U.S. patent application number 11/386616 was filed with the patent office on 2006-08-03 for spinal disc annulus reconstruction method and deformable spinal disc annulus stent.
This patent application is currently assigned to Anulex Technologies, Inc.. Invention is credited to Matthew M. Burns, Joseph C. III Cauthen, Brian L. Dukart, Rodney L. Houfburg, Lawrence W. Wales, Bradley J. Wessman.
Application Number | 20060173545 11/386616 |
Document ID | / |
Family ID | 32849510 |
Filed Date | 2006-08-03 |
United States Patent
Application |
20060173545 |
Kind Code |
A1 |
Cauthen; Joseph C. III ; et
al. |
August 3, 2006 |
Spinal disc annulus reconstruction method and deformable spinal
disc annulus stent
Abstract
A spinal disc annulus repair stent for repair and reconstruction
of the spinal disc wall (annulus) after surgical invasion or
pathologic rupture, which may incorporate suture closure or other
means of stent insertion and fixation, designed to reduce the
failure rate of conventional surgical procedures on the spinal
discs. In an illustrative embodiment, the design of the spinal disc
annulus stent advantageously allows ingrowth of normal cells of
healing in an enhanced fashion strengthening the normal reparative
process.
Inventors: |
Cauthen; Joseph C. III;
(Gainesville, FL) ; Burns; Matthew M.; (Orono,
MN) ; Wales; Lawrence W.; (Maplewood, MN) ;
Dukart; Brian L.; (Brooklyn Park, MN) ; Wessman;
Bradley J.; (Maple Grove, MN) ; Houfburg; Rodney
L.; (Prior Lake, MN) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Anulex Technologies, Inc.
Maple Grove
MN
|
Family ID: |
32849510 |
Appl. No.: |
11/386616 |
Filed: |
March 23, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10352981 |
Jan 29, 2003 |
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11386616 |
Mar 23, 2006 |
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|
10133339 |
Apr 29, 2002 |
7052516 |
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|
10352981 |
Jan 29, 2003 |
|
|
|
09947078 |
Sep 5, 2001 |
6592625 |
|
|
10133339 |
Apr 29, 2002 |
|
|
|
09484706 |
Jan 18, 2000 |
|
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|
09947078 |
Sep 5, 2001 |
|
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10075615 |
Feb 15, 2002 |
|
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|
10352981 |
|
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60160710 |
Oct 20, 1999 |
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Current U.S.
Class: |
623/17.16 |
Current CPC
Class: |
A61B 17/04 20130101;
A61B 2017/00004 20130101; A61B 2017/06176 20130101; A61F 2002/2817
20130101; A61F 2210/0019 20130101; A61B 2017/0641 20130101; A61F
2/4611 20130101; A61F 2002/30092 20130101; A61F 2230/0093 20130101;
A61F 2/441 20130101; A61F 2002/30158 20130101; A61F 2/4601
20130101; A61B 17/86 20130101; A61F 2002/30579 20130101; A61B
17/0642 20130101; A61B 2017/0648 20130101; A61F 2310/00011
20130101; A61F 2002/30062 20130101; A61B 2017/0647 20130101; A61F
2/0063 20130101; A61F 2210/0004 20130101; A61F 2002/30784 20130101;
A61F 2002/30777 20130101; A61F 2/442 20130101; A61B 17/06166
20130101; A61F 2002/444 20130101; A61F 2002/30841 20130101; A61F
2230/0026 20130101; A61F 2002/30299 20130101; A61F 2002/4435
20130101; A61F 2/30907 20130101; A61F 2002/4627 20130101 |
Class at
Publication: |
623/017.16 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. A device for treating an aperture in the annulus of a patient's
intervertebral disc, said device comprising a cylindrical body
formed of a plurality of filamentous elements, said body having a
radial diameter, a first end and a second end subtending a
longitudinal dimension, said device having a first configuration,
and a second configuration, wherein the second configuration, in
use, is characterized by a relatively larger radial diameter along
at least a portion of said longitudinal dimension.
2. The device of claim 1, wherein said body is sized to be inserted
through said aperture in a intervertebral disc into the subannular
space in said first configuration and then placed in said second
configuration to at least partially cover said aperture.
3. The device of claim 1, wherein said second configuration is
additionally characterized by a relatively smaller longitudinal
dimension in said second configuration than in said first
configuration.
4. The device of claim 1, wherein at least a portion of the stent
is formed at least in part of flexible biocompatible material.
5. The device of claim 1, wherein at least a portion of the stent
is formed at least in part of bioresorbable material.
6. The device of claim 1, wherein at least a portion of the stent
is formed at least in part of nylon.
7. The device of claim 1, wherein at least a portion of the stent
is formed at least in part by weaving.
8. The device of claim 1, wherein at least a portion of the stent
is formed at least in part by braiding.
Description
CROSS-REFERENCE TO A RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 10/352,981, filed Jan. 29, 2003, now pending. U.S. patent
application Ser. No. 10/352,981 is a continuation-in-part of U.S.
patent application Ser. No. 10/133,339, filed Apr. 29, 2002, now
pending, which is a continuation-in-part of U.S. patent application
Ser. No. 09/947,078, filed Sep. 5, 2001, now U.S. Pat. No.
6,592,625, which is a continuation of U.S. patent application Ser.
No. 09/484,706, filed Jan. 18, 2000, now abandoned, which claims
the benefit of U.S. Provisional Application No. 60/160,710, filed
Oct. 20, 1999. U.S. patent application Ser. No. 10/352,981 is also
a continuation-in-part of U.S. patent application Ser. No.
10/075,615, filed on Feb. 15, 2002, now pending, and it also claims
the benefit of U.S. Provisional Application No. 60/309,105, filed
Jul. 31, 2001. The entire contents of each of the above are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention generally relates to methods and implantable
medical devices for the closure, sealing, and/or repair of an
aperture in the intervertebral disc annulus. The term "aperture"
refers to a hole in the annulus that is a result of a surgical
incision into the intervertebral disc annulus, or the consequence
of a naturally occurring tear (rent). The invention generally
relates to surgical devices and methods for intervertebral disc
wall repair or reconstruction. The invention further relates to an
annular repair device, or stent, for annular disc repair. These
stents can be of natural or synthetic materials. The effects of
said reconstruction are restoration of disc wall integrity and
reduction of the failure rate (3-21%) of a common surgical
procedure (disc fragment removal or discectomy). This surgical
procedure is performed about 390,000 times annually in the United
States.
BACKGROUND OF THE INVENTION
[0003] The spinal column is formed from a number of bony vertebrae,
which in their normal state are separated from each other by
intervertebral discs. These discs are comprised of the annulus
fibrosus, and the nucleus pulposus, both of which are soft tissue.
The intervertebral disc acts in the spine as a crucial stabilizer,
and as a mechanism for force distribution between adjacent
vertebral bodies. Without the disc, collapse of the intervertebral
space occurs in conjunction with abnormal joint mechanics and
premature development of arthritic changes.
[0004] The normal intervertebral disc has an outer ligamentous ring
called the annulus surrounding the nucleus pulposus. The annulus
binds the adjacent vertebrae together and is constituted of
collagen fibers that are attached to the vertebrae and cross each
other so that half of the individual fibers will tighten as the
vertebrae are rotated in either direction, thus resisting twisting
or torsional motion. The nucleus pulposus is constituted of loose
tissue, having about 85% water content, which moves about during
bending from front to back and from side to side.
[0005] The aging process contributes to gradual changes in the
intervertebral discs. The annulus loses much of its flexibility and
resilience, becoming more dense and solid in composition. The aging
annulus may also be marked by the appearance or propagation of
cracks or fissures in the annular wall. Similarly, the nucleus
desiccates, increasing viscosity and thus losing its fluidity. In
combination, these features of the aged intervertebral discs result
in less dynamic stress distribution because of the more viscous
nucleus pulposus, and less ability to withstand localized stresses
by the annulus fibrosus due to its desiccation, loss of
flexibility, and the presence of fissures. Fissures can also occur
due to disease or other pathological conditions. Occasionally
fissures may form rents through the annular wall. In these
instances, the nucleus pulposus is urged outwardly from the
subannular space through a rent, often into the spinal column.
Extruded nucleus pulposus can, and often does, mechanically press
on the spinal cord or spinal nerve rootlet. This painful condition
is clinically referred to as a ruptured or herniated disc.
[0006] In the event of annulus rupture, the subannular nucleus
pulposus migrates along the path of least resistance forcing the
fissure to open further, allowing migration of the nucleus pulposus
through the wall of the disc, with resultant nerve compression and
leakage of chemicals of inflammation into the space around the
adjacent nerve roots supplying the extremities, bladder, bowel, and
genitalia. The usual effect of nerve compression and inflammation
is intolerable back or neck pain, radiating into the extremities,
with accompanying numbness, weakness, and in late stages, paralysis
and muscle atrophy, and/or bladder and bowel incontinence.
Additionally, injury, disease, or other degenerative disorders may
cause one or more of the intervertebral discs to shrink, collapse,
deteriorate, or become displaced, herniated, or otherwise damaged
and compromised.
[0007] The surgical standard of care for treatment of herniated,
displaced, or ruptured intervertebral discs is fragment removal and
nerve decompression without a requirement to reconstruct the
annular wall. While results are currently acceptable, they are not
optimal. Various authors report 3.1-21% recurrent disc herniation,
representing a failure of the primary procedure and requiring
re-operation for the same condition. An estimated 10% recurrence
rate results in 39,000 re-operations in the United States each
year.
[0008] An additional method of relieving the symptoms is thermal
annuloplasty, involving the heating of sub-annular zones in the
non-herniated painful disc, seeking pain relief, but making no
claim of reconstruction of the ruptured, discontinuous annulus
wall.
[0009] Some have also suggested that the repair of a damaged
intervertebral disc might include the augmentation of the nucleus
pulposus, and various efforts at nucleus pulposus replacement have
been reported. The present invention is directed at the repair of
the annulus, whether or not a nuclear augmentation is also
warranted.
[0010] In addition, there has been experimentation in animals to
assess various surgical incisions with and without the direct
surgical repair of the annulus. These studies were performed on
otherwise healthy animals and involved no removal or augmentation
of nucleus pulposus. The authors of these experiments conclude that
direct repair of the annulus does not influence the healing of the
disc.
[0011] There is currently no known method of annulus
reconstruction, either primarily or augmented with an annulus
stent.
BRIEF SUMMARY OF THE INVENTION
[0012] The present invention provides methods and related materials
for reconstruction of the disc wall in cases of displaced,
herniated, ruptured, or otherwise damaged intervertebral discs. In
accordance with the invention, a method is disclosed for
intervertebral disc reconstruction for treating a disc having an
aperture in the wall of the annulus fibrosis, wherein the aperture
provides a path for the migration of nucleus pulposus from the
subannular space, the method including the steps of providing an
expandable patch having a first configuration dimensioned to pass
through the aperture and a second expanded configuration having at
least one dimension at least as large as the aperture and having at
least one dimension larger than a corresponding dimension in said
first configuration; inserting the patch through the aperture into
the subannular space when the device is in the first collapsed
configuration; and causing or allowing the patch to expand in the
subannular space into the second expanded configuration to bridge
the aperture, thereby occluding the aperture and preventing the
migration of nucleus pulposus therethrough.
