U.S. patent application number 10/842103 was filed with the patent office on 2004-10-21 for anchoring devices and implants for intervertebral disc augmentation.
Invention is credited to Trieu, Hai H..
Application Number | 20040210226 10/842103 |
Document ID | / |
Family ID | 24786496 |
Filed Date | 2004-10-21 |
United States Patent
Application |
20040210226 |
Kind Code |
A1 |
Trieu, Hai H. |
October 21, 2004 |
Anchoring devices and implants for intervertebral disc
augmentation
Abstract
Devices for anchoring spinal implants in an intervertebral disc
space are provided. Spinal implants are also provided that are
resistant to lateral deformation. The implants may include a
flexible peripheral supporting band disposed circumferentially
about an elastic body. Methods for anchoring spinal implants and
methods for reducing deformation of spinal implants are also
provided.
Inventors: |
Trieu, Hai H.; (Cordova,
TN) |
Correspondence
Address: |
Woodard, Emhardt, Moriarty, McNett & Henry LLP
Bank One Center/Tower
Suite 3700
111 Monument Circle
Indianapolis
IN
46204-5137
US
|
Family ID: |
24786496 |
Appl. No.: |
10/842103 |
Filed: |
May 10, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10842103 |
May 10, 2004 |
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09693880 |
Oct 20, 2000 |
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6733531 |
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Current U.S.
Class: |
606/232 ;
606/249; 606/278; 606/907; 606/911; 623/17.11 |
Current CPC
Class: |
A61F 2002/30578
20130101; A61F 2002/30224 20130101; A61F 2002/448 20130101; A61F
2230/0058 20130101; A61F 2310/00023 20130101; A61F 2230/0069
20130101; Y10S 606/911 20130101; A61F 2/442 20130101; A61F
2002/30092 20130101; A61F 2/2846 20130101; A61F 2002/30133
20130101; A61F 2230/0015 20130101; A61F 2002/30909 20130101; A61F
2002/444 20130101; A61F 2002/30179 20130101; A61F 2310/00796
20130101; A61F 2/30965 20130101; A61F 2002/30649 20130101; Y10S
606/91 20130101; Y10S 606/907 20130101; A61F 2310/00928 20130101;
A61F 2002/2817 20130101; A61F 2002/4495 20130101; A61F 2310/00029
20130101; A61F 2002/30566 20130101; A61F 2310/00017 20130101; A61F
2002/3079 20130101; A61F 2210/0014 20130101; A61F 2002/30677
20130101 |
Class at
Publication: |
606/072 ;
623/017.11 |
International
Class: |
A61B 017/84; A61F
002/44 |
Claims
1. A device for anchoring a spinal implant in an intervertebral
disc space, comprising: (a) an anchoring rod having a first end and
a second end, said rod configured to anchor said implant; (b) at
least one securing member attached to said rod, said device
securable to an adjacent vertebra.
2. The device of claim 1, wherein said first end of said anchoring
rod is securable to said adjacent vertebra.
3. The device of claim 1, wherein two opposing securing members are
attached to said anchoring rod, said members spaced apart along the
length of said rod and defining a region for disposing said implant
therebetween, said device securable to an adjacent vertebra.
4. The device of claim 1, wherein said securing member is formed of
material selected from shape memory material, titanium alloy,
titanium, stainless steel, cobalt chrome alloy, carbon fiber
reinforced composite, polyolefins, polyaryletherketone,
polymethylmethacrylate, polycarbonate, polyurethane, silicone and
combinations thereof.
5. The device of claim 4, wherein said shape memory material is a
shape memory alloy that exhibits superelastic behavior.
6. The device of claim 1, wherein said device is comprised of a
metallic material, a non-metallic material, or a combination
thereof.
7. The device of claim 6, wherein said metallic material is
selected from a shape memory material, titanium alloy, titanium,
stainless steel, cobalt chrome alloy, and combinations thereof.
8. The device of claim 8, wherein said non-metallic material is
selected from polyethylene, polyparaphenylene terephthalamide,
cellulose, carbon fiber reinforced composite, polyester, polyvinyl
alcohol and combinations thereof.
9. The device of claim 1, wherein said first end of said anchoring
rod is securable to an adjacent vertebra with a bone screw or a
soft tissue anchor.
10. The device of claim 9, wherein said bone screw is an
interference screw and said soft tissue anchor is a suture
anchor.
11. The device of claim 1, wherein said anchoring rod is securable
to an adjacent vertebra.
12. The device of claim 1, wherein said first end of said anchoring
rod is securable to an adjacent vertebra.
13. The device of claim 1, wherein said device further includes a
bracket, said first end of said rod securable to said bracket.
14.-62. (cancelled)
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to spinal implants, devices
for anchoring, and methods for implantation of, such implants in an
intervertebral disc space.
[0002] The intervertebral disc functions to stabilize the spine and
to distribute forces between vertebral bodies. A normal disc
includes a gelatinous nucleus pulposus, an annulus fibrosis and two
vertebral end plates. The nucleus pulposus is surrounded and
confined by the annulus fibrosis.
[0003] Intervertebral discs may be displaced or damaged due to
trauma or disease. Disruption of the annulus fibrosis allows the
nucleus pulposus to protrude into the spinal canal, a condition
commonly referred to as a herniated or ruptured disc. The extruded
nucleus pulposus may press on the spinal nerve, which may result in
nerve damage, pain, numbness, muscle weakness and paralysis.
Intervertebral discs may also deteriorate due to the normal aging
process. As a disc dehydrates and hardens, the disc space height
will be reduced, leading to instability of the spine, decreased
mobility and pain.
[0004] One way to relieve the symptoms of these conditions is by
surgical removal of a portion or all of the intervertebral disc.
The removal of the damaged or unhealthy disc may allow the disc
space to collapse, which could lead to instability of the spine,
abnormal joint mechanics, nerve damage, as well as severe pain.
Therefore, after removal of the disc, adjacent vertebrae are
typically fused to preserve the disc space.
[0005] Several devices exist to fill an intervertebral space
following removal of all or part of the intervertebral disc in
order to prevent disc space collapse and to promote fusion of
adjacent vertebrae surrounding the disc space. Even though a
certain degree of success with these devices has been achieved,
full motion is typically never regained after such intervertebral
fusions. Attempts to overcome these problems has led to the
development of disc replacements. Many of these devices are
complicated, bulky and made of a combination of metallic and
elastomeric components and thus never fully return the full range
of motion desired. More recently, efforts have been directed to
replacing the nucleus pulposus of the disc with a similar
gelatinous material, such as a hydrogel. However, once positioned
in the disc space, many hydrogel implants may migrate in the disc
space and/or may be expelled from the disc space through an annular
defect. Closure of the annular defect, or other opening, using
surgical sutures or staples following implantion is typically
difficult and, in some cases, ineffective. Moreover, such hydrogel
implants may be subject to extensive deformation. Additionally,
such hydrogel implants typically lack mechanical strength at high
water content and are therefore more prone to excessive
deformation, creep, cracking, tearing or other damage under fatigue
loading conditions.
