements or method steps.
[0035] Applicants have discovered that several of the disadvantages
of the prior art spinal disc replacement systems can be minimized,
or even eliminated, by the use of a cashew-shaped interbody spacer
having a tapered external shape, placing it is far anteriorly as
possible between adjacent vertebral bodies, filling in the
remaining posterior space with bone graft material, and applying
compression to posterior portions of the vertebral bodies to load
the bone graft in compression and restore sagittal alignment.
[0036] Referring now to FIGS. 1-4, there is shown a spacing member,
referred to also herein as an intervertebral spacer or an interbody
spacer, designated generally at 10.
[0037] Briefly stated, the spacer 10 may be utilized, along with
autogenous bone grafting material, to replace a diseased or damaged
spinal disc. Referring now to FIGS. 5-7, the procedure may be
implemented by making an incision 32 in the annulus 34 connecting
adjacent vertebral bodies 31. The spinal disc (not shown) may be
surgically removed from the incision 32, after which the spacer 10
is placed through the incision 32 into position between the
vertebral bodies 31. The spacer may be placed with its convex,
anterior sidewall 12 facing anteriorly, and with its concave,
posterior sidewall 14 facing posteriorly. Bone grafting material
may be placed through the incision 32 to reside behind the spacer
10, after which posterior instrumentation may be attached to
pedicle areas 34 to force the vertebral bodies 31 together in
compression, as illustrated schematically in FIG. 8D and more
particularly in FIG. 9.
[0038] The unique aspects and procedures relating to the spacer 10
will now be explained in more detail. Some of the key features of
the disclosure comprise the size, shape and placement of spacer 10.
The spacer 10 may be made of titanium, thus having a non-porous
quality with a smooth finish. The spacer 10 could also be made of
ceramic, stainless steel or other metallic materials, nitinol,
nylon, polyethylene, polyetheretherketone (PEEK), polyurethane,
polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE) or
any suitable polymer, carbon, hydroxyapatile or any other suitable
material that is inert or biologically compatible, such as bone
including, but not limited to, allogenic or xenogenic bone
implants. The term "non-porous" as used herein shall be construed
broadly in accordance with the common, ordinary meaning of that
term to refer to objects possessing an impediment to flow that
would operate in the presence of fluid to impede or even block
fluid flow through the object. In accordance with such common,
ordinary meaning, such objects are either impermeable by liquid, or
possess a limited degree of permeability that prevents liquid from
passing through the object in a manner that would be considered
flow. Examples of objects that are non-porous and impermeable
include a solid titanium or solid ceramic intervertebral spacer, or
a spacer made from impermeable bone material, or a spacer that is
coated or treated in some way to render it impermeable. Examples of
objects that are non-porous and possess a limited degree of
permeability, and which therefore do not permit fluid to pass
through them in a flowable manner, include biologically compatible
spacers made from bone, such as milled-bone allograft spacers or
particle-bone allograft spacers that are freeze-dried and
thereafter re-hydrated prior to insertion, or any other type of
non-porous spacer made from bone. Under the definition above, the
presence or absence of surface porosity on an object, such as an
intervertebral spacer, is irrelevant to whether the object is
porous or non-porous. The spacer 10 may be thus constructed from a
rigid, non-resilient load-bearing material, one that may be
incapable of elastic deformation. The spacer 10, by its anterior,
convex sidewall 12 and its posterior, concave sidewall 14, has
thereby a concavo-convex contour with respect to one dimension.
[0039] The phrase "solid body" as used herein shall refer to the
concept of the spacer 10 having no through holes, nor any internal
encapsulated voids other than naturally occurring voids existing in
the material used to construct the spacer 10. The phrase "through
hole" as used herein shall refer to a hole formed in and extending
through a body and having an entrance and an opposing exit, in a
manner such that any line, including but not limited to straight,
curved, or tortuous lines, may extend continuously from said
entrance through some portion of the hole along any path to reach
the exit.
[0040] It is to be understood that the concept of an object having
a concavo-convex contour with respect to one dimension of the
object, as referred to herein, shall not require the concave and
convex sides of the object to be parallel to one another, although
such may be preferred. The concept does however refer to a
dimension in which the concave and convex sides of the object are
at least partially facing the direction of that dimension, as
indicated by the dimension 16 of FIG. 1 in relation to the spacer
10. It is also to be understood that the concept of an object being
concavo-convex in a single dimension shall thereby include an
object that has concave and convex sides 14 and 12 in a horizontal
dimension 16, even though those very same sides are linear in a
vertical dimension 20 at all points, such as in the case of the
spacer 10 shown in FIG. 1. For example, the spacer 10 is
concavo-convex in the anterior-posterior direction 16, though not
in a medial-lateral direction 18 or vertical direction 20.