[0013] The objects and various advantages of the invention will be
apparent in consideration of the description which follows. In
general, the implantable medical device is placed, positioned, and
affixed to the annulus to reduce re-extrusion of the nucleus
through the aperture by: acting as a mechanical barrier; restoring
the natural integrity of the wall of the annulus; and promoting the
healing of the annulus through the reapproximation of disc wall
tissue. Increased integrity and faster and/or more thorough healing
of the aperture is intended to reduce future recurrence of
herniation of the disc nucleus from the intervertebral disc, and
the recurrence of resulting back pain. In addition, it is believed
that the repair of the aperture could promote enhanced biomechanics
and reduce the possibility of intervertebral disc height collapse
and segmental instability, thus resulting in a decrease in the
recurrence of back pain after a surgical procedure.
[0014] Moreover, the repair of the aperture with the reduction of
the re-extrusion of the nucleus may also advantageously reduce
adhesion formation surrounding the nerve roots. The nuclear
material of the disc is toxic to the nerves and is believed to
cause increased inflammation surrounding the nerves, which in turn
can cause increased scar formation (adhesions or epidural fibrosis)
upon healing. Adhesions created around the nerve roots can cause
continued back pain. Any reduction in adhesion formation is
believed to reduce future recurrence of pain.
[0015] One of the objects of the present inventions is to act as a
mechanical barrier to the extrusion of the nucleus from the disc
space, add mechanical integrity to the annulus and the tissue
surrounding the aperture, and to promote faster and a more complete
healing of the aperture.
[0016] Although much of the discussion is directed toward the
repair of the intervertebral disc after a surgical procedure, such
as discectomy (a surgical procedure performed to remove herniated
fragments of the disc nucleus), it is contemplated that the device
could be used in other procedures that involve incisions into the
annulus of the intervertebral disc. An example of another procedure
that could require a repair technique involves the replacement of
the nucleus--nucleus replacement--with an implantable nucleus to
replace the functioning of the natural nucleus when it is
degenerated. The object of the invention in this case would be
similar in that the repair would maintain the replacement nucleus
within the disc space.
[0017] According to the invention, a sub-annular patch/stent can be
employed to repair an intervertebral disc annulus. In its simplest
form, the repair of the annulus involves the placement and fixation
of a fascial autograft patch to the sub-annular space which can
additionally employ two or more sutures, while re-approximating the
tissues surrounding the aperture. The invention, through
involvement of the sub-annular space and wall for the repair of the
aperture, has several advantages over the prior art; for example,
sealing the aperture only on the outer surface, or sealing the
aperture only within the aperture. The first advantage of a repair
that involves the sub-annular surface derives itself from the
physical nature of a circular (or an elliptical) compressed chamber
with a radius, like an intervertebral disc. Sealing the inside wall
has the inherent advantage of being at a smaller radius of
curvature versus the outer wall and thus, according to LaPlace's
Law, the patch would be subjected to lower stresses at any given
pressure, all else held equal.
[0018] Another advantage of utilizing the inner surface to
accomplish sealing is that the natural pressure within the disc can
enhance the sealing of the device against the inner wall of the
disc space. Conversely, if the repair is performed on the outer
surface of the annulus there is an inherent risk of leakage around
the periphery of the device, with the constant exposure to the
pressure of the disc.
[0019] Another advantage of the present invention over the prior
art in utilizing the inner surface of the annulus is the reduction
of the risk of having a portion of the device protruding from the
exterior surface of the annulus. Device materials protruding from
the exterior of the annulus pose a risk of damaging the nerve root
and/or spinal canal which are in close proximity. Damage to these
structures can result in continued pain, incontinence, bowel
dysfunction, and paralysis.
[0020] The present invention also incorporates the concept of
pulling the tissues together that surround the aperture, the inner
surface, and the outer surface of the annulus to help increase the
integrity of the repair.
[0021] An example of the technique and placement of the device
according to the invention is as follows:
[0022] 1. An aperture is created measuring approximately, for
example, 6 mm.times.2 mm in the wall of the annulus after
performing a discectomy procedure in which a portion of the nucleus
is also removed from the disc space, as shown in FIGS. 32a, 32b,
33a and 33b.
[0023] 2. Two or more sutures are passed through the upper and
lower surfaces of the aperture and they are pushed within the
intervertebral disc space to create a "sling" to receive the
fascial autograft as shown for example in FIG. 34.
[0024] 3. A piece of para-spinal fascial tissue is removed from the
patient measuring approximately, for example, 10 mm.times.5 mm.
[0025] 4. The autograft is folded and compressed to pass through
the aperture in the annulus, as shown for example in FIG. 35.
[0026] 5. The autograft takes a second shape, within the annulus
that is uncompressed and oriented to be in proximity of the
subannular wall of the annulus, within the sling, as shown for
example in FIG. 36. The autograft may be inserted entirely into the
subannular space, or a portion may extend into the rent as depicted
in FIG. 36.
[0027] 6. The sutures are tightened, as shown for example in FIG.
37, thus tightening the sling surrounding the autograft, to bring
the autograft in close proximity with the subannular wall, while
providing tension to bring the patch at the subannular surface
together with the outer surface of the annular wall, thus creating
increased integrity of the annulus surrounding the aperture, as
well as causing the autograft to take a second shape that is larger
than the aperture. Furthermore, the tightening, and eventual tying
of the sutures also promotes the re-approximation of the tissue at
the outer surface of the annulus and within the aperture.
[0028] 7. The sutures are tied and the ends of the sutures are
cut.
[0029] 8. A piece of autograft fat tissue may be placed over the
discectomy site for the prevention of adhesion formation, a typical
surgical technique.
[0030] 9. Standard surgical techniques are utilized to close the
access site of the surgical procedures.
[0031] Several devices according to the present invention can be
used to practice the above illustrative inventive steps to
accomplish the sealing and/or repair of the intervertebral disc. In
each of the representative devices described herein, there is: an
expandable patch/stent (note: patch, stent and device are used
interchangeably) that has, in use, at least a portion of the device
in proximity to the sub-annular space of the intervertebral disc
annulus; a means to affix the patch to stay in proximity with the
annulus; a means to draw the patch and the annular tissue together
and fasten in tension; and a means to help reduce the relative
motion of the surfaces of the aperture after fixation, and thus
promote healing. According to one feature and object of the present
invention, close approximation of tissue, while reducing the motion
of the surfaces, provides the optimal environment for healing.
[0032] The concepts disclosed hereinbelow accomplish these
objectives, as well as advantageously additionally incorporating
design elements to reduce the number of steps (and time), and/or
simplify the surgical technique, and/or reduce the risk of causing
complications during the repair of the intervertebral disc annulus.
In addition, it is an objective of the following devices to become
incorporated by the surrounding tissues, or to act as a scaffold in
the short-term (3-6 months) for tissue incorporation.
[0033] In an exemplary embodiment, one or more mild biodegradable
surgical sutures can be placed at about equal distances along the
sides of a pathologic aperture in the ruptured disc wall (annulus)
or along the sides of a surgical incision in the annular wall,
which may be weakened or thinned.
[0034] Sutures are then tied in such fashion as to draw together
the sides of the aperture, effecting reapproximation or closure of
the opening, to enhance natural healing and subsequent
reconstruction by natural tissue (fibroblasts) crossing the now
surgically narrowed gap in the disc annulus.
[0035] A 25-30% reduction in the rate of recurrence of disc nucleus
herniation through this aperture has been achieved using this
method.
[0036] In another exemplary embodiment, the method can be augmented
by creating a subannular barrier in and across the aperture by
placement of a patch of human muscle fascia (muscle connective
tissue) or any other autograft, allograft, or xenograft acting as a
bridge or a scaffold, providing a platform for traverse of
fibroblasts or other normal cells of repair existing in and around
the various layers of the disc annulus, prior to closure of the
aperture.
[0037] A 30-50% reduction in the rate of recurrence of disc
herniation has been achieved using the aforementioned fascial
augmentation with this embodiment.
[0038] In still another embodiment, a braided patch can be formed
having a first collapsed configuration having a major longitudinal
dimension with first and second ends. When these ends are moved
toward each other along the longitudinal axis, a portion of the
device between the ends can deploy outwardly to form an expanded
configuration.
[0039] Having demonstrated that human muscle fascia is adaptable
for annular reconstruction, other biocompatible membranes can be
employed as a bridge, stent, patch or barrier to subsequent
migration of the disc nucleus through the aperture. Such
biocompatible materials may be, for example, medical grade
biocompatible fabrics, biodegradable polymeric sheets, or form
fitting or non-form fitting fillers for the cavity created by
removal of a portion of the disc nucleus pulposus in the course of
the disc fragment removal or discectomy. The prosthetic material
can be placed in and around the intervertebral space, created by
removal of the degenerated disc fragments.
[0040] Additional objects and advantages of the invention will be
set forth in part in the description which follows, and in part
will be obvious from the description, or may be learned by practice
of the invention. The objects and advantages of the invention will
be realized and attained by means of the elements and combinations
particularly pointed out in the appended claims.
[0041] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention, as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate illustrative
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0043] FIG. 1 shows a perspective view of an illustrative
embodiment of an annulus stent.
[0044] FIG. 2 shows a front view of the annulus stent of FIG.
1.
[0045] FIG. 3 shows a side view of the annulus stent of FIG. 1.
[0046] FIGS. 4A-4C show a front view of alternative illustrative
embodiments of an annulus stent.
[0047] FIGS. 5A-5B show the alternative embodiment of a further
illustrative embodiment of an annulus stent.
[0048] FIGS. 6A-6B show the alternative embodiment of a further
illustrative embodiment of an annulus stent.
[0049] FIG. 7 shows a primary closure of an opening in the disc
annulus.
[0050] FIGS. 8A-8B show a primary closure with a stent.
[0051] FIG. 9 shows a method of suturing an annulus stent into the
disc annulus utilizing fixation points on vertebral bodies.
[0052] FIGS. 10A-10B show a further illustrative embodiment of an
annulus stent with flexible bladder being expanded into the disc
annulus.
[0053] FIGS. 11A-11D show an annulus stent being inserted into and
expanded within the disc annulus.
[0054] FIGS. 12A-12B show an annulus stent with a flexible bladder
being expanded.
[0055] FIG. 13 shows a perspective view of a further illustrative
embodiment of an annulus stent.
[0056] FIG. 14 shows a first collapsed view of the annulus stent of
FIG. 13.
[0057] FIG. 15 shows a second collapsed view of the annulus stent
of FIG. 13.
[0058] FIGS. 16A-16C show the annulus stent of FIG. 13 being
inserted into the disc annulus.
[0059] FIGS. 17A-17C show a method of inserting the annulus stent
of FIG. 13 into the disc annulus.
[0060] FIGS. 18A-18B show a further illustrative embodiment of an
annulus stent with a flexible bladder.
