Source: http://www.google.com/patents/US20100204797?dq=5537618&ei=urENT6-uEoHegQe698i5Bw
Timestamp: 2015-05-07 07:12:27
Document Index: 729224506

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

Patent US20100204797 - Anulus lesion repair - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsMethods for repairing a damaged or weakened intervertebral disc are disclosed. According to one or more embodiments, a method comprises delivering a support member within an intervertebral disc having an anular defect, anchoring an anchor to a vertebral body adjacent the intervertebral disc, connecting...http://www.google.com/patents/US20100204797?utm_source=gb-gplus-sharePatent US20100204797 - Anulus lesion repairAdvanced Patent SearchPublication numberUS20100204797 A1Publication typeApplicationApplication numberUS 12/702,228Publication dateAug 12, 2010Filing dateFeb 8, 2010Priority dateAug 18, 1999Also published asUS7553329, US7658765, US20050234557, US20050240269Publication number12702228, 702228, US 2010/0204797 A1, US 2010/204797 A1, US 20100204797 A1, US 20100204797A1, US 2010204797 A1, US 2010204797A1, US-A1-20100204797, US-A1-2010204797, US2010/0204797A1, US2010/204797A1, US20100204797 A1, US20100204797A1, US2010204797 A1, US2010204797A1InventorsGregory H. Lambrecht, Robert Kevin Moore, Jacob Einhorn, Sean Kavanaugh, Chris Tarapata, Thomas BoyajianOriginal AssigneeIntrinsic Therapeutics, Inc.Export CitationBiBTeX, EndNote, RefManReferenced by (1), Classifications (98) External Links: USPTO, USPTO Assignment, EspacenetAnulus lesion repair
US 20100204797 A1Abstract
Methods for repairing a damaged or weakened intervertebral disc are disclosed. According to one or more embodiments, a method comprises delivering a support member within an intervertebral disc having an anular defect, anchoring an anchor to a vertebral body adjacent the intervertebral disc, connecting the anchor to the support member, and pulling the support member toward the anchor using the connection.
1. A method for repairing an anular lesion of an intervertebral disc comprising:
locating a defect in an anulus fibrosis, wherein said defect is proximate a herniated segment, wherein the herniated segment comprises anulus fibrosis tissue; delivering a support member within the intervertebral disc, wherein the support member comprises a plate or bar shaped device; securely establishing an anchor to a vertebral body adjacent said intervertebral disc and substantially opposite said defect with an anchor; connecting said anchor to said support member; and returning at least part of the herniated segment to a pre-herniated position substantially within a pre-herniated border of the herniated segment by pulling the support member towards the anchor. 2. The method of claim 1, wherein the vertebral body is a superior vertebral body.
3. The method of claim 1, wherein the vertebral body is an inferior vertebral body.
4. The method of claim 1, wherein the anchor is positioned at a site substantially opposite said defect.
5. The method of claim 1, wherein connecting said anchor to said support member comprises connecting said anchor to said support member with a connection member, wherein the connection member is configured for transmission of a tensile force along its length, thereby causing the herniated segment to move in the direction of its pre-herniated border.
6. The method of claim 5, wherein returning at least part of the herniated segment to a pre-herniated position comprises tightening the connection member.
7. The method of claim 6, further comprising maintaining tension between the anchor and the support member with the connection member once the herniated segment is returned to the pre-herniated position, thereby restricting motion of the herniated segment to within the pre-herniated border of the intervertebral disc.
8. The method of claim 1, further comprising positioning said support member along an innermost layer of the anulus.
9. The method of claim 1, wherein said anchor comprises a bone anchor.
10. The method of claim 1, further comprising closing said defect in the anulus fibrosis.
11. The method of claim 1, wherein delivering a support member within the intervertebral disc comprises delivering the support member through the defect in the anulus fibrosis.
12. A method for reinforcing an intervertebral disc comprising:
locating a herniated segment in an anulus fibrosis in an intervertebral disc; wherein the herniated segment comprises an anulus fibrosis tissue that protrudes outside its pre-herniated border; delivering a support member through said anulus fibrosis, wherein the support member comprises a plate or bar shaped device; securely establishing an anchor to a vertebral body adjacent said intervertebral disc; connecting the support member and the anchor with a connection member; tightening the connection member, thereby returning at least part of the herniated segment to a position substantially within said pre-herniated border by pulling the support member towards the anchor. 13. The method of claim 12, wherein tightening the connection member transmits a tensile force along the length of the connection member, thereby causing the herniated segment to move in the direction of its pre-herniated border.
14. The method of claim 12, wherein said anchor comprises a bone anchor.
15. The method of claim 12, wherein securely establishing said anchor comprises anchoring said anchor into the vertebral body adjacent said herniated segment.
16. The method of claim 15, wherein said vertebral body is a superior vertebral body.
17. The method of claim 15, wherein said vertebral body is an inferior vertebral body.
18. The method of claim 12, further comprising positioning said support member along an innermost layer of the anulus.
19. The method of claim 12, further comprising maintaining a tensile force of the connection member once the at least part of the herniated segment is retuned to the position substantially within the pre-herniated border, thereby restricting motion of the herniated segment to within the pre-herniated border of the intervertebral disc.
20. The method of claim 12, wherein delivering a support member through said anulus fibrosis comprises delivering the support member through a defect in the anulus fibrosis proximate the herniated segment. Description
This application is a continuation of U.S. application Ser. No. 10/972,106, filed Oct. 22, 2004, which is a continuation of U.S. patent application Ser. No. 10/970,589, filed Oct. 21, 2004, now U.S. Pat. No. 7,553,329, which claims benefit to U.S. Provisional Application No. 60/513,437, filed Oct. 22, 2003 and U.S. Provisional Application No. 60/613,958, filed Sep. 28, 2004, and is a continuation-in-part of U.S. application Ser. No. 10/194,428, filed Jul. 10, 2002, now U.S. Pat. No. 6,936,072, and is a continuation-in-part of U.S. application Ser. No. 10/055,504, filed Oct. 25, 2001, now U.S. Pat. No. 7,258,700, which is a continuation-in-part of U.S. application Ser. No. 09/696,636 filed on Oct. 25, 2000, now U.S. Pat. No. 6,508,839, which is a continuation-in-part of U.S. application Ser. No. 09/642,450 filed on Aug. 18, 2000, now U.S. Pat. No. 6,482,235, which is a continuation-in-part of U.S. application Ser. No. 09/608,797 filed on Jun. 30, 2000, now U.S. Pat. No. 6,425,919, and claims benefit to U.S. Provisional Application No. 60/311,586 filed Aug. 10, 2001, U.S. Provisional Application No. 60/149,490 filed Aug. 18, 1999, U.S. Provisional Application No. 60/161,085 filed Oct. 25, 1999 and U.S. Provisional Application No. 60/172,996 filed Dec. 21, 1999, the entire teachings of these applications being incorporated herein by reference.
