Abstract:
The present invention provides methods and devices for annulus disc repair. The methods and devices are particularly suited to the repair and/or reconstruction of the spinal disc wall (annulus) after surgical invasion or pathologic rupture, with reduced failure rate as compared to conventional surgical procedures.

Description:
CROSS-REFERENCE TO A RELATED APPLICATION  
       [0001]     This application is a continuation of U.S. patent application Ser. No. 11/350,843, filed Feb. 10, 2006, which is a continuation of U.S. patent application Ser. No. 10/327,106, filed Dec. 24, 2002, now U.S. Pat. No. 7,004,970, issued Feb. 28, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 10/133,339, filed Apr. 29, 2002, now U.S. Pat. No. 7,052,516, issued May 30, 2006, and claims benefit to U.S. Provisional Patent Application 60/309,105, which is a continuation-in-part of U.S. patent application Ser. No. 10/075,615, filed Feb. 15, 2002, and 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, issued Jun. 26, 2003, 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. This application is also related to, and claims the benefit of, U.S. patent application Ser. No. 10/085,040, filed Mar. 1, 2002. 
     
    
     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 is restoration of disc wall integrity and reduction of the failure rate (3-21%) of a common surgical procedure (disc fragment removal or discectomy).  
       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, contributing to 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]     Surgical repairs or replacements of displaced or herniated discs are attempted approximately 390,000 times in the USA each year. Until the present invention, there was no known way to repair or reconstruct the annulus. Instead, surgical procedures to date are designed to relieve symptoms by removing unwanted disc fragments and relieving nerve compression. 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]     The present inventors have found, advantageously and contrary to accepted practice, that the annulus tissue may be sutured and that annular healing may be facilitated by reapproximation of annular tissue. Methods and devices for carrying out annular repair and/or reconstruction are a subject of the present invention.  
       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 of the invention includes, in one embodiment 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. The method according to the invention occludes the aperture , helps to prevent the migration of nucleus pulposus through the aperture, and promotes healing of the aperture through tissue reapproximation.  
         [0013]     The objects and various advantages of the invention will be apparent from the description which follows. In general, the implantable medical devices are placed, positioned, and affixed to the annulus to reduce re-extrusion of the nucleus through the aperture by: closing or partially closing the aperture; restoring the natural integrity of the wall of the annulus; and promoting 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]     The methods and devices of the present inventions may create 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 promote faster and 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 devices of the present invention may 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 an embodiment of 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. The patch, when used, can be secured in place with 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&#39;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 incorporates the concept of pulling the tissues together that surround the aperture, the inner surface, and the outer surface of the annulus to help close the aperture, increase the integrity of the repair, and promote healing.  
         [0021]     An example of the technique and placement of the device according to one embodiment of the invention is as follows:  
         [0022]     1. An aperture is created measuring approximately, for example, 6 mm×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. 32   a ,  32   b ,  33   a  and  33   b.    
         [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×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 seal and/or repair the intervertebral disc. In each of the representative devices of this embodiment of the invention[[, ,]] 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 herein below 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, the following devices may 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]     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.  
         [0039]     In some clinical instances, for instance, where a wall of an annulus contains a sufficiently small aperture, or where a wall of the annulus is weakened or thin, the present invention may be advantageously accomplished without the use of a patch. Thus, in another embodiment, the present invention also includes a method of repairing or reconstructing an annulus comprising placing at least one fixation device into, or through, the wall of an annulus surrounding the aperture (or weakened or thin portion of the annulus) and causing, or allowing, the devices to be drawn in tension thereby pulling together, wholly or partially, the tissues surrounding annular tissue. Devices for use with the method are also disclosed. The inventive method forms a mechanical barrier, or partial mechanical barrier, to the migration of nucleus pulposus and/or helps to promote healing of the aperture through tissue reapproximation.  
         [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. 32   a  shows a herniated disc in perspective view, and  FIG. 32   b  shows the same disc after discectomy.  
