U.S. patent application number 16/385703 was filed with the patent office on 2019-10-10 for artificial disc replacements with natural kinematics.
The applicant listed for this patent is SpineCore, Inc.. Invention is credited to Bret A. Ferree, David Tompkins.
Application Number | 20190307575 16/385703 |
Document ID | / |
Family ID | 35061613 |
Filed Date | 2019-10-10 |
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United States Patent
Application |
20190307575 |
Kind Code |
A1 |
Ferree; Bret A. ; et
al. |
October 10, 2019 |
Artificial Disc Replacements With Natural Kinematics
Abstract
This invention improves upon prior art total disc replacements
(TDRs) by more closely replicating the kinematics of a natural
disc. The preferred embodiments feature two or more fixed centers
of rotation (CORs) and an optional variable COR (VCOR) as the
artificial disk replacement (ADR) translates from a fixed posterior
COR that lies posterior to the COR of the TDR to facilitate normal
disc motion. The use of two or more CORs allows more flexion and
more extension than permitted by the facet joints and the
artificial facet (AF). AF joint-like components may also be
incorporated into the design to restrict excessive translation,
rotation, and/or lateral bending.
Inventors: |
Ferree; Bret A.;
(Cincinnati, OH) ; Tompkins; David; (Newport,
KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SpineCore, Inc. |
Allendale |
NJ |
US |
|
|
Family ID: |
35061613 |
Appl. No.: |
16/385703 |
Filed: |
April 16, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15840630 |
Dec 13, 2017 |
10299933 |
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16385703 |
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15402610 |
Jan 10, 2017 |
9877841 |
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15840630 |
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14881879 |
Oct 13, 2015 |
9572679 |
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15402610 |
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14308201 |
Jun 18, 2014 |
9168146 |
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14881879 |
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13737500 |
Jan 9, 2013 |
8784492 |
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14308201 |
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10512515 |
Jun 3, 2005 |
8366772 |
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PCT/US03/12500 |
Apr 23, 2003 |
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13737500 |
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10420423 |
Apr 22, 2003 |
6706068 |
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10512515 |
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60449642 |
Feb 24, 2003 |
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60445958 |
Feb 7, 2003 |
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60374747 |
Apr 23, 2002 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/30767 20130101;
A61F 2002/30518 20130101; A61F 2310/00293 20130101; A61F 2002/30884
20130101; A61F 2002/302 20130101; A61F 2002/30616 20130101; A61F
2250/0098 20130101; A61F 2310/00029 20130101; A61F 2002/30769
20130101; A61F 2230/0065 20130101; A61F 2/44 20130101; A61F
2250/0039 20130101; A61B 17/86 20130101; A61F 2002/30016 20130101;
A61F 2002/30245 20130101; A61F 2310/00239 20130101; A61F 2002/30301
20130101; A61F 2310/00203 20130101; A61F 2002/30878 20130101; A61F
2002/30563 20130101; A61F 2002/30507 20130101; A61F 2310/00395
20130101; A61F 2002/30324 20130101; A61F 2250/0019 20130101; A61F
2002/30604 20130101; A61F 2310/00179 20130101; A61F 2002/30649
20130101; A61F 2002/30934 20130101; A61F 2002/30632 20130101; A61F
2002/448 20130101; A61F 2002/30327 20130101; A61F 2002/30841
20130101; A61F 2230/0004 20130101; A61F 2310/00023 20130101; A61F
2/4425 20130101; A61F 2310/00592 20130101; A61F 2002/3008 20130101;
A61F 2002/30578 20130101; A61F 2002/30136 20130101; A61F 2002/443
20130101; A61F 2220/0025 20130101; A61F 2230/0095 20130101; A61F
2310/0058 20130101; A61F 2230/0071 20130101; A61F 2002/30919
20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. An artificial disc replacement (ADR), comprising: a superior
component having an upper contacting portion having a first bone
contacting surface for contacting an endplate of a superior
vertebra and a lower articulating portion having a lowermost
surface and a first concave surface extending upward from the
lowermost surface; and an inferior component having a lower bone
contacting portion having a second bone contacting surface for
contacting an endplate of an inferior vertebra and an upper
articulating portion having an uppermost surface and second concave
surface extending downward from the uppermost surface, wherein the
superior and inferior components are articulable about first and
second centers of rotation (CORs), the first COR being disposed
above the lowermost of the superior component, and the second COR
being disposed below the uppermost surface of the inferior
component.