The present invention relates generally to the surgical treatment of intervertebral discs in the lumbar, cervical, or thoracic spine that have suffered from tears in the anulus fibrosis, herniation of the nucleus pulposus and/or significant disc height loss.
An intervertebral disc provides a dynamic environment that produces high loads and pressures. Typically implants designed for this environment must be capable of enduring such conditions for long periods of time. Also, the difficulty and danger of the implantation procedure itself, due to the proximity of the spinal cord, limits the size and ease of placement of the implant. One or more further embodiments of the invention addresses the need for a durable fatigue resistant repair mesh capable of withstanding the dynamic environment generic to intervertebral discs.
Several embodiments of the present invention relate generally to anulus augmentation devices, including, but not limited to, surgical meshes, barriers, and patches for treatment or augmentation of tissues within pathologic spinal discs. One or more embodiments comprise resilient surgical meshes that may be compressed for minimally invasive delivery and which are robust, stable, and resist fatigue and stress. These meshes are particularly well suited for intervertebral disc applications because they are durable enough to withstand intense cyclical loading and resist expulsion through a defect while not degrading over time.
Several embodiments of the present invention seek to exploit the individual characteristics of various anulus and nuclear augmentation devices to optimize the performance of both within the intervertebral disc. Accordingly, one or more of the embodiments of the present invention provide minimally invasive and removable devices for closing a defect in an anulus and augmenting the nucleus. These devices may be permanent, semi-permanent, or removable. One function of anulus augmentation devices is to prevent or minimize the extrusion of materials from within the space normally occupied by the nucleus pulposus and inner anulus fibrosus. One function of nuclear augmentation devices is to at least temporarily add material to restore diminished disc height and pressure. Nuclear augmentation devices can also induce the growth or formation of material within the nuclear space. Accordingly, the inventive combination of these devices can create a synergistic effect wherein the anulus and nuclear augmentation devices serve to restore biomechanical function in a more natural biomimetic way. Furthermore, in one embodiment, both devices may be delivered more easily and less invasively. Also, in some embodiments, the pressurized environment made possible through the addition of nuclear augmentation material and closing of the anulus serves both to restrain the nuclear augmentation and anchor the anulus augmentation in place.
As used herein, the phrase �anulus augmentation device� shall be given its ordinary meaning and shall also include devices that at least partially cover, close or seal a defect in an intervertebral disc, including, for example, barriers, meshes, patches, membranes, sealing means or closure devices. Thus, in one sense, the anulus augmentation device augments the anulus by sealing a defect in the anulus. In some embodiments, one or more barriers, meshes, patches, membranes, sealing means or closure devices comprise a support member or frame. Thus, in one embodiment, a barrier that comprises a membrane and a frame is provided. As used herein, the terms augmenting or reinforcing (and variations thereto) shall be given their ordinary meaning and shall also mean supporting, covering, closing, patching, or sealing.
In one embodiment, one or more anulus augmentation devices are provided with one or more nuclear augmentation devices. In some embodiments, the anulus barrier is integral with the nucleus augmentation. In other embodiments, at least a portion of the barrier is separate from or independent of the nuclear augmentation.
In one embodiment of the present invention, a disc augmentation system configured to repair or rehabilitate an intervertebral disc is provided. The system comprises at least one anulus augmentation device, and at least one nuclear augmentation material. The anulus augmentation device prevents or minimizes the extrusion of materials from within the space normally occupied by the nucleus pulposus and inner anulus fibrosus. In one application of the invention, the anulus augmentation device is configured for minimally invasive implantation and deployment. The anulus augmentation device may either be a permanent implant, or it may removable.
The nuclear augmentation material may be in the form of liquids, gels, solids, or gases. In one embodiment, the nuclear augmentation material comprises materials selected from the group consisting of one or more of the following: steroids, antibiotics, tissue necrosis factors, tissue necrosis factor antagonists, analgesics, growth factors, genes, gene vectors, hyaluronic acid, noncross-linked collagen, collagen, fibren, liquid fat, oils, synthetic polymers, polyethylene glycol, liquid silicones, synthetic oils, saline and hydrogel. The hydrogel may be selected from the group consisting of one or more of the following: acrylonitriles, acrylic acids, polyacrylimides, acrylimides, acrylimidines, polyacryInitriles, and polyvinyl alcohols.
Solid form nuclear augmentation materials may be in the form of geometric shapes such as cubes, spheroids, disc-like components, ellipsoid, rhombohedral, cylindrical, or amorphous. The solid material may be in powder form, and may be selected from the group consisting of one or more of the following: titanium, stainless steel, nitinol, cobalt, chrome, resorbable materials, polyurethane, polyesther, PEEK, PET, FEP, PTFE, ePTFE, PMMA, nylon, carbon fiber, Delrin, polyvinyl alcohol gels, polyglycolic acid, polyethylene glycol, silicone gel, silicone rubber, vulcanized rubber, gas-filled vesicles, bone, hydroxy apetite, collagen such as cross-linked collagen, muscle tissue, fat, cellulose, keratin, cartilage, protein polymers, transplanted nucleus pulposus, bioengineered nucleus pulposus, transplanted anulus fibrosis, and bioengineered anulus fibrosis. Structures may also be utilized, such as inflatable balloons or other inflatable containers, and spring-biased structures.
The nuclear augmentation material may additionally comprise a biologically active compound. The compound may be selected from the group consisting of one or more of the following: drug carriers, genetic vectors, genes, therapeutic agents, growth renewal agents, growth inhibitory agents, analgesics, anti-infectious agents, and anti-inflammatory drugs.
In one embodiment, the anulus augmentation device comprises materials selected from the group consisting of one or more of the following: steroids, antibiotics, tissue necrosis factors, tissue necrosis factor antagonists, analgesics, growth factors, genes, gene vectors, hyaluronic acid, noncross-linked collagen, collagen, fibren, liquid fat, oils, synthetic polymers, polyethylene glycol, liquid silicones, synthetic oils, saline, hydrogel (e.g., acrylonitriles, acrylic acids, polyacrylimides, acrylimides, acrylimidines, polyacryInitriles, and polyvinyl alcohols), and other suitable materials.
In some embodiments, the anulus augmentation device is constructed from one or more of the following materials: titanium, stainless steel, nitinol, cobalt, chrome, resorbable materials, polyurethane, polyesther, PEEK, PET, FEP, PTFE, ePTFE, PMMA, nylon, carbon fiber, Delrin, polyvinyl alcohol gels, polyglycolic acid, polyethylene glycol, silicone gel, silicone rubber, vulcanized rubber, gas-filled vesicles, bone, hydroxy apetite, collagen such as cross-linked collagen, muscle tissue, fat, cellulose, keratin, cartilage, and protein polymers. Transplanted anulus fibrosis and bioengineered anulus fibrosis may also be used to form the barrier, sealing device, closing device or membrane. Inflatable balloons or other inflatable containers, and spring-biased structures may also be used.
