U.S. patent application number 11/438891 was filed with the patent office on 2007-11-29 for surgical spacer with shape control.
This patent application is currently assigned to SDGI Holdings, Inc.. Invention is credited to Randall L. Allard, Kent M. Anderson, Aurelien Bruneau, Eric C. Lange, Hai H. Trieu.
Application Number | 20070276496 11/438891 |
Document ID | / |
Family ID | 38750530 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070276496 |
Kind Code |
A1 |
Lange; Eric C. ; et
al. |
November 29, 2007 |
Surgical spacer with shape control
Abstract
An interspinous spacer for placement between adjacent spinous
processes includes a flexible, fillable container (e.g., a bag or
balloon) for containing a material that is compressible during end
use, for example, silicone after curing. The container is
impermeable to the material it will be filled with. A structural
mesh, for example, made of PET fabric and interwoven shape-memory
alloy wire, provides structure for and containment of the
container, as well as shape control. The material can be injected
into the container through an optional conduit, for example, a
one-way valve.
Inventors: |
Lange; Eric C.;
(Collierville, TN) ; Trieu; Hai H.; (Cordova,
TN) ; Anderson; Kent M.; (Memphis, TN) ;
Allard; Randall L.; (Germantown, TN) ; Bruneau;
Aurelien; (Memphis, TN) |
Correspondence
Address: |
HESLIN ROTHENBERG FARLEY & MESITI P.C.
5 COLUMBIA CIRCLE
ALBANY
NY
12203
US
|
Assignee: |
SDGI Holdings, Inc.
Wilmington
DE
|
Family ID: |
38750530 |
Appl. No.: |
11/438891 |
Filed: |
May 23, 2006 |
Current U.S.
Class: |
623/17.12 |
Current CPC
Class: |
A61B 17/7067 20130101;
A61F 2002/4495 20130101; A61B 2017/00557 20130101; A61F 2/441
20130101; A61F 2/442 20130101; A61B 17/7065 20130101 |
Class at
Publication: |
623/17.12 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. A surgical spacer, comprising: a flexible container for
containing a material that is compressible during end use, wherein
the container is substantially impermeable to the material; and a
structure for at least part of the container when containing the
material; wherein the structure controls at least part of a shape
of the surgical spacer.
2. The surgical spacer of claim 1, wherein the material is flowable
during filling of the container, the surgical spacer further
comprising a conduit coupled to the container for accepting the
material.
3. The surgical spacer of claim 2, wherein the conduit comprises a
one-way valve.
4. The surgical spacer of claim 1, wherein the container is
situated inside the structure.
5. The surgical spacer of claim 1, wherein the container is
situated outside the structure.
6. The surgical spacer of claim 1, wherein the container is
integral with the structure.
7. The surgical spacer of claim 1, wherein the structure comprises
a shape memory alloy.
8. The surgical spacer of claim 7, wherein the shape memory alloy
is body temperature activated.
9. The surgical spacer of claim 7, wherein the shape memory alloy
is superelastic.
10. The surgical spacer of claim 7, wherein the shape memory alloy
is coupled to an inside of the structure.
11. The surgical spacer of claim 7, wherein the shape memory alloy
is coupled to an outside of the structure.
12. The surgical spacer of claim 11, wherein the structure
comprises a plurality of interlocking links, and wherein the
plurality of interlocking links comprise the shape memory
alloy.
13. The surgical spacer of claim 7, wherein the structure comprises
a structural mesh, and wherein the shape memory alloy comprises at
least one shape memory alloy wire within the structural mesh.
14. The surgical spacer of claim 1, wherein the structure has at
least a partially preformed shape.
15. The surgical spacer of claim 1, wherein the structure comprises
at least one substantially inflexible shaped member.
16. The surgical spacer of claim 15, wherein the at least one
substantially inflexible shaped member comprises a substantially
straight member.
17. The surgical spacer of claim 15, wherein the at least one
substantially inflexible shaped member comprises a roughly U-shaped
member.
