U.S. patent application number 14/166979 was filed with the patent office on 2014-05-29 for intervertebral implant with fixation geometry.
This patent application is currently assigned to DePuy Synthes Products, LLC. The applicant listed for this patent is DePuy Synthes Products, LLC. Invention is credited to David E. Evans, Markus Hunziker, David Koch, Dominique Messerli, Jacqueline Myer, Brandon L. Randall, Ryan T. Walsh.
Application Number | 20140148905 14/166979 |
Document ID | / |
Family ID | 38325403 |
Filed Date | 2014-05-29 |
United States Patent
Application |
20140148905 |
Kind Code |
A1 |
Messerli; Dominique ; et
al. |
May 29, 2014 |
INTERVERTEBRAL IMPLANT WITH FIXATION GEOMETRY
Abstract
An intervertebral spacer implant (80) is provided with a
retention mechanism (86) to help alleviate expulsion and movement
of the implant when placed in the spine while providing an implant
that is easier to insert in the spine. In one embodiment the
retention mechanism comprises a keel on at least one of the
inferior or superior faces of the spacer implant preferably
extending in an anterior-posterior direction. In another embodiment
the implant comprises a spacer (84) and a plate (82), the plate
comprising a supplemental or alternative retention mechanism. In
one embodiment the retention mechanism comprises one or more holes
(88) in the anterior end of the plate. In yet another embodiment,
the retention mechanism comprises one or more blades that are in a
first position when inserted and are preferably rotated to a second
position that engages the superior and inferior vertebrae.
Inventors: |
Messerli; Dominique;
(Downingtown, PA) ; Walsh; Ryan T.;
(Douglassville, PA) ; Randall; Brandon L.;
(Chester Springs, PA) ; Evans; David E.;
(Downingtown, PA) ; Myer; Jacqueline; (Pottstown,
PA) ; Koch; David; (Bubendorf, CH) ; Hunziker;
Markus; (Aarau, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DePuy Synthes Products, LLC |
Raynham |
MA |
US |
|
|
Assignee: |
DePuy Synthes Products, LLC
Raynham
MA
|
Family ID: |
38325403 |
Appl. No.: |
14/166979 |
Filed: |
January 29, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12280917 |
Jul 8, 2010 |
|
|
|
PCT/US2007/005098 |
Feb 27, 2007 |
|
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14166979 |
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60777732 |
Feb 27, 2006 |
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Current U.S.
Class: |
623/17.16 |
Current CPC
Class: |
A61F 2/447 20130101;
A61F 2002/30593 20130101; A61F 2310/00359 20130101; A61F 2002/30784
20130101; A61F 2002/30507 20130101; A61F 2002/30884 20130101; A61F
2002/30187 20130101; A61F 2/442 20130101; A61F 2002/30387 20130101;
A61F 2/28 20130101; A61F 2310/00017 20130101; A61F 2310/00179
20130101; A61F 2220/0025 20130101; A61F 2310/00023 20130101; A61F
2002/30579 20130101; A61F 2/4611 20130101; A61F 2002/30845
20130101; A61F 2002/30904 20130101; A61B 17/86 20130101; A61F
2002/30604 20130101; A61F 2/4455 20130101; A61F 2002/2835 20130101;
A61F 2002/30843 20130101; A61F 2002/30004 20130101; A61F 2250/0014
20130101; A61F 2002/30578 20130101 |
Class at
Publication: |
623/17.16 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. An intervertebral implant comprising: a spacer having a first
insertion end portion, a second end portion, an upper surface, and
a lower surface, the spacer configured and dimensioned for
insertion between adjacent vertebrae; a plate secured to the second
end portion of the spacer, the plate including at least one blade
configured and dimensioned to penetrate the adjacent vertebrae; and
an actuator for causing the at least one blade to move and
penetrate the adjacent vertebrae.
2. The implant according to claim 1, wherein the at least one blade
is configured to rotate from a first position wherein the blade is
adjacent to the plate to a second position wherein the blade is not
adjacent the plate.
3. The implant according to claim 2, wherein the at least one blade
is configured to provide compression when rotated into the second
position.
4. The implant according to claim 2 further comprising a locking
mechanism to prevent the at least one blade from rotating back to
the first position.
5. The implant according to claim 1, wherein the at least one blade
comprises two blades.
6. The implant according to claim 5, wherein the two blades include
a first blade and a second blade, the first blade configured for
extending beyond the upper surface of the spacer into a superior
vertebrae and the second blade configured extending beyond the
lower surface of the spacer into an inferior vertebrae.
7. The implant according to claim 1, wherein the at least one blade
is pointed and wedge-shaped to facilitate penetrating and cutting
through the adjacent vertebrae.
8. The implant according to claim 1, wherein the plate, the spacer,
and the at least one blade are secured with a retention mechanism
configured to be torsionally driven.
9. The implant according to claim 8, wherein the retention
mechanism has a recess configured to receive a tool to rotate the
retention mechanism and the at least one blade relative to the
plate and the spacer.
10. The implant according to claim 9, wherein the recess is
star-shaped.
11. The implant according to claim 8, wherein the retention
mechanism is rotated clockwise to secure the at least one blade
substantially perpendicularly to the adjacent vertebrae.