The anulus augmentation device may comprise a biologically active compound. The compound may be selected from the group consisting of one or more of the following: drug carriers, genetic vectors, genes, therapeutic agents, growth renewal agents, growth inhibitory agents, analgesics, anti-infectious agents, and anti-inflammatory drugs. In some embodiments, the biologically active compound is coupled to the barrier, sealing device, closing device or membrane. In some embodiments, the biologically active compound coats the barrier, sealing device, closing device or membrane.
In one embodiment, an anulus augmentation device for reinforcing an intervertebral disc is provided. In one embodiment, the anulus augmentation device comprises a mesh frame, wherein the mesh frame comprises a plurality of flexible curvilinear members. In one embodiment, the curvalinear elements are interconnected. The interconnected curvilinear members are adapted to provide flexibility and resilience to the mesh frame. In some embodiments, the curvilinear members form a horizontal member or central strut. In one embodiment, the curvilinear members are arranged in a parallel configuration.
In one embodiment, the curvilinear members comprise a metal alloy such as steel, nickel titanium, cobalt chrome, or combinations thereof.
In some embodiments, the curvilinear members are constructed of nylon, polyvinyl alcohol, polyethylene, polyurethane, polypropylene, polycaprolactone, polyacrylate, ethylene-vinyl acetate, polystyrene, polyvinyl oxide, polyvinyl fluoride, polyvinyl imidazoles, chlorosulphonated polyolefin, polyethylene oxide, polytetrafluoroethylene, acetal, poly(p-phenyleneterephtalamide) (Kevlar�), poly carbonate, carbon, graphite, or a combination thereof.
In one embodiment, a membrane encapsulates, covers or coats at least a portion of the mesh frame. In some embodiments, the membrane is coupled to the frame.
The membrane of some embodiments is constructed of polymers, elastomers, gels, elastin, albumin, collagen, fibrin, keratin, or a combination thereof. In several embodiments, the membrane comprises antibodies, antiseptics, genetic vectors, bone morphogenic proteins, steroids, cortisones, growth factors, or a combination thereof. The membrane may be a coating material.
In one embodiment, the mesh frame is concave along at least a portion of at least one axis of said mesh frame. In one embodiment, the mesh frame has a length in the range of about 0.5 cm to about 5 cm. One of skill in the art will understand that other lengths can also be used. In some embodiments, the mesh frame is sized to cover at least a portion of an interior surface of an anulus lamella. In other embodiments, the mesh frame is adapted to extend circumferentially along the entire surface of an anulus lamella.
In one embodiment, an anulus augmentation device comprising at least one projection that radiates from a mesh frame is provided. In one embodiment, the mesh frame has a vertical cross-section that is flat, concave, convex, or curvilinear. The horizontal cross-section can be concave, convex, flat, or kidney bean shaped. Other shapes can also be used.
In one embodiment of the present invention, an anulus augmentation device for reinforcing an intervertebral disc comprises a mesh frame having a horizontal axis and a vertical axis. In one embodiment, the mesh frame is concave along at least a portion the horizontal axis or the vertical axis. In one embodiment, one or more projections radiate from the horizontal axis or the vertical axis of the mesh frame. The projections are adapted to stabilize the anulus augmentation device. In one embodiment, a stabilizing projection has at least one dimension that is larger than the mesh frame. In other embodiments, the projection is smaller than the mesh frame.
In yet another embodiment of the present invention, an intervertebral disc implant comprising a posterior support member having a first terminus and a second terminus is provided. In one embodiment, an anterior projection extends outwardly from the posterior support member. The anterior projection is attached to at least the first terminus or the second terminus of the posterior support member.
In another embodiments, an intervertebral disc implant comprising a posterior support member having a first terminus and a second terminus and an anterior projection having a first end and a second end is provided. The anterior projection extends outwardly from the posterior support member. In one embodiment, the first end of the anterior projection is coupled to the first terminus of the posterior support member; and the second end of the anterior projection is coupled to the second terminus of the posterior support member, thereby substantially forming a bow-shaped implant. The posterior support member and the anterior projection can be constructed of any suitable material, including but not limited to the materials described above for the mesh frame and the membrane.
In a further embodiment of the present invention, a fatigue-resistant surgical mesh comprising rails is provided. In one embodiment, the mesh comprises a top rail, a bottom rail coupled to the top rail, wherein the top rail and said bottom rail are coupled to each other at a first end and second end. In one embodiment, the top rail and the bottom rail extend to form a gap that is defined between the rails along at least a portion of the distance between the ends.
In one embodiment of the present invention, a spinal implant for treatment of an intervertebral disc is provided. In one embodiment, a barrier or patch with a volume corresponding to the amount of material removed during a discectomy procedure is implanted. In one embodiment, the implant has a volume in a range of about 0.2 to about 2.0 cc.
In one embodiment of the invention, an intervertebral disc implant comprising a barrier forming a contiguous band is provided. In one embodiment, the band has variable heights or widths. In one embodiment, the band has different degrees of flexibility along at least one axis.
In another embodiment of the present invention, a method of repairing or rehabilitating an intervertebral disc is provided. The method comprises inserting at least one anulus augmentation device into the disc, and inserting at least one nuclear augmentation material, to be held within the disc by the anulus augmentation device. The nuclear augmentation material may conform to a first, healthy region of the anulus, while the anulus augmentation device conforms to a second, weaker region of the anulus.
In a further embodiment, a method of repairing defective regions within a spinal disc is provided. In one embodiment, the method comprises providing a surgical mesh, implanting the surgical mesh along an anulus surface, and positioning the surgical mesh at least such that about 2 mm of the device spans beyond at least one edge of the defective region of the disc.
Further features and advantages of embodiments of the present invention will become apparent to those of skill in the art in view of the detailed description of preferred embodiments which follows, when taken together with the attached drawings and claims.
FIG. 2A shows a transverse section of one aspect of the present invention prior to supporting a herniated segment, as shown in one embodiment.
FIG. 5A shows a transverse view of another aspect of the present invention, as shown in one embodiment.
FIG. 23A depicts an embodiment of the barrier means of the present invention being secured to an anulus using fixation means, as shown in one embodiment.
FIG. 34 shows a non-axisymmetric expansion means or frame.
FIGS. 40A-I illustrate tubular expansion means. FIGS. 40A-D illustrate a tubular expansion means having an oval shaped cross-section. FIGS. 40E, 40F and 401 illustrate a front, back and top view, respectively of the tubular expansion means of FIG. 40A having a sealing means covering an exterior surface of an anulus face. FIGS. 40G and 40H show the tubular expansion means of FIG. 40A having a sealing means covering an interior surface of an anulus face.
FIG. 67 shows an anulus augmentation device (such as a mesh) mesh having a series of curvilinear elements.
FIGS. 68A-G show profiles and cross-sectional views of an anulus augmentation device (such as a mesh), e.g., �U� shaped, �C� shaped, curvilinear shaped, and �D� shaped to extend along and cover the entire inner anulus surface, or portions.
