U.S. patent application number 14/283613 was filed with the patent office on 2014-09-11 for anterior hybrid implant.
This patent application is currently assigned to WARSAW ORTHOPEDIC, INC.. The applicant listed for this patent is WARSAW ORTHOPEDIC, INC.. Invention is credited to Anthony J. Melkent, Frank J. Schwab, Brian Robert Thoren.
Application Number | 20140257492 14/283613 |
Document ID | / |
Family ID | 37668060 |
Filed Date | 2014-09-11 |
United States Patent
Application |
20140257492 |
Kind Code |
A1 |
Schwab; Frank J. ; et
al. |
September 11, 2014 |
ANTERIOR HYBRID IMPLANT
Abstract
An implant configured for placement through an anterior surgical
approach made of at least two different materials. The implant may
include materials with varying radiolucency and mechanical
properties. Such a hybrid implant may offer controlled radiographic
visibility and optimized structural properties for implant
placement, including placement for use in spinal arthrodesis.
Inventors: |
Schwab; Frank J.; (New York,
NY) ; Melkent; Anthony J.; (Memphis, TN) ;
Thoren; Brian Robert; (Memphls, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WARSAW ORTHOPEDIC, INC. |
Warsaw |
IN |
US |
|
|
Assignee: |
WARSAW ORTHOPEDIC, INC.
Warsaw
IN
|
Family ID: |
37668060 |
Appl. No.: |
14/283613 |
Filed: |
May 21, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11527123 |
Sep 26, 2006 |
8764832 |
|
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14283613 |
|
|
|
|
60720555 |
Sep 26, 2005 |
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Current U.S.
Class: |
623/17.16 |
Current CPC
Class: |
A61F 2002/448 20130101;
A61F 2230/0008 20130101; A61F 2310/00029 20130101; A61F 2250/0032
20130101; A61F 2310/00023 20130101; A61F 2/4465 20130101; A61F
2002/3008 20130101; A61F 2002/30133 20130101; A61F 2002/30062
20130101; A61F 2250/0098 20130101; A61F 2310/00341 20130101; A61F
2230/0019 20130101; A61F 2/30728 20130101; A61F 2310/00131
20130101; A61F 2002/3023 20130101; A61F 2220/0033 20130101; A61F
2/4611 20130101; A61F 2310/00017 20130101; A61F 2002/30331
20130101; A61F 2002/30056 20130101; A61F 2002/2835 20130101; A61F
2002/30784 20130101; A61F 2002/30593 20130101; A61F 2002/30125
20130101; A61F 2230/0065 20130101; A61F 2230/0026 20130101; A61F
2002/305 20130101; A61F 2230/0069 20130101; A61F 2002/30878
20130101; A61F 2230/0015 20130101; A61F 2002/302 20130101; A61F
2002/30158 20130101; A61F 2002/30677 20130101; A61F 2220/0025
20130101; A61F 2250/0018 20130101; A61F 2310/00179 20130101; A61F
2002/30014 20130101; A61F 2210/0004 20130101; A61F 2002/2817
20130101; A61F 2310/00161 20130101; A61F 2002/30616 20130101; A61F
2002/30153 20130101 |
Class at
Publication: |
623/17.16 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1-24. (canceled)
25. A method of implanting an intervertebral implant from an
anterior surgical approach comprising: providing an implant
comprising: a first rim around a periphery of the implant, the
first rim having a detectable radiographic signature, and a member
coupled to the first rim, the member having less of a radiographic
signature than the first rim, wherein the member adds vertebral
spacing height to the first rim; and radiographically observing
placement of the implant between superior and inferior vertebral
bodies by way of one or more of an anterior to posterior
radiographic view and a lateral radiographic view.
26. The method of claim 25 wherein the act of radiographically
observing placement of the implant includes observing relative
alignment of two or more supports coupled to the first rim.
27-30. (canceled)
31. The method of claim 25 wherein the implant comprises a first
support in a posterior half of the implant that blocks radiographic
visualization of a second support in an anterior half of the
implant when the placement of the implant is radiographically
observed from a posterior side of the implant.
32. The method of claim 25 wherein the implant comprises a first
support in a posterior half of the implant that blocks radiographic
visualization of a second support on a contralateral side of the
implant when the placement of the implant is radiographically
observed from a lateral side of the implant.
33. The method of claim 34 wherein a lateral space between the
first and second supports indicates a rotational position of the
implant when the implant is viewed radiographically from a
posterior side.
34. The method of claim 34 wherein alignment of the first and
second supports with ends of the first rim indicates a rotational
position of the implant when viewed from a posterior side.
35. The method of claim 25 wherein the implant comprises a first
support in an anterior half of the implant that blocks radiographic
visualization of a second support on a contralateral side of the
implant when the placement of the implant is radiographically
observed from a lateral side of the implant.