18. The surgical spacer of claim 1, wherein the container and the
structure together comprise a layer of rubber thick enough to
roughly maintain a desired shape.
19. The surgical spacer of claim 1, wherein the container comprises
at least one of silicone, rubber, polyurethane, polyethylene
terephthalate (PET), polyolefin, polycarbonate urethane, and
silicone copolymer.
20. The surgical spacer of claim 1, wherein the material comprises
at least one of a curable polymer and an adhesive.
21. The surgical spacer of claim 1, wherein the structure comprises
at least one of PET fabric, polypropylene fabric, polyethylene
fabric and metal wire.
22. The surgical spacer of claim 1, wherein the surgical spacer
comprises an interspinous spacer, and wherein the structure is
shaped to fit between adjacent spinous processes.
23. The surgical spacer of claim 1, wherein the structure is shaped
for spacing adjacent spinous processes, and wherein the surgical
spacer is capable of resisting a compressive load with a stiffness
of about 40 N/mm to about 240 N/mm.
24. The surgical spacer of claim 1, wherein the structure is shaped
to replace at least part of an intervertebral disc.
25. The surgical spacer of claim 1, wherein the structure is at
least partially permeable.
26. An interspinous spacer, comprising: a flexible container for
containing an injectable material that is compressible during end
use, wherein the container is substantially impermeable to the
injectable material; a conduit coupled to the container for
accepting the injectable material; and a structure for at least
part of the container when containing the material; wherein the
structure has a shape during end use to fit between adjacent
spinous processes.
27. The interspinous spacer of claim 26, wherein the structure is
roughly H-shaped.
28. The interspinous spacer of claim 26, wherein the structure
comprises: at least one substantially inflexible member; and a mesh
for enveloping the at least one substantially inflexible
member.
29. The interspinous spacer of claim 28, wherein the at least one
substantially inflexible shaped member comprises a substantially
straight member.
30. The interspinous spacer of claim 28, wherein the at least one
substantially inflexible shaped member comprises a roughly U-shaped
member.
31. The interspinous spacer of claim 26, wherein the conduit
comprises a one-way valve.
32. The interspinous spacer of claim 26, wherein the container is
situated inside the structure.
33. The interspinous spacer of claim 26, wherein the container is
situated outside the structure.
34. The interspinous spacer of claim 26, wherein the container is
integral with the structure.
35. The interspinous spacer of claim 26, wherein the structure
comprises a shape memory alloy.
36. The interspinous spacer of claim 35, wherein the shape memory
alloy is body temperature activated.
37. The interspinous spacer of claim 35, wherein the shape memory
alloy is superelastic.
38. The interspinous spacer of claim 35, wherein the shape memory
alloy is coupled to an inside of the structure.
39. The interspinous spacer of claim 35, wherein the shape memory
alloy is coupled to an outside of the structure.
40. The interspinous spacer of claim 39, wherein the structure
comprises a plurality of interlocking links, and wherein the
plurality of interlocking links comprise the shape memory
alloy.
41. The interspinous spacer of claim 35, wherein the structure
comprises a structural mesh, and wherein the shape memory alloy
comprises at least one shape memory alloy wire within the
structural mesh.
42. The interspinous spacer of claim 26, wherein the structure has
at least a partially preformed shape.
43. The interspinous spacer of claim 26, wherein the structure
comprises at least one substantially inflexible shaped member.
44. The interspinous spacer of claim 43, wherein the at least one
substantially inflexible shaped member comprises a substantially
straight member.
45. The interspinous spacer of claim 43, wherein the at least one
substantially inflexible shaped member comprises a roughly U-shaped
member.
46. The interspinous spacer of claim 26, wherein the container and
the structure together comprise a layer of rubber thick enough to
roughly maintain a desired shape.
47. The interspinous spacer of claim 26, wherein the container
comprises at least one of silicone, rubber, polyurethane,
polyethylene terephthalate (PET), polyolefin, polycarbonate
urethane, and silicone copolymer.