[0041] The upper surface 22 of the spacer 10 may be a planar,
discontinuous surface as shown, having a plurality of spaced-apart
elongate recesses 24, with a corner point 28 whereby one side 26 or
portion of the spacer 10 begins tapering in the medial-lateral
direction 18, as shown most clearly in FIG. 3. The tapered side 26
may facilitate insertion of the spacer 10 and may be sized to
extend along a portion of a length L such that the tapered side 26
covers less than approximately 25% of the length L. By tapering
less than 25% of the length L of the spacer 10 in a medial-lateral
direction, the upper surface 22 and lower surface 30 may support
the spinal disc without causing a lateral curvature or scoliosis.
The tapered side 26 may begin at a male corner line 28a, which
starts at the corner point 28. It will be appreciated that the
orientation of the male corner line 28a may vary such that the
tapered side 26 may have various different configurations within
the scope of the present disclosure. It will also be understood
that in an alternative implementation of the present disclosure,
the tapered side 26 may be formed as a curved surface without the
presence of the corner point 28. Accordingly, the tapered side 26
may be configured to gradually blend into the upper surface 22 or
the lower surface 30 without a male corner line 28a.
[0042] Accordingly, the spacing member or spacer 10 may be
configured such that the upper surface 22 and the lower surface 30
may terminate in a free insertion end at R.sub.4 in FIG. 2. At
least one of the upper surface 22 and the lower surface 30 may
include the male corner line 28a. The spacer 10 may include a
tapered portion or side 26 between the male corner line 28a and the
free insertion end such that the spacer 10 becomes progressively
thinner from the male corner line 28a toward the free insertion
end. The tapered portion 26 may be characterized by at least one
smooth surface that is a part of either the upper surface 22 or the
lower surface 30 and extends from the male corner line 28a to the
free insertion end, the smooth surface having an absence of
corners, points or other abrupt edges.
[0043] Further taper of the spacer 10 may occur in the
anterior-to-posterior direction 16, in that the spacer 10 may
narrow in thickness in a continuous manner along substantially the
entire width of the spacer 10 as shown most clearly in FIG. 4. The
upper surface 22 and lower surface 30 may form an acute angle
relative to a horizontal plane 23, the angle may be within a range
of approximately two to eight degrees, such as four degrees, for
example. The entire taper may therefore be an eight degree total
taper, with four degrees of taper resulting from the upper surface
22 and the other four degrees of taper resulting from the lower
surface 30.
[0044] As shown most clearly in FIG. 2, the spacer 10 may have an
arc-length AL that may be 1.218 inches, a width W that may be 0.320
inches, a depth D that may be 0.532 inches, an inner radius R.sub.2
that may be 0.271 inches, an outer radius R.sub.1 that may be 0.591
inches, and side radii R.sub.3 and R.sub.4 that each may be 0.160
inches.
[0045] The anterior, convex sidewall 12 and the posterior, concave
sidewall 14 of the spacer 10 each may be linear in the vertical
dimension 20, and may be parallel relative to one another.
Moreover, in one implementation of the present disclosure, the
convex sidewall 12 and concave sidewall 14 may form part of a
perimeter of the spacer 10, such that the perimeter may have a
smooth contour characterized by an absence of corners or abrupt
edges as shown in the plan view of FIG. 2. It will be understood
that the spacer 10 may include attachment means for releasably
attaching positioning means to the spacer 10, such as the opening
10a or other such recesses, and still maintain the smooth contour
to facilitate insertion of the spacer 10.
[0046] The spacer 10 may be also constructed from bone, such as
allogenic bone or allograft material. The allogenic spacer 10 may
be machined from human bone, but could also comprise xenogenic bone
or xenograft material as known to those skilled in the art. The
spacer 10 could also comprise reconstituted pulverized bone in a
manner known to those skilled in the art.
[0047] In other embodiments of the spacer 10, such as those
involving allogenic bone, the spacer 10 may have substantially the
same shape and size as the spacer 10 described in the previous
embodiment. However, the upper and lower surfaces, 22 and 30
respectively, of the spacer 10 may also be either planar or curved.