         [0075]      FIG. 33   a  shows a top view of the disc post-discectomy, and  FIG. 33   b  shows a posterolateral 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 reappoximate 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]     FIGS.  41 A-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.  44 A-G show a still further illustrative embodiment of an introduced and expanded annulus stent/patch being fixated and the aperture reapproximated.  
         [0087]     FIGS.  45 A-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.  46 A-C schematically depict the cinch line of  FIG. 45  being fixated through use of a surgical staple device.  
         [0089]     FIGS.  47 A-B show an illustrative embodiment of a suturing arrangement for securing a patch/stent in the annulus.  
         [0090]     FIGS.  48 A-B depict a still further illustrative embodiment where fixation sutures are placed into the vertebral body or the Sharpey fibers.  
         [0091]     FIGS.  49 A-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.  50 A-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.  52 A-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]     FIGS.  54 A-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]     FIGS.  56 A-C shows a still further exemplary embodiment of the present invention having external fixation anchors.  
         [0099]     FIGS.  57 A-C shows a still further exemplary embodiment of the present invention having external fixation anchors.  
         [0100]     FIGS.  58 A-C 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 delivered configuration of fixation means that may result from the use of a single device to deliver multiple barbs or T-anchors sequentially or simultaneously.  
         [0103]     FIGS.  61 A-B show a suitable configuration of an anchor band delivery device.  
         [0104]      FIG. 62A  shows an anchor band delivery device comprising two devices, each with at least one T-anchor (bards) and band with pre-tied knot and optional knot pusher.  
         [0105]      FIG. 62B  shows the anchor band delivery device of  FIG. 62   a  with bards deployed.  
         [0106]      FIG. 62C  shows the fixation device of  FIG. 62   a - b  in place and optional knot pusher.  
         [0107]      FIG. 62D  shows annular tissues reapproximated with a fixation device according to an embodiment of the invention.  
         [0108]      FIG. 63  shows an anchor and band delivery device according to one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0109]     Reference will now be made in detail to selected illustrative embodiments of the invention, with occasional reference to 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. In all embodiments where biodegradable materials are indicated, suitable biodegradable materials may include, but are not limited to, biodegradable polyglycolic acid, swine submucosal intestine, collagen, or polylactic acid. Other suitable suturing (and band) materials include, e.g., polymeric materials such as PET, polyester (e.g., Dacron™), polypropylene, and polyethylene.  
         [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]     Where necessary or desirable, the method can be augmented by placing 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 . FIGS.  8 A-B, for example, show a biocompatible membrane 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.  
         [0113]     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.  
         [0114]     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 .  
         [0115]     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&#39;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 .  
         [0116]     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 .  
         [0117]     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°-60° below the horizontal plane. The width of the annulus stent  10  may be from about 3 mm-8 mm.  
         [0118]     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 .  
         [0119]     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 .  
         [0120]     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.  
         [0121]     For example, the annulus stent  10  may be made from:  
         [0122]     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.).  
         [0123]     a biodegradable substrate as disclosed in, for example, U.S. Pat. No. 5,964,807 (Gan at al.); or  
         [0124]     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.  
         [0125]     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.  
         [0126]     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.  
         [0127]     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.  
         [0128]     In further embodiments, as shown in FIGS.  5 AB- 6 AB, 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&#39;  42  inner wall.  
         [0129]     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&#39;  42  inner wall and to the cavity created by pathologic extrusion or surgical removal of the disc fragment.  
         [0130]     In an illustrative method of use, as shown in FIGS.  11 A-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.  
         [0131]     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.  
         [0132]     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 .  
         [0133]     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.  
         [0134]     In an additional embodiment, as shown in FIGS.  10 A-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.  
         [0135]     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.  
         [0136]     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.  
         [0137]     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.  
         [0138]     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.  
         [0139]     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 semi-permeable 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.  
         [0140]     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&#39;  42  inner wall when inserted as shown in FIGS.  17 A-C, and where the lower surface  70  contours to the shape of the disc annulus&#39;  42  inner wall when inserted as shown in FIGS.  16 A-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&#39;  42  inner wall and to resist expulsion through the aperture  42 .  