12. The implant according to claim 8, wherein the retention
mechanism is rotated approximately 90.degree. to insert the at
least one blade into the adjacent vertebrae.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/280,917 filed Jul. 8, 2010, which claims
the benefit of International Application No. PCT/US2007/005098
filed Feb. 27, 2007, which claims priority to U.S. Provisional
Application Nos. 60/777,732 filed Feb. 27, 2006, 60/777,663 filed
Feb. 27, 2006, and 60/838,229 filed Aug. 16, 2006, the entire
contents of which are expressly incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to intervertebral
implants, and, more particularly, to a zero or low profile fusion
implant including a retention mechanism that preferably provides
integrated fixation geometry.
BACKGROUND OF THE INVENTION
[0003] Implants for use in spinal fusion surgery are known in the
art. Such implants are used to stabilize and immobilize the spinal
segments in the treatment of degenerative disc disease (single and
multi-level), spinal stenosis, and failed previous fusions. Some
implants use supplemental fixation means, such as a plate and
screws, to retain the implant once introduced between two
vertebrae.
SUMMARY OF THE INVENTION
[0004] The present invention preferably provides for an integrated
retention mechanism and spacer implant construction. As such, the
implant of the present invention preferably may be inserted using a
one-step implantation process, as compared to a two-step process.
The present invention preferably allows for implantation of an
intervertebral implant and fusion of adjacent vertebrae without the
need for additional supplemental fixation means. Preferably, such
an implant will minimize dysphasia and irritation of soft tissue,
provide sufficient segmental stability in flexion, extension and
rotation, provide adequate graft retention, allow for reduced
surgery times, minimize surgical trauma, and still allow for
additional anterior and/or posterior fixation, if necessary. In one
embodiment, the implant may comprise a spacer having a first
insertion end portion, a second end portion opposite the first
insertion end portion, a first lateral side portion, a second
lateral side portion, an upper surface, and a lower surface. The
spacer configured and dimensioned for insertion between vertebrae.
The Spacer may optionally have one or more keels formed on one of
the upper and lower surfaces of the spacer. The keel preferably
extends from the first insertion end portion toward the second end
portion at least about 50 percent of the distance between the first
insertion end portion and the second end portion. Preferably, the
keel extends at least about 80 percent, and more preferably 95
percent of the distance between the first insertion end portion and
the second end portion.
[0005] The keel may have a first insertion end and a second end
where the first insertion end may be wedge shaped. The keel may
have a plurality of projections that are saw-tooth shaped. The keel
may have a first insertion end and a second end portion and the
first insertion end of the keel starts at about the first insertion
end portion of the implant. The keel may be tapered so that it is
higher at its second end relative to the insertion end. The keel
preferably has a height of about 1 mm to about 3.5 mm and
preferably a width of about 0.5 mm to about 3 mm.
[0006] The implant in one embodiment may be formed of an anterior
plate secured to the second end portion of the spacer, the plate
formed of a different material than the spacer. The plate is
preferably formed of a metallic material and the spacer is
preferably formed of a non-metallic material. The plate may include
at least two through holes, the at least two holes configured to
receive screws for securing the implant to adjacent vertebrae and
defining first and second hole axes; wherein the first through hole
exits through the upper surface and the second through hole exits
through the lower surface, and the axes of the first and second
through holes form non-zero angles with respect to the upper and
lower surfaces.
[0007] The plate preferably does not extend beyond the perimeter of
the spacer, and more preferably the height of the plate is no more
than the height of the spacer at the second end so that the plate
does not increase the height profile of the spacer. In this manner
the Spacer-plate construct may have a low profile. The through
holes in the plate at its outer surface may be generally aligned
along a straight line that generally corresponds with the mid-plane
of the implant. The spacer and plate preferably are secured
together before insertion into the spine. In one embodiment the
plate and spacer are connected by at least one dovetail connection,
the dovetail connection preferably extends from the upper surface
to the lower surface, although the dovetail may extend in a
horizontal direction when the spacer is inserted in the spine. The
spacer may be solid, or alternatively the spacer may have vertical
or horizontal windows or channels. The spacer or plate and spacer
construct may have a plurality of projections formed on at least
the upper or lower surface, the projections preferably having a
height less than the height of the keel. The keel in one embodiment
may be formed only on the spacer.
[0008] In yet another embodiment the intervertebral implant may
comprise a spacer having a first insertion end portion, a second
end portion, a first lateral side portion, a second lateral side
portion, an upper surface, and a lower surface, wherein the spacer
configured and dimensioned for insertion between vertebrae; a plate
secured to the first end of the spacer, the plate including at
least two through holes defining first and second central hole
axes, the at least two holes configured and dimensioned to receive
screws for securing the implant to adjacent vertebrae; and at least
one keel extending along the upper or lower surface and extending
at least 50% of the length of the upper or lower surface between
the insertion end portion and the second end portion, wherein the
first and second central hole axes form non-zero angles with
respect to the upper and lower surfaces of the spacer.
[0009] In another embodiment, the intervertebral implant may
comprise a spacer having a first insertion end portion, a second
end portion, an upper surface, and a lower surface, wherein the
spacer is configured and dimensioned for insertion between
vertebrae; a Plate secured to the second end portion of the spacer,
the plate including one or more blades, preferably two blades,
configured and dimensioned to penetrate adjacent vertebrae; and an
actuator for causing the one or more blades to move to penetrate
adjacent vertebrae. The one or more blades may be configured to
rotate from a first position wherein the blades preferably are
adjacent the plate to a second position wherein the blades
preferably are not adjacent the plate. The blades preferably are
configured to provide compression between the vertebrae and the
implant as the blades are rotated into the second position. The
implant may further comprise a locking mechanism to prevent the
blades from rotating back to the first position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The intervertebral implant is explained in even greater
detail in the following exemplary drawings. The drawings are merely
exemplary to illustrate the structure of preferred implants and
certain features that may be used singularly or in combination with
other features. The invention should not be limited to the
embodiments shown.