36. The method of claim 25 further comprising preparing an
implantation space between the superior and inferior vertebral
bodies and implanting the implant into the implantation space from
the anterior approach.
37. The method of claim 25 further comprising implanting the
implant between the superior and inferior vertebral bodies such
that protrusions extending from an outer surface of the first rim
engage one of the superior and inferior vertebral bodies.
38. The method of claim 25 wherein the member comprises a first
segment and a second segment that is spaced apart from the first
segment.
39. The method of claim 38 wherein the wherein the first and second
segments each comprise an arcuate outer surface that is continuous
with that of the first rim.
40. The method of claim 38 wherein: the first and second segments
each comprise an arcuate outer surface that is continuous with that
of the first rim; and the first and second segments each comprise a
planar surface opposite the arcuate outer surfaces of the first and
second segments, the planar surfaces facing one another.
41. The method of claim 38 wherein the first and second segments
each comprise a chord length that is less than two-thirds of an
outer average diameter of the first rim.
42. The method of claim 38 wherein the first and second segments
each have a lower modulus of elasticity than the first rim.
43. The method of claim 38 further comprising disposing bone growth
promoting material between the first and second segments.
44. The method of claim 25 wherein the member comprises a tubular
member having an outer periphery that is continuous with that of
the first rim.
45. The method of claim 44 wherein the wherein the tubular member
comprises a central opening that is continuous with a central
opening of the first rim.
46. The method of claim 45 further comprising disposing bone growth
promoting material in at least one of the central openings.
47. The method of claim 44 wherein the tubular member comprises a
lower modulus of elasticity than the first rim.
48. The method of claim 25 further comprising radiographically
observing bone growth between the superior and inferior vertebral
bodies by way of one or more of the anterior to posterior
radiographic view and the lateral radiographic view.
Description
CROSS REFERENCE
[0001] This application claims priority from U.S. Provisional
Patent Application Ser. No. 60/720,555, filed on Sep. 26, 2005,
entitled "Hybrid Intervertebral Spinal Fusion Implant." The
following applications also claim priority to the above referenced
provisional application and are related to the present application.
They are incorporated by reference herein:
[0002] U.S. Utility patent application Ser. No. 11/527,121
(Attorney Docket No. P24845) filed on Sep. 26, 2006 and entitled
"Transforaminal Hybrid Implant;" and
[0003] U.S. Utility patent application Ser. No. 11/527,122
(Attorney Docket No. P27164) filed on Sep. 26, 2006 and entitled
"Hybrid Intervertebral Spinal Fusion Implant."
TECHNICAL FIELD
[0004] The present invention relates generally to the field of
medical implants and methods, and more specifically to interbody
spinal implants which may be adapted for placement into an
implantation space created across the height of a disc space
between two adjacent vertebral bodies for the purpose of correcting
disease, dysfunction, or degeneration at that interspace, and any
related methods. The spinal implants may be made of a plurality of
implant materials, which bear differing degrees of radiographic
lucency. These materials may include bone and may or may not be
resorbable. The implants of some embodiments are adapted such that
radiographic visualization of operative placement and eventual bone
healing can be observed.
BACKGROUND
[0005] Implants for placement in the intervertebral space between
adjacent vertebral bodies in the spine come in a wide range of
shapes and sizes. These implants are usually made entirely of one
material, although the type of material can vary significantly
between specific implants. Such implants for use in human spinal
surgery include implants made entirely of metals, such as titanium
or stainless steel, or synthetic radiolucent materials such as
carbon-carbon composites or poly-ether-ether-ketone (PEEK).
Implants may have a structure designed to promote fusion across
adjacent vertebral bodies by allowing bone to grow through and
around the implant. The operative placement of intervertebral
implants is optimized by radiographic opacity. However, a
relatively radiolucent implant material optimizes postoperative
evaluation of bone growth and fusion across an intervertebral
space. While these implants may contain marking beads or radio
opaque markers they do not structurally benefit from radio opaque
materials. In some configurations, metals, some of which are opaque
on radiographs, provide greater strength and resistance to
impaction during implantation. Metallic implants may offer reduced
wall thickness of structural components and offer increased volume
for bone graft and other agents within an implant.
[0006] As it is desirable to take advantage of benefits of
radiolucent and radio-opaque materials in an implant, there exists
a need for an improved implant made of different structural
materials with different properties of radiographic appearance. For
some implants, it is desirable to provide optimization of
mechanical properties, while permitting generous bone filling and
bone through-growth. These characteristics may be applied in some
embodiments in combination with an ability to radiographically
determine bone-implant interaction and bone growth into and around
the implant.
