U.S. patent application number 13/669302 was filed with the patent office on 2013-04-04 for anterior lumbar interbody fusion cage devices and related systems and methods.
This patent application is currently assigned to U.S. SPINE, INC.. The applicant listed for this patent is U.S. Spine, Inc.. Invention is credited to John B. Sledge.
Application Number | 20130085574 13/669302 |
Document ID | / |
Family ID | 40955834 |
Filed Date | 2013-04-04 |
United States Patent
Application |
20130085574 |
Kind Code |
A1 |
Sledge; John B. |
April 4, 2013 |
Anterior Lumbar Interbody Fusion Cage Devices and Related Systems
and Methods
Abstract
A cage device for performing spinal fusion surgery and related
methods. In some embodiments, a housing defining one or more ports
may be provided that may be configured to be selectively disposed
in an intervertebral space between adjacent vertebrae. One or more
extensible retention structures may also be provided that may be
configured to be selectively advanced out of the housing through
the one or more ports. The one or more extensible retention
structures may comprise a cutting edge configured such that the
cutting edge is positioned entirely within the housing prior to
selective advancement of the one or more extensible retention
structures out of the housing through the one or more ports. One or
more actuation mechanisms configured for selectively advancing the
one or more extensible retention structures out of the housing
through the one or more ports may also be provided.
Inventors: |
Sledge; John B.;
(Marblehead, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
U.S. Spine, Inc.; |
Salt Lake City |
UT |
US |
|
|
Assignee: |
U.S. SPINE, INC.
Salt Lake City
UT
|
Family ID: |
40955834 |
Appl. No.: |
13/669302 |
Filed: |
November 5, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12371008 |
Feb 13, 2009 |
8323345 |
|
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13669302 |
|
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61028624 |
Feb 14, 2008 |
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Current U.S.
Class: |
623/17.16 |
Current CPC
Class: |
A61F 2002/3008 20130101;
A61F 2250/0098 20130101; A61F 2/4465 20130101; A61F 2002/30841
20130101; A61F 2002/30525 20130101; A61F 2220/0025 20130101; A61F
2002/30593 20130101; A61F 2002/30579 20130101; A61F 2002/3085
20130101; A61F 2002/2835 20130101 |
Class at
Publication: |
623/17.16 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. A cage device for performing spinal fusion, comprising: a
housing defining one or more ports that is configured to be
selectively disposed in an intervertebral space between adjacent
vertebrae; one or more extensible retention structures that are
configured to be selectively advanced out of the housing through
the one or more ports and into one or more endplates of the
adjacent vertebrae, wherein the one or more extensible retention
structures each comprises a cutting edge, and wherein the cutting
edge of each of the one or more extensible retention structures is
configured such that the cutting edge is positioned entirely within
the housing prior to selective advancement of the one or more
extensible retention structures out of the housing through the one
or more ports; and one or more actuation mechanisms configured for
selectively advancing the one or more extensible retention
structures out of the housing through the one or more ports and
into the one or more endplates of the adjacent vertebrae.
2. The cage device of claim 1, wherein the housing is sized and
shaped to cover substantially all of the one or more endplates of
the adjacent vertebrae.
3. The cage device of claim 1, wherein at least one of the one or
more extensible retention structures comprises a pipe
structure.
4. The cage device of claim 3, wherein the pipe structure comprises
an at least substantially unobstructed aperture.
5. The cage device of claim 3, wherein the pipe structure comprises
an annular structure having a substantially circular
cross-sectional shape
6. The cage device of claim 1, wherein the housing comprises an at
least partially a radiolucent material.
7. The cage device of claim 1, wherein the one or more actuation
mechanisms comprise at least one worm gear/mandrel pair.
8. The cage device of claim 7, further comprising drive threads
configured to engage the worm gear.
9. The cage device of claim 1, wherein the one or more extensible
retention structures each comprises a retention structure
configured to prevent the extensible retention structure from
escaping the housing.
10. The cage device of claim 1, wherein the one or more extensible
retention structures are configured to be selectively advanced out
of the housing through the one or more ports and into the one or
more endplates of the adjacent vertebrae with a rotational
motion.