2. The ADR of claim 1, wherein first and second bone contacting
surfaces include keels extending therefrom.
3. The ADR of claim 2, wherein the keels have a plurality of holes
extending therethrough.
4. The ADR of claim 1, wherein the superior and inferior component
defined an anterior edge of the ADR, and the first COR is
positioned closer to the anterior edge than the second COR.
5. The ADR of claim 4, wherein the second concave surface is
positioned closer to the anterior edge of the ADR than the first
concave surface.
6. The ADR of claim 1, the second concave surface includes a
toroidal and spherical region.
7. The ADR of claim 1, wherein the lowermost and uppermost surfaces
are planar.
8. An artificial disc replacement (ADR), comprising: a superior
component having an upper contacting portion having a first bone
contacting surface for contacting an endplate of a superior
vertebra and a lower articulating portion having a first concave
surface and a first perimeter surface extending at least partially
about a perimeter of the first concave surface; and an inferior
component having a lower bone contacting portion having a second
bone contacting surface for contacting an endplate of an inferior
vertebra and an upper articulating portion having a second concave
surface and a second perimeter surface extending at least partially
about a perimeter of the second concave surface, wherein the
superior and inferior components are rotatable relative to each
other about first and second centers of rotation (CORs), the first
COR being disposed below the second perimeter surface of the
inferior component, and the second COR being disposed above the
second perimeter surface of the superior component.
9. The ADR of claim 8, wherein the first and second perimeter
surfaces are planar.
10. The ADR of claim 8, wherein the first and second perimeter
surfaces interface only a portion of the perimeter of the first and
second concave surfaces, respectively.
11. The ADR of claim 8, wherein the first COR is positioned above
the first bone contacting surface, and the second COR is positioned
below the second bone contacting surface.
12. The ADR of claim 8, wherein the superior and inferior
components directly articulate with each other about the CORs.
13. The ADR of claim 8, wherein first and second bone contacting
surfaces include keels extending therefrom.
14. The ADR of claim 8, wherein the keels have a plurality of holes
extending therethrough.
15. An artificial disc replacement (ADR), comprising: a superior
component having an upper contacting portion having a first bone
contacting surface for contacting an endplate of a superior
vertebra and a lower articulating portion having a first concave
surface extending into a first perimeter surface of the superior
component, the first concave surface defining a first center of
rotation (COR), the first perimeter surface at least partially
defining a perimeter of the first concave surface; and an inferior
component having a lower bone contacting portion having a second
bone contacting surface for contacting an endplate of an inferior
vertebra and an upper articulating portion having a second concave
surface extending into a second perimeter surface of the inferior
component, the second concave surface defining a second COR, the
second perimeter surface at least partially about a perimeter of
the second concave surface, wherein the superior and inferior
components are respectively articulable about the first and second
CORs, the first COR being disposed below the second perimeter
surface of the inferior component, and the second COR being
disposed above the first perimeter surface of the superior
component.
16. The ADR of claim 15, wherein the first perimeter surface of the
superior component and the second perimeter surface of the inferior
component are planar.
17. The ADR of claim 16, wherein the first perimeter surface
defines only a portion of a perimeter of the first concave
surface.
18. The ADR of claim 15, wherein the lower articulating portion of
the superior component includes a convex surface for articulation
with the second concave surface of the inferior component.
19. The ADR of claim 18, wherein the first perimeter surface at
least partially defines the convex surface.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 15/840,630, filed on Dec. 13, 2017, which is a
continuation of U.S. patent application Ser. No. 15/402,610, filed
on Jan. 10, 2017, now U.S. Pat. No. 9,877,841, which is a
continuation of U.S. patent application Ser. No. 14/881,879, filed
on Oct. 13, 2015, now U.S. Pat. No. 9,572,679, which is a
continuation of U.S. patent application Ser. No. 14/308,201, filed
on Jun. 18, 2014, now U.S. Pat. No. 9,168,146, which is a
continuation of U.S. patent application Ser. No. 13/737,500, filed
on Jan. 9, 2013, now U.S. Pat. No. 8,784,492, which is a
continuation of U.S. patent application Ser. No. 10/512,515, filed
on Jun. 3, 2005, now U.S. Pat. No. 8,366,772, which is a national
phase entry under 35 U.S.C. .sctn. 371 of International Application
No. PCT/US2003/012500 filed Apr. 23, 2003, published in English,
which is a continuation of U.S. patent application Ser. No.