         [0141]     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 .  
         [0142]     In an alternative embodiment, the radial extension  76  has a greater thickness at the central hub  66  edge than at the outside edge.  
         [0143]     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.  
         [0144]     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.  
         [0145]     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&#39;  42  inner wall and to the cavity created by pathologic extrusion or surgical removal of the disc fragment.  
         [0146]     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.  
         [0147]     In an alternative embodiment, the membrane  88  is made of a semi-permeable biocompatible material.  
         [0148]     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.  
         [0149]     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.  
         [0150]     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&#39;  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.  
         [0151]     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&#39;  42  inner wall, holding the annulus stent  10  in position.  
         [0152]     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.  
         [0153]     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.  
         [0154]      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 .  
         [0155]      FIG. 23  shows a delivery method similar to that depicted in  FIG. 22 , with the exception that the tube  118 A has a reduced diameter so that it may enter into the sub-annular space of the disc  114  through the aperture or rent.  
         [0156]     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  118 A 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  118 A 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  118 A 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  118 A 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.  
         [0157]      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.  
         [0158]      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 band  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.  
         [0159]      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.  
         [0160]      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 .  
         [0161]     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.  
         [0162]     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.  
         [0163]     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.  
         [0164]     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 FIGS.  41 A-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.  
         [0165]     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.  
         [0166]     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.  
         [0167]     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.  
         [0168]     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.  
         [0169]     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.  
         [0170]     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.  
         [0171]     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.  
         [0172]      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 reappoximate the aperture, as the collar size will be selected based on the surgeon&#39;s judgment according to the degree of reapproximation desired.  
         [0173]     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.  
         [0174]     There are a variety of ways to affix the device to the subannular 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 ,  18 A 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.  
         [0175]     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.  
         [0176]     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.  
         [0177]     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.  
         [0178]     Another fixation means includes the passing of “anchoring bands” into the wall of the annulus, vertebral bodies (superior, inferior, or both), or the Sharpey&#39;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&#39;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.  
         [0179]     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.  
         [0180]     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. 44   a  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, as shown in  FIGS. 44 and 46 , 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 tissues together.  
         [0181]      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. 47   a  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.  
         [0182]     The cinching of the anchor 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 a 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.  
         [0183]     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 two 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&#39;s Fibers  802 , as shown in  FIG. 48B  generally at  804 , adequately allowing for placement of barbs into adequate tissue.  
         [0184]     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.  
         [0185]     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 .  
         [0186]     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 by 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.  
         [0187]     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”.  
         [0188]     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.  
         [0189]     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.  
         [0190]     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&#39; ends, at the outer surface of the annulus, are tied after placement through the patch. It is also possible that these “single anchors” could be retained by a suture “pledget” on the outer wall of the annulus to better hold the outer surface, or could include a suture (or band) locking device.  
         [0191]     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.  
         [0192]     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 .  
         [0193]     An alternative embodiment for securing a patch  902  and reapproximating a rent or incision is to provide 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 (which may be referred to as a locking clamp, or band locking device, or band retention device)  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.  
         [0194]     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 barb  916 . Pulling the suture  910  in the direction of arrow B will tighten and lockingly hold in tension to aid in securing and reapproximating the annulus. The adjustable length suture band between the two anchors allows slack to be taken up between the anchors  916 . Two T-type anchors are shown in this example, but multiple anchors of differing configurations could be used. The locking features can be included on the suture 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.  
         [0195]     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.  
         [0196]     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.  
         [0197]      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.  
         [0198]      FIGS. 54   a - 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.  
         [0199]      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.  
         [0200]     Although cinch lines have been described as using a knot to “lock” the length of the suture, other mechanisms could also lock the band locking device, 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.  
         [0201]     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.  
         [0202]     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.).  
         [0203]     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.  