11. A method for performing spinal fusion surgery, the method
comprising the steps of: providing a housing defining one or more
ports, wherein the housing comprises an extensible retention
structure, and wherein the extensible retention structure comprises
a sharpened, non-serrated cutting edge defining an at least
substantially circular opening; positioning the housing in an
intervertebral space between adjacent vertebrae; and advancing the
extensible retention structure out of the housing through the one
or more ports such that the cutting edge defining the at least
substantially circular opening rotates and extends into one or more
endplates of the adjacent vertebrae.
12. The method of claim 11, wherein the cutting edge is part of an
internal bone threading formed on the extensible retention
structure.
13. The method of claim 12, wherein the internal bone threading
extends along an at least substantially an entire length of the
extensible retention structure.
14. The method of claim 11, wherein the housing comprises an at
least partially radiolucent material.
15. The method of claim 11, wherein the extensible retention
structure is configured to prevent the extensible retention
structure from being fully removed from the housing.
16. The method of claim 11, wherein the step of advancing the
extensible retention structure out of the housing comprises
advancing the extensible retention structure from a first
configuration in which the extensible retention structure is wholly
contained within the housing to a second configuration in which the
extensible retention structure extends outside of the housing.
17. The method of claim 11, further comprising placing a bone graft
within the housing.
18. The method of claim 11, wherein the step of positioning the
housing in an intervertebral space between adjacent vertebrae is
performed using an anterior surgical approach.
19. The method of claim 11, wherein the at least substantially
circular opening is at least substantially unobstructed prior to
advancing the extensible retention structure out of the housing,
and wherein the method is performed such that bone material from at
least one of the adjacent vertebrae extends into the at least
substantially circular opening.
20. A method for performing spinal fusion surgery, the method
comprising the steps of: providing a cage device comprising: a
housing defining an at least substantially circular port; an
extensible retention structure, wherein the extensible retention
structure comprises a sharpened, non-serrated cutting edge defining
an at least substantially circular opening in communication with
the at least substantially circular port; and an actuation
mechanism configured for selectively advancing the extensible
retention structure; positioning the cage device in an
intervertebral space between adjacent vertebrae with the extensible
retention structure wholly contained within the housing using an
anterior surgical approach; and advancing the extensible retention
structure out of the housing through the port using the actuation
mechanism such that the cutting edge defining the at least
substantially circular opening rotates and extends into one or more
endplates of the adjacent vertebrae.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation of patent application
Ser. No. 12/371,008 filed Feb. 13, 2009 and titled "Anterior Lumbar
Interbody Fusion Cage Device and Associated Method," which
application claims the benefit of priority of U.S. Provisional
Patent Application No. 61/028,624 filed on Feb. 14, 2008 and titled
"Anterior Lumbar Interbody Fusion Cage Device." The contents of
both of the foregoing applications are incorporated herein by
reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates generally to devices and
methods for performing spinal surgery. More specifically, the
present invention relates to an anterior lumbar interbody fusion
(ALIF) cage device and an associated method for performing fusion
procedures of the lumbar spine. The fundamental concepts underlying
this device and method may be extended to other surgical procedures
as well, such as extreme lateral interbody fusion (XLIF) spinal
procedures, cervical spinal procedures, and the like.
BACKGROUND OF THE INVENTION
[0003] ALIF is a spinal fusion procedure that utilizes an anterior
(i.e. frontal) approach through the abdominal region to fuse
adjacent vertebrae of the lumbar spine. The intervertebral disc is
removed using appropriate rasping and grasping tools and replaced
with a cage device and/or bone graft after appropriate distraction
and spacing tools are used to restore the normal height of the
intervertebral space. ALIF is preferred when either one or multiple
spinal levels are being fused and one or multiple intervertebral
discs must be removed, and may be performed in conjunction with a
posterior decompression (i.e. laminectomy) and/or the placement of
stabilizing instrumentation (i.e. screws and rods, plates, etc.).