[0011] FIG. 1A is a perspective view of an intervertebral implant
according to one embodiment of the present invention positioned
between adjacent vertebral bodies;
[0012] FIG. 1B is a side view of the implant shown in FIG. 1A;
[0013] FIG. 1C is a front view of the implant shown in FIG. 1A;
[0014] FIG. 2A is a perspective view of an intervertebral implant
employing two retention screws according to another embodiment of
the present invention;
[0015] FIG. 2B is a top view of the implant shown in FIG. 2A;
[0016] FIG. 2C is a side view of the implant shown in FIG. 2A;
[0017] FIG. 3A is a perspective view of an intervertebral implant
employing three retention screws according to still another
embodiment of the present invention;
[0018] FIGS. 3B and 3C are front and side views, respectively, of
the implant shown in FIG. 3A;
[0019] FIGS. 4A and 4B are side and front views, respectively, of
the implant shown in FIG. 3A, in position between vertebrae;
[0020] FIG. 5A is a perspective view of an intervertebral implant
employing four retention screws according to still another
embodiment of the present invention;
[0021] FIGS. 5B and 5C are front and side views, respectively, of
the implant shown in FIG. 5A;
[0022] FIG. 5D is a perspective view of two of the implants of FIG.
5A positioned between vertebrae;
[0023] FIG. 6A is a perspective view of an intervertebral implant
employing top and bottom keels and two retention screws according
to still another embodiment of the present invention;
[0024] FIGS. 6B and 6C are front and back views, respectively, of
the implant shown in FIG. 6A;
[0025] FIG. 6D is another perspective view of the implant shown in
FIG. 6A;
[0026] FIGS. 7A and 7B are top views of an implant employing a
dovetail connection between a plate and spacer;
[0027] FIG. 8 is a perspective view of an implant employing a
dovetail connection between a plate and spacer;
[0028] FIG. 9 is a top view of an implant employing two dovetail
connections between the plate and spacer;
[0029] FIGS. 10A and 10B are top and side views, respectively, of
an implant employing a dovetail connection running horizontally
between the plate and spacer;
[0030] FIGS. 11A and 12A are top views of implants employing a
plate and spacer where the plate sides wrap around a portion of the
spacer;
[0031] FIGS. 11B and 12B are perspective views of the plates of
FIGS. 11A and 12A, respectively;
[0032] FIG. 13 is a top view of an implant employing a "jigsaw
puzzle" connection between the plate and spacer;
[0033] FIG. 14A is a perspective view of an implant wherein the
plate and spacer are integrally formed with one another;
[0034] FIGS. 14B-14E are rear, front, side and top views of the
implant depicted in FIG. 14A;
[0035] FIG. 14F is a side view of the implant depicted in FIG. 14A,
in position between adjacent vertebrae;
[0036] FIG. 15A is a perspective view of an intervertebral implant
employing top and bottom keels according to yet another embodiment
of the present invention;
[0037] FIGS. 15B-15D are front, side and top views, respectively,
of the implant depicted in FIG. 15A;
[0038] FIG. 16A is a perspective view of an intervertebral implant
employing top and bottom keels according to yet another embodiment
of the present invention;
[0039] FIG. 16B is a side view of the implant depicted in FIG.
16A;
[0040] FIG. 17A is a perspective view of an intervertebral implant
employing top and bottom keels according to yet another embodiment
of the present invention;
[0041] FIG. 17B is a side view of the implant depicted in FIG.
17A;
[0042] FIG. 18 is a perspective view of an intervertebral implant
employing top and bottom keels according to yet another embodiment
of the present invention; and
[0043] FIG. 19 is a perspective view of an intervertebral implant
employing top and bottom keels according to still another
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] Referring generally to FIGS. 1A, 1B and 1C, an
intervertebral implant 10 according to an embodiment of the present
invention is illustrated. As known in the art, the implant 10 is
inserted between adjacent vertebra (shown schematically as 50 in
FIGS. 1A-1C) of the spinal column. In this embodiment, the implant
includes a plate 11 and a graft/spacer 12 combined with a retention
mechanism 14. As shown, implant 10 includes an upper surface 16 and
a lower surface 18, which may taper, be curved, arcuate or flat as
desired or to conform to the end plates of the vertebrae and the
intervertebral space. As shown, upper and lower surfaces 16, 18 may
include a series of teeth or similar projections 19 to aid in
securing the implant to the vertebral endplates.
[0045] In addition, the implant includes retention mechanism 14
which preferably has two wedge-shaped blades 20, although more or
less blades 20 may be included. Following implantation between
vertebrae, retention mechanism 14 is torsionally driven into
vertebral bodies 50 and rotationally locked. More particularly,
wedge-shaped blades 20 may be rotated to engage, penetrate or cut
through the endplates of vertebral bodies 50 to hold implant 10 in
position. Wedges 20 preferably are pointed and shaped to facilitate
penetrating the end plates. Preferably, retention mechanism has a
recess 15 or projection (not shown) to receive a tool to rotate
retention mechanism 14 relative to plate 11 and spacer 12.
Preferably, retention mechanism 14 includes a locking mechanism 23
to prevent rotation of blades 20 or otherwise lock the position of
the blades 20 in the vertebrae. Retention mechanism 14 may have a
hub (not shown) that projects into and is held in a cavity (not
shown) in the plate 11. The hub is held or retained in the cavity,
but may rotate relative to the plate. Recess 15 is preferably
star-shaped and formed in the hub.
