U.S. patent application number 10/923499 was filed with the patent office on 2005-03-31 for system and methods for inserting a vertebral spacer.
This patent application is currently assigned to Nabil L. Muhanna, M.D.. Invention is credited to Muhanna, Nabil L., Schalliol, David L..
Application Number | 20050071009 10/923499 |
Document ID | / |
Family ID | 26924847 |
Filed Date | 2005-03-31 |
United States Patent
Application |
20050071009 |
Kind Code |
A1 |
Muhanna, Nabil L. ; et
al. |
March 31, 2005 |
System and methods for inserting a vertebral spacer
Abstract
The present invention provides vertebral spacers having a lower
surface and an upper surface, an anterior face and a posterior face
extending from the lower surface, and at least one guiding groove
for engaging an insertion tool. A system for delivering a vertebral
spacer to the spinal column of a patient, includes an insertion
tool, an optional guiding tool, a pusher, a vertebral spacer, and a
cutting tool. The insertion tool accepts any of a pusher, a
vertebral spacer, or a cutting tool and has at least one spacer
guide for engaging with a guiding groove of a vertebral spacer. The
vertebral spacer is inserted into a patient by inserting the
insertion tool into an intervertebral space, engaging the guiding
groove of a vertebral spacer with a space guide of the insertion
tool, advancing a pusher into the insertion tool, thereby pushing
the vertebral spacer into the intervertebral space and thereafter
removing the pusher and the insertion tool. The cutting tool is
optionally used to chisel at least one vertebral space receiving
slot in the vertebrae. A hardening biocompatible composition also
maybe delivered, to bond the vertebral spacer to an adjacent
vertebra or be an osteogenic composition to promote bone
growth.
Inventors: |
Muhanna, Nabil L.;
(Gainesville, GA) ; Schalliol, David L.; (Oakwood,
GA) |
Correspondence
Address: |
WOMBLE CARLYLE SANDRIDGE & RICE
POST OFFICE BOX 7037
ATLANTA
GA
30357-0037
US
|
Assignee: |
Nabil L. Muhanna, M.D.
|
Family ID: |
26924847 |
Appl. No.: |
10/923499 |
Filed: |
August 20, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10923499 |
Aug 20, 2004 |
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09947851 |
Sep 6, 2001 |
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6824565 |
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60231142 |
Sep 8, 2000 |
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Current U.S.
Class: |
623/17.11 ;
606/87 |
Current CPC
Class: |
A61F 2002/30841
20130101; A61F 2230/0082 20130101; A61F 2310/00353 20130101; A61F
2002/30448 20130101; A61F 2310/00137 20130101; A61F 2220/005
20130101; A61F 2002/30158 20130101; A61F 2002/30828 20130101; A61F
2/30965 20130101; A61F 2/4611 20130101; A61F 2002/30131 20130101;
A61F 2230/0026 20130101; A61F 2310/00023 20130101; A61F 2310/00293
20130101; A61F 2230/0013 20130101; A61F 2002/30785 20130101; A61F
2002/30879 20130101; A61F 2230/0019 20130101; A61F 2002/30266
20130101; A61F 2002/30507 20130101; A61F 2002/30492 20130101; A61F
2310/00017 20130101; A61F 2/28 20130101; A61F 2310/00029 20130101;
A61F 2002/30971 20130101; A61F 2220/0025 20130101; A61F 2310/00359
20130101; A61F 2002/4627 20130101; A61F 2002/30153 20130101; A61F
2002/30919 20130101; A61F 2/442 20130101 |
Class at
Publication: |
623/017.11 ;
606/087 |
International
Class: |
A61F 002/44; A61B
017/90; A61F 002/46 |
Claims
1. A vertebral spacer comprising: (a) a body having an upper
surface and a lower surface, an anterior face and a posterior face,
the anterior face and the posterior face extending from the lower
surface to the upper surface; and (b) a first guiding groove in one
of the upper surface and the lower surface.
2.-38. (Canceled)
Description
[0001] The present application claims the benefit of the
provisional U.S. Application Ser. No. 60/231,142 filed Sep. 8,
2000, which is incorporated herein by reference in its
entirety.
FIELD OF INVENTION
[0002] The present invention generally relates to a vertebral
spacer to be inserted into an intervertebral space, thereby
supporting the spinal column of a patient. The present invention
further relates to a system and methods for implanting the
vertebral spacer into the spinal column and securing the spacer
therein.
BACKGROUND OF THE INVENTION
[0003] The spinal column, which is the central support to the
vertebrate skeleton and a protective enclosure for the spinal cord,
is a linear series of vertebral bones. Intervertebral discs
separate and reduce friction between adjacent vertebrae and absorb
compression forces applied to the spinal column. Spinal nerves that
extend from each side of the spinal cord exit the column at
intervertebral forama.
[0004] A typical vertebra comprises an anterior body, and a
posterior arch that surrounds the spinal cord lying within the
vertebral foramen formed by the arch. The muscles that flex the
spine are attached to three processes extending from the posterior
arch. On the upper surface of each vertebra in a standing human,
are two superior articulated processes that oppose two inferior
articulated processes extending from the lower surface of an
adjacent vertebra. Facets on the opposing processes determine the
range and direction of movement between adjacent vertebrae, hence
the flexibility of the spinal column.