SUMMARY
[0007] Embodiments of the invention may include an artificial
interbody spinal fusion implant made of structural materials with
varying radiolucency and mechanical characteristics. Implants may
be provided for insertion at least in part into an implantation
space formed across the height of a disc space between adjacent
vertebral bodies of a human spine. The implant of some embodiments
consists of at least two radiographically distinct imaging
materials: a radiolucent portion, and a radio-opaque portion. The
radio-opaque materials of some embodiments are arranged toward the
vertebral endplates with minimal obstruction to radiographic
visualization through the implant from anterior to posterior and/or
from lateral directions. Embodiments of the implant may include
upper and lower portions adapted to be placed within the
intervertebral space to contact and support the adjacent vertebral
bodies. Upper and lower portions of the implant may include at
least one opening in communication with one another and adapted to
hold bone growth promoting material and/or bone graft for
permitting the growth of bone from vertebral body to vertebral body
through the implant. Embodiments of the invention include an
artificial interbody spinal implant containing at least two
different materials for insertion at least in part into an
implantation space formed across the height of a disc space between
adjacent vertebral bodies of a spine. Implant embodiments may
employ materials that bear a structural role in the design of the
implant, and at least a portion of a leading end of the implant may
have a reduced height to facilitate insertion of said implant
between the two adjacent vertebral bodies. Implants may have a
maximum length less than and approximating the posterior to
anterior or right to left length of the vertebral bodies. Some
embodiments also include a bone engaging surface formed on the
exterior of at least the upper and lower portions for engaging the
adjacent vertebral bodies, such as one or more protrusions,
ratchets, spikes, roughened surfaces or knurling. Embodiments of
the implant may be combined with a bone growth or bone healing
promoting material such as, but not limited to, bone, bone derived
products, demineralized bone matrix, mineralizing proteins,
ossifying proteins, bone forming cell differentiating substance,
bone morphogenetic protein, hydroxyapatite, and gene therapy
material leading to the production of bone. Embodiments of the
implant may also be combined with a therapeutic substance for the
treatment of infection, tumor or other pathologic process. In some
embodiments of the invention, one component material is relatively,
or absolutely radiolucent. In some embodiments of the invention,
one component material is radio-opaque. One component material of
the implant may be at least in part resorbable. In some
embodiments, at least a portion of an implant is treated to promote
bone in-growth between the implant and adjacent vertebral bodies.
Embodiments of the implant may be used in combination with at least
one spinal fixation implant. Embodiments of the implant may include
a hollow interior and at least one area for attachment or
interaction with an insertion device for surgical placement or
removal from the intervertebral space. Upper and lower surfaces of
some embodiments of the implant may include a plurality of
openings. Embodiments of the implant may be designed to be inserted
adjacent to a second implant into a disc space between adjacent
vertebral bodies, the second implant being of identical or
differing shape. At least one opening may be between the leading
and trailing ends of embodiments of the implant. Upper and lower
portions or surfaces of embodiments of the implant may be at least
in part generally parallel to one another or may be configured with
an angular relationship to each other for allowing angulation of
adjacent vertebral bodies relative to each other.
[0008] Another embodiment of the invention is an intervertebral
implant having a generally rounded exterior shape for promoting
fusion between an inferior vertebral body and a superior vertebral
body. The embodiment includes a first rim around a periphery of the
implant, the first rim having a detectable radiographic signature,
and a member coupled to the first rim. The member has less of a
radiographic signature than the first rim, and the member adds
vertebral spacing height to the first rim.
[0009] Yet another embodiment of the invention is a method of
implanting an intervertebral implant from an anterior surgical
approach. The method includes providing an implant comprising: a
first rim around a periphery of the implant, the first rim having a
detectable radiographic signature, and a member coupled to the
first rim. The member having less of a radiographic signature than
the first rim, and the member adds vertebral spacing height to the
first rim. The method further includes radiographically observing
placement of the implant between superior and inferior vertebral
bodies by way of one or more of an anterior to posterior
radiographic view and a lateral radiographic view. The method also
may include radiographically observing bone growth between the
superior and inferior vertebral bodies by way of one or more of an
anterior to posterior radiographic view and a lateral radiographic
view.
[0010] Still another embodiment of the invention is a method of
assembling an intervertebral implant. A implant is provided for the
method comprising: a first rim around a periphery of the implant,
the first rim having a detectable radiographic signature, a support
coupled to the first rim, the support having a detectable
radiographic signature, and a second rim coupled to the support,
the second rim having a detectable radiographic signature. The
method further includes applying a member between the first rim and
the second rim, the member having less of a radiographic signature
than the first rim.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a side view of two adjacent vertebral bodies in a
lumbar spine with an implantation space formed across the height of
the spinal disc space.
[0012] FIG. 2 is a top plan view of a vertebral body in a lumbar
spine with an implantation space formed through a posterior
approach.
[0013] FIG. 3 is a side perspective view of the implantation space
of FIG. 2.
[0014] FIG. 4 is a perspective view of an implantation space formed
through an anterior approach.
[0015] FIG. 5 is a top plan view of a vertebral body in the lumbar
spine with an embodiment of an implant positioned in the
implantation space of FIG. 2.