[0006] A need therefore exists for more durable nucleus pulposus or
other spinal implants, including implants that are less resistant
to deformation, as well as devices and methods that anchor the
implants so that the implants are more resistant to migration
and/or expulsion through an opening in the annulus fibrosis. The
present invention addresses these needs.
SUMMARY OF THE INVENTION
[0007] Devices for anchoring a spinal implant in an intervertebral
disc space are provided. In one form of the invention, a device
includes an elongated anchoring body, such as an anchoring rod, and
at least one securing member attached to the anchoring rod. The
anchoring body or rod is configured to anchor, hold, or otherwise
retain a spinal implant. In certain forms of the invention wherein
more than one securing member is included, the securing members are
spaced apart along the length of the anchoring rod and may define a
region for disposing an implant therebetween. The anchoring rod has
a first end and a second end, wherein the first end is securable to
an adjacent vertebra. The anchoring devices may be made from
metallic materials, non-metallic materials and combinations
thereof.
[0008] Spinal implant systems are also provided that include the
anchoring device described above and an elastic spinal implant. In
certain forms of the invention, the anchoring devices include an
anchoring rod and at least one securing member attached to the
anchoring rod. The anchoring rod includes a first end, a second
end, a longitudinal axis and extends at least partially through the
implant. The anchoring component is securable to an adjacent
vertebra. In one form of the invention, the securing members may be
external to the implant, while in other forms of the invention the
securing members may be internal to the implant or may be both
internal and external to the implant.
[0009] Spinal implants are also provided that are resistant to
lateral deformation as they are restrained, or otherwise
reinforced, by a flexible, peripheral supporting band. In one form
of the invention, the implant includes an elastic body sized for
introduction into the intervertebral disc space. The elastic body
includes an upper surface and a lower surface for contacting
adjacent vertebral endplates. A flexible peripheral supporting band
is disposed circumferentially about the elastic body to reduce
deformation of the body. At least a portion of the upper and lower
surfaces of the elastic body are free of the supporting band. The
implant, including the band, is sized to fit within an
intervertebral disc space which is at least partially defined by an
annulus fibrosis.
[0010] Methods of anchoring a spinal implant are also provided. A
preferred method includes providing an elastic spinal implant and
an anchoring component that includes the anchoring devices
described above, extending the anchoring rod of the device at least
partially through the implant, and securing the anchoring component
to an adjacent vertebra.
[0011] Methods of reducing deformation of a spinal implant are also
provided. In one embodiment, a method includes disposing a flexible
peripheral supporting band circumferentially about the implants
described above.
[0012] One object of the present invention is to provide devices
for anchoring spinal implants so they will be resistant to
excessive migration in, and/or expulsion from, the intervertebral
disc space.
[0013] Yet another object of the invention is to provide spinal
implant systems including an elastic spinal implant and an
anchoring component for anchoring the implant.
[0014] A further object of the invention is to provide spinal
implants that are more resistant to lateral deformation.
[0015] These and other objects and advantages of the present
invention will be apparent from the descriptions herein.
BRIEF DESCRIPTION OF THE FIGURES
[0016] FIG. 1 is a side view of a device for anchoring a spinal
implant in an intervertebral disc space.
[0017] FIG. 2 is an end view of the device of FIG. 1, taken along
line 2-2.
[0018] FIG. 3 is a side view of an alternative embodiment of a
device for anchoring a spinal implant in an intervertebral disc
space, having a ball-and-socket joint.
[0019] FIG. 4 is a perspective view of the device of FIG. 3.
[0020] FIG. 5 depicts a side view of an alternative embodiment of a
device for anchoring a spinal implant in an intervertebral disc
space.
[0021] FIG. 6 is an end view of the device of FIG. 5, taken along
line 6-6.
[0022] FIGS. 7A-7T depict top views of alternative embodiments of
securing members of the anchoring devices described herein. The
anchoring members are shown with a superimposed outline of how an
implant I may be disposed on the anchoring device.
[0023] FIGS. 8A-8H depict top views of further alternative
embodiments of securing members of the anchoring devices described
herein. The anchoring members are shown with a superimposed outline
of how an implant I may be disposed on the anchoring device.
[0024] FIG. 9 is a side view of a spinal implant system.
[0025] FIG. 10 depicts an end view of the system of FIG. 9, taken
along line 10-10.
[0026] FIG. 11 depicts a side view of the spinal implant system of
FIG. 9, implanted in an intervertebral disc space, that includes an
anchoring component 10, an elastic body 100 and, optionally, a
peripheral supporting band 101.
[0027] FIG. 12 depicts a side view of an alternative embodiment of
a spinal implant system.
[0028] FIG. 13 depicts an end view of the system of FIG. 12, taken
along line 13-13.
[0029] FIG. 14 depicts a side view of the system of FIG. 12
implanted in an intervertebral disc space.
[0030] FIG. 15A depicts a perspective view of a spinal implant that
may be anchored with the anchoring devices described herein.
[0031] FIG. 15B depicts a side view of the implant of FIG. 15A.
[0032] FIG. 16 is a side view of a spinal implant reinforced with a
flexible peripheral supporting band.
[0033] FIG. 17 depicts a top view of the implant of FIG. 16.
[0034] FIG. 18A shows the effect of imposing a load, represented by
the darkened arrows, on the deformation of a spinal implant
reinforced with a flexible supporting band. Top to bottom: no load;
low load, moderate load; high load.
[0035] FIG. 18B is a graphical representation of the effect of
imposing a load on the deformation of a spinal implant of FIG.
18A.
[0036] FIGS. 19A-19D depict alternative embodiments of a flexible
peripheral supporting band of the present invention.
[0037] FIG. 20 depicts a side view of a spinal implant of the
present invention that is reinforced, and otherwise supported, by
peripheral supporting band 130' and straps 134 and 135.
[0038] FIG. 21 shows a top view of the implant of FIG. 20.
[0039] FIG. 22 depicts a side view of an alternative embodiment of
a spinal implant of the present invention, that includes a
peripheral supporting band 130" and securing straps 134', 135',
820, 830, 840 and 850.
[0040] FIG. 23 depicts a top view of the implant of FIG. 22.
[0041] FIG. 24 shows a cut-away view of an alternative embodiment
of an anchoring device implanted in an intervertebral disc space
for anchoring implant 100 with a tension band 700 extending between
vertebrae 107 and 109.
[0042] FIG. 25 depicts a side view of the device of FIG. 24.
[0043] FIG. 26 depicts a top, cut-away view of an alternative
embodiment of a device for anchoring a spinal implant that is
implanted in an intervertebral disc space.
[0044] FIG. 27 shows a top, cut-away view of an alternative
embodiment of a device for anchoring a spinal implant that is
implanted in an intervertebral disc space.