[0005] The intervertebral discs include the fibrillar cartilage of
the anulus fibrosus, a fibrous ring, the center of which is filled
with an elastic fibrogelatinous pulp that acts as a shock absorber.
The outer third of the anulus fibrosus is innervated. The entire
spinal column is united and strengthened by encapsulating
ligaments.
[0006] Back pain is one of the most significant problems facing the
workforce in the United States today. It is a leading cause of
sickness-related absenteeism and is the main cause of disability
for people aged between 19 and 45. Published reports suggest that
the economic cost is significant, treatment alone exceeding $80
billion annually. Although acute back pain is common and typically
treated with analgesics, chronic pain may demand surgery for
effective treatment.
[0007] Back pain can occur from pinching or irritation of spinal
nerves, compression of the spine, vertebral shifting relative to
the spinal cord axis, and bone spur formation. The most common
cause of disabling back pain, however, stems from trauma to a
intervertebral disc, resulting from mechanical shock, stress,
tumors or degenerative disease, which may impair functioning of the
disc and limit spinal mobility. In many cases, the disc is
permanently damaged and the preferred treatment becomes partial or
total excision.
[0008] Another cause of back injury is herniation of the
intervertebral disc, wherein the gelatinous fluid of the nucleus
pulposus enters the vertebral canal and pressures the spinal cord.
Again, surgery is often the only method available for permanent
relief from pain or the neurological damage ensuing from the
pressure of fluid on the spinal cord, and requires replacement of
the damaged disc.
[0009] Traumatic injury to an intervertebral disc that is not
removed will frequently promote scar tissue formation. Scar tissue
is weaker than original healthy tissue so that the disc will
progressively degenerate, lose water content, stiffen and become
less effective as a shock absorber. Eventually, the disc may
deform, herniate, or collapse, limiting flexibility of the spinal
column at that position. The only option is for the intervertebral
disc to be partially or totally removed.
[0010] When the disc is partially or completely removed, it is
necessary to replace the excised material to prevent direct contact
between hard bony surfaces of adjacent vertebrae. One vertebral
spacer that may be inserted between adjacent vertebrae, according
to U.S. Pat. No. 5,989,291 to Ralph et al., includes two opposing
plates separated by a belleville washer or a modified belleville
washer. The washer functions to provide a restorative force to
mimic the natural functions of the disc of providing a shock
absorber and mobility between adjacent vertebrae. However,
mechanical devices intended to replicate intervertebral disc
function have had only limited success. An alternative approach is
a "cage" that maintains the space usually occupied by the disc to
prevent the vertebrae from collapsing and impinging the nerve
roots.
[0011] Spinal fusion may be used to restrict motion occurring
between two vertebrae due to spinal segmental instability. Fusing
the vertebrae together, however, reduces the mechanical back pain
by preventing the now immobile vertebrae from impinging on the
spinal nerve.
[0012] The disadvantage of such spacers is that stability is
created at the expense of spinal flexibility.
[0013] Surgical procedures for replacing intervertebral disc
material, rather than the fusing of the vertebrae, have included
anterior approaches and posterior approaches to the spinal column.
The posterior approach (from the back of the patient) encounters
the spinous process, superior articular process, and the inferior
articular process that must be removed before insertion of the disc
replacement material into the intervertebral space. Excessive
removal of the bony process triggers further degradation and
impediment of the normal movement of the spine. The anterior
approach to the spinal column is complicated by the internal organs
that must be bypassed or circumvented to access the vertebrae.
[0014] Many intervertebral spacers require preparation of the
surfaces of the adjacent vertebrae to accommodate the spacer,
causing significant tissue and bone trauma. For example, chiseling
or drilling of the vertebral surface may be required to prepare a
receiving slot. They may also require screwing the spacer into the
intervertebral space, making installation difficult and increasing
trauma to the vertebral tissue. Many spacers include complex
geometries and are costly to manufacture. Examples of such
geometrically complex spacers are described in U.S. Pat. No.
5,609,636 to Kohrs et al., U.S. Pat. No. 5,780,919 to Zdeblick et
al., U.S. Pat. No. 5,865,848 to Baker and U.S. Pat. No. 5,776,196
to Matsuzaki et al. Many of these complex spacers may require
screwing the spacer into the intervertebral space, thereby making
installation difficult and traumatic to the vertebral tissue.
SUMMARY OF THE INVENTION
[0015] There is a need for a vertebral spacer having a simple
geometry that is easily insertable into an intervertebral space
while causing minimal trauma to the surface of the vertebrae as
well as the bony processes thereof. The present invention provides
a vertebral spacer having a simple geometry for supporting adjacent
vertebrae after excision, at least partially or wholly, of an
intervertebral disc. The spacer includes a body having a lower
surface and an upper surface. The lower surface will be supported
by a lower vertebra; the upper surface supports the adjacent upper
vertebra. The body of the vertebral spacer of the present
invention, therefore, provides support between the two adjacent
vertebrae and to the spinal column.
[0016] The body of the vertebral spacer of the present invention
additionally has an anterior face and a posterior face extending
from the lower surface. The height of the anterior face of the body
may be less than, or greater than, the height of the posterior face
to maintain the curvature of the spine when the vertebral spacer is
inserted between two vertebrae. The body of the vertebral spacer
also includes at least one guiding groove suitable for engaging
with an insertion tool for delivering the vertebral spacer to an
intervertebral space.