[0016] FIG. 6 is a side view of two adjacent vertebral bodies with
the implant of FIG. 5 positioned in the implantation space of FIG.
2 through a posterior approach.
[0017] FIG. 7 is a side view of two adjacent vertebral bodies with
an implant positioned in the implantation space of FIG. 2 through
an anterior approach.
[0018] FIG. 8 is a top plan view of the implant of FIG. 5
[0019] FIG. 9 is a rear perspective view of the implant of FIG.
5.
[0020] FIG. 10 is a side view of the implant of FIG. 5.
[0021] FIG. 11 is a rear view of the implant of FIG. 5,
[0022] FIG. 12 is a rear perspective view of another embodiment of
an implant for use in the implantation space of FIG. 2.
[0023] FIG. 13 is a rear view of the implant of FIG. 12.
[0024] FIG. 14 is a side view of the implant of FIG. 12.
[0025] FIG. 15 is a rear perspective view of an embodiment of an
implant suited for anterior placement into a cervical or lumbar
intervertebral disc space.
[0026] FIG. 16 is a top plan view of the implant of FIG. 15.
[0027] FIG. 17 is a side view of the implant of FIG. 15.
[0028] FIG. 18 is perspective view of an embodiment of the
implant.
[0029] FIG. 19 is a view of selected components of the implant of
FIG. 18.
[0030] FIG. 20 is an exploded perspective view of an embodiment of
the implant
[0031] FIGS. 21A, 21B, and 21C are plan (axial), side (lateral),
and posterior views respectively of components of an embodiment of
the invention.
[0032] FIGS. 22A, 22B, and 22C are plan (axial), side (lateral),
and posterior views respectively of components of an embodiment of
the invention.
[0033] FIGS. 23A, 23B, and 23C are plan (axial), side (lateral),
and posterior views respectively of components of an embodiment of
the invention.
[0034] FIGS. 24A, 24B, and 24C are plan (axial), side (lateral),
and posterior views respectively of components of an embodiment of
the invention.
[0035] FIGS. 25A, 25B, and 25C are plan (axial), side (lateral),
and posterior views respectively of components of an embodiment of
the invention.
DETAILED DESCRIPTION
[0036] The following description is intended to be representative
only and not limiting and many variations can be anticipated
according to these teachings, which are included within the scope
of this inventive teaching. Reference will now be made in detail to
embodiments of this invention, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
[0037] FIGS. 1-3 show an implantation space 100 formed across the
height of a spinal disc D between vertebral bodies V in the lumbar
spine. In other embodiments, the vertebral bodies may be bodies of
the cervical or thoracic spine as well. It is understood that
numerous methods exist and that any method and instrumentation
designed for the purpose may be applied to prepare the desired
implantation space and perform disc and soft tissue removal in such
a manner as to be adapted to receive the implants of the present
invention. It is also understood that implantation space
preparation commonly leaves residual disc material D prior to
implant placement.
[0038] FIG. 3 shows the implantation space 100, which has been
prepared by partial disc and soft tissue removal adjacent to the
vertebral body V. The preparation in FIG. 3 is shown as a posterior
lumbar surgical approach, and the opening O into the disc space
from the posterior is shown. The opening O may also be an opening
prepared for transforaminal or oblique surgical approaches.
Residual portions P of the vertebral pedicles are also shown.
[0039] FIG. 4 shows the implantation space 100, which has been
prepared by partial disc and soft tissue removal adjacent to the
vertebral body V. The preparation in FIG. 4 is shown as an anterior
surgical approach and the entrance E into the disc space from the
anterior is shown. This representation can reflect a cervical,
thoracic, or lumbar spinal intervertebral space preparation.
[0040] FIG. 5 shows a unilateral implant 200 seated in the
implantation space 100 in accordance with an embodiment of the
present invention. Bone graft material BG is shown anterior to the
unilateral implant 200, as well as within a central void 210 of the
unilateral implant 200.
[0041] FIG. 6 shows a unilateral implant 200 seated in the
implantation space 100. Bone graft material BG is shown anterior to
the unilateral implant 200 but posterior to remaining disc D, as
well as within the central void 210 of the unilateral implant
200.
[0042] FIG. 7 shows an anterior implant 400 seated in the
implantation space 100. Bone graft material BG is shown within a
cavity 480 of the anterior implant 400.
[0043] FIG. 8 shows the unilateral implant 200 with an anterior
aspect 202 and a posterior aspect 204. The central void 210 is
shown. Traversing support structures 220, 220' extend from anterior
202 to posterior 204 aspects of the implant. In the lateral aspects
of the unilateral implant 200 radiolucent blocks 240, 240' are
shown, each with a central cavity 242, 242'.
[0044] FIG. 9 shows the unilateral implant 200 as described in FIG.
8. The view from a posterior perspective shows the central void
210, the radiolucent blocks 240, 240' and posterior support columns
222, 222' which extend from an inferior aspect 260 to a superior
aspect 264 of the implant.
