U.S. patent application number 16/934478 was filed with the patent office on 2020-11-05 for interbody cage with spill-free biological material compartment.
This patent application is currently assigned to UNIVERSITY OF MARYLAND, Baltimore. The applicant listed for this patent is UNIVERSITY OF MARYLAND, Baltimore. Invention is credited to Steven C. LUDWIG, Charles SANSUR.
Application Number | 20200345503 16/934478 |
Document ID | / |
Family ID | 1000004969987 |
Filed Date | 2020-11-05 |
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United States Patent
Application |
20200345503 |
Kind Code |
A1 |
SANSUR; Charles ; et
al. |
November 5, 2020 |
INTERBODY CAGE WITH SPILL-FREE BIOLOGICAL MATERIAL COMPARTMENT
Abstract
Interbody cages for spinal stabilization having a frame that
surrounds a central compartment suitable for retaining biological
material, such as bone graft material. The central compartment acts
as a spill-free bone and biologic compartment that allows a surgeon
to introduce the interbody cage into the body in an effective
manner without spilling the biological material. Methods for
introducing the interbody cages are disclosed.
Inventors: |
SANSUR; Charles; (Towson,
MD) ; LUDWIG; Steven C.; (Baltimore, MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNIVERSITY OF MARYLAND, Baltimore |
Baltimore |
MD |
US |
|
|
Assignee: |
UNIVERSITY OF MARYLAND,
Baltimore
Baltimore
MD
|
Family ID: |
1000004969987 |
Appl. No.: |
16/934478 |
Filed: |
July 21, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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16047473 |
Jul 27, 2018 |
10765525 |
|
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16934478 |
|
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62537610 |
Jul 27, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2002/30784
20130101; A61F 2/447 20130101; A61F 2/441 20130101; A61F 2002/30387
20130101; A61F 2002/3093 20130101; A61F 2002/30904 20130101; A61F
2002/4629 20130101; A61F 2002/30522 20130101; A61F 2002/30581
20130101; A61F 2/4465 20130101; A61F 2002/2835 20130101; A61F
2/4455 20130101; A61F 2002/30593 20130101; A61F 2002/30578
20130101; A61F 2002/30471 20130101; A61F 2/30744 20130101; A61F
2002/30909 20130101; A61F 2002/30589 20130101; A61F 2002/3092
20130101; A61F 2/30771 20130101; A61F 2002/30476 20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61F 2/30 20060101 A61F002/30 |
Claims
1. An interbody cage for spinal stabilization comprising a) a frame
that surrounds a central compartment, the frame comprising a top
face and a bottom face, the top face comprising one or more top
openings, and the bottom face comprising one or more bottom
openings, b) a cover that covers the one or more bottom openings,
the cover comprising one or more apertures suitable for retaining
biological material, and c) a removable cover configured to be
removably secured to the top face of the frame such that the
removable cover covers the one or more top openings when secured to
the top face of the frame, the removable cover comprising one or
more apertures suitable for retaining biological material, wherein
the top face of the frame is configured to receive the removable
cover, and wherein the removable cover is convex.
2. The interbody cage for spinal stabilization of claim 1, wherein
at least one of the cover and the removable cover comprises
mesh.
3. The interbody cage for spinal stabilization of claim 1, wherein
at least one of the cover and the removable cover comprises
flexible mesh.
4. The interbody cage for spinal stabilization of claim 1, wherein
the cover is convex.
5. The interbody cage for spinal stabilization of claim 1, wherein
the frame further comprises at least one vertical face, wherein the
at least one vertical face comprises one or more apertures suitable
for retaining biological material.
6. The interbody cage for spinal stabilization of claim 5, wherein
the at least one vertical face comprises mesh.
7. The interbody cage for spinal stabilization of claim 1, wherein
at least one of the top face and the bottom face comprises teeth
that extend in an outward direction.
8. The interbody cage for spinal stabilization of claim 1, wherein
the frame is configured to receive an insertion rod.
9. The interbody cage for spinal stabilization of claim 1, wherein
at least one of the cover and the removable cover further comprises
a pivotable attachment mechanism configured to engage at least one
of the top face and the bottom face.
10. An interbody cage for spinal stabilization comprising a) a
frame that surrounds a central compartment, the frame comprising a
top face and a bottom face, the top face comprising one or more top
openings, and the bottom face comprising one or more bottom
openings, b) a cover that covers the one or more bottom openings,
the cover comprising one or more apertures suitable for retaining
biological material, and c) an openable cover configured to be
secured to the top face of the frame in a closed position and
capable of being opened, the openable cover covering the one or
more top openings when secured to the top face of the frame in the
closed position, the openable cover comprising one or more
apertures suitable for retaining biological material, wherein the
openable cover is convex.