[0017] The present invention further provides a system for
delivering a vertebral spacer to the spinal column of a patient,
comprising an insertion tool with a channel; (b) an optional
guiding tool for directing the insertion tool to a selected point
of insertion of a vertebral spacer; (c) a pusher; (d) a vertebral
spacer slideably disposed in the channel of the insertion tool; and
(e) a cutting tool. The cutting tool can be slid into the channel
of the insertion tool providing that the pusher and the vertebral
spacer are not therein.
[0018] The channel of the insertion tool is configured to slideably
accept any of a vertebral spacer, a pusher, a vertebral spacer , or
a cutting tool. The insertion tool further comprises a spacer guide
or a plurality of spacer guides for engagement with a first guiding
groove or a second guiding groove of a vertebral spacer.
[0019] In one embodiment of the insertion tool the spacer guide is
a flange extending from the channel. In another embodiment, the
spacer guide is two opposing flanges configured to slideably engage
with a first guiding groove and a second guiding groove,
respectively.
[0020] In another embodiment of the insertion tool, the spacer
guide is at least one rib longitudinally placed on the inner
surface of the channel of the insertion tool.
[0021] Other embodiments of the insertion tool of the present
invention include spacer guides that may be, but are not limited
to, a segmented longitudinal rib, or a linear series of
protrusions, also on the inner surface of the channel.
[0022] The present invention further provides a method for
delivering a vertebral spacer to a patient, comprising the steps of
inserting the insertion tool into an intervertebral space of the
spinal column of a patient, engaging at least one guiding groove of
a vertebral spacer with a space guide of the insertion tool,
sliding a pusher into the channel of the insertion tool, advancing
the pusher and thereby pushing the vertebral spacer into the
intervertebral space and removing the pusher and the insertion tool
from the patient.
[0023] The method of the present invention may further comprise the
optional step of inserting a guiding tool into an intervertebral
space for directing the insertion tool into the intervertebral
space. The insertion tool may be slid along the guide tool to a
selected position suitable for insertion of a vertebral spacer in
the intervertebral space. The guide tool is then extracted from the
insertion tool leaving the insertion tool inserted between adjacent
vertebrae.
[0024] The cutting tool is optionally slid along the channel of the
insertion tool to engage a vertebra and generally is used to chisel
at least one vertebral space receiving slot in the vertebrae. The
cutting tool is removed from the patient by sliding the cutting
tool back through the channel of the insertion tool. A vertebral
spacer may then be slideably engaged with the insertion tool, with
a space guide on the insertion tool engaging with a guiding groove
of the vertebral spacer. The pusher may be engaged and advanced
along the channel, thereby delivering the vertebral spacer into the
vertebral spacer receiving slot (or receiving slots) in the
adjacent vertebrae. It is also contemplated that a vertebral spacer
receiving slot may not be cut in the adjacent vertebrae and that
the inserted vertebral spacer optionally may contact only the uncut
surface of the vertebrae.
[0025] One embodiment of the method of the present invention
comprises the additional step of delivering a hardening
biocompatible composition to the vertebral spacer. The hardening
biocompatible composition may be used, for example, to bond the
vertebral spacer to an adjacent vertebra or be an osteogenic
composition to promote bone growth from the adjacent vertebrae into
the vertebral spacer. The hardening biocompatible composition can
be, for example, an organic polymer, a mineral composition such as
a hydroxyapatite-based composition, methyl methacrylate, or the
like, or a combination thereof. A hydroxyapatite-based composition
is especially useful in the context of the present invention for
promoting osteocyte growth and bone deposition.
[0026] Various objects, features, and advantages of the invention
will become more apparent upon review of the detailed description
set forth below when taken in conjunction with the accompanying
drawing figures, which are briefly described as follows.
BRIEF DESCRIPTION OF THE FIGURES
[0027] FIG. 1A illustrates an embodiment of the vertebral spacer
according to the present invention having a first guiding groove
and a second guiding groove.
[0028] FIG. 1B illustrates an embodiment of the vertebral spacer
according to the present invention having protrusions on the upper
surface thereof.
[0029] FIG. 2A illustrates an embodiment of the vertebral spacer
according to the present invention wherein a section dissected from
a femur bone is contained within a partial metallic sheath.
[0030] FIG. 2B illustrates an embodiment of the vertebral spacer
according to the present invention wherein a section dissected from
a femur bone is contained within a partial metallic sheath and
having angular protuberances on the metallic sheath.
[0031] FIG. 3 illustrates another embodiment of the vertebral
spacer according to the present invention having two slots
extending from the upper surface thereof.
[0032] FIG. 4 is an end elevation of the embodiment of the
vertebral spacer shown in FIG. 3.
[0033] FIG. 5 is a side elevation of the embodiment of the
vertebral spacer shown in FIG. 3.
[0034] FIG. 6 is a horizontal elevation showing the bottom surface
of the embodiment of the vertebral spacer shown in FIG. 3.
Positions of the slots relative to the second guiding groove are
indicated by dashed lines.
[0035] FIG. 7 illustrates another embodiment of the vertebral
spacer according to the present invention wherein slots extending
from the upper surface thereof accommodate bone material
therein.
[0036] FIG. 8 illustrates another embodiment of the vertebral
spacer comprising alternate layers of bone, a biocompatible
material, and a linking pin.
[0037] FIG. 9 illustrates another embodiment of a layered vertebral
spacer according to the present invention wherein the outermost
layers are bone.