FIG. 69 shows one embodiment of a mesh with curvilinear elements implanted in an intervertebral disc.
FIG. 70 shows a wire-type anulus augmentation device.
FIGS. 71A-E show a frame (e.g., mesh) that has been encapsulated by a membrane or cover to produce an encapsulated mesh.
FIGS. 72A-B show a mesh having a double-wishbone frame.
FIGS. 73A-C shows embodiments of the end or natural hinge portion of the frame, including a looped terminus.
FIGS. 74A-C show some embodiments of the central band or strut.
FIGS. 75A-L show an implant an annulus augmentation device such as a mesh having one or more projections extending into the disc or into a defect.
FIG. 76 shows an implant comprising a bow-like anterior projection that extends outwardly from a posterior support member.
FIGS. 77A-H show various cross-sectional side views along a horizontal axis of an implant comprising a bow, band or projection.
FIGS. 78A-J show various cross-sectional top views of implants along a vertical axis.
FIGS. 79A-F show a frontal view of a portion of several embodiments of an implant projection.
FIGS. 80A-D show various cross-sections of an implant projection.
FIGS. 81A-D show looped or bent bow-type projections.
Several embodiments of the present invention provide for an in vivo augmented functional spine unit. A functional spine unit includes the bony structures of two adjacent vertebrae (or vertebral bodies), the soft tissue (anulus fibrosis (AF), and optionally nucleus pulposus (NP)) of the intervertebral disc, and the ligaments, musculature and connective tissue connected to the vertebrae. The intervertebral disc is substantially situated in the intervertebral space formed between the adjacent vertebrae. Augmentation of the functional spine unit can include repair of a herniated disc segment, support of a weakened, torn or damaged anulus fibrosis, or the addition of material to or replacement of all or part of the nucleus pulposus. Augmentation of the functional spine unit is provided by herniation constraining devices and disc augmentation devices situated in the intervertebral disc space.
In various forms of the invention, the anchor(s) and connection member(s) may be introduced and implanted in the patient, with the connection member under tension. Alternatively, those elements may be installed, without introducing tension to the connection member, but where the connection member is adapted to be under tension when the patient is in a non-horizontal position, e.g., resulting from loading in the intervertebral disc.
FIGS. 5A-C show an alternate embodiment of herniation constraining device 13A. In this series of figures, device 13A, a substantially one-piece construct, is delivered through a delivery tube 6, although device 13A could be delivered in a variety of ways including, but not limited to, by hand or by a hand held grasping instrument. In FIG. 5A, device 13A in delivery tube 6 is positioned against herniated segment 30. In FIG. 5B, the herniated segment is displaced within its pre-herniated borders 40 by device 13A and/or delivery tube 6 such that when, in FIG. 5C, device 13A has been delivered through delivery tube 6, and secured within a portion of the FSU, the device supports the displaced herniated segment within its pre-herniated border 40. Herniation constraining device 13A can be made of a variety of materials and have one of many possible forms so long as it allows support of the herniated segment 30 within the pre-herniated borders 40 of the disc. Device 13A can anchor the herniated segment 30 to any suitable anchoring site within the F SU, including, but not limited to the superior vertebral body, inferior vertebral body, or anterior AF. Device 13A may be used additionally to close a defect in the AF of herniated segment 30. Alternatively, any such defect may be left open or may be closed using another means.
The method consists of inserting the barrier 12 into the interior of the disc 15 and positioning it proximate to the interior aspect of the anulus defect 16. The barrier material is preferably considerably larger in area than the size of the defect 16, such that at least some portion of the barrier means 12 abuts healthier anulus fibrosis 10. The device acts to seal the anulus defect 16, recreating the closed isobaric environment of a healthy disc nucleus 20. This closure can be achieved simply by an over-sizing of the implant relative to the defect 16. It can also be achieved by affixing the barrier means 12 to tissues within the functional spinal unit. In one embodiment of the present invention, the barrier 12 is affixed to the anulus surrounding the anulus defect 16. This can be achieved with sutures, staples, glues or other suitable fixation means or fixation device 14. The barrier means 12 can also be larger in area than the defect 16 and be affixed to a tissue or structure opposite the defect 16, e.g., anterior tissue in the case of a posterior defect.
In several embodiments of the present invention, the barrier (or �patch�) 12 can be placed between two neighboring layers 33, 37 (lamellae) of the anulus 10 on either or both sides of the defect 16 as depicted in FIGS. 24A and 24B. FIG. 24A shows an axial view while 24B shows a sagittal cross section. Such positioning spans the defect 16. The barrier means 12 can be secured using the methods outlined.
In another embodiment of the present invention, the barrier or patch 12 may be used as part of a method to augment the intervertebral disc. In one aspect of this method, augmentation material or devices are inserted into the disc through a defect (either naturally occurring or surgically generated). Many suitable augmentation materials and devices are discussed above and in the prior art. As depicted in FIG. 26, the barrier means is then inserted to aid in closing the defect and/or to aid in transferring load from the augmentation materials/devices to healthy tissues surrounding the defect. In another aspect of this method, the barrier means is an integral component to an augmentation device. As shown in FIGS. 27, 28A and 28B, the augmentation portion may comprise a length of elastic material that can be inserted linearly through a defect in the anulus. A region 300 of the length forms the barrier means of some embodiments of the present invention and can be positioned proximate to the interior aspect of the defect once the nuclear space is adequately filled. Barrier region 300 may then be affixed to surrounding tissues such as the AF and/or the neighboring vertebral bodies using any of the methods and devices described above.
FIGS. 34 through 38 depict alternative patterns to that illustrated in FIG. 33A. FIG. 33A shows the expansion devices 53 within the sealing means 51. The sealing means can alternatively be secured to one or another face (concave or convex) of the expansion means 53. This can have advantages in reducing the overall volume of the barrier means 12, simplifying insertion through a narrow cannula. It can also allow the barrier means 12 to induce ingrowth of tissue on one face and not the other. The sealing means 51 can be formed from a material that resists ingrowth such as expanded polytetraflouroethylene (e-PTFE). The expansion means 53 can be constructed of a metal or polymer that encourages ingrowth. In several embodiments, if the e-PTFE sealing means 51 is secured to the concave face of the expansion means 53, tissue can grow into the expansion means 53 from outside of the disc 15, helping to secure the barrier means 12 in place and seal against egress of materials from within the disc 15.
The patterns shown in FIGS. 34 through 38 can preferably be formed from a relatively thin sheet of material. The material may be a polymer, metal, or gel, however, the superelastic properties of nickel titanium alloy (NITINOL) makes this metal particularly advantageous in this application. Sheet thickness can generally be in a range of about 0.1 mm to about 0.6 mm and for certain embodiments has been found to be optimal if between about 0.003″ to about 0.015″ (0.0762 mm to 0.381 mm), for the thickness to provide adequate expansion force to maintain contact between the sealing means 51 and surrounding vertebral endplates. The pattern may be Wire Electro-Discharge Machined, cut by laser, chemically etched, or formed by other suitable means.