Because during ALIF the spinal nerves and other neurologic
structures do not have to be retracted, wide access to the
intervertebral space(s) of interest is provided without
unacceptable risk of neurologic injury. ALIF is used to treat a
variety of painful spinal conditions, such as spondylolisthesis and
degenerative disc disease, among others.
[0004] Conventional ALIF cage devices typically include some sort
of retention mechanism to hold them securely in the intervertebral
space. Such retention mechanisms include biting and locking
structures that engage the endplate(s) of the vertebral body or
bodies of interest, screw assemblies that engage the vertebral body
or bodies of interest, plate structures that engage the vertebral
body or bodies of interest, etc. All of these retention mechanisms,
however, suffer from the shortcomings that they are difficult to
place, difficult to deploy, and/or tend to allow the associated
cage device and/or bone graft to shift over time and thus fail to
adequately maintain the normal height of the intervertebral space,
for example. Thus, what is needed in the art is an improved ALIF
cage device having an improved retention mechanism.
BRIEF SUMMARY OF THE INVENTION
[0005] In various exemplary embodiments, the present invention
provides an improved ALIF cage device that has one or more
extensible threaded retention pipe structures that are selectively
deployed into one or more endplates of adjacent vertebrae once the
ALIF cage device is disposed in an intervertebral space of
interest. A bone graft is disposed within a housing and the
extensible threaded retention pipe structure(s) of the ALIF cage
device, as appropriate. Advantageously, the extensible threaded
retention pipe structure(s) are selectively deployed into the
endplate(s) of the adjacent vertebrae via the actuation of a simple
keyed screw and gear mechanism or the like. Again, the fundamental
concepts underlying the ALIF cage device of the present invention
may be extended to other surgical procedures as well, such as XLIF
spinal procedures, cervical spinal procedures, and the like.
[0006] In one exemplary embodiment, the present invention provides
a cage device for performing spinal fusion, including: a housing
defining one or more ports that is selectively disposed in an
intervertebral space between adjacent vertebrae; one or more
extensible retention structures that are selectively advanced out
of the housing through the one or more ports and into one or more
endplates of the adjacent vertebrae; and one or more actuation
mechanisms for selectively advancing the one or more extensible
retention structures out of the housing through the one or more
ports and into the one or more endplates of the adjacent vertebrae.
The housing is sized and shaped to cover substantially all of the
one or more endplates of the adjacent vertebrae. Optionally, the
housing is at least partially manufactured from a radiolucent
material. Preferably, the one or more extensible retention
structures each consist of an annular structure having a
substantially constant cross-sectional shape. The one or more
extensible retention structures each include a cutting edge for
engaging bony material of an associated endplate of an adjacent
vertebrae. The one or more extensible retention structures each
also include internal bone threading for engaging bony material of
an associated endplate of an adjacent vertebrae. The one or more
extensible retention structures each further include external
machine threading for engaging corresponding internal machine
threading of the housing and selectively advancing the one or more
extensible retention structures out of the housing through the one
or more ports and into the one or more endplates of the adjacent
vertebrae. Preferably, the machine threading is allowed to escape
the housing. The machine threading that is allowed to escape the
housing serves to compress an associated endplate of an adjacent
vertebrae against the housing. In one exemplary embodiment, the one
or more actuation mechanisms consist of at least one worm
gear/mandrel pair configured to engage the machine threading.
Optionally, the one or more actuation mechanisms consist of at
least one worm gear/mandrel pair configured to engage
longitudinally oriented teeth manufactured into the machine
threading. Preferably, the one or more extensible retention
structures each include a retention structure configured to prevent
that extensible retention structure from escaping the housing.
Thus, the one or more extensible retention structures are
selectively advanced out of the housing through the one or more
ports and into the one or more endplates of the adjacent vertebrae
with a rotational motion. Preferably, the one or more extensible
retention structures are configured such that they may contain a
bone graft. In one exemplary embodiment, the housing is selectively
disposed in the intervertebral space between the adjacent vertebrae
using an anterior surgical approach.