[0038] FIGS. 10-12 illustrate the sectioning of a femur to give at
least one vertebral spacer according to the present invention. FIG.
10 shows the sectioning planes for the excision of a section of a
femur. FIG. 11 shows a cross-sectional view of an excised section
of a femur with minimal portions of the femur shown in cross-hatch
trimmed away to give two vertebral spacers. FIG. 12 shows the
cross-sectional view of two vertebral spacers cut from a femoral
section.
[0039] FIG. 13 shows an end elevation of a vertebral spacer
according to the present invention excised from a femur and having
two guiding grooves therein.
[0040] FIG. 14 shows a side elevation of a vertebral spacer
according to the present invention excised from a femur.
[0041] FIGS. 15 and 16 illustrate an embodiment of the vertebral
spacer of the present invention excised from a femur wherein the
femur medullary cavity not bisected.
[0042] FIG. 17 is a perspective view of a vertebral spacer
according to the present invention excised from a femur.
[0043] FIG. 18 is an end elevation of the vertebral spacer
illustrated in FIG. 17.
[0044] FIG. 19 is a perspective view of another vertebral spacer
according to the present invention cut from the same section of
femur as the spacer in FIG. 17.
[0045] FIG. 20 shows a top elevation of a vertebral spacer
according to the present invention cut from a femur section.
[0046] FIG. 21 shows a bottom elevation of a vertebral spacer
according to the present invention cut from a femur section.
[0047] FIG. 22 illustrates a perspective view of a vertebral spacer
according to the present invention cut from a femur section and
having a plurality of bores therein.
[0048] FIGS. 23-28 illustrate perspective cross-sectional views of
embodiments of the insertion tool according to the present
invention. FIG. 23 shows an embodiment of the insertion tool having
a flange thereon. FIG. 24 shows an embodiment of the insertion tool
having two flanges. FIG. 25 shows an embodiment of the insertion
tool having a rib thereon. FIG. 26 shows an embodiment of the
insertion tool having two ribs. FIG. 27 shows an embodiment of the
insertion tool having a plurality of longitudinal ribs. FIG. 28
shows an embodiment of the insertion tool having protrusions.
[0049] FIG. 29 illustrates a perspective view of the system for
delivering a vertebral spacer to a patient according to the present
invention wherein the vertebral spacer engages two flanges on the
insertion tool.
[0050] FIG. 30 illustrates a perspective view of the system for
delivering a vertebral spacer to a patient according to the present
invention wherein the vertebral spacer engages two ribs on the
insertion tool.
[0051] FIG. 31 illustrates a perspective view of an embodiment of
the system for delivering a vertebral spacer to a patient wherein
the insertion tool has two flanges.
[0052] FIG. 32 illustrates a perspective view of an embodiment of
the system for delivering a vertebral spacer to a patient wherein
the insertion tool has two ribs.
[0053] FIGS. 33-35 illustrate the assembly of an embodiment of the
system for delivering a vertebral spacer to a patient. FIG. 33
shows a vertebral spacer engaging an insertion tool according to
the present invention. FIG. 34 illustrates the system wherein the
distal end of a pusher is configured to accept the vertebral
spacer. FIG. 35 illustrates the direction of delivery of the
vertebral spacer to an intervertebral space by the insertion tool
and the pusher therein.
[0054] FIG. 36 illustrates a vertical cross-sectional view of an
embodiment of the system for delivery of a vertebral spacer to a
patient according to the present invention.
[0055] FIG. 37 illustrates a vertical cross-sectional view of
another embodiment of the system for delivery of a vertebral spacer
to a patient according to the present invention.
[0056] FIG. 38 illustrates the cutting of a vertebral spacer
receiving slot by an embodiment of the cutting tool according to
the present invention.
[0057] FIG. 39 is a side-elevation of an embodiment of the cutting
tool and insertion tool according to the present invention.
[0058] FIG. 40 illustrates an end-elevation of an embodiment of the
cutting tool according to the present invention.
[0059] FIG. 41 is a perspective view of an embodiment of the
cutting tool and the insertion tool according to the present
invention.
[0060] FIGS. 42-45 illustrate the delivery of a vertebral spacer to
an intervertebral space according to the methods of the present
invention. FIG. 42 illustrates the placing of an insertion tool
into an intervertebral space by using a guiding tool. FIG. 43 shows
the rotation of the insertion tool within the intervertebral space
after extraction of the guiding tool. FIG. 44 illustrates the
formation of a vertebral spacer receiving slot by the cutting tool.
FIG. 45 illustrates the delivery of the vertebral spacer into the
intervertebral space and the vertebral spacer receiving slot.
[0061] FIG. 46 is a perspective view showing an embodiment of the
vertebral spacer according to the present invention in situ in an
intervertebral space of a patient.
[0062] FIG. 47 is an overhead view showing two vertebral spacers
formed from a femur on a vertebral surface.
DETAILED DESCRIPTION OF THE INVENTION
[0063] A full and enabling disclosure of the present invention,
including the best mode known to the inventor of carrying out the
invention, is set forth more particularly in the remainder of the
specification, including reference to the accompanying drawings,
wherein like reference numerals designate corresponding parts
throughout several figures. This description is made for the
purpose of illustrating the general principles of the invention and
should not be taken in the limiting sense.