[0046] In the insertion position the pointed tips 17 on the blades
20 are directed toward the vertebrae. In the embodiment shown, one
pointed tip 17 is directed toward the superior vertebrae and one
pointed tip 17 is directed toward the inferior vertebrae. After the
implant 10 is positioned between the vertebrae, the retention
mechanism is rotated clockwise so that the pointed tips 17
preferably are directed in the lateral/medial direction. In the
preferred embodiment, the retention mechanism is rotated
approximately 90.degree., although the retention mechanism may be
rotated by more or less angular amounts. As the blades are rotated
they engage, penetrate into, or cut through the vertebrae. The
blades are preferably wedge-shaped and preferably compress the
adjacent vertebrae together or towards one another as they are
rotated.
[0047] Implant 10 may also include openings 22 for additional
fixation screws, if necessary. Openings 22 may also permit screws
that permit the plate 11 to be attached to the spacer 12. Both
plate 11 and graft/spacer 12 may be formed of PEEK, titanium,
titanium alloy, stainless steel, allograft bone or any other
suitable, biocompatible material. Preferably plate 11 and retention
mechanism 14 are formed of metal or metal alloy and the spacer is
formed of PEEK or other polymer, or alternatively bone or ceramic
or radiolucent biocompatible material. Screws not shown) may be
formed of titanium, titanium alloy or stainless steel. Graft/spacer
12 may include one or more openings (not shown) designed to receive
bone graft material.
[0048] Reference is now made to FIGS. 2A, 2B and 2C, which show an
intervertebral implant 30 according to another embodiment of the
present invention. Implant 30 includes a plate 32 and a
spacer/graft 34. As shown, in this embodiment, the retention
mechanism is provided by screws that provide opposing screw
fixation. In other words, for example, one screw diverges outward
such that it is secured into an upper or superior vertebra and
another screw diverges outward from the implant such that it is
secured in a lower or inferior vertebra so that opposing forces act
on the plate and/or vertebrae. A pair of holes or openings 36
accept two screws 38, which penetrate the vertebral bodies and
secure the implant in place. One of holes 36 is angled upward
toward the upper or superior vertebrae, and the other hole 36 is
angled downward toward the lower or inferior vertebrae, such that
holes 36 form an angle with respect to the upper and lower surfaces
26, 28 of the implant 30. As shown best in FIG. 2C, holes 36 form
an angle .alpha. with respect to the upper and lower surfaces of
the implant, where .alpha. may range between 20.degree. and
50.degree., and preferably ranges between 30.degree. and
45.degree.. Angle .alpha. may be the same for all holes 36 or may
be different for each hole. After the implant is placed between
adjacent vertebrae, screws 38 are inserted through the holes 36 in
plate 32 to penetrate the vertebrae and hold the implant in
position, i.e., one screw is inserted into the upper vertebrae and
the other is inserted into the lower vertebrae. As with the
previous embodiment, upper and/or lower surfaces 26, 28 of the
implant may include a series of teeth 19, or other similar
projections, to aid in securing the implant to the vertebral
endplates. Both plate 32 and graft/spacer 34 may be formed of PEEK,
titanium, titanium alloy, stainless steel, allograft bone or any
other suitable, biocompatible material, or any combination thereof.
Screws 38 may be formed of titanium, titanium alloy or stainless
steel. Graft/spacer 34 may include one or more openings 33 designed
to receive bone graft material.
[0049] Plate 32 is preferably formed of metal or metal alloy and
the spacer 34 is preferably formed of PEEK or other polymer, or
bone (allograft) or ceramic or other radiolucent, biocompatible
material. The plate 32 preferably is of the same height or less
than the height of the spacer 12 so the implant has a low profile.
The plate is preferably connected to the spacer 12 before the
implant 10 is implanted. Preferably the holes 36 are formed
substantially along a single substantially horizontal line 5 or
plane in the plates. The line or plane along which the holes 36 are
formed in the outer surface of the plate 32 is preferably
substantially the mid-plane 5 of the implant. In the embodiment of
FIGS. 2A-2C, the exit openings 37, 39 for the screw holes 36 are
formed in the plate. The plate 32 is preferably connected to the
spacer 34 by a dovetail joint 31 that requires the plate 32 to the
slide vertically relative to the spacer 34.
[0050] Reference is now made to FIGS. 3A, 3B and 3C, which show an
intervertebral implant 40 according to still another embodiment of
the present invention. As with the embodiment shown in FIG. 2A,
implant 40 includes a plate 42 and a spacer/graft 44, and the
retention mechanism is provided by screws that provide opposing
screw fixation. As shown, three holes 46 accept three fixation
screws 48, which penetrate the vertebral bodies and secure the
implant in place, as shown in FIGS. 4A and 4B. As shown best in
FIG. 3C, holes 46 form an angle .alpha. with respect to the upper
and lower surfaces 41, 45 of the implant, where .alpha. may range
between 20.degree. and 50.degree., and preferably ranges between
30.degree. and 45.degree.. Angle .alpha. may be the same for all
holes 46 or may be different for each hole. After the implant is
placed between adjacent vertebrae, screws 48 are inserted through
the holes 46 in plate 42 to penetrate the vertebrae and hold the
implant in position. In this embodiment, one screw 48 penetrates
the upper vertebrae and two screws 48 penetrate the lower
vertebrae. As with the previous embodiment, upper and/or lower
surfaces 41, 45 of the implant 40 may include a series of teeth 19,
or other similar projections, to aid in securing the implant to the
vertebral endplates. Both plate 42 and graft/spacer 44 may be
formed of PEEK, titanium, titanium alloy, stainless steel,
allograft bone or any other suitable, biocompatible material, or
any combination thereof. Screws 48 may be formed of titanium,
titanium alloy or stainless steel. Graft/spacer 44 may include one
or more openings 43 designed to receive bone graft material.