[0007] In another exemplary embodiment, the present invention
provides a method for performing spinal fusion using a cage device,
including: providing a housing defining one or more ports that is
selectively disposed in an intervertebral space between adjacent
vertebrae; providing one or more extensible retention structures
that are selectively advanced out of the housing through the one or
more ports and into one or more endplates of the adjacent
vertebrae; and providing one or more actuation mechanisms for
selectively advancing the one or more extensible retention
structures out of the housing through the one or more ports and
into the one or more endplates of the adjacent vertebrae. The
housing is sized and shaped to cover substantially all of the one
or more endplates of the adjacent vertebrae. Optionally, the
housing is at least partially manufactured from a radiolucent
material. Preferably, the one or more extensible retention
structures each consist of an annular structure having a
substantially constant cross-sectional shape. The one or more
extensible retention structures each include a cutting edge for
engaging bony material of an associated endplate of an adjacent
vertebrae. The one or more extensible retention structures each
also include internal bone threading for engaging bony material of
an associated endplate of an adjacent vertebrae. The one or more
extensible retention structures each further include external
machine threading for engaging corresponding internal machine
threading of the housing and selectively advancing the one or more
extensible retention structures out of the housing through the one
or more ports and into the one or more endplates of the adjacent
vertebrae. Preferably, the machine threading is allowed to escape
the housing. The machine threading that is allowed to escape the
housing serves to compress an associated endplate of an adjacent
vertebrae against the housing. In one exemplary embodiment, the one
or more actuation mechanisms consist of at least one worm
gear/mandrel pair configured to engage the machine threading.
Optionally, the one or more actuation mechanisms consist of at
least one worm gear/mandrel pair configured to engage
longitudinally oriented teeth manufactured into the machine
threading. Preferably, the one or more extensible retention
structures each include a retention structure configured to prevent
that extensible retention structure from escaping the housing.
Thus, the one or more extensible retention structures are
selectively advanced out of the housing through the one or more
ports and into the one or more endplates of the adjacent vertebrae
with a rotational motion. Preferably, the one or more extensible
retention structures are configured such that they may contain a
bone graft. In one exemplary embodiment, the housing is selectively
disposed in the intervertebral space between the adjacent vertebrae
using an anterior surgical approach.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention is illustrated and described herein
with reference to the various drawings, in which like reference
numbers are used to denote like device components/method steps, as
appropriate, and in which:
[0009] FIG. 1 is a top perspective view of one exemplary embodiment
of the top half of the ALIF cage device of the present invention,
highlighting the associated housing and extensible threaded
retention pipe structure;
[0010] FIG. 2 is a bottom perspective view of the top half of the
ALIF cage device of FIG. 1, highlighting the associated housing,
extensible threaded retention pipe structure, worm gear, and
mandrel;
[0011] FIG. 3 is a top perspective view of one exemplary embodiment
of the housing of FIGS. 1 and 2;
[0012] FIG. 4 is a bottom perspective view of the housing of FIG.
3, highlighting the associated worm gear and mandrel;
[0013] FIG. 5 is a top perspective view of one exemplary embodiment
of the extensible threaded retention pipe structure of FIGS. 1 and
2;
[0014] FIG. 6 is a bottom perspective view of the extensible
threaded retention pipe structure of FIG. 5; and
[0015] FIG. 7 is a bottom perspective view of one exemplary
embodiment of the worm gear and mandrel of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Referring to FIG. 1, in one exemplary embodiment, the ALIF
cage device 10 of the present invention includes a housing 12 and
one or more extensible threaded retention pipe structures 14 that
are selectively deployed into one or more endplates of adjacent
vertebrae once the ALIF cage device 10 is disposed in an
intervertebral space of interest. It should be noted that only the
top half of the ALIF cage device 10 is illustrated herein (i.e. the
top half of the housing 12 and the top extensible threaded
retention pipe structure 14). The bottom half of the ALIF cage
device 10 is substantially identical, including the bottom half of
the housing 12 and the bottom extensible threaded retention pipe
structure 14, when used. The top and bottom halves of the ALIF cage
device 10 (i.e. the top and bottom halves of the housing 12) are
joined during the manufacturing process or prior to implantation to
form an integrated whole. A bone graft is disposed within the
housing 12 and the extensible threaded retention pipe structure(s)
14 of the ALIF cage device 10, as appropriate.