[0064] One aspect of the present invention is a vertebral spacer
for insertion between two adjacent vertebrae 20, thereby
maintaining the intervertebral space 23 and preventing compression
of the spinal cord therein. Various embodiments of the vertebral
spacer 10 in accordance with the present invention are shown in
FIGS. 1A-22. The vertebral spacer 10 of the present invention is
useful to replace an intervertebral disc 21 that has degenerated
due to traumatic injury, vertebral displacement, or disease, such
as, for example, autoimmune disease or rheumatoid arthritis or any
other pathological condition of the spinal column that may injure
or shift the intervertebral disc. The vertebral spacer 10 of the
present invention provides support to the vertebrae 20 and
maintains separation between vertebrae while also preserving the
natural curvature of the spine.
[0065] The vertebral spacer 10 of the present invention may have a
plurality of surfaces, including a lower surface 15 and an upper
surface 16, with the lower surface 15 having an anterior face 13
and a posterior face 14 extending therefrom, as shown in FIG. 1A.
The anterior face 13 may be directed towards the inner body cavity
of a patient, and the posterior face 14 may be directed towards the
dorsal surface of the patient. The vertebral spacer 10 can be
configured such that the height of the anterior face 13 is less
than the height of the posterior face 14, as is illustrated, for
example, in FIG. 1A. The difference in the height of the opposing
anterior 13 and posterior 14 faces of the vertebral spacer 10 of
the present invention, so that the lower surface 15 and the upper
surface 16 are non-parallel, is useful to preserve the natural
curvature of the spinal column. The vertebral spacer 10 of the
present invention further comprises a first guiding groove 17 in
the upper surface 16 or the lower surface 15 of the vertebral
spacer 10. The vertebral spacer 10, as contemplated by the present
invention, may also have an optional second guiding groove 18 in
the upper surface 16 or the lower surface 15 not having the first
guiding groove 17 therein.
[0066] It is contemplated that the vertebral spacer 10 of the
present invention may be of any biocompatible or physiologically
inert material or combination of such materials having the
mechanical strength capable of maintaining the intervertebral space
23 (FIG. 46) between two adjacent vertebrae 20. Examples of such
materials include bone, such as bone sections from the femur,
titanium, titanium alloy, stainless steel, chrome cobalt, and
polymeric materials such as methyl methacrylate (MMA), urethane,
polyacetal and the like. The material of the vertebral spacer 10
may, however, also have a degree of resilience and thereby tolerate
a degree of compression. Such materials may include, but are not
limited to, polymers such as carbon fiber reinforced polymer such
as PEEK (polyetherether ketone), polycarbonate, polypropylene,
polyethylene, polyamide and silicone-based polymers.
[0067] It is further contemplated that the vertebral spacer 10 of
the present invention may comprise a bone core 12 such as a femur
and a sheath 35 as shown in FIG. 2.
[0068] In one embodiment, the sheath 35 is metallic, such as a
tungsten sheath. In another embodiment the sheath comprises a
biocompatible polymer. In one embodiment, shown in FIG. 2B, the
metallic sheath 35 has angular protrusions 34 thereon.
[0069] The vertebral spacer 10 of the present invention may have
any conformation that will allow the spacer 10 to be positioned in
an intervertebral space 23 between adjacent vertebrae 20 and which
will maintain an intervertebral space 23 and the natural curvature
of a spinal column when in the desired position. Referring to FIGS.
1A-22, exemplary geometric cross-sections that may be applied to
the vertebral spacer 10 of the present invention include, but are
not limited to, a rectangular cross-section or a trapezoidal
cross-section.
[0070] As shown in FIGS. 1B and 2B, the upper surface 16, and
optionally the lower surface, of the vertebral spacer 10 can also
include at least one protrusion 34 for frictionally engaging a
vertebrae 20 as disclosed in U.S. patent application Ser. No.
______ incorporated herein by reference in its entirety. An
exemplary embodiment of the protrusions 34 of the present invention
traversing the upper surface 16 of the vertebral spacer 10 are
illustrated in FIG. 1B. In another embodiment of the vertebral
spacer 10 of the present invention, as shown in FIG. 2B, the
protrusions are located on a metallic sheath 35 encapsulating a
bone core 12. The protrusions 34 may have any suitable geometric
configuration that will allow the vertebral spacer 10 of the
present invention to be secured to adjacent vertebrae, including
having a triangular, rounded, or rectangular cross-section and the
like, or any combination thereof. The protrusions may be elongated
as shown in FIG. 1B, or any other shape such as square or circular
protrusions or irregular non-elongated protrusions.
[0071] When the vertebral spacer 10 comprises a section of a femur
and wherein the femur medullary cavity 19 connects the anterior
face 13 and the posterior face 14 of the vertebral spacer 10, as
shown in FIG. 2, the hardening biocompatible composition may be
delivered to the portion of the femur medullary cavity 19. With the
alternative embodiments of the vertebral spacer 10 having at least
one slot 11 extending from the upper surface 16 or lower surface
15, the hardening biocompatible composition may be delivered to the
slots 11 thereof. One embodiment of the method of the present
invention, therefore, further comprises the step of delivering a
hardening biocompatible composition to the vertebral spacer 10. The
hardening biocompatible composition may be used, for example, to
bond the vertebral spacer 10 to an adjacent vertebra or be an
osteogenic composition to promote bone growth from the adjacent
vertebrae into the vertebral spacer 10. The hardening biocompatible
composition may be, for example, an organic polymer, a mineral
composition such as a hydroxyapatite-based compositions, methyl
methacrylate or a combination thereof. A hydroxyapatite-based
composition is especially useful in the context of the present
invention for promoting osteocyte growth and bone deposition.