[0045] FIGS. 28-31 depicts cut-away, top views of anchoring
devices, along with anchored implants, inserted via posterior,
lateral, oblique and anterior approaches, respectively.
[0046] FIG. 32 depicts a top, cut-away view of a device for
anchoring a spinal implant that is implanted in an intervertebral
disc space, wherein two implants are advantageously anchored.
[0047] FIG. 33 depicts a top, cut-away view of an alternative
embodiment of a device for anchoring a spinal implant, wherein two
devices are used to anchor two spinal implants.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0048] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to
preferred embodiments and specific language will be used to
describe the same. It will nevertheless be understood that no
limitation of the scope of the invention is thereby intended, such
alterations and further modifications of the invention, and such
further applications of the principles of the invention as
illustrated herein, being contemplated as would normally occur to
one skilled in the art to which the invention relates.
[0049] The present invention relates to devices for anchoring a
spinal implant in an intervertebral disc space to prevent excessive
migration in and/or expulsion from the disc space, as well as novel
spinal implants. Spinal implant systems are also described that
include the anchoring device as well as an anchored elastic spinal
implant. The spinal implants described herein include those that
may be useful as nucleus pulposus replacements, partial or complete
disc replacements, and those that may be useful in other disc
reconstruction or augmentation procedures.
[0050] In other aspects of the invention, spinal implants are
provided that include an elastic body that is constrained and
supported by a flexible supporting member, such as a peripheral
supporting band. The band may advantageously have high resistance
to hoop stress, and may thus function in a similar manner as the
annulus fibrosis. More particularly, the hoop stress in the band
preferably increases exponentially after some small, allowable
initial deformation. Such implants may advantageously be used where
the integrity of the annulus fibrosis has been negatively affected,
or in other circumstances wherein increased support of an implant
is needed.
[0051] In one aspect of the invention, a device for anchoring a
spinal implant in an intervertebral disc space is provided. The
device may include an elongated anchoring body, such as an
anchoring rod, having at least one securing member attached
thereto, or otherwise disposed thereon. Referring now to FIGS. 1
and 2, anchoring device 10 may include an elongated anchoring body,
or rod, 20, first securing member 30 and second securing member 40.
Securing members 30 and 40 may oppose each other, may be spaced
apart along the length of anchoring rod 20 and may define a region
R for disposing a spinal implant therebetween. Moreover, the
longitudinal axes A of the securing members preferably extend
transverse with respect to the longitudinal axis X of the anchoring
rod. The device may advantageously be secured to an adjacent
vertebra.
[0052] For example, in one form of the invention, anchoring device
10 includes a first end 21 and a second end 22, wherein first end
21 is securable to an adjacent vertebra. First end 21 may define a
bracket 23, or other similar structure, for securing first end 21
to an adjacent vertebra. Bracket 23 includes a vertebra-contacting
surface 24 and at least one aperture 25 through which a bone screw,
or other similar securing device, may be placed to secure the
elongated body to an adjacent vertebra as more fully described
below. Moreover, a screw securing mechanism, such as a lock screw
or other known mechanism, may be used to further secure the screw
so it will not back out, or otherwise loosen. Bracket 23 is shown
as generally V-shaped in FIG. 2, although a wide variety of other
shapes are contemplated, as long as first end 21 is securable in
some form to an adjacent vertebra. As seen in FIG. 2, bracket 23
includes arm 23a and arm 23b. Arms 23a and 23b may be formed from
one piece, or may be formed of more than one piece that are
attached, or otherwise connected, to each other by methods known to
the skilled artisan. Moreover, first end 21 may define a bracket
that extends along the length of two adjacent vertebrae, so that
the bracket may be secured both to an upper adjacent vertebra and
to a lower adjacent vertebra in order to more stably secure
anchoring rod 20, and ultimately to more stably secure a spinal
implant.
[0053] In another form of the invention, the bracket described
herein may be mounted on, or otherwise connected to, first end 21.
For example, as shown in FIGS. 3 and 4, first end 21' of anchoring
rod 20' may define a ball or other spherical-shaped end that fits
in a socket 26 on bracket 23' to form a ball-and-socket joint, or
ball joint. The ball joint advantageously allows further movement
of the attached elongated body of anchoring device 10', which may
reduce or eliminate stress that may otherwise exist near end E' of
the elongated body.
[0054] Anchoring rod 20 may be formed from rigid, or otherwise
non-flexible materials, including carbon fiber reinforced
composite, such as carbon fiber/epoxy composites or carbon
fiber/polyaryletherketone composites. Anchoring rod 20 may further
be formed from a wide variety of metallic materials, including, for
example, shape memory materials, stainless steel, titanium,
titanium alloys, cobalt chrome alloys, and combinations thereof.
The shape memory materials may be made from, for example, the
nickel-titanium alloy known as Nitinol. The response of the shape
memory material to deformation generally has two triggers as known
in the art to induce the material to partially or fully recover its
memorized shape. The first trigger is a thermal trigger where the
deformed state is initially at a temperature such that the deformed
state is stable. Upon heating, the temperature rises until the
deformed state is no longer stable and begins to change to the
memorized state. The second trigger is a stress-actuated trigger
and may take advantage of superelasticity. The undeformed state is
at a temperature such that at least some of the material is in the
austenitic state. That is, the temperature may be such that the
material is within the hysterisis loop responsible for the
superelastic phenomenon or behavior. Under the influence of
sufficient stress, the austenitic material will transform into the
martensitic state. Upon the release of some or all of the stress,
the temperature is such that the martensitic state is unstable and
will automatically attempt to revert to the austenitic state with
consequent shape reformation. It should also be understood that the
shape memory material may attempt to recover the memorized shape by
using some combination of thermal and stress actuation. Preferred
shape memory materials will exhibit superelastic behavior. In
devices formed from such rigid materials, anchoring rod 20
preferably includes an end E having an arcuate shape, as seen in
FIG. 1, so that elongated body 20 may be secured to an adjacent
vertebra.
[0055] The anchoring rod component of the device may also, in other
forms of the invention, be formed of flexible materials so that the
anchoring rod acts as a tether, or other flexible anchor. Such a
flexible, anchoring rod component of an anchoring device 50 is
shown in FIGS. 5 and 6. Flexible, anchoring rod 60 also includes a
first securing member 70 and a second securing member 80. Anchoring
rod 60 further includes a first end 61 and a second end 62, wherein
the first end is securable to an adjacent vertebra. First end 61
may also define a bracket, such as bracket 23 as described above.
First end 61 of anchoring rod 60 may also be mounted, or otherwise
attached, to bracket 23' through a ball-and-socket joint as
described above by modifying first end 61 appropriately. In
preferred forms of the invention, first end 61 may be secured to an
adjacent vertebra with an interference screw, especially when the
device is implanted via a posterior approach as discussed below.