10/420,423 filed Apr. 22, 2003, now U.S. Pat. No. 6,706,068, which
claims the benefit of the filing date of U.S. Provisional Patent
Application Nos. 60/374,747 filed Apr. 23, 2002, 60/445,958 filed
Feb. 7, 2003 and 60/449,642 filed Feb. 24, 2003, the disclosures of
which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to artificial disc
replacements (ADRs) and, more particularly, to ADRs facilitating
more natural kinematics.
[0003] Many spinal conditions, including degenerative disc disease,
can be treated by spinal fusion or through artificial disc
replacement (ADR). ADR has several advantages over spinal fusion.
The most important advantage of ADR is the preservation of spinal
motion. Spinal fusion eliminates motion across the fused segments
of the spine. Consequently, the discs adjacent to the fused level
are subjected to increased stress. The increased stress increases
the changes of future surgery to treat the degeneration of the
discs adjacent to the fusion. However, motion through an ADR also
allows motion through the facet joints. Motion across arthritic
facet joints could lead to pain following ADR. Some surgeons
believe patients with degenerative disc and arthritis of the facet
joints are not candidates for ADR.
[0004] Current ADR designs do not attempt to limit the pressure
across the facet joints or facet joint motion. Indeed, prior art
ADRs generally do not restrict motion. For example, some ADR
designs place bags of hydrogel into the disc space which do not
limit motion in any direction. In fact, ADRs of this kind may not,
by themselves, provide sufficient distraction across the disc
space. ADR designs with metal plates and polyethylene spacers may
restrict translation but they do not limit the other motions
mentioned above. The articular surface of the poly spacer is
generally convex in all directions. Some ADR designs limit motion
translation by attaching the ADR halves at a hinge.
[0005] One of the most important features of an artificial disc
replacement (ADR) is its ability to replicate the kinematics of a
natural disc. ADRs that replicate the kinematics of a normal disc
are less likely to transfer additional forces above and below the
replaced disc. In addition, ADRs with natural kinematics are less
likely to stress the facet joints and the annulus fibrosus (AF) at
the level of the disc replacement. Replicating the movements of the
natural disc also decreases the risk of separation of the ADR from
the vertebrae above and below the ADR.
[0006] The kinematics of ADRs are governed by the range of motion
(ROM), the location of the center of rotation (COR) and the
presence (or absence) of a variable center of rotation (VCOR).
Generally ROM is limited by the facet joints and the AF. A natural
disc has VCOR, that is, the COR varies as the spine bends forward
(flexion) and backward (extension). Typically, the vertebra above a
natural disc translates forward 1-2 mm as the spine is flexed.
[0007] Prior art total disc replacements (TDR), that is, ADRs with
rigid plates that attach to the vertebrae, do not replicate the
kinematics of the natural disc. Generally, the COR lies too
anterior. Most prior art TDRs also rely on a single, fixed COR. As
a result, many of the prior art TDRs have a limited ROM.
BRIEF SUMMARY OF THE INVENTION
[0008] This invention improves upon prior art TDRs by more closely
replicating the kinematics of a natural disc. The preferred
embodiments feature two or more fixed centers of rotation (CORs)
and an optional variable COR (VCOR) as the ADR translates from a
fixed posterior COR to a more anterior COR.
[0009] The multiple CORs permit a TDR with a posterior COR that
lies posterior to the COR of the TDR to facilitate normal disc
motion. The use of two or more CORs allow more flexion and more
extension than permitted by the facet joints and the AF. Artificial
facet join-like components may also be incorporated into the design
to restrict excessive translation, rotation, and/or lateral
bending.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a sagittal cross section of a total disc
replacement (TDR) according to the invention having three fixed
centers of rotation (CORs);
[0011] FIG. 2 is a sagittal cross section of the TDR of FIG. 1
extended 5 degrees, more or less;
[0012] FIG. 3 is a sagittal cross section of the TDR of FIG. 1
showing various degrees of flexion;
[0013] FIG. 4 is a sagittal cross section of another embodiment of
a TDR having an anterior COR and a posterior COR;
[0014] FIG. 5 is a sagittal cross section of the TDR of FIG. 4 in a
flexed position.