11. The interbody cage for spinal stabilization of claim 10,
wherein the openable cover is configured to be secured to the top
face of the frame by at least one latching mechanism and at least
one hinge.
12. The interbody cage for spinal stabilization of claim 10,
wherein at least one of the cover and the openable cover comprises
mesh.
13. The interbody cage for spinal stabilization of claim 10,
wherein at least one of the cover and the openable cover comprises
flexible mesh.
14. The interbody cage for spinal stabilization of claim 10,
wherein the cover is convex.
15. The interbody cage for spinal stabilization of claim 10,
wherein the frame further comprises at least one vertical face,
wherein the at least one vertical face comprises one or more
apertures suitable for retaining biological material.
16. The interbody cage for spinal stabilization of claim 15,
wherein the at least one vertical face comprises mesh.
17. The interbody cage for spinal stabilization of claim 10,
wherein at least one of the top face and the bottom face comprises
teeth that extend in an outward direction.
18. The interbody cage for spinal stabilization of claim 10,
wherein the frame is configured to receive an insertion rod.
19. The interbody cage for spinal stabilization of claim 10,
wherein at least one of the cover and the openable cover further
comprises a pivotable attachment mechanism configured to engage at
least one of the top face and the bottom face.
Description
TECHNICAL FIELD
[0001] The present application generally relates to interbody cages
for spinal stabilization. More specifically, the present
application relates to interbody cages for spinal stabilization
with one or more spill-free, biological material compartments.
BACKGROUND
[0002] During spinal fusion procedures, a solid bridge is typically
formed between the two vertebral segments to limit movement in the
section of the spine of the spinal fusion. A common technique for
spinal fusion procedures involves the use of interbody cages to
fill the gap between the two segments in the spine that are being
fused. The addition of bone graft material during the spinal fusion
procedure can additionally provide a suitable foundation and
environment that allows new bone growth and fuses the area of the
procedure over time. Interbody cages can have central cavities that
can be packed with bone graft materials. However, packing these
central cavities tightly with such material can be difficult
because the bone graft materials can fall out of the interbody cage
while setting the interbody cage into place since, for example,
force can be required to insert the interbody cage into the
body.
[0003] Others have attempted to solve these problems by
constructing interbody cages that are configured to retain bone
graft material during spinal fusion procedures. For instance, in
U.S. Pat. No. 5,609,635, the disclosed lordotic implant provides a
solid cage with a sliding door on the rear face of the device. Even
though the configuration disclosed by U.S. Pat. No. 5,609,635
improves upon standard interbody cages, the disclosed lordotic
implant has several disadvantages. One example of a disadvantage is
that the top and bottom faces of the device are rigid, and thus the
disclosed lordotic implant does not allow for maximum graft packing
due to the rigidity of the cage. Another disadvantage is that the
sliding door of the lordotic implant is located on the rear face of
the cage making it difficult to firmly pack the cavity since, for
example, additional bone grafting material cannot be easily added
to the cage after insertion into the body.
[0004] Another attempt to address the above-mentioned problems is
described in U.S. Pat. No. 8,715,355, wherein a three-sided cage
with removable plates for top and bottom faces is disclosed. Once
inserted between two vertebral bodies, the central cavity is packed
with bone graft materials. The top and bottom plates can be
removed, and the rear face is covered to contain the graft
materials. However, the cavity in the disclosed configuration is
difficult to pack tightly. Moreover, the surgeon inserting the
disclosed cage in the body faces difficulty in determining the
total amount of grafting material that should be inserted into the
patient before the rear opening is closed.
[0005] Even further, packing the cage after insertion can cause
problems since the cage may migrate from the desired location. If
such migration occurs, a greater risk to the nerves and/or
surrounding anatomy exists when packing the cage after insertion
since these structures may be inadvertently damaged during the
packing process. Accordingly, the known techniques and devices for
spinal fusion procedures have a number of problems.
BRIEF SUMMARY
[0006] In view of the above-mentioned exemplary problems with
conventional and known interbody cages, the present application
provides interbody cages having a spill-free, biological material
compartment, and further provides associated methods for using the
disclosed interbody cages.
[0007] One aspect of the present application includes an interbody
cage for spinal stabilization comprising a) a frame that surrounds
a central compartment, the frame comprising a top face and a bottom
face, the top face comprising one or more top openings, and the
bottom face comprising one or more bottom openings, b) a cover that
covers the one or more bottom openings, the cover comprising one or
more apertures suitable for retaining biological material, and c) a
removable cover configured to be removably secured to the top face
of the frame such that the removable cover covers the one or more
top openings when secured to the top face of the frame, the
removable cover comprising one or more apertures suitable for
retaining biological material, wherein the top face of frame is
configured to receive the removable cover.
[0008] In another aspect, at least one of the cover and the
removable cover comprises mesh.