The upper and lower surfaces 22 and 30 may be configured without
any recesses 24. Moreover, the spacer 10 may have multiple rows of
teeth (not shown) projecting from the upper and lower surfaces, 22
and 30 respectively.
[0048] In addition, as shown most clearly in FIG. 10, an
alternative embodiment spacer 11 may have an upper surface 22a and
a lower surface 30a that may be oriented at substantial right
angles to the sidewalls 12a and 14a. Thus, the surfaces 22a and 30a
may not taper in an anterior-posterior direction. Accordingly, the
upper surface 22a and the lower surface 30a may be substantially
parallel to a horizontal plane 23a. It will be understood that
other implementations of the present disclosure may include a
spacer with sidewalls that are not oriented at right angles with
the upper surface 22a and the lower surface 30a, but in which the
upper surface 22a may still be substantially parallel to the lower
surface 30a. Moreover, the upper surface 22a and the lower surface
30a may be somewhat dome shaped.
[0049] In one implementation of the present disclosure, the
alternative embodiment spacer 11 may be formed with recesses 24a
having sidewalls 27 and bottom portions 29. As best shown in FIG.
11, opposing sidewalls 27 in the recesses 24a may be configured to
form a non-parallel angle .alpha. with respect to each other. The
angle .alpha. may be formed at various different angles, such as
angles within a range of between approximately 45 to 75 degrees,
for example. One implementation of the present disclosure includes
sidewalls 27 at an angle .alpha. of approximately 60 degrees, for
example. This configuration may allow the spacer 10 to have added
strength at the recesses 24a, since the sidewalls 27 between
recesses 24a may be thicker at the bottom. It will be understood
however, that the sidewalls 27 may be formed at various different
angles a and shapes within the scope of the present disclosure. The
sidewalls may be substantially vertical, and the bottom portions 29
may be substantially horizontal. In other implementations, it will
be understood that the sidewalls 27 of the recesses 24 may be
formed at a slope and the bottom portions 29 may be configured to
be flat, or the sidewalls 27 and bottom portions 29 may both be
curved. The spacer 10 may have flat or pointed surfaces at the top
of the recesses 24.
[0050] Also, the alternative embodiment spacer 11 may have side
recesses 25. FIG. 12 shows a cross-sectional view of the
alternative embodiment spacer 11, taken along the line A-A in FIG.
11, which shows the side recesses 25 extending within the spacer
11. The side recesses 25 may be configured for receiving
positioning means for enabling a surgeon to adjust a position of
the spacer 11 when the spacer 11 resides between the adjacent
intervertebral bodies 31. The positioning means may be formed as a
rod member and may be received in the recesses 25 on both sides of
the spacer 11 to facilitate manipulation of the spacer 11.
[0051] Some of the primary goals in intervertebral fusion are
immobilization of the affected vertebrae, interbody arthrodesis,
restoration of the spinal disc space, and sagittal alignment, and
to provide an environment for bony fusion between vertebral bodies.
Applicants have discovered that these goals may be most effectively
accomplished by the mechanical principle of a cantilever. Using the
spacer 10 as a compression point, a cantilever may be constructed
within the disc space as shown most clearly in FIG. 8D. The
procedure for accomplishing this is as follows.
[0052] FIG. 8A is a schematic side, internal view of the vertebral
bodies 31 indicated in FIG. 5. The spinal disc 33 resides between
the vertebral bodies 31, all of which reside between the anterior
longitudinal ligament (ALL) 36 and the posterior longitudinal
ligament (PLL) 38. The dural nerve (Dura) 40 resides posteriorly to
the vertebral bodies 31 and the PLL 38.
[0053] Referring now to FIG. 8B and FIG. 9, posterior access to the
spine of the patient (not shown) may be accomplished. A right
handed surgeon may be positioned on the patient's left side to
perform the procedure. Posterior instrumentation, such as pedicle
screws 42 (FIG. 9), may be affixed to posterior pedicle portions 34
of the vertebral bodies 31. The associated rods 44 and structure
interconnecting the rods 44 with the pedicle screws 42 are not
affixed until later on in the procedure. A posterior portion of the
lower vertebral body involved in the fusion, namely, the left
inferior articular facet or articular process, may be removed and
saved for future autogenous bone grafting. A lamina spreader or
detractor (not shown, but indicated in FIGS. 8B and 8C), may be
placed between the spinous processes 35 (shown in FIG. 5), and may
be operated to spread the adjacent vertebral bodies 31 apart. A
nerve root retractor (not shown) may be used to protect the dura
during the surgery. The anterior longitudinal ligament 36 and
posterior longitudinal ligament 38 may be left intact and need not
be retracted.