[0051] Plate 42 is preferably formed of metal or metal alloy and
spacer 44 is preferably formed of PEEK, other polymer, bone,
ceramic or other radiolucent, biocompatible material. The plate 32
preferably is the same height or less than the height of the
spacer. As with implant 30, plate 42 is preferably connected to
spacer 44 prior to implantation and holes 46 are preferably formed
substantially along a substantially horizontal line in the outer
end surface 43 of the plate 42 at an angle .alpha. so that at least
two fixation screws are directed in opposed directions, one toward
the superior vertebrae and one toward the inferior vertebrae. In
the embodiment of FIGS. 3A-3C, the exit openings 47, 49 in the
superior and inferior surfaces for the screws are preferably formed
at the junction of the plate and spacer, or in the spacer.
Alternatively, like the embodiment of FIGS. 2A-2C, the exit
openings 47, 49 may be formed entirely with in the plate 42.
[0052] The superior surface, the inferior surface or both surfaces
of the spacer and the implant construct may have a curved surface
to help provide the proper shape to the spine. The particular
surface shape and curvature, or taper in the anterior-posterior
direction as well as between the lateral side surfaces will depend
upon the location the spacer is intended to be inserted. The shape
of the perimeter of the spacer shown in FIGS. 2-14 are generally
for cervical applications and the spacer may have an alternative
shape, such as that illustrated by the perimetral shape of FIG. 15
for other locations such as in the lumbar area of the spine.
[0053] Reference is now made to FIGS. 5A, 5B and 5C, which show an
intervertebral implant 60 according to still another embodiment of
the present invention. As with the embodiment shown in FIG. 3A,
implant 60 includes a plate 62 and a spacer/graft 64, and the
retention mechanism is provided by screws which provide opposing
screw fixation. As shown, four holes 66 accept four fixation screws
68, which penetrate the vertebral bodies and secure the implant 60
in place, as shown in FIG. 5D. As shown best in FIG. 5C, holes 66
form an angle .alpha. with respect to the upper and lower surfaces
61, 65 of the implant 60, where .alpha. may range between
20.degree. and 50.degree., and preferably ranges between 30.degree.
and 45.degree.. Angle .alpha. may be the same for all holes 66 or
may be different for each hole. After the implant is placed between
adjacent vertebrae, screws 68 are inserted through the holes 66 in
plate 62 to penetrate the vertebrae and hold the implant in
position. In this embodiment, the two inner screws 68 penetrate the
upper vertebrae and the two outer screws 68 penetrate the lower
vertebrae. As with the previous embodiment, upper and/or lower
surfaces of the implant may include a series of teeth 19, or other
similar projections, to aid in securing the implant to the
vertebral endplates. Both plate 62 and graft/spacer 64 may be
formed of PEEK, titanium, titanium alloy, stainless steel,
allograft bone, or any other suitable, biocompatible material, or
any combination thereof. Screws 68 may be formed of titanium,
titanium alloy or stainless steel. Graft/spacer 64 may include one
or more openings 63 designed to receive bone graft material.
Preferably the plate 62 is formed of a metal or metal alloy and the
spacer 64 is formed of PEEK, other polymer, bone allograft, ceramic
or other radiolucent biocompatible material. The holes 66 are
formed in the outer surface 3 of the end wall of the plate 62
substantially along a horizontal line or plane at an angle
.alpha..
[0054] The screw holes 66 in the plate 62 preferably are directed
outward from the center of the implant, preferably at an angle
.theta.. The screw hole openings and configurations, as well as the
screws may have the configuration and construction and materials
described in US2005/0177236 which is incorporated by reference
herein in its entirety. The screws inserted in the embodiments of
FIGS. 5A-5C do not intersect a vertical plane cutting the implant
60 into two substantial halves. The screws, and the screw holes, in
the embodiment of FIGS. 5A-5C on the left side, one of which
extends in the superior direction and the other which extends in
the inferior direction may extend laterally outward from the center
plane at different angles .theta., or at the same angle .theta..
Preferably the two outermost holes 66 in the implant 60 extend
toward the inferior vertebrae while the two inner screw holes 66
extend toward the superior vertebrae.
[0055] FIGS. 6A-D show an intervertebral implant 80 according to
yet another embodiment of the present invention. As with the
embodiments shown in FIGS. 2A, 3A and 5A, implant 80 includes a
plate 82 and a spacer/graft 84. However, in this embodiment, the
retention mechanism is provided by a combination of opposing keels
86 on the top and bottom surfaces 81, 85 and screws providing
opposing screw fixation. The upper and lower keels 86 provide
additional additive resistance to torsion or rotation of the
implant. As shown, in addition to upper and lower keels 86, a pair
of holes 88 accept two fixation screws 89, which penetrate the
vertebral bodies and secure the implant in place. As with previous
embodiments, holes 88 form an angle .alpha. with respect to the
upper and lower surfaces of the implant, where .alpha. may range
between 20.degree. and 50.degree., and preferably ranges between
30.degree. and 45.degree.. Angle .alpha. may be the same for all
holes 88 or may be different for each hole.