[0061] FIGS. 19A-19B show another illustrative embodiment of an
annulus stent with a flexible bladder.
[0062] FIG. 20 shows an expanded annulus stent with barbs on the
radial extension.
[0063] FIG. 21 shows a still further illustrative embodiment of an
annulus stent with a compressible core.
[0064] FIG. 22 shows a still further illustrative embodiment of an
introduction device for an annulus stent.
[0065] FIG. 23 shows a modification of the device depicted in FIG.
22.
[0066] FIG. 24 shows an exemplary introduction tool for use with
the devices of FIGS. 22 and 23 with a stent deflected
proximally.
[0067] FIG. 25 shows an exemplary introduction tool for use with
the devices of FIGS. 22 and 23 with a stent deflected distally.
[0068] FIG. 26 shows an exemplary introduction tool for use with
the devices of FIGS. 22 and 23 with a stent deflected partially
distally and partially proximally.
[0069] FIG. 27 shows a still further illustrative embodiment of a
stent device having a grasping feature and fixation devices in the
form of barbs.
[0070] FIG. 28 shows the illustrative embodiment in FIG. 27
deployed subannularly.
[0071] FIG. 29 shows a still further illustrative embodiment of an
annulus stent employing a secondary barbed fixation device.
[0072] FIG. 30 shows a still further illustrative embodiment of an
annulus stent employing another example of a secondary barbed
fixation device.
[0073] FIG. 31 shows the frame of a still further illustrative
embodiment of an annulus stent having a metal substrate being
machined from flat stock.
[0074] FIG. 32a shows a herniated disc in perspective view, and
FIG. 32b shows the same disc after discectomy.
[0075] FIG. 33a shows a top view of the disc post-discectomy, and
FIG. 33b shows a posteriolateral view of the disk showing an
incision.
[0076] FIG. 34 shows schematically the creation of a subannular
sling using sutures.
[0077] FIG. 35 schematically shows the introduction of a compressed
autograft stent/patch into the subannular space.
[0078] FIG. 36 schematically shows the autograft of FIG. 35 in an
expanded shape within the annulus.
[0079] FIG. 37 schematically shows the tightening of the sutures to
reapproximate the annulus aperture and draw the stent/patch of FIG.
35 toward the annular wall.
[0080] FIG. 38 shows an exemplary collar for use in repairing a
disc annulus.
[0081] FIG. 39 schematically depicts the collar of FIG. 38 in use
for disc annulus repair.
[0082] FIG. 40 shows a still further exemplary embodiment of the
present invention using a bag to contain the patch/stent.
[0083] FIG. 41a-e show still further illustrative embodiments of
the present invention having frames.
[0084] FIG. 42 shows an illustrative method for placing a barbed
expandable patch in the subannular disc space.
[0085] FIG. 43 shows the patch of FIG. 42 being fixed to the inside
wall of the annulus fibrosus.
[0086] FIGS. 44a-g show a still further illustrative embodiment of
an introduced and expanded annulus stent/patch being fixated and
the aperture reapproximated.
[0087] FIGS. 45a-c schematically depict a still further embodiment
of the present invention where an expandable stent/patch is
tethered in situ using a cinch line.
[0088] FIGS. 46a-c schematically depict the cinch line of FIG. 45
being fixated through use of a surgical staple device.
[0089] FIGS. 47a-b show an illustrative embodiment of a suturing
arrangement for securing a patch/stent in the annulus.
[0090] FIG. 48a-b depict a still further illustrative embodiment
where fixation sutures are placed into the vertebral body or the
Sharpey fibers.
[0091] FIGS. 49a-c schematically depict a still further embodiment
of the present invention where an expandable stent/patch is
tethered in situ using a cinch line.
[0092] FIGS. 50a-c schematically depict the cinch line of FIG. 49
being fixated through use of a barbed surgical staple device that
penetrates the patch/stent.
[0093] FIG. 51 depicts an exemplary use of filler tissue within the
aperture during placement of a patch/stent tethered by a cinch
line.
[0094] FIGS. 52a-e shows exemplary embodiments of various
additional patch/stent fixation techniques.
[0095] FIG. 53 shows a still further illustrative embodiment of a
stent/patch having a frame.
[0096] FIG. 54a-f shows a still further illustrative embodiment of
an annular stent/patch having a self-contained fixation tightening
feature.
[0097] FIG. 55 shows a still further exemplary embodiment of the
present invention having external fixation anchors.
[0098] FIG. 56a-c shows a still further exemplary embodiment of the
present invention having external fixation anchors.
[0099] FIG. 57a-c shows a still further exemplary embodiment of the
present invention having external fixation anchors.
[0100] FIG. 58 shows a still further exemplary embodiment of the
present invention having external fixation anchors.
[0101] FIG. 59 shows a still further exemplary embodiment of the
present invention having a springing arrangement.
[0102] FIG. 60 shows a lateral view of a still further exemplary
embodiment of the present invention having a braided arrangement in
a collapsed configuration.
[0103] FIG. 61 shows an axial view of the exemplary embodiment of
FIG. 60 in an expanded configuration.
[0104] FIG. 62 shows a lateral view of the exemplary embodiment of
FIG. 60 in a collapsed configuration mounted on an illustrative
delivery device.
[0105] FIG. 63 shows a lateral cutaway view of the exemplary
embodiment of FIG. 60 in a collapsed configuration.
[0106] FIG. 64 shows a lateral cutaway view of the exemplary
embodiment of FIG. 60 in an expanded configuration.
[0107] FIG. 65 shows a lateral view of an illustrative delivery
member as shown in the exemplary embodiment of FIGS. 63 and 64.
[0108] FIG. 66 shows a lateral view of an exemplary embodiment of
the invention in an expanded configuration subannularly.
DETAILED DESCRIPTION OF THE INVENTION
[0109] Reference will now be made in detail to an illustrative
embodiment of the invention, which appears in the accompanying
drawings. Wherever possible, the same reference numbers will be
used throughout the drawings to refer to the same or like
parts.
[0110] In one embodiment of the present invention, as shown in FIG.
7, a damaged annulus 42 is repaired by use of surgical sutures 40.
One or more surgical sutures 40 are placed at about equal distances
along the sides of a pathologic aperture 44 in the annulus 42.
Reapproximation or closure of the aperture 44 is accomplished by
tying the sutures 40 so that the sides of the aperture 44 are drawn
together. The reapproximation or closure of the aperture 44
enhances the natural healing and subsequent reconstruction by the
natural tissue (e.g., fibroblasts) crossing the now surgically
narrowed gap in the annulus 42. Preferably, the surgical sutures 40
are biodegradable, but permanent non-biodegradable may be
utilized.
[0111] Additionally, to repair a weakened or thinned wall of a disc
annulus 42, a surgical incision can be made along the weakened or
thinned region of the annulus 42 and one or more surgical sutures
40 can be placed at about equal distances laterally from the
incision. Reapproximation or closure of the incision is
accomplished by tying the sutures 40 so that the sides of the
incision are drawn together. The reapproximation or closure of the
incision enhances the natural healing and subsequent reconstruction
by the natural tissue crossing the now surgically narrowed gap in
the annulus 42. Preferably, the surgical sutures 40 are
biodegradable, but permanent non-biodegradable materials may be
utilized.
[0112] In an alternative embodiment, the method can be augmented by
the placement of a patch of human muscle fascia or any other
autograft, allograft or xenograft in and across the aperture 44.
The patch acts as a bridge in and across the aperture 44, providing
a platform for traverse of fibroblasts or other normal cells of
repair existing in and around the various layers of the disc
annulus 42, prior to closure of the aperture 44.
[0113] In a further embodiment, as shown in FIGS. 8A-B a
biocompatible membrane can be employed as an annulus stent 10,
being placed in and across the aperture 44. The annulus stent 10
acts as a bridge in and across the aperture 44, providing a
platform for a traverse of fibroblasts or other normal cells of
repair existing in and around the various layers of the disc
annulus 42, prior to closure of the aperture 44. In some
embodiments the device, stent or patch can act as a scaffold to
assist in tissue growth that healingly scars the annulus.
[0114] In an illustrative embodiment, as shown in FIGS. 1-3, the
annulus stent 10 comprises a centralized vertical extension 12,
with an upper section 14 and a lower section 16. The centralized
vertical extension 12 can be trapezoid in shape through the width
and may be from about 8 mm-12 mm in length.
[0115] Additionally, the upper section 14 of the centralized
vertical extension 12 may be any number of different shapes, as
shown in FIGS. 4A through 4C, with the sides of the upper section
14 being curved or with the upper section 14 being circular in
shape. Furthermore, the annulus stent 10 may contain a recess
between the upper section 14 and the lower section 16, enabling the
annulus stent 10 to form a compatible fit with the edges of the
aperture 44.
[0116] The upper section 14 of the centralized vertical extension
12 can comprise a slot 18, where the slot 18 forms an orifice
through the upper section 14. The slot 18 is positioned within the
upper section 14 such that it traverses the upper section's 14
longitudinal axis. The slot 18 is of such a size and shape that
sutures, tension bands, staples or any other type of fixation
device known in the art may be passed through, to affix the annulus
stent 10 to the disc annulus 42.
[0117] In an alternative embodiment, the upper section 14 of the
centralized vertical extension 12 may be perforated. The perforated
upper section 14 contains a plurality of holes that traverse the
longitudinal axis of upper section 14. The perforations are of such
a size and shape that sutures, tension bands, staples or any other
type of fixation device known in the art may be passed through, to
affix the annulus stent 10 to the disc annulus 42.
[0118] The lower section 16 of the centralized vertical extension
12 can comprise a pair of lateral extensions, a left lateral
extension 20 and a right lateral extension 22. The lateral
extensions 20 and 22 comprise an inside edge 24, an outside edge
26, an upper surface 28, and a lower surface 30. The lateral
extensions 20 and 22 can have an essentially constant thickness
throughout. The inside edge 24 is attached to and is about the same
length as the lower section 16. The outside edge 26 can be about 8
mm-16 mm in length. The inside edge 24 and the lower section 16
meet to form a horizontal plane, essentially perpendicular to the
centralized vertical extension 12. The upper surface 28 of the
lateral extensions 20 and 22 can form an angle from about
0.degree.-60.degree. below the horizontal plane. The width of the
annulus stent 10 may be from about 3 mm-8 mm.
[0119] Additionally, the upper surface 28 of the lateral extensions
20 and 22 may be barbed for fixation to the inside surface of the
disc annulus 42 and to resist expulsion through the aperture
44.
[0120] In an alternative embodiment, as shown in FIG. 4B, the
lateral extensions 20 and 22 have a greater thickness at the inside
edge 24 than at the outside edge 26.
[0121] In an illustrative embodiment, the annulus stent 10 is a
solid unit, formed from one or more of the flexible resilient
biocompatible or bioresorbable materials well know in the art. The
selection of appropriate stent materials may be partially
predicated on specific stent construction and the relative
properties of the material such that, after fixed placement of the
stent, the repair may act to enhance the healing process at the
aperture by relatively stabilizing the tissue and reducing movement
of the tissue surrounding the aperture.