48. The interspinous spacer of claim 26, wherein the material
comprises at least one of a curable polymer and an adhesive.
49. The interspinous spacer of claim 26, wherein the structure
comprises at least one of PET fabric, polypropylene fabric,
polyethylene fabric and metal wire.
50. A method of controlling at least part of a shape of a surgical
spacer, the surgical spacer comprising a flexible container for
containing a material that is compressible during end use, wherein
the container is substantially impermeable to the material, and a
structure for at least part of the container when containing the
material, the method comprising creating the structure with at
least one material for controlling at least part of a shape of the
surgical spacer.
51. The method of claim 50, wherein the creating comprises adding a
shape memory alloy to the structure.
52. The method of claim 51, wherein the structure comprises a
structural mesh, and wherein the creating comprises adding at least
one shape-memory alloy wire to the structural mesh.
53. The method of claim 51, wherein the creating comprises coupling
the at least one shape memory alloy to the structure.
54. The method of claim 50, wherein the creating comprises adding
at least one substantially inflexible shaped member to the
structure.
55. The method of claim 50, wherein the creating comprises adding a
layer of rubber thick enough to roughly maintain a desired
shape.
56. A method of spacing adjacent spinous processes, the method
comprising: providing an interspinous spacer, the interspinous
spacer comprising: a flexible container for containing an
injectable material that is compressible during end use, wherein
the container is substantially impermeable to the injectable
material; a conduit coupled to the container for accepting the
injectable material; and a structure for at least part of the
container when containing the material; wherein the structure has a
shape during end use to fit between adjacent spinous processes;
implanting the interspinous spacer between adjacent spinous
processes; and injecting the injectable material into the container
through the conduit such that the shape is achieved.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS/PATENTS
[0001] This application contains subject matter which is related to
the subject matter of the following applications, each of which is
assigned to the same assignee as this application and filed on the
same day as this application. Each of the below listed applications
is hereby incorporated herein by reference in its entirety:
[0002] "Surgical Spacer," by Lange et al. (Attorney Docket No.
P22790.00).
[0003] "Systems and Methods for Adjusting Properties of a Spinal
Implant," by Lange et al. (Attorney Docket No. P23186.00); and
TECHNICAL FIELD
[0004] The present invention generally relates to surgical spacers
for spacing adjacent body parts. More particularly, the present
invention relates to surgical spacers having a flexible container
for containing a material that is compressible during end use, the
container being substantially impermeable to the material, and a
structure for controlling at least part of a shape of the container
when containing the material.
BACKGROUND OF THE INVENTION
[0005] The human spine is a biomechanical structure with
thirty-three vertebral members, and is responsible for protecting
the spinal cord, nerve roots and internal organs of the thorax and
abdomen. The spine also provides structural support for the body
while permitting flexibility of motion. A significant portion of
the population will experience back pain at some point in their
lives resulting from a spinal condition. The pain may range from
general discomfort to disabling pain that immobilizes the
individual. Back pain may result from a trauma to the spine, the
natural aging process, or the result of a degenerative disease or
condition.
[0006] Procedures to address back problems sometimes require
correcting the distance between spinous processes by inserting a
device (e.g., a spacer) therebetween. The spacer, which is
carefully positioned and aligned within the area occupied by the
interspinous ligament, after removal thereof, is sized to position
the spinous processes in a manner to return proper spacing
thereof.
[0007] Dynamic interspinous spacers are currently used to treat
patients with a variety of indications. Essentially, these patients
present a need for distraction of the posterior elements (e.g., the
spinal processes) using a mechanical device. Current clinical
indications for the device, as described at SAS (Spine Arthroplasty
Society) Summit 2005 by Guizzardi et al., include stenosis, disc
herniation, facet arthropathy, degenerative disc disease and
adjacent segment degeneration.