[0056] After the implant is placed between adjacent vertebrae,
screws 89 are inserted through the holes 88 in plate 82 to
penetrate the vertebrae and aid in holding the implant in position.
As with previous embodiments, upper and/or lower surfaces 81, 85 of
the implant 80 may include a series of teeth 19, or other similar
projections, to aid in securing the implant to the vertebral
endplates. Preferably, the keel 86 is at least as high as the teeth
or protrusions 19. The keel preferably may have a height of about 1
mm to about 3.5 mm. The keel 86 may have the shape shown in FIG.
86, although it may have the shapes shown in FIGS. 15-19, or other
shapes. The keel 86 preferably extends in the anterior-posterior
direction. The leading end 85 of the keel may be pointed or tapered
so that it gets wider from the posterior end 83 to the anterior end
83. The keel preferably may be about 0.5 mm to about 3.0 mm wide.
The keel may also get higher as it extends from the posterior end
to the anterior end. The taper in the height and width may permit
easier insertion of the implant.
[0057] The keel 86 may only extend along the spacer as shown, or
may extend along the spacer 84 and plate 82. The length of the keel
may be, and preferably is, greater than the width of the keel. The
length of the keel 86 is preferably greater than about 50 percent
of the length of the implant 80 in the posterior to anterior
direction and in some embodiments preferably greater than about 80
to about 95 percent of the length of the implant 80 in the
anterior-posterior direction.
[0058] Both plate 82 and graft/spacer 84 may be formed of PEEK,
titanium, titanium alloy, stainless steel, allograft bone, or any
other suitable, biocompatible material, or any combination thereof,
while screws 89 may be formed of titanium, titanium alloy or
stainless steel. Graft/spacer 84 may include one or more openings
(not shown) designed to receive bone graft material. As with the
earlier embodiment the plate is preferably a different material
than the spacer, and the plate is preferably a metallic material
whereas the spacer is a non-metallic material. A preferred
embodiment for the implants 10, 30, 40, 60 and 80 may include a
titanium alloy for the plate and an allograft for the spacer.
[0059] FIGS. 7A-13 depict various attachment mechanisms for
attaching the plate and spacer of the implant together. The
attachment mechanisms between spacer and plate are not limited to
the mechanisms depicted. Various figures depict two or three holes
of the retention feature of the implant. It should be noted that
the number of holes two, three, or four of the retention feature of
the implant is not limited by the type of attachment mechanism
between the spacer and plate.
[0060] FIGS. 7A and B depict a top view of dovetail connection 1010
between plate 1100 and spacer 1200 (These figures do not depict the
holes of the retention feature so as to more clearly illustrate the
dovetail connection 1010). The dovetail connection 1010 may extend
from the upper surface to the lower surface of the implant 1000. As
shown in these figures, the thickness T of the plate 1100 may vary
depending on the application. Representative values for T include
about 5 mm to about 7 mm. Furthermore, the size of the dovetail
connection 1010 may also vary in size, both in length and in width.
As shown in FIGS. 7A and B, the male dovetail connector 1011 is
formed as part of the plate 1100 while the female connector 1012 is
formed on the spacer 1200. It is contemplated that the female
connector may be formed on the plate and the male connector may be
formed on the spacer. FIG. 8 is a perspective view of an implant
1000 with a dovetail connection 1010 between the plate 1100 and
spacer 1200. In this figure, the implant 1000 includes three holes
1110 similar to the embodiment depicted in FIGS. 3A-4B.
[0061] FIG. 9 depicts an implant 1000 having two dovetail
connections 1010, 1020 between the spacer 1200 and plate 1100. In
this embodiment, the dovetail connections 1010, 1020 may extend
between the upper surface and lower surface of the implant. It is
contemplated that the dovetail connections may extend from one
lateral side 1001 of the implant 1000 to the other lateral side
1002. FIGS. 10A and 10B depict such a dovetail connection between
the plate 1100 and spacer 1200.
[0062] FIGS. 11 and 12 depict further embodiments of the connection
between the plate 1100 and spacer 1200. In these embodiments, the
sides 1110 of the plate 1100 "wrap" around the proximal end (front)
of the spacer 1200. The length or thickness of the sides 1110 of
the plate 1100 may vary, as depicted in the two figures, depending
on the application.
[0063] FIG. 13 depicts another embodiment of the connection between
the plate 1100 and spacer 1200. In this embodiment, the connection
between the plate and spacer is a "jigsaw puzzle" connection 1040.
The shape of the "jigsaw puzzle" connection 1040 may vary depending
on the application. As with the other embodiments discussed above,
the male and female connectors of the connection may be formed on
the spacer 1200 or plate 1100, depending on the application.
[0064] FIGS. 14A-F depict a cervical spacer-plate implant 2000.
FIG. 14A is a perspective view of the implant 2000, whereas FIGS.
14B-E are various plane views of the implant. In this embodiment,
the plate 2020 and spacer 2010 are integrally formed. The implant
2000 may have an arcuate front face 2100, whereas the end face 2200
of the implant may be plane or arcuate. The implant 2000 may also
have arcuate first and second lateral surfaces 2300, 2400,
respectively, and an upper surface and a lower surface 2500, 2600.