[0122] For example, the annulus stent 10 may be made from:
[0123] A porous matrix or mesh of biocompatible and bioresorbable
fibers acting as a scaffold to regenerate disc tissue and replace
annulus fibrosus as disclosed in, for example, U.S. Pat. No.
5,108,438 (Stone) and U.S. Pat. No. 5,258,043 (Stone), a strong
network of inert fibers intermingled with a bioresorbable (or
bioabsorbable) material which attracts tissue ingrowth as disclosed
in, for example, U.S. Pat. No. 4,904,260 (Ray et al.).
[0124] a biodegradable substrate as disclosed in, for example, U.S.
Pat. No. 5,964,807 (Gan at al.); or
[0125] an expandable polytetrafluoroethylene (ePTFE), as used for
conventional vascular grafts, such as those sold by W.L. Gore and
Associates, Inc. under the trademarks GORE-TEX and PRECLUDE, or by
Impra, Inc. under the trademark IMPRA.
[0126] Furthermore, the annulus, stent 10, may contain hygroscopic
material for a controlled limited expansion of the annulus stent 10
to fill the evacuated disc space cavity.
[0127] Additionally, the annulus stent 10 may comprise materials to
facilitate regeneration of disc tissue, such as bioactive
silica-based materials that assist in regeneration of disc tissue
as disclosed in U.S. Pat. No. 5,849,331 (Ducheyne, et al.), or
other tissue growth factors well known in the art.
[0128] Many of the materials disclosed and described above
represent embodiments where the device actively promotes the
healing process. It is also possible that the selection of
alternative materials or treatments may modulate the role in the
healing process, and thus promote or prevent healing as may be
required. It is also contemplated that these modulating factors
could be applied to material substrates of the device as a coating,
or similar covering, to evoke a different tissue response than the
substrate without the coating.
[0129] In further embodiments, as shown in FIGS. 5AB-6AB, the left
and right lateral extensions 20 and 22 join to form a solid pyramid
or cone. Additionally, the left and right lateral extensions 20 and
22 may form a solid trapezoid, wedge, or bullet shape. The solid
formation may be a solid biocompatible or bioresorbable flexible
material, allowing the lateral extensions 20 and 22 to be
compressed for insertion into aperture 44, then to expand
conforming to the shape of the annulus' 42 inner wall.
[0130] Alternatively, a compressible core may be attached to the
lower surface 30 of the lateral extensions 20 and 22, forming a
pyramid, cone, trapezoid, wedge, or bullet shape. The compressible
core may be made from one of the biocompatible or bioresorbable
resilient foams well known in the art. The core can also comprise a
fluid-expandable membrane, e.g., a balloon. The compressible core
allows the lateral extensions 20 and 22 to be compressed for
insertion into aperture 44, then to expand conforming to the shape
of the annulus' 42 inner wall and to the cavity created by
pathologic extrusion or surgical removal of the disc fragment.
[0131] In an illustrative method of use, as shown in FIGS. 11A-D,
the lateral extensions 20 and 22 are compressed together for
insertion into the aperture 44 of the disc annulus 42. The annulus
stent 10 is then inserted into the aperture 44, where the lateral
extensions 20, 22 expand. In an expanded configuration, the upper
surface 28 can substantially conform to the contour of the inside
surface of the disc annulus 42. The upper section 14 is positioned
within the aperture 44 so that the annulus stent 10 may be secured
to the disc annulus 42, using means well known in the art.
[0132] In an alternative method, where the length of the aperture
44 is less than the length of the outside edge 26 of the annulus
stent 10, the annulus stent 10 can be inserted laterally into the
aperture 44. The lateral extensions 20 and 22 are compressed, and
the annulus stent 10 can then be laterally inserted into the
aperture 44. The annulus stent 10 can then be rotated inside the
disc annulus 42, such that the upper section 14 can be held back
through the aperture 44. The lateral extensions 20 and 22 are then
allowed to expand, with the upper surface 28 contouring to the
inside surface of the disc annulus 42. The upper section 14 can be
positioned within, or proximate to, the aperture 44 in the
subannular space such that the annulus stent 10 may be secured to
the disc annulus, using means well known in the art.
[0133] In an alternative method of securing the annulus stent 10 in
the aperture 44, as shown in FIG. 9, a first surgical screw 50 and
second surgical screw 52, with eyeholes 53 located at the top of
the screws 50 and 52, are inserted into the vertebral bodies,
illustratively depicted as adjacent vertebrae 54 and 56. After
insertion of the annulus stent 10 into the aperture 44, a suture 40
is passed down though the disc annulus 42, adjacent to the aperture
44, through the eye hole 53 on the first screw 50 then back up
through the disc annulus 42 and through the orifice 18 on the
annulus stent 10. This is repeated for the second screw 52, after
which the suture 40 is secured. One or more surgical sutures 40 are
placed at about equal distances along the sides of the aperture 44
in the disc annulus 42. Reapproximation or closure of the aperture
44 is accomplished by tying the sutures 40 in such a fashion that
the sides of the aperture 44 are drawn together. The
reapproximation or closure of the aperture 44 enhances the natural
healing and subsequent reconstruction by the natural tissue
crossing the now surgically narrowed gap in the annulus 42.
Preferably, the surgical sutures 40 are biodegradable but permanent
non-biodegradable forms may be utilized. This method should
decrease the strain on the disc annulus 42 adjacent to the aperture
44, precluding the tearing of the sutures through the disc annulus
42.
[0134] It is anticipated that fibroblasts will engage the fibers of
the polymer or fabric of the intervertebral disc stent 10, forming
a strong wall duplicating the currently existing condition of
healing seen in the normal reparative process.
[0135] In an additional embodiment, as shown in FIGS. 1A-B, a
flexible bladder 60 is attached to the lower surface 30 of the
annulus stent 10. The flexible bladder 60 comprises an internal
cavity 62 surrounded by a membrane 64, where the membrane 64 is
made from a thin flexible biocompatible material. The flexible
bladder 60 is attached to the lower surface 30 of the annulus stent
10 in an unexpanded condition. The flexible bladder 60 is expanded
by injecting a biocompatible fluid or expansive foam, as known in
the art, into the internal cavity 62. The exact size of the
flexible bladder 60 can be varied for different individuals. The
typical size of an adult nucleus is about 2 cm in the semi-minor
axis, 4 cm in the semi-major axis, and 1.2 cm in thickness.
[0136] In an alternative embodiment, the membrane 64 is made of a
semi-permeable biocompatible material. The mechanical properties of
the injectate material may influence the performance of the repair
and it is contemplated that materials which are "softer" or more
compliant as well as materials that are less soft and less
compliant than healthy nucleus are contemplated within the scope of
certain embodiments of the invention. It must be understood that in
certain embodiments the volume added to the subannular space may be
less than equal to or larger than the nucleus volume removed. The
volume of the implant may vary over time as well in certain
embodiments.
[0137] In an illustrative embodiment, a hydrogel is injected into
the internal cavity 62 of the flexible bladder 60. A hydrogel is a
substance formed when an organic polymer (natural or synthetic) is
cross-linked via, covalent, ionic, or hydrogen bonds to create a
three-dimensional open-lattice structure, which entraps water
molecules to form a gel. The hydrogel may be used in either the
hydrated or dehydrated form.
[0138] In a method of use, where the annulus stent 10 has been
inserted into the aperture 44, as has been previously described and
shown in FIGS. 12 A-B, an injection instrument, as known in the
art, such as a syringe, is used to inject the biocompatible fluid
or expansive foam into the internal cavity 62 of the flexible
bladder 60. The biocompatible fluid or expansive foam is injected
through the annulus stent 10 into the internal cavity 62 of the
flexible bladder 60. Sufficient material is injected into the
internal cavity 62 to expand the flexible bladder 60 to fill the
void in the intervertebral disc cavity. The use of the flexible
bladder 60 is particularly useful when it is required to remove all
or part of the intervertebral disc nucleus.
[0139] The surgical repair of an intervertebral disc may require
the removal of the entire disc nucleus, being replaced with an
implant, or the removal of a portion of the disc nucleus thereby
leaving a void in the intervertebral disc cavity. The flexible
bladder 60 allows for the removal of only the damaged section of
the disc nucleus, with the expanded flexible bladder 60 filling the
resultant void in the intervertebral disc cavity. A major advantage
of the annulus stent 10 with the flexible bladder 60 is that the
incision area in the annulus 42 can be reduced in size, as there is
no need for the insertion of an implant into the intervertebral
disc cavity.
[0140] In an alternative method of use, a dehydrated hydrogel is
injected into the internal cavity 62 of the flexible bladder 60.
Fluid, from the disc nucleus, passes through the semipermeable
membrane 64 hydrating the dehydrated hydrogel. As the hydrogel
absorbs the fluid the flexible bladder 60 expands, filling the void
in the intervertebral disc cavity.
[0141] In an alternative embodiment, as shown in FIG. 13, the
annulus stent 10 is substantially umbrella shaped, having a central
hub 66 with radially extending struts 67. Each of the struts 67 is
joined to the adjacent struts 67 by a webbing material 65, forming
a radial extension 76 about the central hub 66. The radial
extension 76 has an upper surface 68 and a lower surface 70, where
the upper surface 68 contours to the shape of the disc annulus' 42
inner wall when inserted as shown in FIG. 17A-C, and where the
lower surface 70 contours to the shape of the disc annulus' 42
inner wall when inserted as shown in FIG. 16A-C. The radial
extension 76 may be substantially circular, elliptical, or
rectangular in plan shape. Additionally, as shown in FIG. 20, the
upper surface 68 of the radial extension 76 may be barbed 82 for
fixation to the disc annulus' 42 inner wall and to resist expulsion
through the aperture 42.
[0142] As shown in FIGS. 14 and 15, the struts 67 are formed from
flexible material, allowing the radial extension 76 to be collapsed
for insertion into aperture 44, then the expand conforming to the
shape of the inner wall of disc annulus 42. In the collapsed
position, the annulus stent 10 is substantially frustoconical or
shuttlecock shaped, and having a first end 72, comprising the
central hub 66, and a second end 74.
[0143] In an alternative embodiment, the radial extension 76 has a
greater thickness at the central hub 66 edge than at the outside
edge.
[0144] In an embodiment, the annulus stent 10 is a solid unit,
formed from one or more of the flexible resilient biocompatible or
bioresorbable materials well known in the art.
[0145] Additionally, the annulus stent 10 may comprise materials to
facilitate regeneration of disc tissue, such as bioactive silica
based materials that assist in regeneration of disc tissue as
disclosed in U.S. Pat. No. 5,849,331 (Ducheyne, et al.), or other
tissue growth factors well known in the art.
[0146] Alternatively, as shown in FIG. 21, a compressible core 84
may be attached to the lower surface 70 of the radial extension 76.
The compressible core 84 may be made from one of the biocompatible
or bioresorbable resilient foams well known in the art. The
compressible core 84 allows the radial extension 76 to be
compressed for insertion into aperture 44 then to expand conforming
to the shape of the disc annulus' 42 inner wall and to the cavity
created by pathologic extrusion or surgical removal of the disc
fragment.