[0072] The direction of insertion of the vertebral spacer 10 by the
methods of the present invention can be selected by the surgeon
according to the needs of the patient. The anterior face 13 of the
vertebral spacer 10, for example, may be positioned relative to the
spine to maintain a desired curvature thereof, as shown in FIG. 46.
The vertebral spacer 10 may be inserted posteriorly as shown, for
example in FIG. 46, anteriorly, or laterally, relative to the
spinal column. Once inserted into a desired position in the
intervertebral space 23, as shown in FIG. 46, the lower surface 15
and the upper surface 16 of the vertebral spacer 10 are
substantially contacting the adjacent vertebrae 20. For example,
the lower surface 15 of the vertebral spacer 10 may contact the
lower vertebra 20, and the upper surface 16 may support the
adjacent upper vertebra 20. Optional protrusions 34 extending from
the upper surface 16 as shown, for example, in FIG. 1B, and/or the
lower surface 15 can increase the frictional resistance between the
vertebral spacer 10 and the adjacent vertebrae 20. As shown in FIG.
46, the vertebral spacer 10 of the present invention can support
adjacent vertebrae 20 after the partial or total surgical removal
of an intervertebral disc 21, thereby preventing collapse and/or
compression of the spine in this region that might otherwise lead
to severe neurological damage.
[0073] In another embodiment of the vertebral spacer 10 of the
present invention, at least one slot 11 may be formed in the upper
surface 16 and extend towards, but not connecting with, the
opposing lower surface 15, as shown in FIGS. 3-6. Alternatively,
the at least one slot 11 may be formed in the lower surface 15 and
extend towards the upper surface 16.
[0074] In still another embodiment of the vertebral spacer 10 of
the present invention, the at least one slot 11 has a bone core 12
disposed therein, as shown in FIG. 7. Alternatively, a hardening
biocompatible composition may be deposited in the at least one slot
11, wherein the hardening biocompatible composition generally
comprises an osteogenic compound such as, for example,
hydroxyapatite.
[0075] In another embodiment of the vertebral spacer 10 of the
present invention, shown in FIGS. 8 and 9, the spacer 10 comprises
a plurality of layers, wherein at least one layer is a bone core
12. The plurality of layers may be bonded by any suitable method
such as an adhesive, screws, bolts, a linking pin, or the like, and
which will hold the layers immobile relative to each other. In one
embodiment of the vertebral spacer 10 of the present invention, as
shown in FIG. 9, may be bonded by at least one pin 9. In another
embodiment of the vertebral spacer 10, the plurality of layers may
be bonded by two pins positioned to prevent movement of the layers
relative to each other. The bonding method will not impede
installation of the vertebral spacer 10 into the intervertebral
space 23 (FIG. 46) of a patient. The alternate layers may have bone
cores 12 as inner layers as shown in FIGS. 7 and 8, or as the
outermost layers of the vertebral spacer 10, as shown in FIG.
9.
[0076] Referring now to FIGS. 10-22, in another embodiment of the
vertebral spacer 10 of the present invention, the vertebral spacer
10 is formed from a femoral section 24 taken from the shaft 22 of a
femur, as shown in FIG. 10. The femoral section 24, having a
central femur medullary cavity 19 therein, may be trimmed as shown
in FIGS. 11, 12, 15 and 16 to yield at least one vertebral spacer
10. Each vertebral spacer 10 obtained from a femur shaft 22 will
have at least a portion of the femur medullary cavity 19 connecting
the upper 16 and lower 15 surfaces of the vertebral spacer 10. The
indented portion of the femur medullary cavity 19 is useful to
partially surround a spinal cord when the vertebral spacer 10 is
positioned within an intervertebral space, thereby allowing the
vertebral spacer 10 to be positioned closer to the spinal cord than
would be possible if the cavity 19 were not present. The vertebral
spacer 10 of the present invention, when excised from a femur shaft
22 (FIG. 10) also has a first guiding groove 17, and optionally, a
second guiding groove 18, in the upper 16 and/or lower 15 surfaces
respectively of the vertebral spacer 10, as shown in FIGS.
11-22.
[0077] Referring now to FIG. 22, the vertebral spacer 10 of the
present invention may further include a bore 46, or a plurality of
bores 46, extending from the upper surface 16 and/or the lower
surface 15 of the vertebral spacer 10. Bony or other tissue growth
from adjacent vertebrae that extends into the bore 46, or plurality
of bores 46, of the vertebral spacer 10 of the present invention
may bond the vertebrae and the vertebral spacer 10. The bony growth
will, therefore, effectively fuse the adjacent vertebrae. It is
further contemplated that a tissue growth factor or an osteogenic
material may be inserted into the bores to increase the bony growth
and, therefore, the rate of this fusion. Suitable growth factors
include, but are not limited to, growth hormones, steroids, tissue
growth factors and the like.