FIG. 34 shows an embodiment of a non-axisymmetric expander 153 having a superior edge 166 and an inferior edge 168. The expander 153 can form a frame of barrier 12. This embodiment comprises dissecting surfaces or ends 160, radial elements or fingers 162 and a central strut 164. The circular shape of the dissecting ends 160 aids in dissecting through the nucleus pulposus 20 and/or along or between an inner surface of the anulus fibrosis 10. The distance between the left-most and right-most points on the dissecting ends is the expansion means length 170. This length 170 preferably lies along the inner perimeter of the posterior anulus following implantation. The expander length 170 can be as short as about 3 mm and as long as the entire interior perimeter of the anulus fibrosis. The superior-inferior height of these dissecting ends 160 is preferably similar to or larger than the posterior disc height.
For example, in order for expander 153 of FIG. 34B to move around the inner circumference of anulus fibrosis 10 (e.g., from the posterior wall 21 onto the lateral 23 and/or anterior 27 wall), the stiff central region of expander 153 spanning the posterior wall 21 would have to bend around the acute curves of the posterior lateral corners of anulus 10. The stiffer this section of expander 153 is, the higher the forces necessary to force it around these corners and the less likely it is to migrate in this direction. This principle was also used in this embodiment to resist migration of fingers 162 away from the vertebral endplates: The slots 174 cut along the length of expander 153 create a central flexibility that encourages expander 153 to bend along an axis running through these slots as the posterior disc height increases and decreased during flexion and extension. In order for the fingers 162 to migrate away from the endplate, this central flexible region must move away from the posterior anulus 21 and toward an endplate. This motion is resisted by the greater stiffness of expander 153 in the areas directly inferior and superior to this central flexible region.
The embodiment of the frame 153 as shown in FIGS. 37A-C, can also be employed without the use of a covering membrane. The nucleus pulposus of many patients with low back pain or disc herniation can degenerate to a state in which the material properties of the nucleus cause it to behave much more like a solid than a gel. As humans age, the water content of the nucleus declines from roughly 88% to less than 75%. As this occurs, there is an increase in the cross linking of collagen within the disc resulting in a greater solidity of the nucleus. When the pore size or the largest open area of any given gap in the lattice depicted in FIGS. 37A-37C is between about 0.05 mm2 (7.75�10−5 in2) and about 0.75 mm2 (1.16�10−3 in2), the nucleus pulposus is unable to extrude through the lattice at pressures generated within the disc (between about 250 KPa and about 1.8 MPa). The preferred pore size has been found to be approximately 0.15 mm2 (2.33�10−4 in2). This pore size can be used with any of the disclosed embodiments of the expander or any other expander that falls within the scope of embodiments of the invention to prevent movement of nucleus toward the outer periphery of the disc without the need for an additional membrane. The membrane thickness is preferably in a range of about 0.025 mm to about 2.5 mm.
FIGS. 39 through 41 depict another embodiment of the expander 153 of some embodiments of the present invention. These tubular expanders can be used in the barrier 12 embodiment depicted in FIG. 31A. The sealer 51 can cover the expander 153 as shown in FIG. 31A. Alternatively, the sealer 51 can cover the interior surface of the expander or an arc segment of the tube along its length on either the interior or exterior surface.
FIGS. 49A through 49G illustrate a method of implanting an intradiscal implant. An intradiscal implant system consists of an intradiscal implant 400, a delivery device or cannula 402, an advancer 404 and at least one control filament 406. The intradiscal implant 400 is loaded into the delivery cannula 402 which has a proximal end 408 and a distal end 410. FIG. 49A illustrates the distal end 410 advanced into the disc 15 through an annulotomy 416. This annulotomy 416 can be through any portion of the anulus 10, but is preferably at a site proximate to a desired, final implant location. The implant 400 is then pushed into the disc 15 through the distal end 410 of the cannula 402 in a direction that is generally away from the desired, final implant location as shown in FIG. 49B. Once the implant 400 is completely outside of the delivery cannula 402 and within the disc 15, the implant 400 can be pulled into the desired implant location by pulling on the control filament 406 as shown in FIG. 49C. The control filament 406 can be secured to the implant 400 at any location on or within the implant 400, but is preferably secured at least at a site 414 or sites on a distal portion 412 of the implant 400, e.g., that portion that first exits the delivery cannula 402 when advanced into the disc 15. These site or sites 414 are generally furthest from the desired, final implant location once the implant has been fully expelled from the interior of the delivery cannula 402.
The implant 400 can be any one of the following (including a combination of two or more of the following): nucleus replacement device, nucleus augmentation device, anulus augmentation device, anulus replacement device, the barrier of the present invention or any of its components, drug carrier device, carrier device seeded with living cells, or a device that stimulates or supports fusion of the surrounding vertebra. The implant 400 can be a membrane which prevents the flow of a material from within the anulus fibrosis of an intervertebral disc through a defect in the disc. The material within the anulus fibrosis can be, for example, a nucleus pulposus or a prosthetic augmentation device, such as hydrogel. The membrane can be a sealer. The implant 400 can be wholly or partially rigid or wholly or partially flexible. It can have a solid portion or portions that contain a fluid material. It can comprise a single or multitude of materials. These materials can include metals, polymers, gels and can be in solid or woven form. The implant 400 can either resist or promote tissue ingrowth, whether fibrous or bony.
In one embodiment, the nuclear augmentation material or device 7, 554 constructed therefrom is phase changing, e.g., from liquid to solid, solid to liquid, or liquid to gel. In situ polymerizing nuclear augmentation materials are well-known in the art and are described in U.S. Pat. No. 6,187,048, herein incorporated by reference. Phase changing augmentation preferably changes from a liquid to a solid or gel. Such materials may change phases in response to contact with air, increases or decreases in temperature, contact with biologic liquids or by the mixture of separate reactive constituents. These materials are advantageous because they can be delivered through a small hole in the anulus or down a tube or cannula placed percutaneously into the disc. Once the materials have solidified or gelled, they can exhibit the previously described advantages of a solid augmentation material. In a preferred embodiment, the barrier device is used to seal and pressurize a phase changing material to aid in its delivery by forcing it into the voids of the disc space while minimizing the risk of extrusion of the material while it is a fluid. In this situation, the barrier or anulus augmentation device 12 may be permanently implanted or used only temporarily until the desired phase change has occurred.
In another embodiment, an anulus augmentation device 12 that exploits the characteristics of nucleus augmentation devices or materials to improve its own performance is provided. Augmenting the nucleus 20 pressurizes the intervertebral disc environment which can serve to fix or stabilize an anulus repair device in place. The nucleus 20 can be pressurized by inserting into the disc 15 an adequate amount of augmentation material 7, 554. In use, the pressurized disc tissue and augmentation material 7, 554 applies force on the inwardly facing surface of the anulus augmentation device 12. This pressure may be exploited by the design of the anulus prosthesis or barrier 12 to prevent it from dislodging or moving from its intended position. One exemplary method is to design the inwardly facing surface of the anulus prosthesis 12 to expand upon the application of pressure. As the anulus prosthesis 12 expands, it becomes less likely to be expelled from the disc. The prosthesis 12 may be formed with a concavity facing inward to promote such expansion.