[0045] FIG. 10 shows the unilateral implant 200 as described in
FIG. 8 from a lateral view. The radiolucent block 240 is shown
positioned between the superior aspect 264 and the inferior aspect
260 of the implant. A posterior support column 222 and an anterior
support column 223 between the superior aspect 264 and inferior
aspect 260 are shown. In a lateral projection, anterior 202 and
posterior 204 aspects to the implant are noted.
[0046] FIG. 11 shows a posterior view of the implant as described
in FIGS. 8 and 9 without appearance of the radiolucent blocks 240,
240', in order to show radiographic appearance. Only the posterior
support columns 222, 222' extending between the inferior aspect 260
and the superior aspect 264 of the implant are visualized
radiographically due to the selected radio-opaque nature of the
material implemented in this embodiment. Anterior support columns
223, 223' are hidden behind posterior support columns 222, 222'
when the unilateral implant 200 is visualized radiographically
directly from the posterior.
[0047] FIG. 12 shows another embodiment of the invention with a
center-support implant 300 in rear perspective view. A central
volume 310, and radiolucent lateral blocks 340, 340', as well as
anterior support structure 324, and posterior support structure 322
are noted.
[0048] FIG. 13 shows a posterior view of the implant as described
in FIG. 12 without appearance of the radiolucent lateral blocks
340, 340' in order to show radiographic appearance. Only the
posterior support structure 322, which overlaps in this view the
anterior support structure 324, seen in FIG. 12, is visualized
radiographically between the inferior portion 360 and the superior
portion 364 of the implant due to the selected radio-opaque nature
of the material implemented in this embodiment.
[0049] FIG. 14 shows the center-support implant 300 as described in
FIG. 12 from a lateral view. The radiolucent lateral block 340 is
shown positioned between the superior portion 364 and the inferior
portion 360 of the implant. In this lateral projection the anterior
support structure 324 and posterior support structure 322 of the
implant are noted.
[0050] FIG. 15 illustrates an anterior implant 400. In some
embodiments, the anterior implant 400 may be placed through an
anterior surgical approach. However, the anterior implant 400 may
also be placed by other surgical approaches such as, but not
limited to, an anterior-oblique approach or a lateral approach. A
large central strut 410 made of radiolucent material is shown
traversing the implant. Upper rim 420 and lower rim 422 are
attached to the central strut 410 and further supported and
connected to one another through supportive structures 440, 442,
444, 446. Openings through the sides of the implant are noted 450,
452, 454, 456. These openings may permit for the growth of bone
through and into anterior implant 400, though the invention is not
so limited.
[0051] FIG. 16 shows a top plan view of the anterior implant 400 as
described in FIG. 15. The large central strut 410 is noted. Two
cavities 480,480' within the anterior implant 400 are shown on
either side of the strut 410. These cavities may permit for the
growth of bone through and into anterior implant 400, though the
invention is not so limited.
[0052] FIG. 17 shows a lateral view of the anterior implant 400 as
described in FIGS. 15 and 16. Upper rim 420 and lower rim 422 are
shown, as is the lateral view of the central strut 410. Given the
radiolucent nature of the central strut 410, on radiographic
visualization only the upper rim 420 and lower rim 422 as well as
radio-opaque supportive structures 440,442 would be noted. The
remaining two supportive structures 444,446 noted in FIG. 15 are
obscured in a lateral view by the supportive structures 440,442.
Further, angulation between the upper rim 420 and lower rim 422 may
facilitate insertion of anterior implant 400 between the two
adjacent vertebral bodies and permit control of sagittal plane
intervertebral alignment.
[0053] FIG. 18 illustrates another embodiment of an implant
designed primarily for implantation from an anterior surgical
approach. The open anterior implant 600 illustrates an implant
having a generally rounded exterior shape for promoting fusion
between an inferior vertebral body and a superior vertebral body.
Many generally rounded shapes are contemplated under the invention.
By way of example and without limitation, the exterior shape may be
round, oval, the shape of the cortical rim of a vertebral body, the
general shape of the cross-section of a kidney, or the general
shape of a racetrack having straight sides connecting substantially
rounded ends.
[0054] A first rim 620 is shown around a periphery of the open
anterior implant 600, the first rim 620 has a detectable
radiographic signature. The term radiographic signature as used
herein refers to a resulting visualization on radiographic devices.
A radiolucent block, for example, is faintly to indistinguishably
visible on a radiograph, and would therefore be considered to have
less of a radiographic signature than a radio-opaque metal such as
titanium.
[0055] The illustrated first rim 620 has a substantially uniform
width. In other embodiments, the width of the first rim 620 may
vary to improve engagement with other portions of the implant or
cooperating implants, or may vary to accomplish better anatomical
fit. The first rim 620 shown is continuous about the periphery.