[0078] Another aspect of the present invention is a system for
delivering a vertebral spacer 10 to the spinal column of a patient,
generally illustrated in FIGS. 24-41. The system for delivering the
vertebral spacer comprises (a) an insertion tool 60 for delivering
the vertebral spacer 10 to the spinal column of a patient, wherein
the insertion tool 60 has a channel 61 and an inner surface 62 as
shown in FIGS. 24-28; (b) an optional guiding tool 80; (c) a pusher
63 (as in FIGS. 31-37) having a distal end 65 slideably disposable
in the channel 61 of the insertion tool 60; (d) a vertebral spacer
10 slideably disposable in the channel 61 of the insertion tool 60;
and (e) a cutting tool 70 (FIGS. 38-41) having a shaft 72 with a
distal end 74 and a proximal end 75, and a cutting head 71 secured
to the distal end 74 of the shaft 72.
[0079] The channel 61 of the insertion tool 60 of the system of the
present invention generally is configured to slideably accept any
of the various vertebral spacers 10, according to the present
invention, a pusher 63 and/or a cutting tool 70. The insertion tool
60 further comprises at least one spacer guide 66 for slideably
engaging with a first guiding groove 17 or a second guiding groove
18 of a vertebral spacer 10.
[0080] Referring now to FIGS. 23-28, in one embodiment of the
insertion tool 60 of the present invention, as shown in FIG. 23,
the spacer guide 66 is a flange extending along an outside edge of
the channel 61. In another embodiment of the insertion tool 60 of
the present invention, as shown in FIG. 24, the spacer guide 66 is
two opposing flanges along the upper and lower outside or distal
side edges of the insertion tool 10 configured to slideably engage
with a first guiding groove 17 (FIGS. 1, 3-9, 11-14) and a second
guiding groove 18 of a vertebral spacer 10.
[0081] In still another embodiment of the insertion tool 60 of the
present invention as shown in FIGS. 25 and 26, the spacer guide 66
is formed as one or more ribs longitudinally disposed on an inner
surface 62 of the channel 61.
[0082] In other embodiments of the insertion tool 60 of the present
invention, the spacer guide 66 may be formed by at least one
segmented longitudinal rib disposed on the inner surface 62 of the
channel 61, as shown in FIG. 27, or a linear series of spaced
protrusions, also disposed on the inner surface 62 of the channel
61, as shown in FIG. 28. It is to be understood, however, that any
configuration of spacer guides 66 may be used by the insertion tool
60 that will allow a vertebral spacer to be slideably engaged with
the insertion tool 60 and not resist insertion of the vertebral
spacer into the spinal column of a patient.
[0083] As shown in FIGS. 29-35, the spacer guide 66, or a plurality
of guides 66, may slideably engage the first 17 and optional second
18 guiding groove with at least a portion of the vertebral spacer
10 positioned externally to the channel 61, as illustrated in FIGS.
29 and 31.
[0084] The present invention also provides an optional guide tool
80 that can be slideably disposed in the channel 61 of the
insertion tool 60. The elongated optional guide tool can be
inserted into an intervertebral space 23 as indicated in FIGS.
42-43, to a position selected by a surgeon for guiding the
insertion tool 60 to the same selected position.
[0085] As shown in FIGS. 31-32, 34-37, and 45, the system for
delivery of a vertebral spacer 10 to the spinal column of a patient
further comprises a pusher 63 having a distal end 65 for contacting
a vertebral spacer 10 disposed in the channel 61. It is
contemplated that the pusher 63 can be slideably engaged in the
channel 61 of the insertion tool 60 and is suitable for enabling a
surgeon to push a vertebral spacer 10 along the channel 61, out of
the insertion tool 60 and into an intervertebral space 23.
[0086] In one embodiment of the pusher of the present invention as
illustrated in FIGS. 31 and 32, the distal end 65 may be
substantially parallel to the posterior face 14 of the vertebral
spacer 10. This orientation is especially useful for inserting a
vertebral spacer 10 of the present invention in the lumbar region
of a spinal column. It is to be understood, however, that the
vertebral spacer 10 may be inserted in the insertion tool 60 in the
opposite orientation for insertion in another region of the spine
where reverse curvature to that of the lumbar region is to be
maintained. In other embodiments of the present invention such as
shown, for example, in FIGS. 34, 35 and 37, the configuration of
the distal end 65 of the pusher 63 may be defined by the anterior
face 13 and the upper surface 16 of the vertebral spacer 10.
[0087] As illustrated in FIGS. 38-41, the system for the delivery
of a vertebral spacer 10 to the spinal column of a patient further
provides a cutting tool 70 suitable for cutting a vertebral spacer
receiving slot 78 into a vertebra 20. The cutting tool 70 of the
present invention has a shaft 72 with a distal end 74 and a
proximal end 75. A cutting head 71 is connected to the distal end
74 of the shaft 72 of the cutting tool 70. In one embodiment of the
cutting tool 70 of the present invention, a striking head 73 is
disposed on the proximal end 75 of the shaft 72.
[0088] The cutting head 71 of the cutting tool 70 may be an
integral configuration of the distal end 74 of the shaft 72, or
connected to the distal end 74 of the shaft 72. In one embodiment
of the cutting tool 70 of the present invention, the cutting head
71 is connected to the shaft by an attachment member 76 which may
be, for example, a threaded attachment member 76, as shown in FIGS.
39 and 40. The cutting head 71 will be capable of being slideably
disposed within the channel 61 of the insertion tool 60 providing
that the pusher 63 and the vertebral spacer 10 are not disposed
therein
[0089] Another aspect of the present invention is a method for
delivering a vertebral spacer 10 to a patient using the system of
the present invention comprising the insertion tool 60, an optional
guide tool 80, the vertebral spacer 10, the pusher 63 and the
cutting tool 70. Such a method is generally illustrated in FIGS.