[0009] In another aspect, at least one of the cover and the
removable cover comprises flexible mesh.
[0010] In another aspect, at least one of the cover and the
removable cover is convex.
[0011] In another aspect, the frame further comprises at least one
vertical face, wherein the at least one vertical face comprises one
or more apertures suitable for retaining biological material.
[0012] In another aspect, the at least one vertical face comprises
mesh.
[0013] In another aspect, at least one of the top face and the
bottom face comprises teeth that extend in an outward
direction.
[0014] In another aspect, the frame is configured to receive an
insertion rod.
[0015] In another aspect, at least one of the cover and the
removable cover further comprises a pivotable attachment mechanism
configured to engage at least one of the top face and the bottom
face.
[0016] Another aspect of the present application includes an
interbody cage for spinal stabilization comprising a) a frame that
surrounds a central compartment, the frame comprising a top face
and a bottom face, the top face comprising one or more top
openings, and the bottom face comprising one or more bottom
openings, b) a cover that covers the one or more bottom openings,
the cover comprising one or more apertures suitable for retaining
biological material, and c) an openable cover configured to be
secured to the top face of the frame in a closed position and
capable of being opened, the openable cover covering the one or
more top openings when secured to the top face of the frame in the
closed position, the removable cover comprising one or more
apertures suitable for retaining biological material.
[0017] In another aspect, the openable cover is configured to be
secured to the top face of the frame by at least one latching
mechanism and at least one hinge.
[0018] In another aspect, at least one of the cover and the
openable cover comprises mesh.
[0019] In another aspect, at least one of the cover and the
openable cover comprises flexible mesh.
[0020] In another aspect, at least one of the cover and the
openable cover is convex.
[0021] In another aspect, the frame further comprises at least one
vertical face, wherein the at least one vertical face comprises one
or more apertures suitable for retaining biological material.
[0022] In another aspect, the at least one vertical face comprises
mesh.
[0023] In another aspect, at least one of the top face and the
bottom face comprises teeth that extend in an outward
direction.
[0024] In another aspect, the frame is configured to receive an
insertion rod.
[0025] In another aspect, at least one of the cover and the
openable cover further comprises a pivotable attachment mechanism
configured to engage at least one of the top face and the bottom
face.
[0026] Other objects, features and advantages of the present
invention will be apparent to those of ordinary skill in the art in
view of the following detailed description of the invention and
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The drawings as provided for herein set forth some exemplary
embodiments of the interbody cages for spinal stabilization and
methods of the present application, the detailed description of
which follows. The drawings are merely exemplary, and are clearly
not intended to limit the invention.
[0028] FIG. 1A is a planar view of one embodiment of the interbody
cage.
[0029] FIG. 1B is a planar view of a removable cover that is mesh
for the intervertebral cage of FIG. 1A.
[0030] FIG. 1C is an elevation view of the intervertebral cage of
FIG. 1A.
[0031] FIG. 1D is a series of side views of an interbody cage
inserted between vertebral members and having a pivotable
attachment mechanism.
[0032] FIG. 2 is a planar view of another embodiment of the
interbody cage.
[0033] FIG. 3 is a flow chart of a method for installing the
interbody cage.
[0034] FIG. 4 is a photograph of another embodiment of the
interbody cage.
[0035] FIG. 5 is a photograph showing a perspective view of the top
of the interbody cage of FIG. 4 having a partially open mesh
covering, revealing an opening.
[0036] FIG. 6 is a photograph of the top of the interbody cage of
FIG. 4 having a fully open mesh covering, revealing two
openings.
[0037] FIG. 7 is a photograph of the bottom of the interbody cage
of FIG. 4.
[0038] FIG. 8 is a photograph showing a top view of the top of the
interbody cage of FIG. 4 having a closed mesh covering.
[0039] FIG. 9 is a front perspective view of another embodiment of
an interbody cage.
[0040] FIG. 10 is a front perspective view of the interbody cage of
FIG. 9 having a cover placed thereon.
[0041] FIG. 11 is a rear perspective view of the interbody cage of
FIG. 9
[0042] FIG. 12 is a rear perspective view of the interbody cage of
FIG. 9 having a cover placed thereon.
DETAILED DESCRIPTION
[0043] The interbody cages for spinal stabilization and methods of
the present application are now described by reference to the
embodiments. The description provided herein is not intended to
limit the scope of the claims, but to exemplify the variety
encompassed by the present application. The embodiments are
described more fully hereinafter with reference to the accompanying
drawings in which like numerals represent like elements throughout
the several figures, and in which example embodiments are shown.
Embodiments of the claims may, however, be embodied in many
different forms and should not be construed as limited to the
embodiments set forth herein. The examples set forth herein are
non-limiting examples and are merely examples among other possible
examples.