Securing members 70 and 80 also define a region R' for disposing a
spinal implant therebetween. Moreover, although rod 20 is shown as
being cylindrical herein, it is realized that the rods described
herein may assume a wide variety of shapes as known in the art,
including pyramidal, square and other polygonal shapes. The shapes
of the rods may be advantageously chosen so that the rods are
effective in anchoring the implants described herein.
[0056] A wide variety of materials may be used to form flexible
anchoring rod 60, including the same materials that may be used to
form a rigid anchoring rod described above, although the thickness
or diameter of the rod will be smaller than with the rigid rod so
that the rod will be flexible. The metallic materials may be in the
form of a wire, cable, chain or have some other appropriate
configuration. Other suitable materials include non-metallic,
polymeric materials, such as polyaryletherketone,
polymethylmethacrylate, polycarbonate, polyurethane, silicone,
polyolefins, including polytetrafluoroethylene, and combinations
thereof; non-metallic, fiber or fabric materials, including
cellulose, polyester, polyvinyl alcohol, polyacrylonitrile,
polyamide, polytetrafluoroethylene, polyparaphenylene
terephthalamide, polyolefins such as polyethylene, or from
combinations of these materials. The polymeric materials may be
braided, in the form of a cord, cable, or may have some other
appropriate configuration, and combinations thereof. The elongated
anchoring bodies described herein, as well as other portions of the
anchoring component, may also be formed from a combination of
flexible and rigid components. For example, bracket 23 or 23' of an
elongated anchoring body may be formed from a non-flexible material
whereas the remainder of the body may be formed from a flexible
material. Other combinations are possible as one skilled in the art
would be aware after reviewing the description herein.
[0057] The securing members may be either integral with the
anchoring rod or may be otherwise attached thereto. Referring again
to FIGS. 1 and 2, securing members 30 and 40 are disposed on
anchoring rod 20 and include an inner surface 31 and 41,
respectively, for contacting and securing a spinal implant, as well
as an outer surface 32 and 42, respectively. As mentioned above,
securing members 30 and 40 define a region R along anchoring rod 20
wherein a spinal implant may be disposed and secured. Thus, inner
surfaces 31 and 41 of securing members 30 and 40, respectively,
preferably abut the outer surface of an implant. The securing
members may be attached to anchoring rod 20 in a variety of ways.
For example, securing member 40 may include threads so that
securing member 40 may be screwed onto an end 22 of anchoring rod
20 that is threaded. Moreover, the securing members may be attached
with an adhesive, or other non-resorbable, biocompatible securing
materials, including cyanoacrylate adhesive and epoxy glue.
Furthermore, securing members may be secured by other means,
including clamps, pins, knots, by friction fit, mechanical
interlocking or combinations thereof.
[0058] Securing members 30, 40, 70 and 80 may, for example, be
formed from the same materials as described above for the elongated
anchoring body, or rod. In one preferred form of the invention,
wherein the anchoring rod is formed from a flexible, non-rigid
material, such as a braided fabric, the securing members may also
be formed from fabric. For example, securing member 70 may be
formed from a fabric that has been formed into a knot and secured
to the anchoring rod and end 62 may be formed into, and otherwise
define, a knot to form securing member 80.
[0059] As briefly mentioned above, the elongated body, or rod, of
the anchoring device described herein may include at least one
securing member, and may include two, three, four or more securing
members disposed thereon or attached thereto. Furthermore, the
securing members may be variously-shaped and may be configured to
internally secure, externally secure, or both internally and
externally secure an implant, including the implants described
herein. Anchoring components that may be used to internally secure
implants are shown, for example, in FIGS. 7A-7T.
[0060] Referring now to FIGS. 7A-7D, anchoring devices (200, 220,
240, and 260) including elongated bodies, or anchoring rods (201,
221, 241, and 261, respectively) having a second end (203, 223,
243, and 263, respectively) defining at least one securing member
(210, 230, 250 and 270, respectively), shaped in the form of one or
more hooks are shown. FIG. 7E depicts an anchoring device 280
having a securing member 290 that includes at least one, preferably
two or more, such as four, rod extending radially from second end
293 of anchoring rod 291. A multiplicity of such a set of four
projecting rods, such as securing members 290' and 295', may be
present, and may be spaced apart along the length of elongated
member 291' of anchoring device 280' as seen in FIG. 7F. In
alternative forms of the invention as seen in FIG. 7G, anchoring
device 300 includes a single rod defining securing member 310 that
has a longitudinal axis aligned transverse, in this case
perpendicular, to the longitudinal axis of anchoring rod 301,
although two or more of these extending rods 310 and 310',
preferably separated along the length of elongated body 301 from
each other, may be present as seen in FIGS. 7H and 7I (anchoring
components 500 and 520, respectively). In these, as well as other
forms of the invention, an adhesive or other similar agent that
bonds, or otherwise secures the implant to the anchoring device may
be disposed along the length of the elongated body that will be in
contact with the implant to further secure the implant. The
adhesive may further be used without any other securing member
being present and may thus act as a securing member itself.
Suitable adhesives include, for example, cyanoacrylate adhesives,
epoxy adhesives and silicone adhesives.
[0061] In other embodiments of the invention, second end 323 or
323' of elongated body 321 or 321' of anchoring component 320 or
320' may further define a spherical-shaped body 324 or a
rectangular-shaped body 324' as seen in FIGS. 7J and 7L,
respectively. A single spherical-shaped securing member may be
present, or more than one member may be present wherein each
securing member is preferably spaced apart along the length of the
elongated body as seen, for example, in FIGS. 7K and 7M (anchoring
devices 340 and 360). These configurations of the securing members
may provide mechanical locking for increased fixation. Other
anchoring components having securing members that may provide for
mechanical locking include anchoring components 380 and 390 in
FIGS. 7Q and 7R, respectively. In other forms of the invention, the
second ends of the securing members of the anchoring components may
further define sinusoidal or other wave shapes as seen in FIG. 7N
(anchoring component 400) or may be a coiled, or spring element,
(anchoring component 420) as seen in FIG. 7O. A multi-lobed
securing member 430 is also encompassed as seen with anchoring
component 440 in FIG. 7S. Moreover, securing member 470 may be
defined by a tapered second end 463 of anchoring rod 461 of
anchoring device 460 as seen in FIG. 7P.
[0062] An anchoring device, such as anchoring device 480, may
include securing members 490, such as fibers or other flexible
elements, extending radially from anchoring rod 481, preferably
from second end 483 of the anchoring rod as seen in FIG. 7T. It is
realized that the anchoring devices described above having securing
members that internally secure an implant may, if the implant is
appropriately positioned on the anchoring device, act to externally
secure, or both externally and internally secure, the implant.