The upper surface 2500 may be arcuate to conform to the contour of
the endplate of the upper vertebra. The lower surface 2600 is
generally a substantially flat planar surface. The distance between
the upper and lower surfaces 2500, 2600 at the front face 2100 may
be greater than at the end face 2200. The front face 2100 may be
wider than the end face 2200 such that the first and second lateral
surfaces 2300, 2400, connected to the front and end faces 2100,
2200 are further apart from each other at the front face than at
the end face. The implant 2000 may include one or more openings
designed to receive bone graft material. In particular, one or more
vertical windows/channels 2700 may extend through the implant from
the lower surface 2600 to the upper surface 2500. In some
embodiments, the implant 2000 may also have one or more horizontal
channels 2800 extending from the first lateral surface 2300 to the
second lateral surface 2400, and/or from the front face 2100 to the
end face 2200.
[0065] The front face 2100 has a height greater than the height of
the spacer 2010 to accommodate a retention feature provided by
opposing screw fixation. As shown, four holes 2900 accept four
fixation screws 2950 which penetrate the vertebral bodies 50 and
secure the implant 2000 in place, as shown in FIG. 14F. The holes
2900 form an angle .alpha. with respect to the upper and lower
surfaces 2500, 2600 of the implant 2000, where the angle may range
between 20.degree. and 50.degree., and preferably ranges between
30.degree. and 45.degree.. The angle .alpha. may be the same for
all holes or may be different for each hole. After the implant 2000
is placed between adjacent vertebrae 50, screws 2950 are inserted
through the holes 2900 to penetrate the vertebrae and hold the
implant in position. As with previous embodiments, the upper and/or
lower surfaces 2500, 2600 of the implant may include a series of
teeth 19, or similar projections, to aid in securing the implant to
the vertebral endplates. It is also contemplated that the upper
and/or lower surfaces 2500, 2600 may be smooth, having ridges that
run laterally with respect to the spacer 2010, or ridges running
from the front face 2100 to the end face 2200. The implant 2000 may
be formed of PEEK, titanium, titanium alloy, stainless steel,
allograft bone, or any other suitable, biocompatible material, or
any combination thereof, while screws 2950 may be formed of
titanium, titanium alloy or stainless steel.
[0066] It should be noted that the screw holes provided in the
plates of the embodiments of FIGS. 2-14 may be threaded or smooth,
and the screw inserted through the plate may have a head that also
may be threaded or smooth. In the embodiment where the screw holes
are threaded the heads of the screws are also preferably threaded
so that the screw will lock with the plate forming a relatively
rigid construct.
[0067] Reference is now made to FIGS. 15A-D, which shows an
intervertebral implant 70 according to still another preferred
embodiment of the present invention. FIG. 15A is a perspective view
of the implant, while FIGS. 15B-D are plane views of the implant.
In this embodiment, a pair of opposing dovetail keels 72 on the
upper and lower surfaces 71, 73 of the implant 70 provide the
retention feature. The implant may have arcuate anterior and
posterior faces, both curved in the same direction to form a
generally kidney bean shape. The keel is generally centrally
located and preferably extends about 50 percent the length of the
superior and inferior surfaces in an anterior to posterior
direction, and more preferably about 80 to about 95 percent of the
length in the anterior to posterior direction. The dovetail shape
of the keel 72 preferably assists in retaining the implant 100 in
position and helps to prevent expulsion of the implant. In
particular, the dovetail shape will help to retain contact between
the upper and lower surface of the implant and the end plates of
the vertebrae. The dovetail shape may also be configured to provide
compression. The shape of the implant 70 is generally preferred for
the lumbar region of the spine.
[0068] No additional plates or screws may be necessary. Implant 70
may be formed of PEEK, titanium, titanium alloy, stainless steel,
allograft bone, or any other suitable, biocompatible material, or
any combination thereof. Implant 70 may include one or more
openings designed to receive bone graft material. In particular,
one or more vertical windows/channels 75 may extend through the
implant 70 from the lower surface 73 to the upper surface 71. In
some embodiments, the implant 70 may also have one or more
horizontal channels 74 extending from a first lateral surface 77 to
a second lateral surface 78, and/or from the front face 79a to the
end face 79b.
[0069] The implant 100, shown in FIGS. 16A and B, may have arcuate
anterior and posterior faces 110, 112, respectively. Superior and
inferior faces, 114, 116, respectively, may have projections or
teeth 118 for engaging the adjacent vertebrae and aiding in
securing the implant 100 in the disc space. The projections 118 may
be pyramidal in shape as shown, or may have other shapes. One or
more vertical windows/channels 124, designed to receive bone graft
material, may extend through the implant 100 from the inferior face
116 to the superior face 114. In some embodiments, the implant 100
may also have one or more horizontal channels 126 designed to
receive bone graft material. The implant also has longitudinal
sides 102, 103, wherein a first longitudinal side's 102 height may
be, and preferably is, less than the height of the second
longitudinal side 103.
[0070] The implant 100 further may have a retention feature
comprising a first fixation member 105 projecting from the superior
face 114 and a second fixation member 115 projecting from the
inferior face 116. The first and second fixation members 105, 115
resemble a "keel" such that the keel is oriented from the anterior
face 110 to the posterior face 112. The length of the keel may be,
and preferably is, greater than the width of the keel, and whose
length preferably is 80 to 95 percent of the width of the superior
and inferior faces 114, 116. The first and second fixation members
105, 115 have a height greater than the height of the projections
or teeth 118. The first and second fixation members 105, 115 may
have projections 106, such as in the form of a saw-tooth, for
engaging the adjacent vertebrae and aiding in securing the implant
100 in the disc space without the need for supplemental fixation
means. The saw-tooth shape of the projections allows the implant to
be inserted while requiring a larger force for the implant to be
removed from between vertebrae. The keel also helps prevent
rotation or turning of the implant. No additional plates or screws
may be necessary to retain the implant between two vertebrae.