[0044] FIGS. 1A and 1C show an interbody cage 100 for spinal
stabilization with a spill-free, biologic material compartment. The
biological material can include, but is not limited to, bone
grafting material selected from one or more of autograft,
allograft, demineralized bone matrix, ceramic bone extenders, stem
cells, crushed cancellous allograft bone, and collagen sponge
containing bioactive material, such as bone morphogenetic protein.
However, the biological materials can include. The interbody cage
100 is configured to contain biological material, such as bone
graft material, therein and also support the spine of a patient.
Furthermore, the interbody cage 100 is configured to receive
biological material, such as bone graft material, without the need
for additional special equipment and having the ability to remain
secured when placed into the interbody spinal space of a
patient.
[0045] The interbody cage 100 for spinal stabilization has a frame
110 that extends around the perimeter of the interbody cage 100 and
surrounds a central compartment 120. As seen in FIGS. 1A and 1C,
the frame 110 can have a vertical face 111, wherein the vertical
face 111 can have at least a front face 112, side faces 113, and a
rear face 114. Each of the front face 112, the side faces 113, and
the rear face 114 may be separated by one or more edges similar to
the embodiment shown in FIGS. 4 to 8, or may be configured to be
one contiguous curved body as illustrated in FIGS. 1A and 1C.
Alternatively, the vertical face 111 can include a combination of
one or more edges and one or more curves. In the exemplary
embodiment shown in FIGS. 1A and 1C, the front face 112 is
configured to substantially fill a gap between two vertebral
bodies, such that the front face 112 may have a curvature and
thickness greater than a curvature and thickness of rear face 114.
Alternatively, the front face 112 may have a curvature and
thickness less than a curvature and thickness of rear face 114. In
the embodiment shown in FIG. 1A, the front face 112 and the rear
face 114 have substantially the same thickness such that the angle
therebetween is 0.degree.. The actual angle will be determined
based upon the location of the spinal fusion and the degree
necessary for the spinal fusion. Angulation of interbody cage 100
can be determined based upon typical human morphometric
angularities of the disc space, and based on the goals of the spine
surgeon for the correction of a spinal deformity. The frame 110 can
be made of rigid material that is suitable to withstand the
compressive forces of the spine when fully loaded. The side faces
113 can be generally be rigid and solid, and can join the front
face 112 to the rear face 114.
[0046] At least a portion of the vertical face 111 of frame 110 can
be open to allow for new bone growth into central compartment 120.
In the illustrated embodiment shown in FIG. 1C, the vertical face
111 includes mesh. The mesh of the vertical face 111 can be rigid,
or can be flexible to enable an additional volume of bone graft
material to be placed inside the central compartment 120. In other
embodiments, the vertical face 111 is made of a rigid material
having one or more openings that are larger than what is provided
by the mesh.
[0047] The frame 110 can have a top face 116 and a bottom face 118.
The top face 116 and the bottom face 118 can be generally flat, but
may have one or more teeth 119 extending outward from the top face
116 and/or the bottom face 118, respectively, as seen in FIG. 1C.
The teeth 119 can be configured to prevent slippage of the
interbody cage 100 once the interbody cage 100 is inserted into the
body. The surfaces the interbody cage 100 can have a prefabricated
texture to facilitate osseointegration. Furthermore, ridges on
surface of the cage where endplates are located prevent the cage
from backing out. The bottom face 118 can have one or more bottom
openings 130 that open the central compartment 120 to the vertebral
body below the interbody cage 100. Each of the one or more bottom
openings 130 can have a cover 132, which can be removable from the
interbody cage 100 or can be secured to the interbody cage 100. The
cover 132 can be partially or entirely mesh. A single cover 132 can
cover one, some, or all of the one or more bottom openings 130. The
cover 132 can have mesh pores that are configured to retain the
graft material in the central compartment 120 and to enable bone
growth into the middle of the interbody cage 100. The mesh pores
can have a diameter that is small enough to retain the graft
material within the cage 100 and large enough to allow bone growth
through the cover 132.
[0048] In the illustrated embodiment of FIGS. 1A and 1C, a single
bottom opening 130 is shown, but other embodiments may have two,
three, four, or more separate openings 130. The cover 132 may be
flat or convex. The cover 132 can be generally pliable to
frictionally fit into the space between the vertebral bodies. The
cover 132 can also be convex to maximize the amount of graft
material that can be packed into the central compartment 120.
Furthermore, the convex shape of the cover 132 can generally
flatten when pressure is applied, such as when the weight of a
patient compresses the interbody cage 100 when fully loaded into
adjacent vertebral bodies. The interbody cage 100 can also be
convex to maximize the amount of grafting material that can be
packed into the central compartment, while providing greater
contact with concave endplates of the vertebrae. The convex shape
can also be compressible to allow for temporary compression during
insertion process with re-expansion onto the concave endplates of
the adjacent vertebrae when in the final position.