[0063] For example, anchoring device 300 may externally secure an
implant as shown in FIG. 8A. Anchoring device 500 may be used to
both internally and externally secure an implant as seen in FIG. 8B
with appropriate adjustment in the spacing of the securing members
and/or the size of the implant. Similarly, one skilled in the art
would be aware that repositioning the implant on many of the
anchoring devices described herein with internal securing members
may provide for both internal and external securement of an
implant.
[0064] In yet other embodiments shown in FIGS. 8C-8E, anchoring
devices with external securing members are shown, but may aid in
internally securing an implant due to their construction. Anchoring
device 560 includes an anchoring rod 561 that is bent at end 562
and is attached, or otherwise connected, to securing member 40, or
other similar securing member as described herein. In a further
form of the invention shown in FIG. 8D, anchoring device 580
includes an elongated anchoring body, or rod, 581 that connects, or
otherwise attaches, to a connecting rod 585 preferably at a point
equidistant from the ends 586 of the rod. Securing members, such as
securing members 40, may be attached, or otherwise connected, to
rod 585. Referring now to FIG. 8E, anchoring device 600 that
includes an anchoring body 601 having opposing securing members,
such as securing members 30 and 40, spaced along the length of the
implant and defining a region R for disposing an implant
therebetween is depicted. A connecting member, or bar 605 is
attached to the anchoring rod in region R, preferably at a point
equidistant from ends 606 of the bar and preferably extends
radially from the anchoring body. Ends 606 of bar 605 are
preferably connected to two other securing members, such as
securing members 40. FIG. 8F depicts a variation of anchoring
device 500 wherein securing members 630 and 640 of anchoring device
620 are wave-shaped and are therefore configured to extend through
the implant they will secure. FIG. 8G depicts an anchoring device
640 that includes a combination of the mechanical locking features
650 similar to those previously described herein as well as an
external securing element 651.
[0065] In other forms of the invention, an anchoring device is
provided that helps to reinforce an implant to prevent the implant
from undergoing excessive creep under high load. Referring now to
FIG. 8H, anchoring device 660 includes internal securing member 670
that is rectangular-shaped and is sized to prevent the implant from
undergoing excessive creep under high load. It is noted in all of
FIGS. 7 and 8 that implant I is shown in outline to denote how the
anchoring bodies may be positioned therein and it is realized that
I may represent any of the implants described herein.
[0066] The devices described herein are advantageously utilized
with a spinal implant, thus forming a spinal implant system.
Referring now to FIGS. 9-11, spinal implant system 90 includes a
spinal implant 100 and a spinal implant anchoring device 10 as
described in reference to FIGS. 1 and 2. Inner surface 31 and 41 of
securing members 30 and 40, respectively, abut outer surface 105 of
implant 100. As seen in FIG. 11, anchoring rod 20 extends through
aperture, or other defect, 104 in annulus fibrosis 115 so that the
first end 21 of anchoring device 10 may be anchored to upper
vertebra 107 with a bone screw 108. First end 21 may, of course, be
anchored to lower vertebra 109, or may be secured to both vertebrae
107 and 109 if first end 21 is appropriately configured as
discussed above. The longitudinal axis X of the rod may extend
parallel to the longitudinal axis Y of the implant, but may extend
through the implant in a wide variety of directions, as long as the
rod functions to anchor the implant in the disc space. Furthermore,
the anchoring rod preferably extends at least partially through the
implant, but may extend completely through the implant, entering
one location, such as an end, and exiting another location, such as
another end, including an opposing end. In preferred forms of the
invention, implant 100 may include a peripheral supporting band 101
as further described below to provide further lateral support for
the implant, as well as to improve the strength of the implant. In
one form of the invention, band 101 may have apertures, or other
openings therethrough, on opposing sides of the band which are in
contact with the securing member to allow the anchoring rod of the
anchoring component, or device, to be placed therethrough.
Moreover, implant 100 further includes a channel 103 extending
therethrough through which the anchoring rod may be disposed. The
implant is preferably molded such that the channel is formed during
the molding process. However, the channel may be formed after
formation of the implant in a variety of ways, including drilling
to form a channel having a desired shape with an appropriate drill
bit.
[0067] Referring now to FIGS. 12-14 in another form of the
invention, a spinal implant system 120 is shown which includes
spinal implant 100 and spinal implant anchoring device 50.
Anchoring rod 60 extends through aperture, or defect, 104 of
annulus fibrosis 115. Furthermore, first end 61 of anchoring rod 60
of the anchoring device is secured to upper vertebra 107, but may
be secured to lower vertebra 109, or both upper and lower
vertebrae, with an interference screw 110 as more fully described
below and as shown in FIG. 14. As seen in FIG. 14, one end of the
anchoring rod is wedged between the screw and the bone.
Furthermore, first end 61 of anchoring device 50 may be secured to
both vertebra 107 and 109 for added stability if first end 61 is
appropriately configured as discussed above.
[0068] The interference screws described herein can be
non-resorbable, resorbable and made form a wide variety of
materials, including metals, ceramics, polymers and combinations
thereof. Non-resorbable metallic materials include stainless
steels, cobalt chrome alloys, titanium, titanium alloys, shape
memory materials as described above, especially those exhibiting
superelastic behavior and including metals, and alloys thereof.
Resorbable materials include polylactide, polyglycolide,
tyrosine-derived polycarbonate, polyanhydride, polyorthoester,
polyphosphazene, bioactive glass, calcium phosphate, such as
hydroxyapatite, and combinations thereof. The anchoring devices may
also be anchored with other soft tissue anchors known in the art,
including suture anchors commonly used in arthroscopy or sports
medicine surgeries, for example. In the case of a soft tissue or
suture anchor, the end of the elongated body of the anchoring
device is attached to the end of the anchor, which is embedded and
anchored in an adjacent vertebral body.
[0069] A wide variety of spinal implants for serving differing
functions may be anchored with the anchoring devices described
herein, including implants sized and configured for nucleus
pulposus replacements, sized and configured for partial or full
disc replacements or other disc reconstruction or augmentation
purposes. Elastic, or otherwise resilient, implants are most
preferred. For example, implants may be formed from hydrophilic
materials, such as hydrogels, or may be formed from biocompatible
elastomeric materials known in the art, including silicone,
polyurethane, polyolefins such as polyisobutylene and polyisoprene,
copolymers of silicone and polyurethane, neoprene, nitrile,
vulcanized rubber and combinations thereof. In a preferred
embodiment, the vulcanized rubber is produced by a vulcanization
process utilizing a copolymer produced, for example, as in U.S.