In one embodiment, the anulus augmentation device comprises a mesh. FIG. 67 shows one example of a meshed anulus augmentation device. In one embodiment, a repair mesh that is resilient is provided. In some embodiments, the mesh is particularly advantageous because it can withstand millions of motion cycles within the disc environment, and is resistant to fatigue. In several embodiments, fatigue resistance is accomplished by material properties, structural design, or a combination thereof. For a given material, a fatigue resistant structure can be designed to distribute the strain of deformation as evenly as possible over as much material as possible so as to minimize stress concentrations that could initiate fatigue cracks. For example, a coiled spring may deform millions of times without failure or cracking because the strain is distributed evenly over a length of metal. For an anulus repair mesh, the same effect maybe achieved by means such as, but not limited to, providing more material for a given deformation site by having mesh members curved throughout their lengths, alternating mesh curves in a sine-wave or zigzag pattern to provide more material and distributed strains, or having longer non linear members such that a given deformation results in less material strain, or pre-shaping the implant to minimize strain at the implantation site. The curvilinear, nonlinear, coiled, or angled members can be interconnected, woven, networked, or emanate from or be attached to rails or members to form a framework or define a mesh or barrier.
In one embodiment, a mesh can be used in a variety of locations in and around the intervertebral disc. It can be placed on an external surface of the anulus, along an endplate, within the anulus, between the anulus and nucleus, within the nucleus, or within both the anulus and nucleus. The mesh can be held in place via counteracting forces of the mesh as it flexes from its unstressed shape to stressed shape or friction with disc tissue, between disc and vertebral body tissue or between disc augmentation material or another implant and disc tissue. The mesh can also have a porosity or macrotexture including ridges, spikes or spirals to increase bioincorporation and fixation. Fixation devices, including but not limited to, sutures, glue, screws, and staples can be used to permanently fix the mesh in place.
In one embodiment, the anulus augmentation device is a barrier comprising a membrane and a frame. In some embodiments, the frame is the mesh. In other embodiment, the mesh is coated with the membrane. In another embodiment, the anulus augmentation device comprises only a frame.
In one embodiment, the mesh or frame region of the implant can preferably be formed from a relatively thin sheet of material. The material may be a polymer (including in-situ polymerizing), metal, or gel. However, as discuss infra, the superelastic properties of nickel titanium alloy (NITINOL) makes this metal particularly advantageous in this application. Other materials suitable for this application include one or more of the following: nylon, polyvinyl alcohol, polyethylene, polyurethane, polypropylene, polycaprolactone, polyacrylate, ethylene-vinyl acetates, polystyrene, polyvinyl oxide, polyvinyl fluoride, polyvinyl imidazole, chlorosulphonated polyolefins, polyethylene oxide, polytetrafluoroethylene and nylon, and copolymers and combinations thereof, polycarbonate, Kevlar�, acetal, cobalt chrome, carbon, graphite, metal matrix composites, stainless steel and other metals, alloys and composites. Some materials may be coated to achieve biocompatibility. These materials can also be used for frames or support member that do not comprise meshes.
In some embodiments, the mesh or frame designs may have sharp edges or have gaps that may allow for tissue transfer outside of the disc. In one embodiment, a membrane may be secured to one or more sides or portions of the mesh or frame in order to resist transfer of particles across its periphery and outside of the disc or to shield the body from the mesh's sharp edges. Also, a membrane can prevent the flow of a material bounded by the anulus fibrosis of the intervertebral disc through a defect in the anulus fibrosis if the device is positioned across the defect.
In a preferred embodiment, the size of the mesh device is dictated by the particular region of the functional spinal unit sought to be treated. For example, In one embodiment, a mesh intended for coverage the interior surface of the posterior lateral anulus can be about 2 cm to about 4 cm in length and about 2 mm to about 15 mm in height. Likewise, the mesh can be sized to cover the entire exterior or interior surface of a disc. Also, if a defect or weakened segment of the disc is pre-opertively identified, the size of the mesh can be selected to adequately span it in more than one direction. In one embodiment, the mesh is sized such that it spans all directions by at least about 2 mm. The overlap provided by the about 2 mm or more mesh, in some embodiments, provides mechanical means by which the mesh resists extrusion through a defect. Where a case dictates that a device is not available for full coverage of a portion of the anulus, the surgeon can select a mesh, barrier, or patch that is sized such that even if the barrier shifts along an axis in either direction, the selected width ensures that there remains about 2 mm or more of the device beyond the edge of the defect in all positions along that portion of the anulus. In this way a surgeon can determine a minimum implant size that will still be efficacious.
In one embodiment, the anulus augmentation device, such as a mesh or a membrane/frame combination, has a thickness in a range between about 0.025 mm to about 3 mm. Nucleus pulposus particles have been measured at around 0.8 mm2. Accordingly, in one embodiment, the anulus augmentation device, such as a mesh or a membrane/frame combination, has pores slightly smaller (e.g., about 0.05 mm2 to about 0.75 mm2) and still function as a means to prevent extrusion of nuclear material from the disc. Alternatively, one of ordinary skill in the art can through experimentation determine the size of disc particles sought to be contained by the mesh and size the pores slightly smaller. Such a design affords the fluid transfer of other smaller particles and especially water, blood, and other tissue fluids.
In several embodiments, the cross-section of the mesh can be flat, concave, convex or hinged (or flexibly connected) along at least a portion of one or more horizontal axes or vertical axes. One of skill in the art will understand that other cross-sections can also be used in accordance with several embodiments of the invention.
It has been determined that in procedures wherein only a limited amount of nucleus or anulus tissue is removed from a pathologic disc, approximately 0.2 to about 2.0 cc of tissue is typically removed. Accordingly, to replace this volume loss and contribute to the biomechanical function of the spine, spinal implants can be designed to replace this volume (about 0.2 to 2.0 cc) through selection of materials and their dimensions. Accordingly, in one embodiment, an implant having a volume of about 0.2 to about 2.0 cc is provided. The implant can include an anulus augmentation device, a nuclear augmentation device or an anulus augmentation/nuclear augmentation combination device. Preferably, a device having an overall volume of about 0.5 cc is provided because this is the most typical volume removed. Also, greater volumes may be used to further increase the volume of the disc in cases where disc height has decreased over time and the fragments have been metabolized (and thus do not require removal).