[0049] The cover 132 thickness can be uniform or non-uniform to
provide flexibility and/or strength of the cover 132. For example,
the cover 132 may be thinner at an apex of convexity to allow for
flexibility, and the cover 132 may be thicker near the outer frame
110 that extends around the perimeter of the interbody cage 100 to
strengthen the cover 132 and ease insertion of the cover 132 into
the sliding groove of interbody cage 100. The mesh pores of each of
the meshes discussed herein can be about 2 mm wide, and the mesh
material can have a thickness of between approximately 1 mm and 2.5
mm. Further, the mesh pores may have diameters of between
approximately 0.5 mm and 10 mm in width. The thickness of the cover
132 may be between approximately 0.1 mm and 5 mm.
[0050] The top face 116 can have one or more top openings 140 that
open the central compartment 120 to the vertebral body above the
interbody cage 100. The top face 116 can be configured to receive a
removable cover 134, which can be generally similar to cover 132.
The removable cover 134 can be partially or entirely mesh. The
removable cover 134 can include a frame surrounding the perimeter
thereof such that the frame of the removable cover 134 can create a
base lattice for the removable cover 134 and be helpful to help
engage the channel 136. In the illustrated embodiment of FIG. 1C,
the removable cover 134 is configured to slide into channel 136 on
the outer surface of top face 116. A locking mechanism can be used
to secure the cover 134 into place in the channel 136. For
instance, a clamp could be inserted into the channel 136 to prevent
the removable cover 134 from exiting the channel 136. However,
other locking mechanisms can be appropriately used, such as one or
more screws, pins, adhesives, etc. The removable cover 134 may be
flat or may be convex to maximize an amount of grafting material
that can be packed into central compartment 120, and to increase
flexibility and/or strength of the removable cover 134, as
described above. The convexity of the removable cover 134 can be
predetermined such that the removable cover 134 can be manufactured
to have a desired convexity.
[0051] The present application is not limited to an embodiment
wherein the removable cover 134 is configured to slide into channel
136 on the outer surface of top face 116. The removable cover 134
can be secured to the top face by alternative methods. For
instance, as seen in FIG. 1D, an attachment mechanism 138 can be
located on an outer surface of the removable cover 134 and can be
configure to pivot. The attachment mechanism 138 can have one or
more arms that are configured to engage, for example, one or more
channels on the top face 116 when the attachment mechanism is
pivoted. In such an embodiment, the removable cover 134 could be
placed onto the top face 116 with the attachment mechanism 138
pivoted so that the attachment mechanism 138 does not interfere
with the placement of the removable cover 134. Once the removable
cover 134 is placed onto the top face 116, the attachment mechanism
138 could pivot to engage the top face 116, thereby securing the
removable cover 134 to the frame. For instance, the top face 116
and the attachment mechanism 138 could have interlocking channels
that engage when the attachment mechanism is pivoted to engage the
top face 116. The attachment mechanism 138 could be centrally
located on the removable cover 134 such that the arms of the
attachment mechanism 138 can be substantially the same length, and
engage the interlocking channels on substantially opposite sides of
the top face 116 when the attachment mechanism 138 is pivoted.
Alternatively, the attachment mechanism 138 could be non-centrally
located on the removable cover 134 such that the arms of the
attachment mechanism can be different lengths, and engage the
interlocking channels on different sides of the top face 116 when
the attachment mechanism 138 is pivoted. Even further, the
attachment mechanism 138 can be additionally secured to the frame
via a locking mechanism, such as one or more screws, pins,
adhesive, etc. Alternatively, the attachment mechanism 138 can be
located on the cover 132 and can be used with additional
embodiments discussed below, including on the openable cover
236.
[0052] The attachment mechanism 138 can also extend beyond the top
face 116 such that the attachment mechanism can be secured to one
or more vertebral bodies. In such an embodiment, the portion of the
attachment mechanism 138 that extends beyond the top face 116 could
have one or more apertures 139 therein to secure such a portion to
the vertebral body via a locking mechanism, such one or more of
screws, pins, adhesives, etc., as seen in FIG. 1E. The one or more
aperture 139 can also be countersunk to provide a substantially
smooth surface on the faces of the attachment mechanism when
secured to one or more vertebral bodies.
[0053] The top face 116 can have one or more top openings 140 that
open the central compartment 120 to the vertebral body above the
interbody cage 100. The removable cover 134 can cover one or more
of the one or more top openings 140. In the illustrated embodiment
of FIGS. 1A and 1C, a single top opening 140 is shown, but other
embodiments may have two, three, four, or more separate top
openings 140.