Pat. No. 5,245,098 to Summers et al., from 1-hexene and
5-methyl-1,4-hexadiene. Preferred hydrophilic materials are
hydrogels. Suitable hydrogels include natural hydrogels, and those
formed from polyvinyl alcohol, acrylamides such as polyacrylic acid
and poly (acrylonitrile-acrylic acid), polyurethanes, polyethylene
glycol, poly(N-vinyl-2-pyrrolidone), acrylates such as
poly(2-hydroxy ethyl methacrylate) and copolymers of acrylates with
N-vinyl pyrolidone, N-vinyl lactams, acrylamide, polyurethanes and
polyacrylonitrile or may be formed from other similar materials
that form a hydrogel. The hydrogel materials may further be
cross-linked to provide further strength to the implant. Examples
of polyurethanes include thermoplastic polyurethanes, aliphatic
polyurethanes, segmented polyurethanes, hydrophilic polyurethanes,
polyetherurethane, polycarbonate-urethane and silicone
polyether-urethane. Other suitable hydrophilic polymers include
naturally-occurring materials such as glucomannan gel, hyaluronic
acid, polysaccharides, such as cross-linked carboxyl-containing
polysaccharides, and combinations thereof. The nature of the
materials employed to form the elastic body should be selected so
the formed implants have sufficient load bearing capacity. In
preferred embodiments, a compressive strength of at least about 0.1
MPa is desired, although compressive strengths in the range of
about 1 MPa to about 20 MPa are more preferred.
[0070] The implants can be shaped as desired. For example, the
nucleus pulposus implants may take the form of a cylinder, a
rectangle, or other polygonal shape or may be substantially oval.
The implants may include elastic bodies 750 that are tapered, such
as at one end, as seen in FIGS. 15A and 15B, in order to create or
maintain lordosis. Furthermore, in certain forms of the invention,
the implants generally conform to the shape of the nuclear disc
space. Additionally, implants can be sized to fit within an
intervertebral disc space, preferably surrounded by an annulus
fibrosis, or at least partially surrounded by an annulus fibrosis.
That is, the implants preferably are of a height and have a
diameter that approximates the height and diameter of an
intervertebral disc space. In certain forms of the invention, a
spinal implant may be a nucleus pulposus implant and may thus be
sized to fit within the natural intervertebral disc space. In other
embodiments, the spinal implants may be disc replacements as
described herein, and may be sized to fit within the intervertebral
disc space that includes the space resulting when the inner annulus
fibrosis layer, or a portion thereof, is removed. Such a spinal
implant would therefore be sized to fit within the larger
intervertebral disc space that includes the space resulting from
removal of a portion of the annulus fibrosis, and would thus
typically have a width or diameter that is substantially larger
than the natural nucleus pulposus.
[0071] As mentioned above, the implant to be anchored preferably is
reinforced for increased strength and to decrease lateral
deformation of the implant. Accordingly, in yet another aspect of
the invention, a reinforced spinal implant is provided. Referring
now to FIGS. 16 and 17, implant 120 includes a load bearing elastic
body 121 with an upper surface 122 and a lower surface 123. Implant
120 includes a preferably flexible, supporting member, such as
peripheral supporting band 130 disposed circumferentially about
body 121. Band 130 is similar to band 100 discussed above, with the
exception that band 130 does not have openings therethrough on
opposing sides of the band. As the implant, including the elastic
body and supporting band, advantageously may replace all or a
portion of the natural nucleus pulposus, while retaining the
annulus fibrosis or a portion thereof, the implant may be sized to
fit within the intervertebral disc space defined by the annulus
fibrosis or a portion thereof.
[0072] As seen in FIG. 16, elastic body 121 includes upper and
lower surfaces 122 and 123, respectively, portions of which are
exposed to directly contact adjacent vertebral endplates. This
exposure allows the lubricated upper and lower surfaces of elastic
body 121 to articulate against the endplates to minimize abrasive
wear of supporting band 130 and the endplates. Although the amount
of the upper and lower surfaces of elastic body 121 that are
exposed may vary, typically at least about 50%, preferably at least
about 70%, more preferably at least about 80% and most preferably
at least about 90% of the surfaces are exposed. In certain forms of
the invention, the elastic body core may function as a nucleus
pulposus, and thus functions as a load bearing component with
stress transfer capabilities.
[0073] Peripheral supporting band 130 helps restrict excessive
horizontal deformation of elastic body 121 upon loading conditions,
as seen progressively in FIG. 18A, thereby helping to restore and
maintain disc height. The hoop stress in the band increases
exponentially after some small, initial deformation as seen in FIG.
18B. Band 130 preferably decreases lateral deformation, compared to
deformation of an implant without the circumferential reinforcing
band, as desired. Band 130 may, for example, decrease lateral
deformation by at least about 20%, preferably at least about 40%,
further preferably at least about 60%, more preferably at least
about 80% and most preferably at least about 90%. An implant, such
as one that includes an elastic body, having such a flexible
supporting band, will be flexible and otherwise resilient to allow
the natural movements of the disc and provides shock absorption
capability at low to moderate applied stress, but will resist
excessive deformation for disc height maintenance under high
loading conditions. As described herein in the case of a lumbar
disc, for example, low applied stress includes a force of about 100
Newtons to about 250 Newtons, moderate stress includes a force of
about 250 Newtons to about 700 Newtons, and high loading
conditions, or high stress, includes a force of about above 700
Newtons. Such a reinforced implant may be advantageously anchored
with the anchoring devices described herein. Moreover, other outer
covers, or jackets, as described in U.S. Pat. No. 5,674,295 may be
utilized to reinforce implants to be anchored with the devices
described herein. In preferred forms of the invention, the bands,
jackets, or other outer covers or similar supporting members are
flexible in that they may be folded or otherwise deformed, but are
substantially inelastic so that the implant is more fully
reinforced or otherwise supported.
[0074] Peripheral supporting band 130, as well as other outer
covers, or jackets, may be made from a wide variety of
biocompatible polymers, metallic materials, or combination of
materials that form a strong but flexible support to prevent
excessive lateral (horizontal) deformation of the core under
increasing compressive loading. Suitable materials include
non-woven, woven, braided, or fabric materials made from polymeric
fibers including cellulose, polyethylene, polyester, polyvinyl
alcohol, polyacrylonitrile, polyamide, polytetrafluoroethylene,
polyparaphenylene terephthalamide, and combinations thereof. Other
suitable materials include non-reinforced or fiber-reinforced
elastomers such as silicone, polyolefins such as polyisobutylene
and polyisoprene, polyurethane, copolymers of silicone and
polyurethane, neoprene, nitrile, vulcanized rubber and combinations
thereof. In a preferred form of the invention, a combination, or
blend, of silicone and polyurethane is used. Furthermore, the
vulcanized rubber is preferably produced as described above for the
spinal implants. Supporting band 130 is advantageously made from
materials described herein that allow it to be porous, which, in
the case of an elastic body made from a hydrogel, or other
hydrophilic material, allows fluid circulation through the elastic
core body to enhance pumping actions of the intervertebral disc.
Supporting members may further be formed from carbon fiber ceramic,
ceramic fibers, metallic fibers, or other similar fibers described,
for example, in U.S. Pat. No. 5,674,295, or from metallic materials
that include shape memory materials as described above, especially
those exhibiting superelastic behavior, titanium, titanium alloys,
stainless steel, cobalt chrome alloys and combinations thereof.