Some embodiments include a rim that only extends between select
portions of the periphery of the implant.
[0056] The first rim 620 illustrated in FIG. 18 includes
protrusions 665 configured to face an adjacent vertebral body and
engage the vertebral body. In embodiments where the first rim 620
is made from a metallic material, an advantage may be established
in forming protrusions 665. Metal teeth, protrusions, and other
surface characteristics may be both stronger and capable of being
more effectively sharpened to better engage bone surfaces. In some
embodiments, the first rim 620 is made from titanium, a
biocompatible, radio-opaque metal.
[0057] FIG. 18 also illustrates a member embodied in a first
segment 610 and coupled to the first rim 620. The first segment 610
has less of a radiographic signature than the first rim 620 in some
embodiments. The first segment 610 may be made from a radiolucent
material such as PEEK or any other biocompatible material that is
less radiographically visible than the material of the first rim
620. As shown, the first segment 610 added to the first rim 620
increases the height of the spacing provided by the open anterior
implant 600.
[0058] Another member embodiment of the invention is illustrated in
FIG. 20 and includes tubular member 612. The tubular member 612 is
continuous about the periphery of the implant. The tubular member
612 may also be mated with the first rim 620.
[0059] The first segment 610 illustrated in FIGS. 18 and 19 has a
chord length C1. The cord length C1 of embodiments of the invention
is less than ninety percent of the length of an outer average
diameter of the first rim 620. In some more specific embodiments,
the cord length C1 is less than two-thirds of the length of an
outer average diameter of the first rim 620. FIGS. 18 and 19 also
illustrate an second segment 611 which is generally on the opposite
side of the open anterior implant 600 from the first segment
610.
[0060] In some embodiments, the first segment 610 is configured for
positioning on an anterior side of an implant. In other
embodiments, the first segment 610 is configured for positioning on
a posterior side of an implant. In still other embodiments, the
first segment 610 is configured for positioning on a lateral side
of an implant. The second segment 611 may be configured for
placement adjacent to or opposite from the first segment 610 in
conjunction with any placement of the first segment 610.
[0061] FIGS. 18 and 20 illustrate a second rim configured to couple
to the first and second segments 610, 611 and the tubular member
612 respectively. The second rim 622 may be coupled around a
periphery of the open anterior implant 600, the second rim 622 has
a detectable radiographic signature. The illustrated second rim 622
has a substantially uniform width. In other embodiments, the width
of the second rim 622 may vary to improve engagement with other
portions of the implant or cooperating implants, or may vary to
accomplish better anatomical fit. The second rim 622 shown is
continuous about the periphery.
[0062] The second rim 622 illustrated in FIG. 18 includes
protrusions 665 configured to face an adjacent vertebral body and
engage the vertebral body. In embodiments where the second rim 622
is made from a metallic material, an advantage may be established
in forming protrusions 665. Metal teeth, protrusions, and other
surface characteristics may be both stronger and capable of being
more effectively sharpened to better engage bone surfaces. In some
embodiments, the second rim 622 is made from titanium, a
biocompatible, radio-opaque metal.
[0063] As shown in FIGS. 18 and 20, the first and second segments
610, 611 and the tubular member 612 respectively are illustrated as
approximately the same anterior, posterior, and lateral size as the
first and second rims 620, 622. However, in some embodiments, the
first and second segments 610, 611 and the tubular member 612
extend beyond the extents of the first and second rims 620, 622 and
may encapsulate at least portions of the first and second rims 620,
622.
[0064] In some embodiments, implants of multiple sizes and
configurations may be formed by assembling two or more of various,
cooperating rims, supports, and members. An embodiment of the
invention may include a kit of variously sized rims, supports, and
members that are intended to be assembled by surgeons, product
resellers, other users, and distributors.
[0065] Members such as, but not limited to, the first and second
segments 610, 611 and the tubular member 612 may also be made at
least in part of material with a lower modulus of elasticity than
the rims or supports. In some circumstances, it may be desirable to
provide a modulus of elasticity that more nearly approximates the
modulus of elasticity of bone, or that at least reduces the
rigidity of the implant somewhat.
[0066] FIGS. 21A-25C are simplified graphical representations of
various configurations of implant embodiments of the invention.
FIG. 21A is a plan view consistent with an axial radiographic
image. FIG. 21B is a side view consistent with a lateral
radiographic image. FIG. 21C is a posterior view consistent with a
posterior to anterior radiographic image.
[0067] Each implant depicted in FIGS. 21A-25C will be represented
by a superior rim 20, an inferior rim 22, posterior supports 40,
46, anterior supports 44, 42, and lateral supports 25, 26 where
appropriate. Each of the supports is represented here as a
cylindrical component. However, each may be of any desired
configuration, such as but not limited to, rectangular, square,
circular, oval, polygonal, or variable in cross-section along its
length. Less radiographic or radiolucent members such as the
central strut 410, first segment 610, second segment 611 and the
tubular member 612, as have been disclosed above, are not shown in
FIGS. 21A-25C, but any size or configuration of such members is
contemplated for each of the implants represented. Although
angulation for lordotic and kyphotic correction is not illustrated
in FIGS. 21A-25C, such angulation is contemplated for each
embodiment.