[0054] In the embodiment illustrated in FIGS. 1A and 1C, the
central compartment 120 is one space. However, in other
embodiments, the central compartment 120 can be divided into two,
three, four, or more compartments. Support structures may extend
across the vertical face 111 and through the central compartment
120. Such structural supports can increase the load capacity of the
cage 100, when necessary, and/or may also provide additional
surface area for bone growth and integration through the interbody
cage 100. The structural supports can be solid and/or may include
one or more apertures therein.
[0055] FIG. 2 illustrates another embodiment of an interbody cage
100. As seen in FIG. 2, an openable cover 236 is connected to the
top face 116 at one or more locations by a plurality of hinges 210.
Even though FIG. 2 shows a plurality of hinges 210, a single hinge
210 is also acceptable. In this embodiment, the openable cover 236
can be opened into an opened position so that, for example, bone
grafting material can be inserted into the central compartment 120.
The openable cover 236 can also be closed into a closed position.
In the closed position, the openable cover 236 can be secured to
the top face 116 by one or more latching mechanisms 220. The one or
more latching mechanisms 220 can be located generally across from
the one or more hinges 210 to secure the openable cover 236 to the
frame 110 when the openable cover 236 is in the closed position.
The one or more latching mechanisms 220 can be distributed on the
top face 116. Even though FIG. 2 shows a plurality of latching
mechanisms, one or more latching mechanisms 220 can be acceptably
used to secure the openable cover 236 to the cage frame 110. The
latching mechanism 220 may be a latch, snap, set-screw, strap, pin,
adhesive, or other means known in the art for securing two bodies
together. In yet other embodiments, the openable cover 236 is not
hinged to top face 116. Instead, the openable cover 236 is set into
place and secured to the top face 116 by at least one of the
latching mechanisms 220 identified above, but without the use of
the one or more hinges 210.
[0056] In certain embodiments, the rear face 114 is configured to
receive a tool to assist with the insertion of the cage 100. For
example, the rear face 114 can have a threaded slot 230 for the
attachment of an insertion rod, as shown in FIG. 2. The insertion
rod can be used to tap the cage 100 into place with a mallet or
hammer.
[0057] The cage 100 may be made of any one or a combination of
biocompatible materials known in the art that have mechanical
properties required for use in interbody inserts. Certain,
non-limiting examples of materials include metals, such as titanium
and titanium alloys, stainless steel, alloys (including additive
manufactured-materials such as titanium-plasma sprayed metals),
plastics, such as polyether ether ketone (PEEK), poly(methyl
methacrylate) (PMMA), polyethylene (PE), and nylon, and composites,
such as carbon fiber. Furthermore, the cage 100 may be formed of a
combination of materials, in addition to coatings of materials
(e.g., titanium-coated PEEK, PE-coated stainless steel, or the
like), or other biocompatible material with suitable mechanical
properties.
[0058] FIGS. 4 to 8 show another embodiment of an interbody cage
400. The interbody cage 400 is generally similar to the interbody
cage 100 in materials, use, and construction. The above-description
of, for example, the mesh is, therefore, not repeated. The
interbody cage 400 has a frame 410 that extends around the
perimeter of the interbody cage 400 and surrounds a central
compartment 420. The frame 410 has a vertical face 411, having at
least a front face 412, side faces 413, and a rear face 414. Each
of the front face 412, the side faces 413, and the rear face 414
may be separated by one or more edges as shown in FIGS. 4 to 8, or
they may be configured as one contiguous curved body similar to the
embodiments shown in FIGS. 1A and 1C. Alternatively, the vertical
face 411 can include a combination of one or more edges and one or
more curves. In one embodiment, the front face 412 is configured to
substantially fill a gap between the two vertebral bodies such that
the front face 412 may have a curvature and thickness greater than
a curvature and thickness of rear face 414. Alternatively, the
front face 412 may have a curvature and thickness less than a
curvature and thickness of rear face 414. In the embodiment shown
in FIGS. 4 to 8, the front face 412 and the rear face 414 have
substantially the same thickness such that the angle therebetween
is approximately 0.degree.. The actual angle will be determined
based upon the location of the spinal fusion and the degree
necessary for the spinal fusion. The frame 410 can be made of rigid
material suitable to withstand the compressive forces of the spine
when fully loaded. The side faces 413 can be generally rigid and
solid, and can join the front face 412 to the rear face 414.