[0008] Marketed interspinous devices include rigid and flexible
spacers made from PEEK, titanium or silicone. Clinical success with
these devices has been extremely positive so far as an early stage
treatment option, avoiding or delaying the need for lumbar spinal
fusion. However, all devices require an open technique to be
implanted, and many require destroying important anatomical
stabilizers, such as the supraspinous ligament.
[0009] Current devices for spacing adjacent interspinous processes
are preformed, and are not customizable for different sizes and
dimensions of the anatomy of an interspinous area of an actual
patient. Instead, preformed devices of an approximately correct
size are inserted into the interspinous area of the patient.
Further, the stiffness or flexibility of the devices must be
determined prior to the devices being inserted into the
interspinous area.
[0010] Thus, a need exists for improvements to surgical spacers,
such as those for spacing adjacent interspinous processes.
SUMMARY OF THE INVENTION
[0011] Briefly, the present invention satisfies the need for
improvements to surgical spacers by providing shape control. A
flexible container is provided that is fillable in situ to a
desired amount, with a structure for at least part of the container
providing shape control thereto. An optional conduit coupled to the
container allows for filling of the container, for example, by
injecting a material into the container.
[0012] The present invention provides in a first aspect, a surgical
spacer. The surgical spacer comprises a flexible container for
containing a material that is compressible during end use, wherein
the container is substantially impermeable to the material. The
surgical spacer further comprises a structure for at least part of
the container when containing the material, wherein the structure
controls at least part of a shape of the surgical spacer.
[0013] The present invention provides in a second aspect, an
interspinous spacer. The interspinous spacer comprises a flexible
container for containing an injectable material that is
compressible during end use, wherein the container is substantially
impermeable to the injectable material. The interspinous spacer
further comprises a conduit coupled to the container for accepting
the injectable material, and a structure for at least part of the
container when containing the material, wherein the structure has a
shape during end use to fit between adjacent spinous processes.
[0014] The present invention provides in a third aspect, a method
of controlling at least part of a shape of a surgical spacer. The
surgical spacer comprises a flexible container for containing a
material that is compressible during end use, wherein the container
is substantially impermeable to the material. The surgical spacer
further comprises a structure for at least part of the container
when containing the material. The method comprises creating the
structure with at least one material for controlling at least part
of a shape of the surgical spacer during end use.
[0015] The present invention provides in a fourth aspect, a method
of spacing adjacent spinous processes. The method comprises
providing an interspinous spacer, the interspinous spacer
comprising a flexible container for containing an injectable
material that is compressible during end use, wherein the container
is substantially impermeable to the injectable material. The
interspinous spacer further comprises a conduit coupled to the
container for accepting the injectable material, and a structure
for at least part of the container when containing the material,
wherein the structure has a shape during end use to fit between
adjacent spinous processes. The method further comprises implanting
the interspinous spacer between adjacent spinous processes, and
injecting the injectable material into the container through the
conduit such that the shape is achieved.
[0016] Further, additional features and advantages are realized
through the techniques of the present invention. Other embodiments
and aspects of the invention are described in detail herein and are
considered a part of the claimed invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
objects, features, and advantages of the invention are apparent
from the following detailed description taken in conjunction with
the accompanying drawings in which:
[0018] FIG. 1 depicts adjacent vertebrae of the lumber region of a
human spinal column.
[0019] FIG. 2 depicts a more detailed view of a portion of a human
spinal column including the vertebrae of FIG. 1.
[0020] FIG. 3 depicts the spinal column portion of FIG. 2 after
implantation and filling of one example of an interspinous spacer
in accordance with an aspect of the present invention.
[0021] FIG. 4 is a partial cut-away view of one example of an
unfilled surgical spacer with the container in the structure, in
accordance with an aspect of the present invention.
[0022] FIG. 5 depicts an example of a surgical spacer with
integrated container and structure, in accordance with an aspect of
the present invention.
[0023] FIG. 6 is a cross-sectional view of one example of a
surgical spacer with external container, in accordance with an
aspect of the present invention.