[0017] Once the ALIF cage device 10 is disposed in the
intervertebral space of interest, the extensible threaded retention
pipe structure(s) 14 are selectively deployed into the endplate(s)
of the adjacent vertebra(e) by deflecting outwards with respect to
the housing 12, optionally accompanied by a rotational motion. This
deflection outwards is along the cranial/caudal axis of the
spine.
[0018] Referring to FIG. 2, in this exemplary embodiment, the
extensible threaded retention pipe structure(s) 14 are each
deployed into the endplate(s) of the adjacent vertebra(e) by a worm
gear/mandrel pair 16,18. The worm gear 16 is disposed along the
anterior/posterior or lateral axis of the ALIF cage device 10,
while the mandrel 18 is disposed along the cranial/caudal axis of
the ALIF cage device 10. The worm gear 16 disposed along the
anterior/posterior or lateral axis of the ALIF cage device 10 has a
portion that protrudes or is accessible through a port (not
specifically illustrated) manufactured into the associated half of
the housing 12. The mandrel 18 disposed along the cranial/caudal
axis of the ALIF cage device 10 has portions that are seated in
both the top and bottom halves of the housing 12. Thus, the worm
gear 16 rotates about the anterior/posterior or lateral axis of the
ALIF cage device 10, engages and rotates the mandrel 18, which
rotates about the cranial/caudal axis of the ALIF cage device 10
and engages drive threads 20 disposed concentrically about the
outside diameter of the associated extensible threaded retention
pipe structure 14. Specifically, the mandrel 18 engages
longitudinal teeth manufactured into the drive threads 20 disposed
concentrically about the outside diameter of the associated
extensible threaded retention pipe structure 14. Thus, as the worm
gear 16 is actuated by a surgeon and turns the mandrel 18, the
extensible threaded retention pipe structure 14 is "spun up" or
"spun down" via the longitudinal teeth of these drive threads 20,
which engage a complimentary thread manufactured into the interior
of the housing 12, or, alternatively, a lip 24 (FIGS. 3 and 4)
manufactured into the interior/surface of the housing 12.
Preferably, each of the one or more extensible threaded retention
pipe structures 14 is capable of extending a distance on the order
of millimeters to centimeters from the housing 12 and into the
endplate(s) of the adjacent vertebra(e). It will be readily
apparent to those of ordinary skill in the art that different
mechanisms could also be used to deploy the one or more extensible
threaded retention pipe structures 14, using gears and threads or
not, employing rotational as well as extension motion or not, etc.
For example, one set of worm gears/mandrels 16, 18 could be used to
deploy both top and bottom extensible threaded retention pipe
structures 14 simultaneously. Likewise, different actuation
mechanisms and tools could be used for deployment.
[0019] Referring to FIG. 3, in one exemplary embodiment, each half
of the housing 12 is sized and shaped such that, collectively, the
housing 12 fits comfortably within the intervertebral space into
which it is inserted. In the exemplary embodiment illustrated, the
housing 12 is substantially oval or "kidney"-shaped, mimicking the
shape of the vertebral endplates adjacent to which it is disposed.
It is desirable that the ALIF cage device 10 (FIGS. 1 and 2) cover
as much of the vertebral endplates as possible. Each half of the
housing includes a port 22 through which the associated extensible
threaded retention pipe structure 14 (FIGS. 1, 2, 5, and 6) is
deployed. As described above, this port 22 may include a thread
(not specifically illustrated) manufactured into its interior, or,
alternatively, a lip 24 manufactured into its interior, for
engaging the longitudinal teeth of the drive threads 20 (FIGS. 1,
2, 5, and 6) of the associated extensible threaded retention pipe
structure 14. Preferably, each half of the housing 12 is
manufactured from a metal or another biocompatible material, and
some or all components of the housing 12 may be manufactured from a
radiolucent material that is transparent to X-ray, CT, and MRI
imaging modalities, such that anatomical structures may be
visualized without interference. As alluded to above, a one-piece
housing may be substituted for the two-piece housing illustrated
and described without departing from the spirit and scope of the
present invention.