42-45 and comprises the steps of inserting the insertion tool 60
into an intervertebral space 23 of the spinal column of a patient
(FIG. 42), rotating the insertion tool 60 in the intervertebral
space 23 (FIG. 43), cutting a vertebral spacer receiving slot 78
(FIG. 44), and engaging the first guiding groove 17, and optionally
a second guiding groove 18, of a vertebral spacer 10 with a space
guide 66 of the insertion tool 60. The vertebral spacer 10 is
pushed into the intervertebral space 23 by slideably disposing a
pusher 63 into the channel 61 of the insertion tool 60, and
advancing the pusher 63 (FIG. 45). The pusher 63 and the insertion
tool 60 are then removed from the patient.
[0090] The insertion tool 60 further optionally may be directed
into the selected position within the intervertebral space 23 by
the guide tool 80 that may be inserted by the surgeon into the
intervertebral space 23. The method of the present invention,
therefore, further comprises the optional step of inserting a
guiding tool 80 into an intervertebral space 23.
[0091] The insertion tool 60 may then be slid along the guide tool
80 until the insertion tool 60 is at the selected position for
insertion of a vertebral spacer 10 in the intervertebral space 23.
The guide tool 80 is then removed from the channel 61 of the
insertion tool 60, as shown in FIG. 42, leaving the insertion tool
60 inserted between adjacent vertebrae 20. Alternatively, the guide
tool 80 may remain in the insertion tool 60 while the insertion
tool 60 is rotated in the intervertebral space 23, thereby
providing torsional strength to the insertion tool 60. The
insertion tool 60 may be inserted into the intervertebral space 23
with the channel 61 facing a vertebra 20, as shown in FIG. 42. The
insertion tool 60 may then be rotated so that the open channel 61
of the tool 60 is not facing a vertebra 20, as shown in FIG.
43.
[0092] As shown in FIG. 44, the cutting tool 70 is optionally slid
along the channel 61 of the insertion tool 60 to engage a vertebra
20 and to chisel a vertebral space receiving slot 78 in the
vertebrae 20. Alternatively, two vertebral spacer receiving slots
78 may be cut in opposing faces of adjacent vertebrae 20. The
striking head 73 of the cutting tool 70 may be struck with a
striking tool 77 to increase the cutting action of the cutting head
71.
[0093] As shown in FIG. 45, the cutting tool 70 is removed from the
patient by slideably withdrawing the cutting tool 70 back through
the channel 61 of the insertion tool 60. A vertebral spacer 10
according to the present invention may then be slideably engaged
with the insertion tool 60, wherein at least one space guide 66 on
the insertion tool 60 engages with a first guiding groove 17 and
optionally a second guiding groove 18 of the vertebral spacer 10.
The pusher 63 may then be slideably engaged with the channel 61 and
contacted with the vertebral spacer 10. The pusher 63 is advanced
along the channel 61 of the insertion tool 60 thereby pushing the
vertebral spacer 10 into the vertebral spacer receiving slot 78 or
receiving slots 78 in the adjacent vertebrae 20. It is also
contemplated, however, that a vertebral spacer receiving slot 80
may not be cut in the adjacent vertebrae 20 and that the inserted
vertebral spacer 10 may optionally contact the uncut surface of the
vertebrae 20.
[0094] It is to be understood that the methods of the present
invention for the delivery of a vertebral spacer 10 to an
intervertebral space 23 may also be used to deliver two vertebral
spacers 10, as shown in FIG. 47, it is further understood that a
hardening biocompatible composition may be delivered between the
vertebral spacers, thereby forming a larger effective spacer and
optionally promoting bone growth to secure the vertebral spacers 10
to the vertebrae.
[0095] Yet another aspect of the present invention is a kit for
delivering a vertebral spacer to the spinal column of a patient,
comprising an insertion tool for delivering a vertebral spacer to
the spinal column of a patient and having a channel having an inner
surface, a pusher having a distal end is slideably disposable in
the channel of the insertion tool, a vertebral spacer slideably
disposable in the channel of the insertion tool, a cutting tool
having a shaft with a distal end and a proximal end, and a cutting
head secured to the distal end of the shaft, wherein the cutting
tool is slideably disposable in the insertion tool providing that
the pusher and the vertebral spacer are not disposed therein.
Instructions for the use of the system and its various components
to deliver a vertebral spacer to the spinal column of a patient
also generally are included or provided.
[0096] The kit of the present invention further can include an
optional guiding tool configured to slideably engage the channel of
the insertion device, and instructions for the operation
thereof.
[0097] With respect to the above description, it is to be realized
that the optimum dimensional relationships for the parts of the
invention, to include variations in size, materials, shape, form,
function and manner of operation, assembly, and use, are deemed
readily apparent and obvious to one skilled in the art, and all
equivalent relationships to those illustrated in the drawing and
described in the specification are intended to be encompassed by
the present invention. Further, the various components of the
embodiments of the invention may be interchanged to produce further
embodiments and these further embodiments are intended to be
encompassed by the present invention.
[0098] Although the invention has been described in detail for the
purpose of illustration, it is understood that such detail is
solely for that purpose, and variations can be made therein by
those skilled in the art without departing from the spirit and
scope of the invention which is defined by the following
claims.
* * * * *