[0024] FIG. 7 depicts one example of the construction of a
structure for use with one example of a surgical spacer, in
accordance with another aspect of the present invention.
[0025] FIG. 8 depicts another example of a surgical spacer with
integrated container and structure, in accordance with another
aspect of the present invention.
[0026] FIG. 9 depicts one example of a structure for a surgical
spacer including at least one substantially inflexible shaped
member, in accordance with another aspect of the present
invention.
[0027] FIG. 10 depicts another example of a structure for a
surgical spacer including at least one substantially inflexible
shaped member, in accordance with another aspect of the present
invention.
[0028] FIG. 11 depicts still another example of a structure for a
surgical spacer including a supra-structure, in accordance with
another aspect of the present invention.
[0029] FIG. 12 depicts a portion of a surgical spacer with a
structural mesh coupled at least one least one substantially
inflexible shaped member, in accordance with another aspect of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] A surgical spacer of the present invention can be formed in
situ during a procedure. The spacer includes the following basic
aspects: a flexible container, and a structure for at least part of
the container that controls at least part of the shape of the
surgical spacer. The flexible container can be filled or injected
though an optional conduit after placement. Further, the structure
may be folded or otherwise reduced in size prior to use in some
aspects. Together with an unfilled container, in some aspects, the
spacer can create a smaller footprint during implantation. Once
filled, the structure provides support and containment for the
container, as well as providing shape control for at least part of
the spacer.
[0031] FIG. 1 depicts adjacent vertebrae 100, 102 of the lumbar
region of a human spinal column. As known in the art, each
vertebrae comprises a vertebral body (e.g., vertebral body 104), a
superior articular process (e.g., superior articular process 106),
a transverse process (e.g., transverse process 108), an inferior
articular process (e.g., inferior articular process 110), and a
spinous process (e.g., spinous process 112). In addition, between
vertebral bodies 104 and 114 is a space 116 normally occupied by an
intervertebral disc (see FIG. 2), and between spinous processes 112
and 118 is a space 120 normally occupied by an interspinous
ligament (see FIG. 2).
[0032] FIG. 2 depicts the vertebrae of FIG. 1 within an area 200 of
the lumbar region of a human spine. As shown in FIG. 2, spinous
processes 112 and 118 are touching and pinching interspinous
ligament 202, calling for spacing of the spinous processes.
[0033] FIG. 3 depicts spinous processes 112 and 118 after spacing
with an interspinous spacer 300 in accordance with one aspect of
the present invention. As shown in FIG. 3, interspinous ligament
202 has been removed in a conventional manner prior to insertion of
spacer 300. Although shown in its filled state, in this example,
spacer 300 is implanted in its unexpanded state, as described more
fully below. The spacer is filled with a material described below
through a conduit 302 after implantation. For example, the material
may be injected into the spacer through the conduit (e.g., a
one-way valve). Prior to implantation and filling, measurement of
the space between the interspinous processes and determination of
the spacer size and desired amount of filling can be performed.
Conventional methods can be used, such as, for example, the use of
templates, trials, distractors, scissor-jacks or balloon
sizers.
[0034] FIG. 4 depicts a partially cut-away view of one example of a
spacer 400, in accordance with one aspect of the present invention.
As shown in FIG. 4, the spacer comprises an unfilled container 402
inside a structure 404. Preferably, the container is in an
evacuated state during implantation and prior to being filled.
Where a valve (e.g., a one-way valve) is coupled to the container,
the container is preferably evacuated prior to or during the
process of coupling the valve thereto. In the present example, the
structure is outside the container. However, as will be described
in more detail below, the container can be outside the structure,
or the container and structure can be integrated. In addition,
although the structure is shown to be roughly H-shaped to fit
between adjacent spinous processes, the structure can have any
shape necessary for the particular surgical application. For
example, the structure could instead have a roughly cylindrical
shape to replace an intervertebral disc. As another example, the
structure could be spherically or elliptically shaped to replace
part of the intervertebral disc, for example, the nucleus pulpous,
leaving the rest of the disc intact. Further, although the
structure is shown enveloping the container, the structure could be
for only a portion of the container, depending on the particular
application. For example, it may be desired to prevent bulging of
the container only in a particular area. Coupled to the container
is an optional conduit 406 for accepting a material that is
compressible during end use. The structure provides support for and
containment of the container when filled.