FIGS. 19A-19D show supporting bands of various patterns, including
braided patterns (bands 140, 145 and 150) or porous patterns (band
155). It is realized that the braided materials may also be
porous.
[0075] In addition to reinforcing the implants described herein
with an outer cover, jacket or supporting band as described above,
spinal implants 100, such as those formed from a hydrogel material,
that are advantageously anchored with the anchoring devices
described herein may be reinforced by forming the implant by
molding hydrogels of different stiffness together and by annealing
methods that include dipping the hydrogel in a hot oil bath, as
described in U.S. Pat. No. 5,534,028. Other suitable reinforced
spinal implants, such as nucleus pulposus implants, that may
advantageously be used in the system of the present invention
include those described in U.S. Pat. No. 5,336,551, as well as the
novel implants described herein. As discussed above, the implant
may be advantageously shaped to conform to the intervertebral disc
space, or shaped as otherwise desired, as long as the implant has
load bearing capability. Although the amount of load the implant is
required to bear may vary depending on several factors, including
the particular location in which the implant will be positioned, as
well as the general health of the surrounding intervertebral discs,
it is preferred that the implant be able to bear a load of at least
about 20 Newtons for cervical discs, at least about 50 Newtons for
thoracic discs and at least about 100 Newtons for lumbar discs.
[0076] In yet other forms of the invention, an implant reinforced
with a peripheral supporting band as described above is provided
that is further reinforced with one or more straps. The straps may
be advantageous in preventing the peripheral supporting band
described herein from slipping, or otherwise sliding off the
implant. Referring now to FIGS. 20 and 21, at least one strap 134
extends along upper surface 122 and at least one strap 135 extends
along lower surface 123 of elastic body 121 of implant 140. Ends
136 of strap 134 and ends 137 of strap 135 are each preferably
connected, or otherwise attached, to peripheral supporting band
130'. The point of attachment may be any location that will secure
the strap, including at the upper margins 138 of the band, lower
margins 139 of the band or any region between the upper and lower
margins. Although two straps 134 and 135 are shown extending along
upper surface 122 and lower surface 123, respectively, in FIGS. 20
and 21, one continuous strap may be utilized that extends
completely around the implant, or the strap utilized may be in
multiple pieces, as long as the combination of straps are
sufficient to prevent excessive slipping and or sliding of the
supporting band. Furthermore, more than one strap may extend along
upper surface 122 and more than one strap may extend along lower
surface 123. For example, as seen in FIGS. 22 and 23, straps 820,
830, 840 and 850 of implant 150 are attached to strap 130". Straps
820 and 830 are also attached to strap 134' and straps 840 and 850
are also attached to strap 135'.
[0077] As mentioned above, the spinal implant with the flexible
peripheral supporting band may be anchored utilizing the anchoring
devices described herein. In other forms of the invention, implants
as described herein may be anchored with an outer, preferably
resorbable, shell as described in U.S. patent application Ser. No.
09/650,525 to Trieu, filed Aug. 30, 2000. In further forms of the
invention, the implant may further include various outer surface
features that may further restrain movement of the implant in the
intervertebral disc space, with or without the outer shell. Such
surface features are also more fully described in U.S. patent
application Ser. No. 09/650,525 to Trieu, filed Aug. 30, 2000.
[0078] In yet other forms of the invention, a tension band 700 may
be secured to the anchoring device and to an adjacent vertebra to,
for example, provide further stabilization of the device,
especially wherein the annulus and/or the ligament surrounding the
annulus at the defect site are compromised. Referring now to FIGS.
24 and 25, one end 701 of band 700 may be attached to an anchoring
device, such as anchoring device 10" (similar to anchoring device
10 except that bracket 123" is utilized), at, for example, bracket
123", and the other end 702 may be secured to a plate 710, such as
a metal plate, that is secured to the adjacent vertebra utilizing
screws 108 as described herein. Band 700 may be attached to the
anchoring device in a variety of ways, including crimping, tying,
mechanical locking or may be secured with the same screws used to
secure the anchoring device to the vertebral bodies. If two
anchoring devices are utilized as described below, or if a single
anchoring device is used that is secured to both adjacent
vertebrae, one end 701 of tension band 700 may be attached to one
of the brackets, or other areas, of the first anchoring device and
the other end 702 of band 700 may be attached to the other bracket,
or other area, of the second anchoring device. The tension band is
preferably flexible to allow some degree of motion, but is
substantially inelastic to prevent excessive extension.
[0079] The tension band may be formed from a wide variety of
natural or synthetic tissue biocompatible materials. Natural
materials include autograft, allograft and xenograft tissues.
Synthetic materials include metallic materials and polymers. The
metallic materials can be formed from shape memory alloy, including
shape memory materials made from, for example, the nickel-titanium
alloy known as Nitinol as described above. The shape memory
materials may exhibit shape memory as described above, but
preferably exhibit superelastic behavior. Other metallic materials
include titanium alloy, titanium, stainless steel, and cobalt
chrome alloy. Suitable polymeric materials include, for example,
polyethylene, polyester, polyvinyl alcohol, polyacrylonitrile,
polyamide, polytetrafluoroethylene, poly-paraphenylene,
terephthalamide and combinations thereof. The materials used to
form the tension band can be in a variety of forms, including the
form of a fiber, woven, or non-woven fabric, braided, bulk solid
and combinations thereof. The tension band may further be treated,
such as by coating and/or impregnating, with bioactive materials
that may enhance tissue ingrowth and/or attachment, including
hydroxyapatite, bioglass, and growth factors. Suitable growth
factors include transforming growth factors, insulin-like growth
factors, platelet-derived growth factors, fibroblast growth
factors, bone morphogenetic proteins as further described herein
and combinations thereof.
[0080] In yet another aspect of the invention, methods of anchoring
a spinal implant are provided. In one form of the invention, a
method includes providing an elastic spinal implant and an
anchoring component as described herein. The elongated body, or
anchoring rod, component of the anchoring component is at least
partially extended, or otherwise disposed, through the implant. The
implant may include a pre-formed channel therethrough, preferably
formed during formation of the implant, through which the anchoring
rod may be extended. In alternative embodiments, the implant may be
formed around internal securing members as discussed above. The
longitudinal axis of the anchoring rod may also extend parallel to
the longitudinal axis of the implant, or any other direction as
mentioned above that will allow the anchoring rod to anchor,
secure, restrain or otherwise hold the implant in the disc space.
As an example, the anchoring rod, as well as the securing members,
may take a tortuous path through the implant, especially when the
anchoring bodies have ends defining variously-shaped securing
members, as more fully described above, with reference to, for
example, FIGS. 7N, & 7O and 7T.