[0068] FIGS. 21A-23C and 25A-25C will further illustrate
relationships between relative alignments among two or more of the
supports, as viewed radiographically from at least one of the
anterior, posterior, and lateral sides, and rotational position of
the implant about a vertical axis. A vertical axis for the purpose
of this orientation is considered vertical as viewed in the
posterior views illustrated.
[0069] FIGS. 21A-21C illustrate supports 40, 46 in the posterior
half of the implant that are configured to block radiographic
visualization of supports 42, 44 in the anterior half of the
implant when the implant is radiographically viewed from a
posterior side of the implant. FIGS. 21A-21C also illustrate a
support 40 in the posterior half of the implant configured to block
radiographic visualization of a support 46 on the contralateral
side of the implant when the implant is radiographically viewed
from a lateral side of the implant; and a support 42 in the
anterior half of the implant are configured to block radiographic
visualization of a support 44 on the contralateral side of the
implant when the implant is radiographically viewed from a lateral
side of the implant.
[0070] FIGS. 22A-22C show a support 25 in the posterior half of the
implant configured to block radiographic visualization of a support
26 on the contralateral side of the implant when the implant is
radiographically viewed from a lateral side of the implant. As used
herein, the posterior half will include a centerline between the
anterior and posterior halves. As shown in FIG. 22C, when the
implant is viewed radiographically from a posterior side, the
lateral space between supports 25, 26 indicates the rotational
position of the implant. Additionally, the alignment of the
supports 25, 26 with ends of the superior rim 20 when viewed from a
posterior side indicates rotational position of the implant.
[0071] FIGS. 23A-23C illustrate a support 40 in the posterior half
of the implant configured to block radiographic visualization of a
support 42 in the anterior half of the implant when the implant is
radiographically viewed from a posterior side of the implant. When
the implant is viewed radiographically from a lateral side, the
anterior to posterior spaces between the support 40 in the
posterior half of the implant and the support 42 in the anterior
half of the implant indicates the rotational position of the
implant. Additionally, the alignment of the supports 40, 42 with
ends of the superior rim 20 when viewed from a lateral side
indicates rotational position of the implant.
[0072] FIGS. 24A-24C illustrate an implant with a superior rim 20
and an inferior rim 22 that are coupled to one another by one or
more less radiographically detectable or radiolucent members.
[0073] FIGS. 25A-25C illustrate and implant where, when the implant
is viewed radiographically from a posterior side, lateral spaces
S1, S2 between the support 40 in the posterior half of the implant
and the supports 42, 44 in the anterior half of the implant are
substantially equidistant. FIGS. 25A-25C also illustrate a support
42 in the anterior half of the implant configured to block
radiographic visualization of a support 44 on the contralateral
side of the implant when the implant is radiographically viewed
from a lateral side of the implant.
[0074] While the implants are intended primarily for use in spinal
fusion, it is appreciated that they may be modified or adapted to
receive fusion promoting substances and/or materials within them
such as, but not limited to cancellous bone, bone derived products,
chemotherapeutic agents, antimicrobial agents, or others. In some
embodiments, the implants consists of materials such as, but not
limited to, titanium and its alloys, ASTM material, cobalt chrome,
tantalum, ceramic, poly-ether-ether-ketone (PEEK), various
plastics, plastic composites, carbon fiber composites, coral, and
can include artificial materials which are at least in part
bioresorbable. The radiographic appearance of the structural
materials employed in the implants are intended to be of varying
nature such that optimal visualization of implant placement,
implant-bone interfaces and/or bone ingrowth and through-growth can
be achieved.
[0075] While the descriptions reveal various relationships,
parallel or not, of upper to lower surfaces of the implants, it
should be noted that deliberate angulation between surfaces
relative to each other is possible. Subsequently, when implanted
into the spine, such implants permit position of the adjacent
vertebral bodies in angular relationship to each other to restore
the natural curvature of the spine, such as lordosis for example.
It should also be noted that significant variations in shape of the
implants are possible including but not limited to: kidney shaped,
rounded, wedge shaped, cylindrical, trapezoidal, rectangular,
oblong, and oval.