[0035] The container is flexible and substantially impermeable to
the material it will be filled with. However, depending on the
application, the container may be permeable to other materials, for
example, it may be air and/or water permeable. In the present
example, the container takes the form of a bag or balloon, but can
take other forms, so long as flexible and substantially impermeable
to the material it will be filled with. Thus, the container must be
substantially impermeable to the filling material, for example, in
a liquid state during filling and prior to curing. Examples of
container materials include silicone, rubber, polyurethane,
polyethylene terephthalate (PET), polyolefin, polycarbonate
urethane, and silicone copolymers.
[0036] Conduit 406 accepts the material being used to fill the
container. Preferably, the conduit comprises a one-way valve,
however, a two-way valve is also contemplated, as another example.
The conduit can comprise any material suitable for implanting, for
example, various plastics. Also preferably, the conduit is
constructed to be used with a delivery system for filling the
container, such as, for example, a pressurized syringe-type
delivery system. However, the delivery system itself forms no part
of the present invention. As noted above, the conduit is optional.
Other examples of how to fill the container comprise the use of a
self-sealing material for the container, or leaving an opening in
the container that is closed (e.g., sewn shut) intraoperatively
after filling. Using a curable material to fill the container may
also serve to self-seal the container.
[0037] In use, the container is filled with a material that is
compressible during end use. The compressibility characteristic
ensures that the material exhibits viscoelastic behavior and that,
along with the structure, the spacer can accept compressive loads.
Of course, the degree of compressibility will depend on the
particular application for the surgical spacer. For example, if a
spacer according to the present invention is used between adjacent
spinous processes, the spacer would need to accept compressive
loads typically experienced in the posterior region of the spine,
for example, up to about 80 shore A. In other words, the spacer is
preferably capable of resisting compressive motion (or loads) with
a stiffness of about 40 to about 240 N/mm (newtons per millimeter).
The material is preferably injectable, and may be compressible
immediately or after a time, for example, after curing. For
purposes of the invention, the compressibility characteristic is
necessary during end use, i.e., after implantation. Materials that
could be used include, for example, a plurality of beads (e.g.,
polymer beads) that in the aggregate are compressible, or materials
that change state from exhibiting fluid properties to exhibiting
properties of a solid or semi-solid. Examples of such
state-changing materials include two-part curing polymers and
adhesive, for example, platinum-catalyzed silicone, epoxy,
polyurethane, etc.
[0038] As noted above, the structure provides support for and
containment of the container when filled, as well as at least
partial shape control of the spacer. The structure comprises, for
example, a structural mesh comprising a plurality of fibers and/or
wires 408. Within the structural mesh are shape-control fibers
and/or wires 410. In one example, shape control is provided by
wires of a shape-memory alloy (e.g., Nitinol). The shape-memory
alloy wire(s) can be coupled to the structural mesh (inside or
outside), or weaved into the mesh (i.e., integrated). Coupling can
be achieved, for example, by stitching, twisting, or closing the
wire on itself. Alternatively, shape control can be provided by
other wires or fibers that do not "give" in a particular direction,
for example, metal or metal alloys (e.g., tantalum, titanium or
steel, and non-metals, for example, carbon fiber, PET,
polyethylene, polypropalene, etc.). The shape-memory alloy can be
passive (e.g., superelastic) or active (e.g., body-temperature
activated). The use of metal, metal alloy or barium coated wires or
fibers can also improve radiopacity for imaging. The remainder of
the structure can take the form of, for example, a fabric jacket,
as shown in FIG. 4. Although the shape-memory alloy wires make up
only a portion of the structural mesh of FIG. 4, it will be
understood that there could be more such wires, up to and including
comprising the entirety of the mesh. The fabric jacket in this
example contains and helps protect the container from bulging and
damage from forces external to the container, while the
shape-memory alloy provides shape control of the spacer in a center
region 412. The fibers of the jacket comprise, for example, PET
fabric, polypropylene fabric, polyethylene fabric and/or steel,
titanium or other metal wire. Depending on the application, the
structure may be permeable to a desired degree. For example, if
bone or tissue growth is desired to attach to the structure,
permeability to the tissue or bone of interest would be
appropriate. As another example, permeability of the structure may
be desired to allow the material used to fill the container to
evacuate air or water, for example, from the container, in order to
prevent bubbles from forming inside. Where a mesh is used, for
example, the degree of permeability desired can be achieved by
loosening or tightening the weave.