[0059] As seen in FIGS. 4 to 8, at least a portion of the vertical
face 411 of frame 410 is open to allow for new bone growth into
central compartment 420. In the illustrated embodiment of FIGS. 4
to 8, the vertical face 411 includes a cover 432. The cover 432 can
be partially or entirely mesh. The cover 432 can be rigid or it may
be flexible to enable additional volume of bone graft material to
be placed inside the central compartment 420. Additionally, a cover
434 can be present on a side opposite to the cover 432. The cover
434 can have the same properties as the cover 432, and the cover
434 and 432 can act together to close the top and bottom openings
of the central compartment 420. The cover 434 can also be fixed in
place to the frame 410, whereas the cover 432 can be inserted into
channels in the frame 410. Mechanisms to fix the cover 432 into
place in the frame 410 are discussed in other embodiments above,
and can be used herein. In other embodiments, the vertical face 411
can be made of a rigid material having one or more larger openings
than what is provided by the cover 432. The frame 410 also can have
a top face 416 and a bottom face 418. The top face 416 and the
bottom face 418 can be generally flat, but may have one or more
teeth extending outward from the top face 416 and the bottom face
418, similar to the teeth shown in FIG. 1C.
[0060] The top face 416 can have one or more openings 430, as shown
in FIG. 5 having two openings, that open the central compartment
420 to the vertebral body above the interbody cage 400. Each of one
or more openings 430 can be covered by a cover 432, which can be
removable from the interbody cage 400. The cover 432 can have mesh
pores that are configured to retain the graft material in the
central compartment 420 and to enable bone growth into the middle
of the interbody cage 400. The mesh pores can have a diameter that
is small enough to retain the graft material within the interbody
cage 400 and large enough to allow bone growth through the cover
432 that is mesh.
[0061] FIGS. 4 to 6 and 8 show mesh cover 432 may be flat or
convex, as described above. The cover 432 can be pliable to
frictionally fit into the interbody space. In certain embodiments,
the cover 432 can be convex to maximize the amount of graft
material that can be packed into central compartment 420.
Furthermore, the convex shape of cover 432 can generally flatten
when pressure is applied, such as when the weight of the patient
compresses the interbody cage 400 when fully loaded between
vertebral bodies.
[0062] FIGS. 9 to 12 show yet another embodiment of an interbody
cage 600. The interbody cage 600 is generally similar to the
interbody cage 100 and the interbody cage 400 in materials, use,
and construction. The above-description of, for example, the mesh
is, therefore, not repeated. The interbody cage 600 has a frame 610
that extends around the perimeter of the interbody cage 600 and
surrounds a central compartment 620. Even though the frame 610 has
a plurality of edges generally forming a rectangular shape in FIGS.
9 to 12, the frame 610 may also be configured as one contiguous
curved body similar to the embodiments shown in FIGS. 1A and 1C or
can include a combination of one or more edges and one or more
curves.
[0063] In an embodiment, the interbody cage 600 is configured to
substantially fill a gap between the two vertebral bodies such that
the interbody cage 600 may have a curvature and thickness where one
side is greater than the other side. In FIGS. 9 to 12, the
aforementioned sides have substantially the same thickness such
that the angle therebetween is approximately 0.degree.. As
mentioned above, the actual angle will be determined based upon the
location of the spinal fusion and the degree necessary for the
spinal fusion. The frame 610 can be made of rigid material suitable
to withstand the compressive forces of the spine when fully
loaded.
[0064] As seen in FIGS. 9 to 12, at least a portion of the frame
610 is open to allow for new bone growth into central compartment
620. In the illustrated embodiment of FIGS. 4 to 8, the frame 610
includes a cover 632. The cover 632 can be partially or entirely
mesh, and may be convex, as discussed in other embodiments above.
The cover 632 can be rigid or it may be flexible to enable
additional volume of bone graft material to be placed inside the
central compartment 620. The frame 610 can also include ridges 612
on the surfaces thereof, but can also or alternatively include
different prefabricated textures to facilitate
osseointegration.
[0065] Additionally, a cover 634 can be present on a side opposite
to the cover 632, as seen in FIG. 10. The cover 634 can have the
same properties as the cover 632, and the cover 634 and 632 can act
together to close the top and bottom openings of the central
compartment 620. The cover 632 can also be fixed in place to the
frame 610, whereas the cover 634 can be inserted into channels or
placed on grooves 614 in the frame 610, as shown in FIGS. 9 and 11.
The cover 634 can engage the frame 610 to be secured to the frame
610 thereby securely enclosing the central compartment 620. The
frame 610 can include one or more slots 616 to engage the
extensions 618 of the cover 634. When the slots 616 engage the
extensions 618, the cover 634 can be secured to the frame 610, as
seen in FIGS. 11 and 12. Additional and/or alternative mechanisms
to fix the cover 634 to the frame 610 are discussed in other
embodiments above, and can be used herein. Also, in certain
embodiments, the the frame 610 can be configured to receive a tool
to assist with the insertion of the interbody cage 600. For
example, a threaded slot for the attachment of an insertion rod can
be used in a similar manner to those discussed in detail above. The
insertion rod can be used to tap the interbody cage 600 into place
with a mallet or hammer.