[0076] Outer surfaces may contain threading or particular
unevenness for improved insertion or anchorage into surrounding
tissues or bone. In any of the embodiments of the present
invention, the implants may include, be made of, treated, coated,
filled, used in combination with, or have a hollow space or opening
for containing artificial or naturally occurring materials and/or
substances suitable for implantation in the human spine. These
materials, and/or substances, may include any source of
osteogenesis, bone growth promoting materials, bone, bone derived
substances or products, demineralized bone matrix, mineralizing
proteins, ossifying proteins, bone morphogenetic proteins,
hydroxyapatite, genes coding for the production of bone, and bone
including, but not limited to, cortical bone, antibiotics, cancer
treating substances, infection treating substances or other disease
treating substances. The implant can include, at least in part
materials that are bioabsorbable and/or resorbable in the body. The
implants of the present invention can be formed of a porous
material or can be formed of a material that intrinsically
participates in the growth of bone between adjacent vertebral. At
least a portion of the implant may be treated to promote bone
ingrowth between the implant and the adjacent vertebral bodies.
[0077] The implant of the present invention may be used in
combination with a spinal fixation device such as any device,
regardless of material, that can be inserted into any portion of
the spine, such as but not limited to interbody spinal implants,
structural bone grafts, mesh, cages, spacers, staples, bone screws,
plates, rods, tethers of synthetic material or wires, or other
spinal fixation instrumentation. While the invention has been
described with reference to particular embodiments, it will be
appreciated by those of ordinary skill in the art that various
modifications can be made to the invention itself without departing
from the spirit and scope thereof. All changes and modifications
that are within the spirit of the invention are hereby anticipated
and claimed.
[0078] A method under the invention includes implanting an
intervertebral implant from an anterior surgical approach. An
implant comprising the following is provided: a first rim around a
periphery of the implant, the first rim having a detectable
radiographic signature, and a member coupled to the first rim, the
member having less of a radiographic signature than the first rim.
The member adds vertebral spacing height to the first rim. Other
implants with compatible radiographic characteristics are also
contemplated for use under embodiments of the method.
[0079] The method further includes radiographically observing
placement of the implant between superior and inferior vertebral
bodies. This observation may be accomplished by capturing
radiographic images along one or more of an anterior to posterior
radiographic view and a lateral radiographic view. Such
radiographic viewing in some embodiments includes viewing from any
lateral direction and is not limited to direct posterior, anterior,
and lateral directly, but includes oblique departures from these
directions. Effective radiographic viewing is enabled by
embodiments of the invention that provide medial-lateral and
anterior-posterior viewing paths. However, selective placement of
radio-opaque materials that both structurally support and notify a
surgeon of implant orientation are present in some embodiments of
the invention in combination with these viewing paths.
[0080] Radiographically observing placement of the implant may
include observing relative alignment of two or more supports
extending between the superior and inferior portions of the
implant. By observing relative alignment of two or more supports
coupled to the first rim, orientation of the implant may be
determined.
[0081] The method may also include radiographically observing bone
growth between the superior and inferior vertebral bodies by
capturing radiographic images along one or more of an anterior to
posterior radiographic view and a lateral radiographic view. Such
radiographic viewing in some embodiments includes viewing from any
lateral direction and is not limited to direct posterior, anterior,
and lateral, but includes oblique departures from these directions.
Observation of bone growth is enhanced by the provision of viewing
paths provided through an implant that only include bone growth
volumes and radiolucent materials.
[0082] A method of assembling an intervertebral implant includes
providing an implant with a first rim around a periphery of the
implant, the first rim having a detectable radiographic signature,
a support coupled to the first rim, the support having a detectable
radiographic signature, and a second rim coupled to the support,
the second rim having a detectable radiographic signature.
[0083] Embodiments of the method include applying a member between
the first rim and the second rim. The member of the embodiment
having less of a radiographic signature than the first rim. By way
of example, the member may be a radiolucent material, such as PEEK.
As illustrated herein, the member may include one or more of a
central strut 410, a first segment 610, a second segment 611, or a
tubular member 612.
[0084] Applying the member may be accomplished in various ways. The
distal end may be formed around at least a portion of one of the
first rim, the second rim, and the support. To accomplish this, the
material of the member may be cast, injected, or molded directly
around at least a portion of one of the first rim, the second rim,
and the support. The body may be included as a part of a mold or
cast, or encapsulated within a mold or cast for application to a
portion of one of the first rim, the second rim, and the
support.
[0085] Applying the member may also include interconnecting a
material with at least a portion of at least one of the first rim,
the second rim, and the support. Interconnecting may also include
casting, injecting, or molding material, but without encapsulating
a portion of at least one of the first rim, the second rim, and the
support. Interconnecting material may also involve forming a member
completely separately from the first rim, the second rim, and the
support by milling, casting, forming, injecting, or molding. After
the member is formed, it may then be applied to the body by any
method of adhesion, interdigitation, or interconnection. In some
embodiments, interconnecting may be accomplished by snapping the
material of the member to, between, or among the first rim, the
second rim, and the support.
[0086] While embodiments of the invention have been illustrated and
described in detail in the disclosure, the disclosure is to be
considered as illustrative and not restrictive in character. All
changes and modifications that come within the spirit of the
invention are to be considered within the scope of the
disclosure.
* * * * *