[0147] In an additional embodiment, as shown in FIGS. 18A and 18B,
a flexible bladder 80 is attached to the lower surface 70 of the
annulus stent 10. The flexible bladder 80 comprises an internal
cavity 86 surrounded by a membrane 88, where the membrane 88 is
made from a thin flexible biocompatible material. The flexible
bladder 86 is attached to the lower surface 70 of the annulus stent
10 in an unexpanded condition. The flexible bladder 80 is expanded
by injecting a biocompatible fluid or expansive foam, as known in
the art, into the internal cavity 86. The exact size of the
flexible bladder 80 can be varied for different individuals. The
typical size of an adult nucleus is 2 cm in the semi-minor axis, 4
cm in the semi-major axis and 1.2 cm in thickness.
[0148] In an alternative embodiment, the membrane 88 is made of a
semi-permeable biocompatible material.
[0149] In a method of use, as shown in FIGS. 16A-16C, the radial
extension 76 is collapsed together, for insertion into the aperture
44 of the disc annulus 42. The radial extension 76 is folded such
the upper surface 68 forms the outer surface of the cylinder. The
annulus stent 10 is then inserted into the aperture 44, inserting
the leading end 72 though the aperture 44 until the entire annulus
stent 10 is within the disc annulus 42. The radial extension 76 is
released, expanding within the disc 44. The lower surface 70 of the
annulus stent 10 contours to the inner wall of disc annulus 42. The
central hub 66 is positioned within the aperture 44 so that the
annulus stent 10 may be secured to the disc annulus 42 using means
well known in the art.
[0150] It is anticipated that fibroblasts will engage the fibers of
the polymer of fabric of the annulus stent 10, forming a strong
wall duplicating the currently existing condition of healing seen
in the normal reparative process.
[0151] In an alternative method of use, as shown in FIGS. 17A-17C,
the radial extension 76 is collapsed together for insertion into
the aperture 44 of the disc annulus 42. The radial extension 76 is
folded such that the upper surface 68 forms the outer surface of
the stent, for example in a frustoconical configuration as
illustrated. The annulus stent 10 is then inserted into the
aperture 44, inserting the tail end 74 through the aperture 44
until the entire annulus stent 10 is in the disc. The radial
extension 76 is released, expanding within the disc. The upper
surface 68 of the annulus stent 10 contours to the disc annulus' 42
inner wall. The central hub 66 is positioned within the aperture 44
so that the annulus stent 10 may be secured to the disc annulus 42,
using means well known in the art.
[0152] In one illustrative embodiment, the barbs 82 on the upper
surface 68 of one or more strut 67 or other feature of the radial
extension 76, engage the disc annulus' 42 inner wall, holding the
annulus stent 10 in position.
[0153] In a method of use, as shown in FIGS. 12A-12B, where the
annulus stent 10 has been inserted into the aperture 44, as has
been previously described. Similarly, for the stent shown in FIGS.
18 through 21, an injection instrument, as known in the art, such
as a syringe, can be used to inject the biocompatible fluid or
expansive foam into the internal cavity 86 of the flexible bladder
80. The biocompatible fluid or expansive foam is injected through
the annulus stent 10 into the internal cavity 86 of the flexible
bladder 80. Sufficient material is injected into the internal
cavity 86 to expand the flexible bladder 80 to fill the void in the
intervertebral disc cavity. The material can be curable (i.e.,
glue). The use of the flexible bladder 80 is particularly useful
when it is required to remove all or part of the intervertebral
disc nucleus.
[0154] It should be noted that in any of the "bag" embodiments
described herein one wall or barrier can be made stiffer and less
resilient than others. This relatively stiff wall member can then
be placed proximate the annulus wall and can advantageously
promote, in addition to its reparative properties, bag containment
within the annulus.
[0155] FIG. 22 shows a further aspect of the present invention.
According to a further illustrative embodiment, a simplified
schematic cross section of a vertebral pair is depicted including
an upper vertebral body 110, a lower vertebral body 112 and an
intervertebral disc 114. An aperture or rent 116 in the annulus
fibrosus (AF) is approached by a tube 118, which is used to deliver
a device 120 according to a further aspect of the present
invention. The device 120 may be captured by a delivery tool 122
through the use of a ring or other fixation feature 124 mounted on
the repair device 120.
[0156] FIG. 23 shows a delivery method similar to that depicted in
FIG. 22, with the exception that the tube 118A has a reduced
diameter so that it may enter into the sub-annular space of the
disc 114 through the aperture or rent.
[0157] Turning to FIG. 25, according to a further aspect of the
present invention, the delivery of the device 120 through the
delivery tube 118 or 118A may be facilitated by folding the arms or
lateral extensions 128, 130 of the device to fit within the lumen
of the tube 118 or 118A so that the stent or device 120 is
introduced in a collapsed configuration. The device 120 is moved
through the lumen of the tubes 118 or 118A through the use of
delivery tool 122. FIG. 25 shows the arms deflected in a distal, or
forward direction for insertion into the delivery tube 118 or 118A
while FIG. 24 shows the arms 128, 130 deflected into a proximal
position. FIG. 26 shows the device 120 curled so that one arm 128
is projecting distally, or in a forward direction, and the other
arm 130 is projecting proximally, or in a rearward direction.
Because the lateral extent of the device is relatively flexible,
whether the device is of natural or synthetic material, other
collapsible configurations consistent with the intent of this
invention are also possible, including twisting, balling, crushing,
etc.
[0158] FIG. 27 shows the device 120 having a series of peripheral
barb structures typified by barb 132 located at the edges. In
operation, these barbs may be forced into the annulus fibrosus as
seen in connection with FIG. 28. Barb placement can be anywhere on
the device 120 provided that at least some number of barbs are
likely to find annulus fibrosus tissue to anchor in during
placement. For a simple aperture or rent, placement on the
periphery of the device body is a reasonable choice, but for
complex tears, it may be desirable to place a plurality of barbs on
the device not knowing in advance which barbs will find tissue to
anchor in during placement.
[0159] FIG. 29 shows an alternative fixation strategy where a pair
of barbs 134 and 136 are plunged into the annulus fibrosus from the
exterior of the annulus while the device 120 is retained in the
sub-annular space by means of a tether 142. Although there are a
wide variety of fixation devices in this particular example, a
tether 142 may be knotted 145 with the band 144 holding the barbs
134 and 136 together to fix the device in the sub-annular space.
The knot is shown in an uncinched position to clarify the
relationship between the tether 142 and the bands 144. Using this
approach, the device can be maintained in a subannular position by
the barbed bands while the tether knot is cinched, advantageously
simultaneously reapproximating the annulus to close the aperture
while drawing the device into sealing, bridging engagement with the
subannular wall of the annulus fibrosus.
[0160] FIG. 30 shows an alternative fixation strategy where the
barbs 148 and 150 are sufficiently long that they can pierce the
body of the device 120 and extend all the way through the annulus
fibrosus into the device 120. In this configuration, the band 144
connecting the barbs 148 and 150 may be tightened to gently
restrain and position the device 120 in the sub-annular space, or
tightened with greater force to reapproximate the aperture or
rent.
[0161] FIG. 31 shows a still further illustrative embodiment
according to another aspect of the present invention. In this
embodiment, a metal substrate 160 is incorporated into the device
120. This piece can be machined from flat stock and includes the
loop 162 as well as barbs typified by barb 164. When formed in to
the device 120 the structure shown in FIG. 31 is used in a manner
analogous to FIG. 27 and FIG. 28.
[0162] Stents can expand to be planar, for example as shown
hereinabove in FIGS. 4, 8, 9, 11 and 12, or they can expand to be
three-dimensional as shown hereinabove in FIGS. 5 and 10. FIGS.
34-36 depict a further three dimensional patch/stent using an
autograft formed of fascial tissue. FIG. 34 shows the superior
vertebral body 202 and the inferior vertebral body 204 surrounding
a disc having an annulus fibrosus 206 and nucleus pulposus 203 in
the subannular space. According to this illustrative embodiment of
the invention, a suture 210 is passed from outside the annulus
through the wall of the annulus on one side of an aperture 208 and
into the subannular space as shown. The suture is then passed back
out through the annular wall on an opposing side of the aperture
208 leaving a loop or sling 212 of suture in the subannular space.
As shown in the posterior view on the right side of FIG. 34, more
than one suture can be applied. Turning to FIG. 35, a fascial
autograft 214 is then inserted through the aperture 208 into the
subannular space using, for example, forceps 216. FIG. 36 shows the
fascial stent/patch 214 fully inserted into the subannular space
within the suture sling 212. The closure of the aperture is
accomplished simultaneously with pulling the autograft 214 toward
the annular wall as shown in FIG. 37. The suture 210 can be cinched
218 or tied to maintain the closure and the fixation of the
patch/stent.
[0163] Patches can be folded and expanded in a single plane or in
three dimensions. As shown in FIGS. 24-25 and 41 for example,
collapsing the patch can be accomplished laterally, whether the
device is a single material or composite. Other embodiments, such
as that shown in FIG. 1 can collapse vertically, and still others
such as that shown in FIG. 26, longitudinally. Others can collapse
in three dimensions, such as those shown in FIGS. 13-15 and 36.
Devices which expand in three dimensions can be packaged in a
restraining jacket, such as a gelatine shell or "gelcap" for
example, or a mesh of biosorbable or dissolvable material, that
would allow for facile placement and subsequent expansion.
[0164] Patches can also be constructed of a single component, as
shown for example in FIG. 36, made of autograft or a synthetic
material such as Dacron, or for example where the stent is a
gelcap. They can be made of multiple components. An exemplary stent
(not shown) can be made from a polymeric material, for example
silicone rubber, which can be formed to have a natural unstressed
shape, for example that of a "Bulb". A stylet or push-rod can, for
example, be inserted on the inside of the bulb to stretch the bulb
into a second shape which is thinner and elongated. The second
shape is sufficient to place within the aperture in the annulus.
Upon placement of the device within the sub-annular space, the
push-rod is removed and the bulb assumes it natural, unstressed
state, assuming a larger dimension within the sub-annular space.
Although silicone is used in this example, other metallic
constructs could also be envisioned such as a Nitinol braided
device that has a natural unstressed shape and assumes a second
shape under tension for the delivery of the device. It is also
contemplated that the opposite scenario can also accomplish the
similar objective. In this alternative embodiment, the device can
have a first configuration that is unstressed and elongated and
assumes a second, larger configuration (bulb) under stress. In this
embodiment, a portion of the stylet or rod that is used to
mechanically activate the device would be left behind to hold the
expansion element in its stressed configuration.
[0165] Multiple components could include a frame to help with
expansion of the device and a covering to obtain biocompatibility
and tissue ingrowth. Examples of different frame configurations
might include an expandable "Butterfly" or "Figure-8" configuration
that could be constructed of wire material, such as Nitinol or
multiple wires. Exemplary embodiments showing frame members 502 are
depicted in FIG. 41A-E. Of course, other configurations such as
diamonds or other rounded or polygonal shapes can be used. The
diamond frame is a construct that takes a first form that is
smaller and expands to a larger frame. The diamond elements could
be constructed from a single wire or from multiple wires.