[0015] FIGS. 6A and 6B are drawings that show the articulating
surfaces of the TDR drawn in FIG. 4.
[0016] FIG. 7 is a sagittal cross section of another embodiment
having an anterior and a posterior COR;
[0017] FIG. 8 is a sagittal cross section of the TDR of FIG. 7 in a
more flexed position;
[0018] FIG. 9 is a view of the articulating surfaces of the TDR of
FIG. 7;
[0019] FIG. 10 is an oblique view of the assembled TDR drawn in
FIG. 7;
[0020] FIG. 11A is a view of the anterior side of a cervical
embodiment of the TDR of FIG. 7;
[0021] FIG. 11B is a view of the lateral side of the TDR of FIG.
11A;
[0022] FIG. 11C is a view of the interior of the TDR drawn in FIG.
11A;
[0023] FIG. 12A is a sagittal cross section of yet a further
embodiment of an artificial disc replacement according to the
invention;
[0024] FIG. 12B is a sagittal cross section of the embodiment of
the ADR of FIG. 12A;
[0025] FIG. 12C is a view of the side of the ADR of FIG. 12A;
[0026] FIG. 13A is a view of the side of the ADR of FIG. 12A
including modular shims; and
[0027] FIG. 13B is an exploded view of the embodiment of the ADR
shown in FIG. 13A.
DETAILED DESCRIPTION
[0028] My U.S. Provisional Patent Application Ser. No. 60/374,747,
incorporated herein by reference, describes various improved
artificial disc replacements (ADRs), including various embodiments
that restrict spinal extension, rotation, translation, and/or
lateral bending. In one disclosed configuration, rotation and
translocation are limited by a "spoon-on-spoon" type of
cooperation. Wedge or trapezoid-shaped ADRs are also presented to
preserve lordosis. Fasteners may be used to fix the ADR to upper
and lower vertebrae. An optional lip may additionally be provided
to prevent the trapping of soft tissue during the movement from a
flexion to neutral position.
[0029] The present invention extends such teachings through total
disc replacements (TDRs) that more closely replicate the kinematics
of a natural disc. The preferred embodiments feature two or more
fixed centers of rotation (CORs) and an optional variable COR
(VCOR) as the ADR translates from a fixed posterior COR to a more
anterior COR. The multiple CORs permit a TDR with a posterior COR
that lies posterior to the COR of the TDR to facilitate normal disc
motion. The use of two or more CORs allow more flexion and more
extension than permitted by the facet joints and the AF. Artificial
facet joint-like components may also be incorporated into the
design to restrict excessive translation, rotation, and/or lateral
bending.
[0030] FIG. 1 is a sagittal cross section of a TDR 10 according to
the invention having three fixed CORs 12, 14, and 16. Articulation
occurs at the posterior COR 12 when the spine is in a neutral to
extended position. FIG. 2 is a sagittal cross section of the TDR
drawn in FIG. 1 with the ADR 10 extended 5 degrees, more or less.
FIG. 3 is a sagittal cross section of the TDR drawn in FIG. 1 in
various degrees of flexion. As illustrated in the figure, the COR
migrates anteriorly from a more posterior COR to a more anterior
COR as the TDR is flexed.
[0031] FIG. 4 is sagittal cross section of another embodiment TDR
110 of the invention having an anterior COR 112 and a posterior COR
114. In this case, the TDR 110 articulates at the posterior COR 114
with the TDR in neutral to extended position. FIG. 5 is a sagittal
cross section of the TDR 110 drawn in FIG. 4 in a flexed position.
Note that the superior TDR endplate 110a translates forward from
the posterior COR to the anterior COR as the ADR 110 moves from a
neutral or extended position to a flexed position. FIGS. 6A and 6B
are a view of the articulating surfaces of the TDR 110 drawn in
FIG. 4. The inferior TDR endplate 110b is shown in FIG. 6A, and the
inferior surface of the superior TDR endplate 110a is shown in FIG.
6B.