[0020] Referring to FIG. 4, in this exemplary embodiment, each half
of the housing 12 includes a substantially hollow interior portion
26, to conserve weight, defining channels or access spaces for the
worm gears/mandrels 16,18 and other structures/devices disposed
within the housing 12.
[0021] Referring to FIGS. 5 and 6, in one exemplary embodiment,
each extensible threaded retention pipe structure 14 is an annular
structure with a substantially circular cross-sectional shape.
However, any suitable cross-sectional shape, being constant or
variable along the longitudinal axis of the extensible threaded
retention pipe structure 14, may be used. Likewise, each extensible
threaded retention pipe structure 14 may be a substantially solid
structure. Each extensible threaded retention pipe structure 14 is
manufactured from a metal or another biocompatible material.
Preferably, each extensible threaded retention pipe structure 14
includes a cutting edge 28 along the surface or edge that engages
the associated vertebral endplate, such that the extensible
threaded retention pipe structure 14 securely seats itself in this
bony structure upon deployment. The extensible threaded retention
pipe structure 14 also includes threads 30, 32 disposed
concentrically about its outside and/or inside diameter(s) for this
purpose. The outer threads 30 cover about one-half the length of
the extensible threaded retention pipe structure 14 and are
preferably machine threads, while the inner threads 32 cover
substantially the entire length of the extensible threaded
retention pipe structure 14 and are preferably bone threads.
Finally, each extensible threaded retention pipe structure 14
includes a retention thread or lip 34 configured to engage the lip
24 (FIGS. 3 and 4) manufactured into the interior/surface of the
housing 12 (FIGS. 1-4), such that the extensible threaded retention
pipe structure 14 cannot be expelled from the housing 12 when "spun
up" or "spun down." Preferably, the machine threads 30 stop at
least a full tum before the retention thread or lip 34, such that
they may "escape" the housing. These machine threads 30 are wider
than the retention thread or lip 34. The machine threads 30 may or
may not be integral with the drive threads 20 (FIGS. 1, 2, 5, and
6) described above. The pitch of the drive threads 20/machine
threads 30 determine the rate at which the extensible threaded
retention pipe structure 14 advances out of the housing 12. Once
the machine threads 30 are clear of the housing 12, they serve to
compress the vertebral endplate(s) against the housing 12.
[0022] Again, a bone graft is disposed within the housing 12 and
the extensible threaded retention pipe structure(s) 14 of the ALIF
cage device 10 (FIGS. 1 and 2), as appropriate. Optionally, the
bone graft is accessible through an anterior window (not
specifically illustrated) of the ALIF cage device 10 when
positioned and seated. This anterior window may be capped at
will.
[0023] FIG. 7 is an isolation view of the worm gears/mandrels 16,18
of the exemplary embodiment provided above. Each of these worm
gears/mandrels 16, 18 is manufactured from a metal or another
biocompatible material. Again, it will be readily apparent to those
of ordinary skill in the art that different mechanisms could also
be used to deploy the one or more extensible threaded retention
pipe structures 14 (FIGS. 1, 2, 5, and 6), using gears and threads
or not, employing rotational as well as extension motion or not,
etc. For example, one set of worm gears/mandrels 16, 18 could be
used to deploy both top and bottom extensible threaded retention
pipe structures 14 simultaneously. Likewise, different actuation
mechanisms and tools could be used for deployment.
[0024] Although the present invention is illustrated and described
herein with reference to preferred embodiments and specific
examples thereof, it will be readily apparent to those of ordinary
skill in the art that other embodiments and examples may perform
similar functions and/or achieve like results. All such equivalent
embodiments and examples are within the spirit and scope of the
present invention, are contemplated thereby, and are intended to be
covered by the following claims.
* * * * *