Alternatively, the members could be constructed of elements that
are moveable fixed at each of the ends to allow expansion. A tether
or attachment device 504 is also depicted, which may be a suture, a
wire, a screw, or other attachment means known in the art.
[0166] The frame could be cut from a single material, such as flat
stock Nitinol to accomplish the same objective, as shown for
example in FIG. 31. Such shapes can be cut from flat stock using
known methods, for example, laser cutting. A heat forming step
could also be employed, as known in the art, to form barbs 132 in a
shape that passes out of the flat plane of the stock material, as
shown in FIG. 27 for example.
[0167] Another frame configuration, also not shown, is that of a
spiral or coil. The "Coil" design can be, for example, a spring
steel or other biocompatible material that is wrapped to a first
"wound" smaller configuration and expands to a larger unwrapped,
unwound configuration.
[0168] Depending on the size of the openings in the frames
described above, each of these concepts may or may not have a
covering over them in order to assure that the nucleus does not
re-extrude from the intervertebral disc space after placement of
the device, as well as to serve as substrate for the surrounding
tissue to naturally incorporate the device. Coverings might include
ePTFE, polyester, silicone, or other biocompatible materials.
Coverings could also include natural materials such as collagen,
cellulose, autograft, xenograft, allograft or similar materials.
The covering could also be biodegradable in nature, such as
polyvinyl lactic acid.
[0169] Frames that are not covered may be permeable, such as a
patch that is porous and allow for normal movement of fluids and
nutrients through the patch into and out of the annular ring while
maintaining nucleus fragments larger than the porosity of the
stent/patch within the subannular space. Depending on the material
that the frame is constructed, a surface finish may be added to
promote tissue ingrowth into the patch. For example, a titanium
sputtering of the device may allow it to be more easily
incorporated within the disc space. Alternatively, a NiTi or
tantalum foam could be added to the outer surface of the patch to
promote tissue ingrowth.
[0170] It is understood that there can be a variety of device
designs of patches to accomplish the expansion of a device from a
first configuration, to a second configuration to occupy the
sub-annular space and reduce re-extrusion of the nucleus. The
following device concepts are further discussed for additional
embodiments of a device and/or system for the repair of an
intervertebral disc annulus.
[0171] As mentioned hereinabove, the stent/patch according to the
present invention may comprise a mass of fascial autograft, and
that autograft may be contained in a covering of material to form
what will be referred to herein as a "bag". Of course, this term is
used not necessarily to connote a five-sided closed container so
much as to denote the notion of flexibly surrounding the volume of
a patch/stent material so that it can be manipulated in space.
[0172] In the most simplistic form, a prefabricated device of
sutures could be used to form the "sling" to hold the fascial
implant as discussed above. The advantage of this design over
simple placement of sutures to hold the autograft is better
containment and control of the autograft during and after
implantation. The "sling" or a "bag" surrounds the fascial
autograft to hold it in place. It is contemplated that other
materials, such as a polyester mesh, could be used instead of the
fascial autograft.
[0173] FIG. 38 shows an example of a pre-fabricated sling 300.
There are three sutures used in this example, 302, 304, and 306,
although there could be more or less sutures as would be understood
by one of ordinary skill in the art. A collar member 308 has
apertures or other features for attaching to the sutures. In this
example, the third suture 306 passes along or within the collar 308
to form a loop extending from the lateral extent of the collar 308.
The first and second sutures 302, 304 form loops from the superior
and inferior extents of the collar 308. Intersections 310 can
secure the loops to each other with small loops or knots in the
sutures, small fabric attachment pieces, or by small preformed
devices resembling grommets placed on the suture to aid in
securement. Other knot tying techniques known in the art can also
be employed. Turning to FIG. 39, the collar is depicted within the
subannular space where the loops surround a fascial autograft 314
which by pulling proximally the sutures 302, 304, 306 the graft is
collapsed into contact with the annular wall in a sealing manner.
The sutures can be made of known materials, e.g., biodegradable,
bioabsorbable or bioresorbable Vicryl or biocompatible nylon. The
collar can be made of a fabric material, e.g., polyester. During
placement, one end of some or each suture can be passed through the
inferior wall of the annulus and the other end can be passed
through the superior wall surrounding the aperture. After the
placement of the sling into the wall of the annulus, the fascial
autograft is placed within the sling. The sutures are tightened to
bring the tissues together and also to help reapproximate the
aperture, as the collar size will be selected based on the
surgeon's judgment according to the degree of reapproximation
desired.
[0174] Other constructions can also be used to accomplish the same
objective, such as a "bag" 404 formed of expandable PTFE as shown
in FIG. 40. The bag is placed through an aperture in the annulus
402. Additionally, a one way seal 406 can be positioned behind the
aperture 408. Suturing techniques for introducing cardiac valves
could be employed to place the seal. It is understood that there
could be multiple constructs to accomplish the same objective and
this is only given as an example.
[0175] The are a variety of ways to affix the device to the
sub-annular wall of the annulus in addition to those discussed
hereinabove. The following exemplary embodiments are introduced
here to provide inventive illustrations of the types of techniques
that can be employed to reduce the time and skill required to affix
the patch to the annulus, versus suturing and tying a knot.
Discussed hereinabove is the use of sutures, staples and other
fixation devices, such as those passed through slot 18 to affix the
patch to the annulus as shown in FIG. 1. FIG. 20 also depicts the
use of "barbs" on the surface of the stent to facilitate fixation
to the annulus. In a simple example, as shown in FIG. 20, a
patch/stent could be compressed, passed through a guide tube such
as tubes 18, 18A shown in FIGS. 22 and 23, and expanded within the
sub-annular space. As shown in FIG. 42, the expanded patch 602 is
shown having barbs 604, along with detachable delivery tool 608 and
guide tube 606. Once expanded, barbs 604 on the outer surface of
patch 602 can be used to fix the patch into the inner wall 610 of
the annulus 612 by pulling the patch back proximally, into the
sub-annular wall 610, and pushing forward distally on the guide
tube 606, thus driving the barbs 604 into the annulus and drawing
the inner and outer tissues of the annulus together and
reapproximating the disc on either side of the aperture, as shown
in FIG. 43. After the placement of the patch, the delivery tool and
guide tube are removed.
[0176] The advantage of this design described above is that it
requires very little time and skill to place and secure the patch
to the annulus while also drawing the tissues together.
[0177] Materials of the patch could be similar to materials
discussed hereinabove. Anchoring barbs could be made of a
biocompatible material, for example a metallic material (e.g., NiTi
alloy, Stainless steel, Titanium), or a polymeric material (e.g.,
polypropylene, polyethylene, polyurethane). Anchoring barbs could
also be a biodegradable/bioabsorbable material, such as a
polyglycolic acid (PGA), a polylevolactic acid (PPLA), a
polydioxanone (PDA) or for example a racemic polylactic acid
(PDLLA). If the barbs included a biodegradable/bioabsorbable
material, it is anticipated that the barbs might have sufficient
holding strength for a sufficient period of time to allow the patch
to be incorporated into the annulus during the healing process. The
advantage of having the anchoring barb of FIGS. 42 and 43 being
biodegradable/bioabsorbable is that after the incorporation of the
patch into the annulus there may be no need for the barbs to
provide fixation. However, barbs pointing toward the outer surface
of the annulus could pose a long term risk of penetration out of
the annulus due to migration, and potentially impinging on the
nerve root and spinal canal. Biodegradable/bioabsorbable barbs
address and advantageously reduce any long-term risk in this
regard.
[0178] It is also possible that the barbs could be made of both a
biocompatible component and a biodegradable/bioabsorbable
component. For example, the very tip of the barb could be made of a
biodegradable material. The barb could penetrate the annulus wall
with a rather sharp point, but after degradation the point of the
barb would become dull. In this embodiment, the point would no
longer induce continued scar formation after the patch has been
incorporated, nor pose a risk of penetrating out of the annulus
onto the nerve root.
[0179] Another fixation means includes the passing of "anchoring
bands" into the wall of the annulus, vertebral bodies (superior,
inferior, or both), or the Sharpey's Fibers (collagenous fibers
between the junction of the annular fibers and vertebral bodies).
In the following example of anchors, the barbs or bands are affixed
to the annulus/vertebral bodies/Sharpey's fibers. Another element,
for example a suture, cinch line, or a staple is utilized to attach
the anchor bands to the patch, and thus hold the patch in proximity
to the inner wall of the annulus. In addition, these bands may
re-approximate the tissues at the aperture.
[0180] Revisiting one example of using barbs to anchor the device
is shown in FIG. 9, described hereinabove. Barbs or bone anchor
screws 50 ands 52 are passed into the superior and inferior
vertebral bodies 54 and 56, respectively. Superiorly, suture 40 is
passed through the outer wall of the annulus, to the sub-annular
space. The suture is then passed through the eyelet 53 of bone
anchor 52 and then passed through the wall of the annulus from the
sub-annular space to the outer wall of the annulus. The inferior
end of the suture is similarly passed through the annulus, eyelet
of the bone anchor, and back through the wall of the annulus. Both
ends of suture 40 are tightened and tied. The advantage of this
concept is that it allows for fixation of the device to a surface
that is known to be present in all discectomy procedures--the
vertebral bodies. Whereas, it is possible, depending on the
location and size of a natural rent that there may not be
sufficient annulus accessible to fixate the device directly to the
annulus. In addition to providing a location for fixation,
anchoring into the vertebral bodies may provide a more stable
anchor surface.
[0181] Another example of fixating the device to inner wall of the
annulus is shown in FIG. 29, and is further illustrated by FIGS.
44-47. As discussed hereinabove, with reference to FIGS. 22-30, a
patch 120 is placed with a delivery tool 122, through the inner
lumen of a guide tube 118, into the sub-annular space and then
expanded. This step can also be seen in FIGS. 45 and 46, where a
patch 702 is folded and passed through a guide tube 706 and is held
by a delivery tool 704. Also shown is a anchor band or staple 709
and an anchor band delivery device 708. Within the guide tube, or
within the delivery tool, there is a suture line or cinch line 710
that is attached to the center of the patch 702. This can be seen
in FIG. 44a with the guide tube 706 removed. As seen in FIGS. 45C
and 46A, the guide tube 706 is retracted after the patch 702 has
been expanded and deployed. Next, an anchor band delivery tool 708
is used to deliver one or more "bands" 709 onto the outer surface
of the annulus. These are intended to be anchored into the wall of
the annulus with barb shapes that do not allow for the barbs to be
pulled back through the annulus. The anchor bands resemble a
construction of a "staple". The bands could actually be constructed
by connecting two barbed elements with, for example, a suture
between the two barbed elements. The barbs and the connection band
between the barbs could be constructed of the same material or of
different materials. For example, the barbed part of the anchor
band could be a biodegradable/bioabsorbable material (such as
polyglycolic acid) or could be constructed of a metallic or
polymeric biocompatible material (e.g., titanium, NiTi alloy,
stainless steel, polyurethane, polypropylene). In addition, the
band that connects these barbs can be constructed of materials that
are similar to the barbs, or different materials. For example, the
connection band could be a biodegradable/bioabsorbable suture, such
as Vicryl, or a biocompatible material such as polypropylene. In
addition, it is possible that these elements are constructed from
multiple materials to accomplish the objective of anchoring into
the annulus and providing for a fixation site to draw the patch
within proximity of the sub-annular wall.