         [0204]     The foregoing discussion relates to the use of a patch (or stent). In some clinical instances, the method of the invention may be accomplished without the use of a patch, however. Moreover, a patch may be unnecessary to repair small apertures or apertures of certain shapes, or certain weakened or thin portion(s) of an annulus. The invention therefore also encompasses methods for repairing or reconstructing annular tissue that do not necessarily involve the use of a patch, and to fixation devices and tools useful in carrying out these methods.  
         [0205]     A comparatively simple embodiment of this method is shown in  FIG. 7 . In this embodiment, an annulus may be repaired or reconstructed by use of surgical sutures  40 . One or more surgical sutures  40  may be placed at suitable (e.g., about equal) distances along the sides of an aperture  44  (or along the boundaries of thin or weakened regions) in the annulus  42 . Any suitable surgical needle or its functional equivalent may be used to place the suture. In cases where thinned or weakened regions of the annulus wall are in need of repair or reconstruction, it may be advantageous to place a surgical incision in the affected region to create an aperture prior to proceeding with the method. Reapproximation or closure of the aperture  44  may be accomplished by tying the sutures  40  so that the sides of the aperture  44  (or boundaries of a thin or weakened region) are drawn together. Without wishing to be bound by theory, it is believed that 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 sutures may be utilized.  
         [0206]     The use of sutures alone may be insufficient. Accordingly, the present invention also provides additional fixation devices that may be used to reapproximate and hold annular tissue. Such fixation devices, as described above, may contain an anchor portion and a band portion. The anchor portion serves to fix the fixation device in the annular tissue. The band portion, attached to the anchor portion, serves to reapproximate annular tissue when tightened and secured. At least one fixation device is placed into, or though, the wall of an annulus in a portion surrounding the aperture (or in a boundary region surrounding a thin or weakened portion of the annulus). The device is then drawn in tension to pull together, wholly or partially, the surrounding annular tissue.  
         [0207]     The anchor portion and bands are as described above, and preferably (though not necessarily) shaped to enter the annular tissue relatively easily and to resist removal. Examples of suitable anchor devices include but are not limited to barbs, T-anchors, or combinations thereof.  FIG. 44   d  depicts an exemplary anchor device containing barbs.  
         [0208]     The band and the barbs may be separate elements or comprise one continuous element. Bands and barbs may be made of the same or different materials.  
         [0209]     The bands may be string-like, made from suture or similar material, or of any construction or dimension that is amenable to the delivery and engagement of the fixation device. For example, the band may have a width greater than, in some embodiments far greater than, its thickness. The suture material may in some embodiments have a width:height ratio of 1.25:1. In some embodiments, bands may be constructed, wholly or partially, of a mesh tube. Moreover, different segments along the length of the band may have different dimensions and constructions. For example, the band may be constructed of thin material, such as nickel titanium alloy or stainless steel wire, close to the anchor barbs, while the middle portion that spans the aperture may comprise a much wider band made of optionally softer material.  
         [0210]     As described above, the fixation materials may be biocompatible or reabsorbable, or both. Examples of biocompatible or reabsorbable materials for use, e.g., in band and/or barb (or anchor), include, but are not limited to, polylactic acid, polyglycolic acid, silk suture, polyethylene, stainless steel, polypropylene, nickel titanium alloy, polyester and their functional equivalents. Advantageously, the very tip of the barb could be made of biodegradable material. The barb may be constructed of a material having a shape sufficiently sharp to penetrate the annulus wall, but sufficiently susceptible to wear to dull upon insertion.  
         [0211]     As an example of the foregoing, the embodiment depicted in  FIG. 29  may be adapted for use without patch  120 . In this embodiment, barbs  134  and  136  are plunged (inserted) into the annulus fibrosus from the exterior of the annulus. Band  144  resides on the outer surface of the annulus and connects barbs  134  and  136 . When knot  145  is tightened or cinched with tether  142  and band  144 , the tissues surrounding the aperture, the inner wall of the annulus, and the outer wall of the annulus, are drawn together. Similarly, the arrangement shown in  FIG. 30  may be modified by deletion of the patch  120 . Anchoring barbs  148  and  150 , attached to band  144 , may be cinched, pulling the appropriate tissues together.  