[0081] As further discussed above, in those forms of the invention
wherein a securing member is at an end of the implant, the securing
member may be attached after the elongated body component is
extended through the implant. For example, with reference to FIGS.
1 and 7, securing member 40 may be attached to end 22 of elongated
body 20 after anchoring rod 20 is extended through channel 103 of
implant 100. Moreover, the securing member may also be formed after
rod 20 is extended through channel 103, as in the case where
securing member 40 is defined by a knot structure. In other forms
of the invention, the channel may be formed after the implant is
formed by forming a channel with an appropriate tool, such as a
drill with an appropriately sized and shaped drill bit. One of the
ends of the anchoring component are then secured to an adjacent
vertebra.
[0082] In further aspects of the invention, methods of reducing
deformation of a spinal implant are provided. In one embodiment, a
method includes disposing a flexible peripheral supporting band as
described above circumferentially about the implant.
[0083] The implants formed from a hydrogel, or other similar
hydrophilic material described herein, including the supporting
band of the reinforced implants, may advantageously deliver desired
pharmacological agents. The pharmacological agent may include a
growth factor that may advantageously repair a damaged annulus
fibrosis, endplates or may have some other beneficial effect. A
wide variety of growth factors may advantageously be employed in
the present invention. For example, the growth factor may include a
bone morphogenetic protein, transforming growth factors, such as
transforming growth factor-.beta. (TGF-.beta.), insulin-like growth
factors, platelet-derived growth factors, fibroblast growth
factors, or other similar growth factor having the ability to
repair the endplates, annulus fibrosis and/or nucleus pulposus of
an intervertebral disc, or the ability to have some other
beneficial effect. The growth factors, or other pharmacological
agents, are typically included in the implant in therapeutically
effective amounts. For example, the growth factors may be included
in the implants in amounts effective in repairing an intervertebral
disc, including repairing the endplates, annulus fibrosis and
nucleus pulposus. Although these amounts will depend on the
specific case, the implants may typically include no more than
about five weight percent of the growth factors, and preferably no
more than about one weight percent of the growth factors. In a
preferred form of the invention, the growth factor is a bone
morphogenetic protein. Recombinant human bone morphogenetic
proteins (rhBMPs) are further preferred because they are available
in large quantities and do not transmit infectious diseases. Most
preferably, the bone morphogenetic protein is a rhBMP-2, rhBMP-4 or
heterodimers thereof. However, any bone morphogenetic protein is
contemplated, including bone morphogenetic proteins designated as
BMP-1 through BMP-18.
[0084] BMPs are available from Genetics Institute, Inc., Cambridge,
Mass. and may also be prepared by one skilled in the art as
described in U.S. Pat. No. 5,187,076 to Wozney et al.; U.S. Pat.
No. 5,366,875 to Wozney et al.; U.S. Pat. No. 4,877,864 to Wang et
al.; U.S. Pat. No. 5,108,922 to Wang et al.; U.S. Pat. No.
5,116,738 to Wang et al.; U.S. Pat. No. 5,013,649 to Wang et al.;
U.S. Pat. No. 5,106,748 to Wozney et al.; and PCT Patent Nos.
WO93/00432 to Wozney et al.; WO94/26893 to Celeste et al.; and
WO94/26892 to Celeste et al. All bone morphogenic proteins are
contemplated whether obtained as above or isolated from bone.
Methods for isolating bone morphogenetic protein from bone are
described, for example, in U.S. Pat. No. 4,294,753 to Urist and
Urist et al., 81 PNAS 371, 1984.
[0085] In other forms of the invention, the pharmacological agent
may be one that is used for treating various spinal conditions,
including infected spinal cords, cancerous spinal cords and
osteoporosis. Such agents include antibiotics, analgesics and
anti-inflammatory drugs, including steroids. Other such agents are
well know to the skilled artisan. These agents are also used in
therapeutically effective amounts that will treat the various
conditions and the symptoms they cause. Such amounts may be
determined by the skilled artisan depending on the specific
case.
[0086] The pharmacological agents are preferably dispersed within
the hydrogel, or other hydrophilic, implant for in vivo release,
and/or, with respect to implants with an elastomeric resorbable
outer shell or those with a flexible supporting band, may be
dispersed in either the band, the outer shell, or both. The
hydrogel can be cross-linked chemically, physically, or by a
combination thereof, in order to achieve the appropriate level of
porosity to release the pharmacological agents at a desired rate.
The agents may be released upon cyclic loading, and, in the case of
implants including a resorbable outer shell, upon resorption of the
shell. The pharmacological agents may be dispersed in the implants
by adding the agents to the solution used to form the implant, as
long as the processing conditions will not adversely affect the
agent. Alternatively, the implants may be soaked in an appropriate
solution containing the agent, or by other appropriate methods
known to the skilled artisan.
[0087] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only the preferred embodiment has been shown
and described and that all changes and modifications that come
within the spirit of the invention are desired to be protected. For
example, in addition to being straight, the elongated bodies of the
anchoring device may exhibit other advantageous shapes as shown in
FIGS. 26 and 27. As seen in FIG. 26, anchoring rod 920' is arcuate.
As seen in FIG. 27, anchoring rod 920" has a bend adjacent to
securing member 40. Other bent or angled anchoring components may
be understood by those of ordinary skill in the art, and such
embodiments are encompassed by this invention. Furthermore, the
devices described herein may be inserted and anchored via a wide
variety of approaches, including posterior, lateral, oblique and
anterior as shown in FIGS. 28-31, respectively. Moreover, the
nucleus pulposus implant systems may include one or more implants
disposed on the anchoring rods of the anchoring devices described
herein. As seen in FIG. 32, two implants 100' are disposed on
anchoring rod 20 of anchoring device 10. Thus, typically at least
one implant is included in the implant systems described
herein.
[0088] Additionally, in other forms of the invention, the spinal
implant systems may include one or more elastic bodies and one or
more anchoring devices. Referring now to FIG. 33, two anchoring
devices are included in the system along with two elastic bodies,
each elastic body disposed on a different anchoring device 950 or
960. Each anchoring device may be independently anchored to an
adjacent vertebra. In alternative embodiments, first ends 951 and
961 of anchoring rods 953 and 963, respectively, may be connected,
or otherwise attached to each other to form a single extension, or
end, of the anchoring rods, which may in turn be attached to an
adjacent vertebra or bracket as described herein. The latter case
is shown in FIG. 33, wherein first ends 951 and 961 of elongated
bodies 953 and 963, respectively, of anchoring devices 950 and 960
are integral with each other. Utilizing such a system with anterior
and posterior implants I.sub.A and I.sub.P, respectively, implants
having different heights may be used to create or maintain
lordosis. For example, if a cylindrical implant is desired,
anterior implant I.sub.A may have a larger diameter, and thus a
larger height, than posterior implant I.sub.P.
[0089] All references cited herein are indicative of the level of
skill in the art and are hereby incorporated by reference in their
entirety.
* * * * *