[0182] FIGS. 44B and 44C show the placement of the anchor bands 709
into the annulus 712 with the anchor band delivery tool 708. FIGS.
46A and 46B schematically show the placement of the anchor bands
709 into the wall of the annulus 712 and the retraction of the
anchor band delivery device 708, with the patch delivery tool 704
still in place. FIG. 44D depicts a representative anchor band 709,
having a pair of stainless steel barbs 709'' connected by a suture
709'. FIG. 44E shows the patch 702, anchor bands 709, and cinch
line or suture 710 with the delivery tools removed, prior to
drawing the patch and the tissues of the annulus together. In this
embodiment there is a pre-fabricated knot 714 on the cinch line,
which is described further in FIG. 47B, although other knots are
possible. FIG. 47a also shows a posterior view of the patching of
the annulus with this device with knot 714. In this stent/patch 702
a pair of loops of 7 mm suture 709 are shown, which engage the
cinch line and slip knot. These suture loops connect to the barbs
directly, as in FIG. 44, or loop to surgical staples, or are placed
directly into the annulus. The presence of a pre-fabricated knot on
the cinch line makes the process of repairing quicker since there
is no need to tie a knot. It also facilitates drawing the tissues
together. The use of the cinch line and a pre-fabricated knot can
be placed by, for example, an external tube such as a knot pusher.
FIG. 44E is similar to the FIG. 29 described hereinabove prior to
"tying" the knot 145. FIG. 44F shows the drawing of the patch and
the annular tissues together by pulling on the suture in the
direction "A" indicated by the arrow. In this case, the Knot Pusher
has been removed from the cinch line 710. The suture 710 is drawn
proximally to draw the patch 702 into engagement with the inner
wall of the annulus to seal the aperture from within, as well as
draw the walls of the annulus together to reapproximate the annular
aperture. FIG. 46C and FIG. 44G show the cinch line suture 710 tied
and drawing the annular tissues together, after the excess suture
line has been cut. It is also apparent from this device, fixation
and delivery system that the outer surfaces of the aperture are
also drawn together for re-approximation.
[0183] The cinching of the bands and the patch also allows for
taking-up the slack that allows for the accommodation of varying
sizes. For example, the thickness of the annular wall surrounding
the aperture can vary from 1 mm up to 10 mm. Therefore, if the
anchor bands have a set length, this design with an cinch line
accommodates different dimensions of the thickness of the wall of
the annulus by drawing the "slack" of the bands together within the
aperture.
[0184] Although it has been described here as patch placement that
involves two lateral anchor bands with a suture to draw the patch,
bands and tissues together, one or more bands could be used and two
bands is only an example. Furthermore, the anchor bands were placed
with the barbs in a superior-inferior fashion. One skilled in the
art would recognize that these could be placed at different
locations surrounding the aperture. Moreover, although it was
described that the bands are placed into the annulus, these anchor
bands could also be placed in the vertebral bodies as shown in FIG.
48A generally at 800, or the Sharpey's Fibers 802, as shown in FIG.
48B generally at 804.
[0185] Although the patch depicted in the example above does not
have barbs attached to the patch, it is also possible to have the
barbs as described hereinabove to further promote the fixation of
the patch to the inner wall of the annulus.
[0186] Finally, although the drawings depict an aperture that lends
itself to re-approximating the tissues, it is conceivable that some
apertures, whether natural or surgically made, may be relatively
large and therefore might require the placement of additional
material within the aperture to act as a scaffold for tissue in
growth, between the patch on the inner wall of the annulus and the
anchor bands located on the outer wall. An example of material to
fill the aperture might include autograft para-spinal fascial
tissue, xenograft, allograft, or other natural collagenous
materials. The filler material could also be of a biocompatible
material such as a Dacron material. FIG. 51 shows the illustrative
filling of an aperture with implant material 716 prior to cinching
the suture 710.
[0187] As an alternative embodiment of the present invention, the
anchor bands 709 as described previously (anchor bands into
annulus) could be sufficiently long enough to pass through the
annulus and then through the patch. The barbs in this embodiment
have an engaging involvement with the patch. This concept was
previously discussed hereinabove in connection with FIG. 30.
Further illustration of such a system is schematically shown in
FIGS. 49 and 50. Passing the barbs through the patch, in this
embodiment, provides additional security and safety of reducing the
possibility that the barbs may migrate after implantation. In this
application of the invention, the suture cinch line may (FIG. 50)
or may not (FIG. 30) be used in addition to the anchor bands to
draw the tissues together and reduce tissue movement surrounding
the aperture.
[0188] In addition, although the bands shown in FIGS. 49 and 50
take the form of a "barb", they could as easily take a form of a
simple T-barb 720, as shown in FIG. 52E, or a C-type element
wherein the object is to have irrevocable engagement with the patch
device 702 after the penetration through the patch. A T-type
attachment, when aligned longitudinally with the suture, passes
through the patch. The T section then rotates to prevent the suture
anchor from being pulled back through the patch. In another
embodiment a "C` retainer made of a superelastic material may be
attached to the end of the suture band. The C retainer is loaded
into a needle wherein it is held straight. The needle is used to
pass the C retainer and suture through the patch and deploy the
retainer in a second configuration in the shape of a "C".
[0189] It is also foreseen within the scope of the invention that
there may be patch designs which will accommodate the placement and
securement of the anchor to the fabric that covers the frame of the
patch. For example, a frame for a patch that is made out of metal
such as Nitinol can provide for "windows". The device, covered with
a mesh fabric, for example silicone or Dacron, would therefore
allow the anchoring barbs to be passed through the "windows" in the
frame of the patch. In this case, the barb can be secured to the
patch in the fabric covering the frame.
[0190] Alternatively, the patch can be secured by passing barbs
that engage the lattice of the patch frame. These embodiments of
the invention illustrate designs in which the barbs engage with the
vertical, horizontal or criss-crossed structures/members of the
frame. In this case, the barbs would pass through the mesh or
lattice of the frame and they would be unable to pass back out of
the structure.
[0191] Although this discussion refers to "anchor bands" that are
shown to be two anchors connected by a suture, it is also
contemplated that single barbs with sutures are placed and the
sutures' ends, at the outer surface of the annulus, are tied after
placement through the patch.
[0192] One objective in the designs discussed hereinabove is to
provide a way to "pull up the slack" in a system to adjust the
length of sutures and for anchor bands. According to the present
invention, a technique referred to as the "Lasso Cinch Knot" was
developed as a means to draw the anchor bands together with a
suture cinch line that is incorporated into the patch design. FIG.
53 gives further description of the use of the Lasso embodiment. In
essence, patch and frame constructs are used that incorporate the
"barbs through the patch" design. Once the barbs have passed
through the patch, an internal lasso 722 is drawn tight around the
sutures of the anchor bands and thus draws the extra suture
material within the patch. The internal lasso gathers the sutures
of the bands, and as the lasso is tightened, it cinches together
the sutures of the bands and therefore tightens them and eliminates
slack, bringing the patch/stent into closer or tighter engagement
with the annulus wall. The patch in FIG. 53 additionally provides
for a diamond shape grid pattern, which advantageously provides a
grid which will while allowing a probe or similar instrument to
pass through with little resistance, provides resistance to a barb
or other restraining feature on the instrument. The frame shown can
be made from nitinol, and the locking and holding windows shown at
the center of the figure would allow for rotation about the z-axis
during placement. A slipknot technique using, for example a knot
pusher, would aid in the loop pulling process by the lasso. The
internal loop (lasso) can be tacked to the outside corners of the
patch/stent, in order to hold the loop at the outer edges of the
patch frame. When cinching the lasso knot, the loop can be pulled
free from some or all of its tacked attachment points to the frame,
to prevent deformation of the planar shape of the frame when
cinching the lasso. As above, the frame can be a composite
structure or sandwich formed with some type of mesh fabric. The
proximal mesh fabric can be bonded fully to the patch frame, for
example through the use of an adhesive, for instance a silicone.
Adhesive, advantageously, can fill the interstices of the grid
pattern while allowing for easy probe penetration and protection of
the suture lines. Protection of the suture lines is advantageous
when the lasso is used to pull and bunch a group of band sutures
together.
[0193] It is also contemplated within the scope of the present
invention that sutures 710' can be preattached directly to a
stent/patch. As shown in FIG. 52A several separate barbs 709'''
into the annulus 712 can be directly attached to the patch 702.
Each "barb" of FIG. 52A can be independently placed into the
annulus after the patch is deployed. This can be seen to be similar
to the embodiment including barbs 709'''' of FIG. 55.
[0194] An alternative embodiment for securing a patch 902 and
reapproximating a rent is providing each of the separate barbs with
sutures having variable lengths as shown in FIG. 56. Each
independent suture barb 904 is placed into the annulus 906 or into
the patch 902 with the barb delivery tool 908. After the placement,
all of the suture lines 910 are drawn taught, by drawing on the
free ends that exit the patch delivery tool 912. A locking element
914 that uses a gasket 916 and threading mechanism is attached to
the patch 902 and is used to tighten the gasket 916 around the
distal ends of the sutures 910. The patch delivery tool 912 is
removed and the extra suture length is cut. It is also possible
that the gasket mechanism could be a press-fit to accommodate the
tightening of the sutures to the patch.
[0195] Alternatively, the locking mechanism can be as shown in FIG.
57, although in this case the engagement of the locking element
914' takes part on the patch. Pulling the suture 910 in the
direction of arrow B will tighten and lockingly hold in tension to
aid in securement and reapproximation. The adjustable length suture
band between the two anchors allows slack to be taken up between
the anchors 916. Two T-type anchors are illustratively shown in
this example, but multiple anchors of differing configurations
could be used. The locking features can be included on the feature
band, as depicted here, and allow for substantially one-way locking
engagement with the anchor members. This adjustability
advantageously promotes for the accommodation of varying thickness
of the annulus from patient to patient. The suture slack in this
embodiment may be taken up to close the defect in the annulus
and/or to shorten the band between anchors for a secondary cinching
of multiple tensioned suture bands as described hereinabove.
[0196] The cinch line and the Lasso concepts in essence try to
facilitate the re-approximation and drawing of tissues together in
a fast and simple way. Other contemplated embodiments for "tension"
elements include using an elastic coupler as a part of the anchor
band used to fixate the device. The elastic coupler can be expanded
for placement, and upon release, can draw tension to pull the
tissues together. The coupler could be made of a biocompatible
metal or polymer, or could be constructed of a
biodegradable/bioabsorbable material.