[0039] Although the structure is shown in a roughly H-shape in the
example of FIG. 4, it will be understood that in practice, the
structure can be made to be folded, unexpanded, or otherwise
compacted. This is particularly true where, for example, the
structure comprises a fabric or other easily folded material. A
folded or unexpanded state facilitates implantation, allowing for a
smaller surgical opening, and unfolding or expansion in situ upon
filling of the container. Further, the structure can have a
different final shape, depending on the shape-control material
used. For example, the shape-memory wires in FIG. 4 may be in their
inactive state, whereupon activation by body temperature causes
contraction thereof, making the spacer of FIG. 4 "thinner" than
shown in the center region.
[0040] One example of the construction of a structural mesh 700 for
use as one example of a structure of the present invention will now
be described with reference to FIG. 7. Two roughly cylindrical
members 702 and 704 are sewn together around a periphery 706 of an
opening along a side (not shown) in each. Each member in this
example comprises a fabric mesh (e.g., fabric mesh 714) similar in
composition to the fabric jacket of FIG. 4. Interwoven with the
fabric are a plurality of shape-memory alloy wires both
horizontally (e.g., wire 716) and vertically (e.g., wire 718). An
opening 708 is created in one of the members for accepting the
container, for example, by laser cut. In one example, a conduit
described above would poke through opening 708. The ends of the
cylindrical members (e.g., end 710) are then trimmed and sewn shut,
as shown in broken lines (e.g., lines 712) in FIG. 7.
[0041] FIG. 5 depicts an outer view of another example of a
surgical spacer 500 in accordance with an aspect of the present
invention. A container conduit 501 is shown pointing outward from
an opening 503. As shown, the structure 502 delimits the final
shape of the spacer, in this example, a rough H-shape. The
structure comprises a mesh 504 of shape-memory alloy wire, that is
soaked through with a dispersion polymer 506 (e.g., silicone). The
dispersion polymer (after curing) acts as the container and is
shown filled in FIG. 5. This is one example of the container and
the structure being integral. Although the mesh of FIG. 5 is
described as being all shape-memory alloy wire, it will be
understood that, like FIG. 4, the shape-memory alloy could only
form a part of the structure.
[0042] FIG. 6 is a cross-sectional view of another example of a
surgical spacer 600 in accordance with the present invention.
Surgical spacer 600 is similar to the spacer of FIG. 5, except that
instead of being soaked in a dispersion polymer, a structural mesh
602 of a shape-memory alloy wire is coated with a dispersion
polymer (e.g., silicone) 604 or other curable liquid appropriate
for the container material, creating an outer container. The
coating can be done in a conventional manner, for example, by dip
molding on the outside of the mesh.