[0032] FIG. 7 is a sagittal cross section of a further embodiment
of the invention, including an anterior and a posterior COR 212 and
214, respectively. The design also includes novel artificial facet
joint-like components that prevent excessive translation, rotation,
or lateral bending. FIG. 8 is a sagittal cross section of the TDR
210 drawn in FIG. 7 in a more flexed position. The drawing
illustrates a gap between the artificial facet joint-like portions
of the device. FIG. 9 is a view of the articulating surfaces of the
TDR 210 drawn in FIG. 7. The superior surface of the inferior TDR
endplate 210b is drawn on the left. FIG. 10 is an oblique view of
the assembled TDR 210 drawn in FIG. 7. This embodiment of the TDR
210 illustrates the use of a toroidal patch and two spherical
patches to form the anterior articulating surface of the lower
plate. The novel torodial-spherical surface facilitates lateral
bending.
[0033] FIG. 11A is a view of the anterior side of a cervical
embodiment of the TDR 210 drawn in FIG. 7. Screws can be inserted
through the holes in the TDR 210 to attach the TDR 210 to the
vertebrae. A reversible locking mechanism can be used to prevent
the screws from backing out of the vertebrae. FIG. 11B is a view of
the lateral side of the TDR 210 drawn in FIG. 11A. FIG. 11C is a
view of the anterior of the TDR 210 drawn in FIG. 11A. The superior
surface of the inferior component of the TDR is drawn on the
left.
[0034] FIG. 12A is a sagittal cross section of another embodiment
TDR 310 wherein, in contrast to the embodiment of FIG. 7, the
articulating surfaces of the anterior and/or the posterior CORs are
not congruent. The use of non-congruent articulating surfaces
uncouples translation from rotation. ADRs with non-congruent joint
surfaces allow greater spinal flexion and extension without
corresponding subluxation of the vertebrae. The spherical
projections from the upper and lower ADR endplates 310a and 310b
can cooperate to prevent the upper ADR endplate 310a from
translating posteriorly over the inferior ADR endplate 310b. The
drawing illustrates the different radius of curvature of the
components forming the joint in the posterior aspect of the
ADR.
[0035] FIG. 12B is a sagittal cross section of the embodiment of
the ADR 310 drawn in FIG. 12A in a flexed position. The drawing
illustrates the different radius of curvature of the components
forming the joint in the anterior aspect of the ADR 310. FIG. 12C
is a view of the side of the ADR 310 drawn in FIG. 12A. Artificial
facet joint-like components, similar to those drawn in FIG. 7,
prevent excessive forward translation of the upper ADR endplate
relative to the lower ADR endplate. The artificial fact joint-like
components can also limit axial rotation and lateral bending.
[0036] FIG. 13A is a view of the side of the ADR 310 drawn in FIG.
12A, with modular sims. Modular shims can be used to increase
lordosis, or wedge shape, of the ADR 310. The modular shims can be
attached to the top of the superior ADR endplate 310a and/or the
bottom of the inferior ADR endplate 310b. The shims could fasten to
the keels of the ADR 310. Alternatively the shims could attach to
another part of the ADR endplates 310a and 310b. Lastly, the shims
could simply lay on the ADR endplates 310a and 310b. The shim
inventory would include shims with different thickness and
different angles. FIG. 13B is an exploded view of the embodiment of
the ADR drawn in 13 A.
[0037] Although surfaces depicted herein are shown as being
`congruent,` this is not necessary according to the invention. For
example, a concave surface may have a radius of curvature that is
larger than the radius of curvature of an articulating convex
surface such that the two surfaces are not in direct or intimate
contact at all times. Both symmetrical and asymmetrical joints may
also be used. A portion of the back of the posterior joint may be
removed to move the posterior COR further posterior and to increase
the surface area of the posterior joint by increasing the radius of
the surface. The articulating surface may be formed by a toroidal
region and a spherical region, in this and other embodiments
non-spherical surfaces may also be used to permit translation,
rotation or other movements between more controlled articulations.
TDRs according to the invention may be used in the cervical,
thoracic, or lumbar spine.
[0038] ADR/TDRs according to the invention may also be composed of
various materials. For example, the components may be constructed
of a metal such as chrome cobalt or a ceramic such as aluminum
oxide. The novel TDR can also be made of a metal or ceramic coated
with a harder or softer second material. That is, one or both of
the components may be a metal coated with a ceramic, or a metal or
ceramic coated with a diamond-like material or other hardened
surface. Alternatively, one or both of the components may be coated
with a polymeric (i.e., polyethylene) surface or liner.
* * * * *