[0197] Similarly, an alternative embodiment to cause tension within
the device and draw the tissues together after placement of the
anchor bands might include an elastic band or band with a spring
which one end can be attached to the anchor bands and the other end
attached to the patch. Alternatively, the anchor bands might, in
and of themselves may be made of an elastic band between the barbs,
or may contain a spring element between the barbs. Such an
embodiment can be made to resemble a so-called "Bobber Spring."
Again, it is contemplated that the elastic or resilient element
could be made from a wide variety of metals, polymeric, or
biodegradable/bioabsorbable material.
[0198] FIG. 59 describes an embodiment where the patch element 1002
takes the form of a mesh seal. The securement is effected by a hook
having a barb element 1004 that penetrates the inner surface of the
annulus 1006, while the inner connection of the hook (barb) 1004 is
attached to the patch in such a fashion as to add tension between
the outer surface of the annulus and the inner surface in proximity
to the patch, thus drawing the annular tissues together. The
patch/stent 1002 contains a spring ribbon element 1008 which can be
formed from nitinol or other spring material. Hooks 1010 are then
deployed to "grab" the annulus, either through penetration or
through grasping into the aperture 1012 as shown.
[0199] FIGS. 54a-f shows another embodiment of a means to draw the
suture lines together to cause tension between the inner and outer
tissues of the annulus. Anchor bands, for example T-barbs 720' are
placed through the annulus and the patch, and they are secured to
the patch 702. "Slack" in the suture of the anchor band is
"rotated" around a detachable portion of the delivery tool 704' and
a locking element, for example a screw configuration 724 as shown
in the drawing, is used to lock the extra suture line in place
affixed to threads 726 with the patch 702. The delivery tool 704'
is then removed.
[0200] FIG. 58 shows alternative embodiments for tightening
"anchoring barbs" with different configurations of sutures and
cinch lines. For example in FIG. 58B each independent barb has a
looped suture attached to it. Through each of these loops is passed
a cinch line, which contains a knot. After placement of the barbs
within the annulus, and possibly through the patch, the cinch line
draws the loops of the barbs together. The advantage of this
embodiment is that it allows for the independent placement of
multiple barbs and the ability to draw all of them together.
[0201] Although cinch lines have been described as using a knot to
"lock" the length of the suture, other mechanisms could also lock
the length, as shown in FIG. 57. The locking of the suture length
is accomplished through a mechanical element located on the barb
which engages with three dimensional elements attached to the
suture line which mechanically press fit through the engagement
element on the barb, thus locking the length of the suture line
into place.
[0202] Although the embodiments of FIG. 57 and FIG. 58 depict the
use of a single locking mechanism (e.g., knot on cinch line), it is
conceivable that various designs could use more than one locking
element to achieve the re-approximation and drawing together the
tissue surrounding an aperture.
[0203] A further exemplary embodiment of the invention further
describes a concept illustrated by FIG. 41e, for example. A braided
patch 1100 such as depicted in FIGS. 60 through 66, is a further
illustrative embodiment of the present invention that can be
deployed into the subannular space to act as a barrier to the
extrusion of the nucleus pulposus.
[0204] The "patch" 1100 is constructed from a braided tube of
filaments 1102. The ends 1104 of the braided tube are heat-sealed
to keep the braid from unraveling and the seals also provide
structural integrity to the patch when deployed. The braided patch
1100 is woven on a braiding machine with multiple filaments 1102 to
create the structure. For example, the patch can be woven with 72
polyester filaments in order to create the construct that readily
deploys into the annular defect, promotes cell ingrowth into the
device, and retains an anchor after it has been placed through the
wall of the annulus and through the patch. Changing the number of
filaments 1102 in the patch, the material of the filaments, the
dimension of the filaments (e.g., diameter), as well as the
configuration of the filaments (e.g., cross-sectional area), or
changing the braid pattern, can create differences in the
characteristics of the patch. The braided patch can be made on a
standard Steeger braider, or similar type braiding machine, that
can handle braiding from anywhere from 16 filaments at a time, to
up to 196 filaments. Preferably the patch is braided with between
32 to 144 filaments.
[0205] The filaments 1102 of the patch can be made of different
materials or all of the filaments in a patch can be of like
material and dimensions. The filaments can be metallic, such as a
stainless steel, a nickel titanium alloy, or other metallic
materials. The patch 1100 can also be made from biocompatible
polymeric material such as polyethyleneteraphthalate, polyester,
polyethylene, or polypropylene, for example. It is also conceivable
that the patch can be braided from biodegradable materials, such as
polyglycolic acid (PGA), polylactic acid (PLA), or other material
that may degrade and be re-absorbed by the body over time.
[0206] It is also possible to braid the patch 1100 with multiple
materials and/or multiple dimensions of the filaments. For example,
the patch can be braided with 32 filaments of a polymeric PET
material and 32 filaments of polyester yarn material to create a
patch that is optimal for sealing an annulus. The combination of
different filament materials, sizes, cross-sectional configuration,
number of filaments, and braiding pattern can be used to construct
a braided patch that can be delivered into the sub-annular space,
while acting as a scaffold to induce healing of the aperture.
[0207] The braided patch has advantages in that it can be placed
through an aperture in the wall of the annulus that is relatively
small, but then expand to a dimension that is substantially greater
than the aperture. For example, it is possible to construct the
braided tube to be less than 5 mm in diameter, whereas in its fully
deployed state it could be greater than, for example, 20 mm.
[0208] Referring to FIG. 62, the non-deployed braided patch 1100 is
affixed on the distal end of the patch delivery tool 1200. It is
situated in a fashion that is co-axial with the delivery tool's
delivery members. Further detail of the deployment mechanism can be
seen in FIG. 63. The braided patch 1100 is placed on the distal end
of the inner delivery member 1202. The heat-set distal cuff 1104 of
the patch is situated within a depressed region on the distal
region of the inner delivery member 1216. The distal portion of the
delivery member 1216 is slotted as shown in FIG. 65, and, in the
non-deployed state, contains a co-axial retention member 1208 that
acts to press the slotted potions of the inner delivery member
apart, and thus securing the distal cuff of the patch 1104 on the
distal region of the inner delivery member 1202. The proximal
portion of the patch abuts and is in contact with an outer pusher
member 1204. In the non-deployed state, the delivery device is
passed into the aperture of the annulus. Once inside the annular
aperture, the outer pusher member 1204 of the delivery device 1200
is pushed toward the distal end of the device, while the inner
delivery member 1202 is pulled proximally. This action of moving
these members in such a fashion results in the braided patch
expanding perpendicular to tube's axis, as shown in FIGS. 61 and
64.
[0209] Once the patch 1100 has been expanded to its fully expanded
state, a cinch line 1212 that is connected to the distal and
proximal ends of the patch can be tightened and a knot, such as a
Roeder knot, can be used to hold the braided patch in its expanded
configuration. Although, the device is shown with a cinch knot
1214, it is possible that a locking element may not be needed,
depending on the means used to fixate the patch into the annulus.
It is possible that no locking means is necessary. It is also
possible that alternative locking means can be contemplated to keep
the braided patch in its expanded form. A knot pusher 1210 can also
be employed to manipulate the knot locking device 1214.
[0210] Once the device patch has been expanded into its final
configuration in the aperture and subannular space, the retention
member can be removed from the distal portion of the inner member
by slidably pulling the proximal end of the retention member in a
proximal direction. Removing the retention member relieves the
stress holding the distal cuff of the patch in place and allows the
patch to be slideably removed from the distal end of the delivery
device, and thus deployed into the subannular space.
[0211] As depicted in FIG. 66, the patch 1100 can be affixed to the
inner surface either before or after the deployment of the patch
from the delivery device. It is also contemplated that this patch
can be affixed to the inner surface of the annulus by the various
fixation means described in other parts of this application. For
example, anchor bands as shown in FIG. 29 could be used to
penetrate the annulus and the patch to anchor the patch into the
sub-annular space. It is also conceivable that single T-anchors
1310 with a band 1314 (e.g., suture) could be delivered through the
annulus 1306 and patch 1100 with the portion of the suture on the
outer surface of the annulus locked to the outer surface with a
knot, pledget, or other locking device 1316. It is also conceivable
that the patch could be affixed to the inner surface of the annulus
through the use of adhesives, such as cyanoacrylate, fibrin glue,
polymer protein, polyurethane or other material used to cure the
patch in the subannular space in situ. Path 1312 illustrated
another possible suture path through the bone of the vertebra to
penetrate and hold a T-anchor member 1310 in the patch.
[0212] A device suitable for affixing a stent or patch to a disc
annulus is disclosed in copending U.S. patent application Ser. No.
10/327,106, filed on Dec. 24, 2002, and commonly assigned herein,
the contents of which are incorporated herein by reference.
[0213] The advantages of this design, given the right selection of
filament dimension, configuration, material, braid pattern, and
number of filaments is that it can be easily delivered to the
annular repair site, have the flexibility to take the shape of the
annular defect while maintaining the mechanical integrity needed to
remain within the disc space upon loading. Another advantage, again
with the appropriate selection of material, filament configuration,
braiding, dimensional considerations, and multiple filament weaves,
is that one can construct a patch that is conducive, in its
deployed state, for incorporation of fibrosis and the fibrotic
healing of the annular defect. Finally, the patch can be designed
so that when it is in its delivered state, it can easily receive
one or more anchor bands through the braided filaments while
retaining the T-anchor or other similar type fixation device, after
passing the fixation device through the patch.
[0214] All patents referred to or cited herein are incorporated by
reference in their entirety to the extent they are not inconsistent
with the explicit teachings of this specification, including; U.S.
Pat. No. 5,108,438 (Stone), U.S. Pat. No. 5,258,043 (Stone), U.S.
Pat. No. 4,904,260 (Ray et al.), U.S. Pat. No. 5,964,807 (Gan et
al.), U.S. Pat. No. 5,849,331 (Ducheyne et al.), U.S. Pat. No.
5,122,154 (Rhodes), U.S. Pat. No. 5,204,106 (Schepers at al.), U.S.
Pat. No. 5,888,220 (Felt et al.) and U.S. Pat. No. 5,376,120
(Sarver et al.).
[0215] Various materials know to those skilled in the art can be
employed in practicing the present invention. By means of example
only, the body portions of the stent could be made of NiTi alloy,
plastics including polypropylene and polyethylene, stainless steel
and other biocompatible metals, chromium cobalt alloy, or collagen.
Webbing materials can include silicone, collagen, ePTFE, DACRON,
polyester, polypropylene, polyethylene, and other biocompatible
materials and can be woven or non-woven. Membranes might be
fashioned of silicone, propylene, polyester, SURLYN, PEBAX,
polyethylene, polyurethane or other biocompatible materials.
Inflation fluids for membranes can include gases, liquids, foams,
emulsions, and can be or contain bioactive materials and can also
be for mechanical, biochemical and medicinal purposes. The stent
body, webbing and/or membrane can be drug eluting or bioabsorbable,
as known in the medical implant arts.
[0216] Other embodiments of the invention will be apparent to those
skilled in the art from consideration of the specification and
practice of the invention disclosed herein. It is intended that the
specification and examples be considered as exemplary only, with a
true scope and spirit of the invention being indicated by the
following claims.
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