[0043] FIG. 8 depicts another example of a surgical spacer 800 with
an integrated container and structure, in accordance with another
aspect of the present invention. The container and structure in the
example of FIG. 8 both comprise a single layer 802 of rubber that
is thick enough for a given application to perform the functions of
both the container and structure (including shape control). Such a
rubber shell would be able to return to its original shape when
unconstrained. In addition, spacer 800 preferably includes a
conduit 804 (preferably, a one-way valve) for filling internal
space 806. The material can be any of the filling materials
described above, for example, silicone. Where the spacer is used,
for example, to space adjacent spinous processes, the thickness of
layer 802 is preferably in the range of about 0.2 mm to about 2.5
mm. A layer of rubber of that thickness will contain the material
chosen, and, when filled, will sufficiently maintain the shape of
the spacer for the intended use.
[0044] In an alternate aspect, the rubber shell of FIG. 8 can be
augmented with internal, external, or integrated features to
further control shape. Examples of such features include thread,
wires (e.g., metal, including shape-memory alloys), cables,
tethers, rings or a mesh.
[0045] FIG. 9 depicts one example of a structure for a surgical
spacer including at least one substantially inflexible shaped
member, in accordance with another aspect of the present invention.
The substantially inflexible member(s) are used to achieve at least
part of a preformed shape for a given application. Structure 900
comprises blades 902 and 904 that are substantially inflexible and
are substantially straight. In one example, the blades comprise
metal, such as, for example, a nickel-titanium alloy. The blades
provide a specific shape for at least part of the surgical spacer.
Coupling the blades is, for example, a structural mesh 906. The
structure can be paired with any of the types of containers
described herein. In addition, the structural mesh can take any of
the forms described herein. For example, the structural mesh could
take the form of a PET fabric mesh, with or without other
shape-enhancing elements (e.g., shape-memory alloy fabric or wire).
In one example, the mesh covers the blades. In another example, the
mesh is coupled at a periphery of the blades.
[0046] As shown in the example of FIG. 12, a portion of a surgical
spacer 1200 comprises a blade 1202 and structural mesh 1204. At the
periphery 1206 of the blade, the mesh is coupled to the blade by
stitching through a plurality of holes (e.g., hole 1208).
[0047] Similarly, FIG. 10 depicts another example of a structure
1000 including at least one substantially inflexible shaped member.
In this example, there are two substantially inflexible shaped
members 1002 and 1004, each being roughly U-shaped. In one example,
the U-shaped members comprise metal blades, such as, for example,
nickel-titanium allow blades. Coupling the blades is, for example,
a structural mesh 1006 similar to that described above with respect
to FIG. 9. In addition, as also noted above with respect to FIG. 9,
the structure of FIG. 10 can be paired with any of the containers
described herein.
[0048] FIG. 11 depicts still another example of a structure 1100
for a surgical spacer, in accordance with another aspect of the
present invention. In this example, the structure comprises a
supra-structure 1102 coupled to a main structure 1104. The main
structure need not provide shape control, since that is provided by
the supra-structure, however, it could also provide shape control.
For example, the main structure could provide shape control in one
or more directions, while the supra-structure provides shape
control in one or more other directions. Of course, the
supra-structure could provide shape control uniformly, e.g., if
added to all surfaces. In one example, the main structure comprises
a fabric mesh (e.g., PET fabric) with or without added shape memory
control fibers or wires. In one example, shown inset in FIG. 11,
supra-structure 1102 comprises a plurality of interlocking links
1106, the links comprising, for example, a shape-memory alloy. The
links could provide resistance to expansion in one or more
directions or uniformly, and/or could allow pliability, permitting
deformation in one or more directions. The supra-structure can be
loosely or rigidly coupled to the main structure, for example, via
loops, hooks, stitches or frictional mechanisms. Of course, the
supra-structure could instead be coupled to an inside 1108 of the
main structure in another example. As with other embodiments
herein, the shape-memory alloy can be passive (e.g., superelastic)
or active (e.g., body-temperature activated).
[0049] Although preferred embodiments have been depicted and
described in detail herein, it will be apparent to those skilled in
the relevant art that various modifications, additions,
substitutions and the like can be made without departing from the
spirit of the invention and these are therefore considered to be
within the scope of the invention as defined in the following
claims.
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