[0054] After coagulation of the veins (not shown), the incision 32
(FIG. 5) may be made, with a #15 scalpel, or any suitable surgical
instrument, in a side section of the annulus 37. The disc 33 may
then be detached from the vertebral end plates (not shown) with the
proper surgical instrumentation, and may be removed through the
incision 32. Curettes (not shown) and pituitary rongeurs (not
shown) may be used to remove the disc material. Care should be
taken not to violate the bony vertebral end plate, which would
cause excessive bleeding and compromise the resistance to axial
load when the spacer 10 is inserted.
[0055] When as much disc material has been removed as can safely be
accomplished, a trial spacer 50 may be used to determine the
correct spacer size. The trial spacer 50 may have the same shape as
the spacer 10, both of which are part of a set having various
sizes, except that the trial spacer 50 may not include the recesses
24. The trial spacer 50 may be inserted into the incision 32 with a
sheathed trocar device 52. The main purpose of trial spacer 50 is
to evaluate a snugness of fit of said trial spacer 50 as it resides
between the adjacent vertebral bodies 31, which enables the surgeon
to determine a spacer size thereby. The trial spacer 50 may also
dilate the disc space between the adjacent vertebral bodies 31. The
trial spacer 50 may also have sharp edging, and may be used to
clear away any remaining unwanted tissue.
[0056] When the spacer size has been determined, a bone graft may
be prepared using autogenous bone graft material 54 as shown in
FIG. 8C. Care is taken to remove all soft tissue from the
autogenous bone, which will facilitate successful osteointegration
of the graft. Additional bone can also be harvested from the
spinous processes 35. Optimally, 6-10 cm.sup.3 of morselized bone
graft material may be used, but it will be at the discretion of the
surgeon to determine how much bone grafting material will be used.
The harvested autogenous bone may then be passed through a bone
mill (not shown) to form suitable bone grafting material as known
and understood to those having ordinary skill in the art.
[0057] The spacer 10 may be inserted through the incision 32 with
the sheathed trocar device 52. The sheathed trocar device 52
includes a trocar rod 56 that may be slidably disposed within a
hollow sheath 58. The trocar rod 56 and the hollow sheath 58 may
moveably engaged with each other in any suitable manner.
[0058] Both the trial spacer 50 and the spacer 10 may include a
female-threaded opening 50a and 10a formed therein, respectively,
in which a male-threaded portion 57 of the trocar rod 56 may be
releasably inserted. The trocar rod 56 may of course be releasably
attached to the trial spacer 50 and spacer 10 in any other suitable
manner. The trocar rod 56 may have a longer length than the sheath
member 58, such that a proximal portion 60 of the trocar rod 56
protrudes from the sheath member 58 when the trocar rod 56 is
attached to the trial spacer 50 or the spacer 10.
[0059] The sheathed trocar device 52 accordingly may provide an
efficiently stabilized, releasable connection with the spacer 10.
With the trocar rod 56 being attached directly to the spacer 10,
the sheath member 58 may provide additional support by abutting up
against the spacer and contactably circumscribing the point of the
attachment of the trocar rod 56 with the spacer 10, thereby
providing additional stability and control over the positioning of
the spacer 10.
[0060] The surgeon may then selectively position the spacer 10
within the space residing between the adjacent vertebral bodies 31,
as far anteriorly as possible such that the spacer 10 may reside in
contact with the anterior longitudinal ligament 36. Proper
placement of the spacer 10 can be checked with the use of
X-rays.
[0061] With the spacer 10 in place, the bone grafting material 54
may be placed through the incision 32 and into position between the
adjacent vertebral bodies 31, such that said bone grafting material
54 resides posteriorly to the concave sidewall 14 of the spacer 10,
and thus between the sidewall 14 and the posterior longitudinal
ligament 38. A bone funnel (not shown) as known to those having
ordinary skill in the field may be used to funnel morselized bone
grafting material into the incision 32. A bone tamp (not shown) may
be used by the surgeon to tamp the bone grafting material against
the spacer 10.