In one embodiment, an implant comprising a frame and a membrane is provided. In other embodiments, the implant comprises only one or more membranes. In one embodiment, the implant comprises only one or more frames. The frame may be coated. The membrane (or coating) can be comprised of any suitably durable and flexible material including polymers, elastomers, hydrogels and gels such as polyvinyl alcohol, polyethylene, polyurethane, polypropylene, polycaprolactone, polyacrylate, ethylene-vinyl acetates, polystyrene, polyvinyl oxides, polyvinyl fluorides, polyvinyl imidazole, chlorosulphonated polyolefin, polyethylene oxide, polytetrafluoroethylene, a nylon, silicone, rubber, polylactide, polyglycolic acid, polylactide-co-glycolide, polycaprolactone, polycarbonate, polyamide, polyanhydride, polyamino acid, polyortho ester, polyacetal, polycyanoacrylate, degradable polyurethane, copolymers and derivatives and combinations thereof. Biological materials including keratin, albumin collagen, elastin, prolamines, engineered protein polymers, and derivatives and combinations thereof, may also be used.
In one embodiment, at least a portion of the anulus augmentation device (e.g., the membrane, mesh, barrier, etc) can be impregnated with, coated with, or designed to carry and deliver diagnostic agents and/or therapeutic agents. Diagnostic agents include, but are not limited to, radio-opaque materials suitable to permit imaging by MRI or X-ray. Therapeutic agents include, but are not limited to, steroids, genetic vectors, antibodies, antiseptics, growth factors such as somatomedins, insulin-like growth factors, fibroblast growth factors, bone morphogenic growth factors, endothelial growth factors, transforming growth factors, platelet derived growth factors, hepatocytic growth factors, keratinocyte growth factors, angiogenic factors, immune system suppressors, antibiotics, living cells such as fibroblasts, chondrocytes, chondroblasts, osteocytes, mesenchymal cells, epithelial cells, and endothelial cells, and cell-binding proteins and peptides. In other embodiments, the nuclear augmentation device can be impregnated, coated, or designed to carry diagnostic and/or therapeutic agents.
In one embodiment, as shown in FIG. 67, a mesh having a series of curvilinear elements 602 is provided. In one embodiment, the curvilinear elements 602 are interconnected. One of skill in the art will understand that the curvilinear elements 602 can exist independently of each other, or only be partially connected. The interconnections 602 can be distributed to form one or more contiguous horizontal bands, rails, members, struts, or axes 604. FIG. 67 shows such a device with a central horizontal axis 604 and �S� shaped curvilinear elements 602. In one embodiment, the �S� shaped elements 602 tend to distribute the stress generated under compression over a larger area. In one embodiment, only portions of the �S� move out of plane during loading providing stiffness. In some embodiments, the curvilinear elements are particularly advantageous because they provide flexibility, resilience and/or rigidity.
In some embodiments, the curvilinear elements 602 can be oriented about 90 degrees (curving in the ventral/dorsal axis) such that the curves appear in the overall horizontal cross-section of the implant. In other embodiments, the curvilinear elements 602 are substantially flat. The curvilinear elements 602 can also be oriented at any angle (e.g., from about 1 degree to about 179 degrees) from the plane. The mesh 600 can be straight, convex or concave in cross-section. FIGS. 68A-G show the profile of a mesh with various curvilinear elements. FIGS. 68D-G show top cross-sectional views of the mesh being elongated �U� shaped, �C� shaped, curvilinear shaped (like a typical posterior anulus interior surface), and �D� shaped to extend along and cover the entire inner anulus surface.
FIG. 69 shows yet another embodiment of a mesh 600 implanted in an intervertebral disc. Here, the curvilinear elements 602 comprise springs, coils, or telescopic members that are adapted to compress axially (like pneumatic pistons or coil springs) under loading rather than bending and conforming to a tissue surface, e.g. the inner surface of the anulus. One advantage of a spring or coil-type mesh is that the mesh can be fairly rigid and resistant to lateral or transverse force but is flexible enough to span around the curvatures of the disc while maintaining contact with the endplates under compression and expansion. Like other curvilinear elements, the springs or coils can be interconnected, linked in a loose or hinge-like arrangement, attached to a horizontal band or axis, attached to a membrane, or encapsulated within a membrane, or portions thereof.
In one embodiment, the mesh may also be configured (e.g., from wire or stock) in a pattern comprising a series of repeating curved peaks and valleys oriented in a lateral manner. Two or more curved wires may be superimposed out of phase such that one peak is inferior to the adjacent wires valley. The two wires can be independent, contiguous and formed from a single wire, connected at one or more points, attached to a membrane, or encapsulated within a membrane. FIG. 70 shows a wire-type anulus augmentation device.
As discussed above, an annulus augmentation device can comprise, for example, a frame, a membrane or a frame/membrane combination. FIG. 70 shows just the frame, which can be, for example, a wire or mesh-like device. FIGS. 71A-E show a mesh that has been encapsulated by a membrane or cover to produce an encapsulated mesh 606. FIG. 71C shows a top view cross-section wherein the mesh is elongated U shaped and 71D through 71F show various side view cross-sections wherein the mesh is straight or possesses varying degrees of concavity. As with other barriers disclosed herein, the membrane or encapsulation material may be of substantial thickness or may be substantially thin. Indeed, the encapsulation material may simply be a coating.
In another embodiment, as shown in FIGS. 72A-B, a mesh 600 having a double-wishbone frame with or without membrane cover is provided. In some embodiments, this design is particularly advantageous because it reduces the compression and stress experienced by the implant under flexion, extension, and lateral bending. FIG. 72A shows the frame without a membrane situated along a posterior portion of the disc. The implant (e.g., the frame) can also be placed on the outside of the anulus, within the anulus, between the nucleus and anulus or within the nucleus. Also shown is a defect 16 in the anulus 10 and placement of the frame 600 across the defect and spanning beyond it in more than a single direction. FIG. 72B shows the mesh in a perspective view outside of the disc. The frame (e.g., mesh) can be flat or an elongated �U� shaped corresponding to the inner surface of the posterior anulus. In one embodiment, the frame can be a single continuous band or wire forming two ends, a first end and a second end. In one embodiment, each end functions as a living hinge and forms an apex which may be in the form of a curve, a bend, or series of bends such that the wire is generally redirected in the opposite direction. Accordingly, if a load is applied along the vertical axis at the midpoint of the frame, e.g., the midpoint of the top and bottom (superior, inferior) rail, each corner or apex is loaded equally and the wire rails act as levers.
In one embodiment, the mesh 600 can be implanted such that the midpoint of the mesh frame 600 is in the posterior of the disc and the ends reside medially or even in the anterior portion of the disc. In this way the portion of the mesh 600 that undergoes the greatest compression is furthest away from each end. Accordingly, a relatively large range of motion can be traversed by the middle of the device but this will only translate to limited motion at each end or living hinge, thus reducing stress and fatigue. Also, by placing each end (which has a relatively small profile) at opposing sides at the midline of the disc (the center of rotation) it is subjected to almost no direct loading under lateral bending, flexion, extension, or compression by the endplates.
FIGS. 73A-C shows other embodiments for the end or natural hinge portion of the frame (e.g., mesh 600), including a loop formation.