         [0212]     The function of the fixation devices of  FIGS. 29 and 30  are similar to anchor bands  709  shown in  FIGS. 44   c - 44   e  and  46   a - 46   c . In each of these embodiments, the fixation device spans the aperture and is used to draw together the tissues surrounding the aperture, the inner surface of the annulus, and the outer surface of the annulus. Thus, in certain clinical situations, such as in the repair of a small aperture, it is possible that a patch may be unnecessary and that cinching the fixation devices may be sufficient to close the aperture.  
         [0213]      FIGS. 57   a - c ,  58   a - c ,  60 ,  61   a ,  61   b ,  62   a - d , and  63  show additional examples of embodiments of the invention for annular repair or reconstruction without the use of a patch. For instance, in  FIGS. 57   a - c , in lieu of (or optionally in addition to) a patch, two anchors  916  are shown having been passed through the annulus to the subannular space. By drawing on band  910 , the inner and outer walls of the annulus are drawn together in tension, which reapproximates the tissue surrounding the aperture.  FIG. 57   c  shows a single anchor band across the opening in the annulus. Multiple anchor bands may also be placed along an incision or tear in the annulus.  
         [0214]     The fixation devices of the invention could be delivered as a pair of barbs attached by a single band, as shown in  FIG. 44   d , or each barb could be delivered individually. Alternatively, multiple barbs may be pre-attached to single or multiple bands for ease and speed of delivery. For example,  FIG. 60  shows a fixation device that has multiple anchors  916  (or barbs, not shown) connected together in a configuration similar to  FIGS. 58   b  and  58   c , with each anchor  916  being delivered individually into, or through, the nucleus of the annulus  712 . The anchors  910 , if present, may be shown as in the Figure. By drawing on the cinch line, the tissues surrounding the aperture, the inner wall of the annulus, and the outer wall of the annulus are drawn together. The knot of  FIG. 60  can be similar to the knot shown in  FIG. 47   b . Other types of knots, such as the knot shown in  FIG. 7 , may be used, however. Although knots are shown to affix the suture lines together, other means to lock, fasten, clip, retain, or secure the sutures together may also be used. For example,  FIG. 56   a  shows an alternative way to lock individual bands with barbs together with locking mechanism.  
         [0215]      FIG. 56   a  also shows an alternative embodiment of the fixation device which is contemplated wherein multiple anchor barbs  904  are placed individually with each anchor barb having a single band  910  that are drawn together with other barbs and bands.  
         [0216]     As previously mentioned, the present invention also encompasses delivery devices of the following description. The delivery devices of the present invention are configured to deliver at least one fixation device into (or through) the annulus or other surface or tissue. The delivery device will typically comprise a device or shaft having proximal and distal ends.  
         [0217]     The shaft of the device may be of any convenient length, typically from, e.g., 1 inch to 10 inches.  
         [0218]     Materials of which to make the device include, but are not limited to: metals, such as stainless steel, nickel, titanium alloy, and titanium; plastics, such as PTFE, polypropylene, PEEK, polyethylene, and polyurethane.  
         [0219]     Advantageously, the shaft of the device will have a cross-sectional shape suitable to accommodate an ejection rod and at least one fixation device. In one embodiment, at least a portion of the shaft of the device may be hollow, having a circular, elliptical, triangular, trapezoidal or other suitable cross-sectional area sufficient to accommodate an ejection rod, described below.  
         [0220]     The delivery device may also contain a handle or raised surface configured to accommodate the shape of surgeon&#39;s hands or fingers for easier handling. Such raised or configured portion may be made of the same or different material as the tube or shaft. Suitable materials include polymers, such as acrylic polymers, polyurethane; and metals, such as stainless steel and titanium.  