[0062] It is noted that the concavo-convex shape of the spacer 10,
and the method of implantation with the spacer 10 residing as far
anteriorly as possible, operates to provide a larger bone-graft
interface between the adjacent vertebral bodies 31.
[0063] Referring now to FIG. 8D and FIG. 9, the lamina spreader may
be removed and the pedicle screws 42 may be interconnected with the
rods 44 as known in the field. Mild compression may be applied by a
compression instrument 46 to thereby slide rods 44 downwardly,
after which the pedicle screws 42 may be tightened to hold the rods
44 in place and maintain the compression. Further compression may
be applied as desired, with the result being illustrated
schematically in FIG. 8D. The bone grafting material 54 may thereby
be loaded in compression by the posteriorly compressed adjacent
vertebral bodies 31 as shown. After final inspection of the
placement of the bone grafting material 54, routine closure of the
wound may be completed. The use of drains may be made at the
discretion of the surgeon.
[0064] The spacer 10 may thus operate to cause the adjacent
vertebral bodies 31 to be suspended in the manner of a cantilever.
The posterior compression provided by the pedicle screws 42 and
rods 44, which may alternatively be provided by any other suitable
holding structure, causes the adjacent vertebral bodies 31 to be
brought closer together on their posterior side than on their
anterior side, consistent with the natural sagittal alignment in
which they were originally positioned, as understood by those
having ordinary skill in the field.
[0065] It will be appreciated that the structure and apparatus of
the trocar rod 56 and sheath 58 constitute a positioning means for
enabling a surgeon to adjust a position of the spacer 10 when the
spacer 10 resides between the adjacent intervertebral bodies 31.
That structure is merely one example of a means for positioning the
spacer 10, and it should be appreciated that any structure,
apparatus or system for positioning which performs functions that
are the same as, or equivalent to, those disclosed herein are
intended to fall within the scope of a means for positioning,
including those structures, apparatus or systems for positioning
which are presently known, or which may become available in the
future. Anything which functions the same as, or equivalently to, a
means for positioning falls within the scope of this element.
[0066] In accordance with the features and combinations described
above, a useful method of implanting an artificial intervertebral
disc includes:
[0067] (a) making an incision in an annulus of a human spinal
column between adjacent vertebral bodies of said spinal column to
thereby expose a space residing between said adjacent vertebral
bodies;
[0068] (b) removing the disc material from between said adjacent
vertebral bodies, being careful not to injure the disc plates;
[0069] (c) inserting a spacing member and autogenous bone grafting
material through the incision and into position between the
adjacent vertebral bodies, and positioning said spacing member at
an anterior location with respect to the spinal column such that
more intervertebral space resides posteriorly to said spacing
member than anteriorly thereto; and
[0070] (d) applying compression to posterior portions of the
adjacent vertebral bodies.
[0071] Those having ordinary skill in the relevant art will
appreciate the advantages provided by the features of the present
disclosure. For example, it is a feature of the present disclosure
to provide an intervertebral spacing system that does not require
an additional, anterior surgical procedure. It is another feature
of the present disclosure, in accordance with one aspect thereof,
to provide such an intervertebral spacing system by which sagittal
alignment of the spine may be restored. It is a further feature of
the present disclosure, in accordance with one aspect thereof, to
provide such an intervertebral spacing system that can accommodate
a larger host-graft interface between adjacent vertebral bodies. It
is an additional feature of the present disclosure, in accordance
with one aspect thereof, to provide such an intervertebral spacing
system in which bone grafting material may be loaded in compression
between adjacent vertebral bodies of the spine. It is yet another
feature of the present disclosure, in accordance with one aspect
thereof, to provide such an intervertebral spacing system that does
not require retraction of the dural nerve, or of the anterior or
posterior longitudinal ligaments, for implantation of the
spacer.
[0072] It is to be understood that the above-described arrangements
are only illustrative of the application of the principles of the
present disclosure. Numerous modifications and alternative
arrangements may be devised by those skilled in the art without
departing from the spirit and scope of the present disclosure and
the appended claims are intended to cover such modifications and
arrangements. Thus, while the present disclosure has been shown in
the drawings and described above with particularity and detail, it
will be apparent to those of ordinary skill in the art that
numerous modifications, including, but not limited to, variations
in size, materials, shape, form, function and manner of operation,
assembly and use may be made without departing from the principles
and concepts set forth herein.
* * * * *