[0066] FIG. 3 illustrates flow chart 300 depicting example steps
for installing the interbody cages of the present application into
a patient, and can be applied to any of the embodiments of the
present application. The flow chart 300 is intended to be
illustrative of one example method for installing the interbody
cage 100. In alternative methods, one or more steps may be omitted
or the steps may be performed in a different order. Additional
steps may also be added, as needed. In step 310, the cover 134 is
removed from the interbody cage 100 so that the central compartment
120 is open to receive grafting material. Next, in step 320, the
desired amount of bone grafting material is inserted into the
central compartment 120. The desired amount can be determined by
the surgeon performing the surgery, but, in general, the central
compartment 120 will be filled to the maximum capacity that is
possible. Once full, removable mesh covering 134 is slid into
channel 136 and is locked into place in step 330. In step 340, the
insertion rod is attached to the rear face 114 of interbody cage
100. The interbody cage 100 is then inserted into the
intervertebral space by tapping the insertion rod with, for
example, a mallet in step 350. In step 360, the insertion rod is
removed from the interbody cage 100.
[0067] Table 1 illustrates some example dimensions of the interbody
cages of the present application. While Table 1 provides exact
dimensions, it should be understood that these are illustrative in
nature, and do not limit the dimensions of the interbody cages
described herein. The exact size of the interbody cages will depend
on the physical characteristics of the patient and the location of
the spine where the interbody cage will be placed. For example, the
footprints of the interbody cages of the present application have a
width between approximately 10 mm and 40 mm and a depth of between
approximately 15 mm and 75 mm. The interbody cages of the present
application may have a height between approximately between 4 mm
and 25 mm. The interbody cages of the present application may have
a sagittal profile between approximately 0 degrees and 30
degrees.
TABLE-US-00001 TABLE 1 Footprints Heights Sagittal Profiles (mm) (1
mm increments) (degrees of lordosis) Anterior Lumbar or Thoracic
Interbody Fusion Cages 20 .times. 25 7-21 mm 0, 6, 12, 24 22
.times. 29 7-21 mm 0, 6, 12, 24 24 .times. 35 7-21 mm 0, 6, 12, 24
28 .times. 39 7-21 mm 0, 6, 12, 24 Oblique/Lateral Lumbar or
Thoracic Interbody Fusion Cages 15 wide .times. 20-25* 6-18 mm 0,
6, 8, 12, 24 17 wide .times. 40-60* 6-18 mm 0, 6, 8, 12, 24 21 wide
.times. 40-60* 6-18 mm 0, 6, 8, 12, 24 25 wide .times. 40-60* 6-18
mm 0, 6, 8, 12, 24 *increments of 5 mm
[0068] Further, the interbody cages of present application can be
used for cervical fusions. Such interbody cages for cervical fusion
include, but are not limited to, two exemplary footprints: (small)
13.5 mm.times.15.5 mm; and (large) 17.5 mm.times.15.5 mm. The
height of such interbody cages for cervical fusion include, but are
not limited to, 4.5, 5.5, 6.5, 7.5, 8.5, 9.5, and 10.5 mm. Also,
the sagittal profiles (degrees of lordosis) for such interbody
cages for cervical fusion include, but are not limited to, 0 to 7
degrees for the heights of 4.5-7.5 mm and 5-12 degrees for the
heights of 5.5 to 10.5 mm.
[0069] The angularity of each of the interbody cages of present
application will be determined based on typical spinal morphometric
analysis of the angularity of the disc space across the
cervical-thoraco-lumbar-sacral spine, and thus the above-mentioned
angles are provided as non-limited examples. The angularity of each
of the interbody cages of present application can be predetermined
such that the interbody cages are manufactured to have a
predetermined angle rather than being modified by surgical staff
prior to a procedure.
[0070] The interbody cages and the associated methods allow
biological material, such as bone graft material, to be easily and
securely provided while also supporting the spine. Furthermore, the
interbody cages can receive biological material, such as bone graft
material, without additional special equipment and remain secured
when placed into the interbody spinal space.
[0071] In the foregoing description, the interbody cages and
methods of the present application have been described with
reference to specific embodiments thereof. It will, however, be
evident that various modifications and changes may be made thereto
without departing from the broader spirit and scope of the
invention. The specification and drawings are, accordingly, to be
regarded in an illustrative rather than a restrictive sense.
Throughout this specification, unless the context requires
otherwise, the word "comprise" and its variations, such as
"comprises" and "comprising," will be understood to imply the
inclusion of a stated item, element or step or group of items,
elements or steps, but not the exclusion of any other item, element
or step or group of items, elements or steps. Furthermore, the
indefinite article "a" or "an" is meant to indicate one or more of
the item, element or step modified by the article.
* * * * *