         [0221]     The delivery device may be configured to accommodate and deploy at least one fixation device, such as a barb or T-anchor with one or more associated bands. Advantageously, the distal end of the delivery device will comprise a hollow needle or cannula  711 , having a circular, elliptical, triangular, hexagonal or other inner cross sectional area, suitable to accommodate the cross-sectional shape of the fixation device within. The distal point of the cannula  711  is advantageously sharpened, as a needle, to accommodate insertion. The cannula  711  is advantageously cut obliquely as shown in  FIG. 63  to form a sharp leading surface or point for ease of insertion. The cannula  711  may contain a cut or groove along its side to accommodate one or more anchors  709  as shown (or barbs, not shown), e.g., in  FIG. 61   b  or  63 . In one embodiment, the at least one fixation device (including band and barb or T-anchor) is disposed within the cannula  711  as shown in  FIGS. 61   a ,  61   b , and/or  63 . Alternatively, the T-anchor  709  (or barb, not shown), or other fixation device may be hollow and disposed in a manner surrounding the device of the delivery device.  
         [0222]     The delivery device  708  will also advantageously contain within it an ejection rod  715 . The proximal end of the ejection rod  715  typically will contain an end portion  713  to function as a stopper, e.g., having a diameter larger than the remaining portion of the rod, such as is shown in  FIG. 61   a . The diameter of the remaining portion of the ejection rod  715  will be small enough for insertion within the shaft of the device  708 . Upon insertion of the cannula  711  into the location of choice, the ejection rod is pushed to deliver the fixation device. The delivery device is then removed.  
         [0223]     Advantageously, the ejection rod  715  and delivery device may be configured to deliver multiple fixation devices, sequentially or simultaneously. Thus, if multiple fixation devices are contained within the device, the ejection rod  715  and delivery device may be configured such that the rod  715  be pushed a first distance, sufficient to deliver a first fixation device. The device is then removed from the first insertion point and inserted into a second insertion point, where the ejection rod is then pushed a second distance for delivery of a second fixation device, and so-on as desired. For simultaneous delivery of multiple fixation devices, multiple delivery devices may be arranged in parallel (or substantially parallel). The distance between (or among) the delivery devices may be fixed or adjustable, as desired.  
         [0224]     The distance the ejection rod  715  is pushed to define a first, second, and subsequent distances may be regulated by feel. Alternatively, the distance can be regulated by the architecture of the device. For example, the shaft and ejection rod may be fitted with a notch-and-groove configuration, respectively. In such configuration, the notch in the outer surface of the ejection rod may be aligned with a groove in the inner surface of the device. The length of the groove defines a first distance. The ejection rod  715  would be then turned or rotated within the device, aligning the notch within the device to a second groove defining a second distance, and so-on. In an alternative embodiment, the ejection rod and anchor portion of the fixation device (e.g., barb or T-anchor) may surround the shaft of the device, as a sleeve surrounds an arm. In such a configuration, the delivery device would comprise a solid shaft and the ejection rod and fixation device would be at least partially hollow and disposed over the distal portion of the delivery device. Pushing the ejection rod in a proximal to distal direction would deploy the anchor portion of the fixation device.  
         [0225]      FIGS. 61   a  and  61   b  describe one embodiment of an anchor band delivery device  708  and fixation means.  FIG. 61 a  shows a general drawing of a delivery device.  FIG. 61   b  further depicts the distal end of the delivery device. Anchor band delivery device  708  contains two pointed needles or cannulas  711 . Each cannula  711  contains an anchoring T-type anchor  709  (or barb) positioned within the distal end of the cannula  711 . A band  709 ′ links the two anchors  709  (or barbs) together and a cinch knot  714  secures the anchors (or barbs). Cinch line  710  is pulled to decrease the length of the band  709 ′ that attaches the anchors  709 .  