Implant 100 may be formed of PEEK, titanium, titanium alloy,
stainless steel, allograft bone, or any other suitable,
biocompatible material, or any combination thereof.
[0071] FIGS. 17A and B depict another embodiment of the implant
200. The implant 100 may have end faces 210, 212, respectively. The
end faces 210, 212 may be substantially flat or arcuate shaped.
Face 210 may have a greater length than face 212. The implant also
may have arcuate first and second longitudinal surfaces 202, 203,
respectively, and an inferior face 216 and a superior face 214. One
or more vertical windows/channels 224 may extend through the
implant 200 from the inferior face 216 to the superior face 214.
Additional vertical channels 230, extending from the inferior face
216 to the superior face 214 may be positioned on the perimeter of
the superior and inferior faces 214, 216. In some embodiments, the
implant 200 may also have one or more horizontal channels 226. The
height of the first face 210 may be greater than the height of the
second face 212.
[0072] The implant 200 further may have a retention feature
comprising a first fixation member 205 projecting from the superior
surface 214 and a second fixation member 215 projecting from the
inferior surface 216. The first and second fixation members 205,
215 resemble a "keel" such that the keel is oriented from face 210
to face 212. The length of the keel may be, and preferably is,
greater than the width of the keel, and whose length preferably is
80 to 95 percent of the length of the superior and inferior faces
214, 216. The first and second fixation members 205, 215 may have
projections 206, such as in the form of a saw-tooth, for engaging
the adjacent vertebrae and aiding in securing the implant 200 in
the disc space, preferably without the need for supplemental
fixation means. No additional plate or screws may be necessary to
retain the implant between two vertebrae. Implant 200 may be formed
of PEEK, titanium, titanium alloy, stainless steel, allograft bone,
or any other suitable, biocompatible material, or any combination
thereof.
[0073] The intervertebral implant 300, shown in FIG. 18, has
arcuate end faces 310, 312, respectively. Superior and inferior
faces, 314, 316, respectively, which may be curved and may have
projections or teeth 318 for engaging the adjacent vertebrae and
aiding in securing the implant 300 in the disc space. The
projections 318 may be pyramidal in shape. The implant also has
longitudinal sides 302, 303. The intervertebral implant 300 of this
embodiment differs from the implant 100 in that intervertebral
implant 300 has no horizontal or vertical channels, such that
superior and inferior faces 314, 316 and longitudinal surfaces 302,
303 has no openings.
[0074] The implant 300 further has a retention feature comprising a
first fixation member 305 projecting from the superior face 314 and
a second fixation member 315 projecting from the inferior face 316.
The first and second fixation members 305, 315 resemble a "keel"
such that the keel is oriented from front face 310 to end face 312.
The length of the keel may be, and preferably is, greater than the
width of the keel, and whose length is 80 to 95 percent of the
width of the superior and inferior faces 314, 316. The first and
second fixation members 305, 315 have a height greater than the
height of the projections or teeth 318. The first and second
fixation members 305, 315 may have projections 306, such as in the
form of a saw-tooth, for engaging the adjacent vertebrae and aiding
in securing the implant 300 in the disc space, preferably without
the need for supplemental fixation means. No additional plate or
screws may be necessary to retain the implant between two
vertebrae. Implant 300 may be formed of PEEK, titanium, titanium
alloy, stainless steel, allograft bone, or any other suitable,
biocompatible material, or any combination thereof.
[0075] FIG. 19 depicts yet another embodiment of an implant 400
having first and second fixation members 405, 415 that resemble a
"keel" such that the keel is oriented from front face 410 to end
face 412. The first and second fixation members 405, 415 may have
generally parallel side walls 416, 417 from the front towards the
rear or end of the fixation members 405, 415. The side walls 416,
417 of the first and second fixation members 405, 415 near the end
of the keel may be angled towards each other forming a wedge 418 at
the end of the members 405, 415. The wedge 418 may allow for easier
insertion between two vertebrae 50. The length of the keel may be,
and preferably is, greater than the width of the keel, and whose
length is 80 to 95 percent of the width of the superior and
inferior faces 414, 416. The first and second fixation members 405,
415 have a height greater than the height of the projections or
teeth 418. The first and second fixation members 405, 415 may
include a recess 422. The recess 422 may be sized to fit an
insertion tool (not shown), such that the front 420 of the first
and second fixation member 405, 415 have an opening allowing the
insertion tool to grip the implant 400 for insertion between two
vertebrae. Implant 400 may be formed of PEEK, titanium, titanium
alloy, stainless steel, allograft bone, or any other suitable,
biocompatible material, or any combination thereof.
[0076] The implants described herein are generally sized and
configured for anterior insertion, although different
configurations may be possible for posterior approaches. In
addition to the features shown the implants, spacers, and
plate/spacer constructs may have threaded holes, slots or channels
to mate with instruments to facilitate holding and inserting the
implants.
[0077] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions, and alterations can be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims. Moreover, the scope of the present application is
not intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure of the present invention, processes, machines,
manufacture, composition of matter, means, methods, or steps,
presently existing or later to be developed that perform
substantially the same function or achieve substantially the same
result as the corresponding embodiments described herein may be
utilized according to the present invention.
[0078] It will be appreciated by those skilled in the art that
various modifications and alterations of the invention can be made
without departing from the broad scope of the appended claims. Some
of these have been discussed above and others will be apparent to
those skilled in the art. For example, the present invention may be
employed in different sections of the spinal column, including, but
not limited to, the cervical area.
* * * * *