         [0226]     Referring to  FIG. 62   a , anchor band delivery device  708  is inserted into the annulus  712  sufficiently to engage the inner layers of the annulus  712 , and preferably located at the inner wall of the annulus  712 . The anchors  709  are ejected from the delivery device by pressing the ejection rod  715  in a fashion to expel the T-anchors  709  (or barbs, not shown) from the device. For example, pressing on the proximal end of ejection rod  715  as shown in  FIG. 61   a  drives the ejection rod  715  in a distal direction, thus expelling the anchor from the device.  FIG. 62   b  shows the anchors  709  (or barbs) after being ejected.  FIG. 62   c  shows a knot pusher  716  attached to the device that can be used to tighten the knot  714  once the fixation device is secured into the annular tissue.  FIG. 62   c  shows the placement of two anchors  709 , or fixation devices (anchors and bands), after they have been delivered to the annulus and before the bands  709  have been tightened. The knot pushers  716  of both devices are still in contact with the knots and the delivery needles have been pulled back, away from the annulus.  FIG. 62   d  shows the final placement of the two anchor bands after drawing together the tissues surrounding the aperture  717 , the inner wall of the annulus  712 , and the outer wall of the annulus; and, after tightening and cutting the knot located on each anchor band.  
         [0227]     Although this drawing shows the passage of the bands superior and inferior to the aperture, these bands could also be placed in a multitude of locations to effect desired or equivalent outcomes.  
         [0228]     In addition, as previously described, one could use barbs having a multitude of configurations. One could also configure delivery devices to deliver one (as in  FIG. 63 ), two (as in  FIG. 61   a ), or more barbs simultaneously, and according to predetermined or variable distances or patterns. The delivery devices may also be configured to eject one, two, or more barbs sequentially. Further, the barbs could be delivered by a delivery device that does not require a cannula to cover the barb. In such a configuration, the barb may be disposed on the tip or outside of the delivery device&#39;s shaft, and removed therefrom upon injection into the desired location of the annulus or other tissue. Bands and knots may be pre-tied to accommodate each configuration, as previously discussed.  
         [0229]     For example, although  FIGS. 61 and 62   a - b  depict a device that places two anchors  709  banded together with one device, one could accomplish an equivalent or other desired result with a single device that delivers multiple barbs at the same time, as shown in  FIGS. 44   b  and  44   c.    
         [0230]      FIG. 63  shows an alternative delivery device that delivers two or more anchors (or barbs) from a single cannula  711 . In this embodiment, a first single anchor  709  is ejected from the cannula  711  by pushing the ejection rod  715  a first distance sufficient to eject the first anchor  709 , but insufficient to eject the second. Then the delivery device is removed from the first site and passed into another annular location. The second anchor (or barb), not shown, connected to the first anchor or barb by band, is ejected out of the cannula  711  by pushing the ejection rod  715  an additional distance sufficient to eject the second anchor (or barb) into a second fixation point in the annulus.  
         [0231]     Although much of this description has described placement of the anchors into the annulus (or soft tissue) of the disc, one could perform anchoring into other tissues surrounding the aperture, including the bone or Sharpey&#39;s fibers as previously described in  FIGS. 48   a  and  48   b , it is also contemplated that, given the delivery device construction, a bone drill or similar device may be necessary to facilitate the placement of the delivery device through the bony or similar tissue.  
         [0232]     The band  709 ′ connecting the thus implanted anchors (or barbs) advantageously contains a moveable knot  714  between the anchors. Suitable knots include, but are not limited to, the Roeder knot and its functional equivalents, and are advantageously, but not necessarily, pre-tied. After insertion of both anchors  709  (or barbs), the band  709 ′ is advantageously tightened by hand or by pushing on the knot with a knot-pusher or similar device. Although not shown in  FIG. 63 , the knot pusher may be integral to the delivery device. After drawing together the tissues surrounding the aperture, inner wall, and outer wall of the annulus, the excess suture line can be cut. It is also possible to use a cutting device integral to the delivery device to cut the band after cinching. Although the device shown in  FIG. 63  depicts two anchors being delivered from a single device, multiple anchors or barbs could be delivered from the same or a similar type of device.  FIG. 60  shows a delivered configuration of fixation means that may result from the use of a single device to deliver multiple anchors sequentially.  
         [0233]     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.