FIGS. 74A-C show some embodiments of the central band or strut 604. FIGS. 74A-B show a central reinforcement band 604 disposed between the ends or apexes of the frame (e.g., mesh). As shown in FIG. 74B, the central band 604 can be positioned between the top rail (or wire) 603 and bottom rail (or wire) 605. As shown in FIG. 74C, the central band 604 can be elongated to form a concave cross-section between the top and bottom rail or wire.
In several embodiments of the invention, an implant (e.g., an anulus augmentation device, such as a mesh) can exhibit different mechanical properties along various axes. For example, an implant can exhibit rigidity along a first axis and flexibility (or less rigidity) along a second axis transverse or perpendicular to the first. Such an implant might find particular utility along the wall of an anulus between two adjacent vertebrae because such an environment will subject the implant to vertical compression (e.g., along the superior/inferior axis) yet will not compress the implant laterally. As such, the implant can retain its rigidity along its horizontal axis. Rigidity along the horizontal axis of anulus augmentation device is especially useful in some embodiments if the implant is placed in front of a weakened or defective surface of the anulus because a point load will like form at that region when the disc is compressed under loading and could cause the implant to bend and extrude. Accordingly, an implant having a certain degree of rigidity along its lateral axis resists such bending and extrusion. Moreover, because of the less rigid and more flexible behavior of the implant along its vertical axis loads caused flexion and extension of the spine will allow the implant to flex naturally with the spine and not injure the endplates.
In some embodiments, to achieve the differences in mechanical properties, any number of construction, material selection or fabrication techniques known in the art can be used. For example, the implant may be made thicker or thinner at points along a particular axis or voids or patterns may be cut into the material. Also, a composite implant having different material sandwiched together can also be used. Struts, members, rails and the like may be added to, secured to, or integral to the implant to provide stiffness and rigidity. Further, such stiffening elements can be added during the implantation procedure.
In one embodiment, the implant can also be corrugated along an axis or otherwise be provided with bents or curves to provide stiffness. A gentle curve or �C� shaped cross-section that could also conform or correspond to the inner curved surface of an anulus is also preferable for making a seal with the anulus and for resisting bending along the implant horizontal axis e.g., the curve would resist flattening out, flexing or bending laterally. Also, in some embodiments the implant can be oversized such that it remains in compression along one or more of its axes in its implanted state such that even under flexion and extension of the spine the corrugations or curved sections never flatten out and thus retain rigidity (or less flexibility) along an axis perpendicular to the curves.
One of skill in the art will understand that, in several embodiments, the implant (e.g., an anulus augmentation device, such as a mesh) can be more or less rigid or flexible, according to the preference of the practitioner or disc environment. The degree of desired rigidity and flexibility along each axis can be determined based on factors such as defect size, intervertebral pressure, implant deliverability, desired degree of compression and disc height.
According to one embodiment of the invention, an implant has a �C� cross-section, a central rail and top and bottom rails, and curvilinear elements connect the rails. The frame or mesh can be comprised of any of the suitable materials discussed herein, (e.g. nickel titanium) and can also be coated, covered, bonded, or coupled to a cover or membrane. In one embodiment, the implant is more rigid along its lateral axis because of its �C� cross-section or the rails and less rigid along its vertical axis because of the void caused by the pattern and lack of corrugations or stiffening elements.
Though some embodiments of the invention disclose a mesh frame, patch, plate, biocompatible support member or barrier adapted to extend along the inner circumference of an anulus fibrosus, other embodiments contemplate partial coverage of the anulus or tissue surface. For some embodiments that that cover less than the entire inner surface of the anulus or that are not fully anchored in place, and are susceptible to migration, one or more projections extending outward from, or off-angle to the implant can be configured to resist migration or movement of the implant within the disc under cyclical loading and movement of the spine. One advantage of such embodiments is that they can reduce or prevent migration. Undesired migration may render the implant ineffective or cause it to pathologically interfere with adjacent tissue including the anulus, nucleus, endplates and spinal cord.
According to one embodiment, an implant can be stabilized within an intervertebral disc by providing a support member or patch with an off-angle projection functioning as a lever arm or keel. In some embodiments, even a slightly angled projection (e.g., about 5 to about 10 degrees) can serve to reduce the tendency of the device to rotate or migrate if it has sufficient surface area and length (about 3 mm to about 30 mm). As shown previously in FIGS. 25 and 34, one embodiment of an anulus augmentation device can have one or more corners, sides or projections connected at the opposing end of the devices midsection or middle portion. Such a configuration is especially effective when implanted into an intervertebral disc such that the midsection of the barrier is inserted along the posterior anulus and the corners and side projections are inserted along the posterio-lateral corners and lateral anulus respectively. In one embodiment, the corner sections extend away from the posterior anulus toward the anterior of the disc. The projections that project away from the posterior anulus at an angle (about 90 degrees or through a radius of curvature resulting in an angle from about 30 to about 150 degrees) are substantially parallel with or adjacent to the lateral anulus. Thus, the projection portion of the implant in its implanted orientation is at once off-angle to the posterior anulus or midsection of the barrier and parallel to the lateral anulus. Because the anulus defines a bounded area such a projection may indeed collide with or be parallel with another adjacent or opposing surface of the anulus but still function to stabilize the device along the other surface. The device can also be designed with one or more projections that are angled toward the medial, anterior, posterior, or lateral portion of the disc such that the projection contacts mostly or exclusively nucleus tissue or endplate. For example, a looped projection connected at the top and bottom and/or opposing ends of the support member, frame, or patch can be configured to extend across the disc from about 3 mm to about 30 mm and only contact nucleus tissue. In another embodiment, one or more projections can be oriented into a defect in the anulus and occupy less than or all of its volume. In another embodiment, a projection situated within a defect may be anchored into an endplate adjacent the defect. FIGS. 75A-L show an implant 610 (e.g., an annulus augmentation device such as a mesh) having one or more projections extending into the disc or into a defect.
A stabilizing projection according to one or more embodiments of the invention can be integral or affixed to the surgical mesh, patch, plate, biocompatible support member or barrier device. The stabilizing projection can also be independent of or coupled to at least a portion of the frame or the membrane. The stabilizing projection can be constructed from the same material as the frame or the membrane, or it can be constructed from different material. The stabilizing projection can extend from any point or points along the device or device frame including its opposing ends, mid-section, along the top edge or along the bottom edge. The projection can also form a loop in one or more planes including parallel and perpendicular to the face of the device. For example, in one embodiment opposing end projections are connected to, or are integral to, the barrier and extend out from the barrier at an angle from about 0 to about 160 degrees. In another embodiment, the projections are joined or are simply contiguous and form a bow-shaped or curved projection extending away from the barrier. In this embodiment, the barrier can be placed along a portion of the anulus and the bow would extend medially into the disc. In another embodiment, the barrier can be placed along at least a portion of the posterior anulus and the bowed projection, attached at the opposing ends of the barrier frame or membrane, would extend toward the anterior of the disc.
FIG. 76 shows an implant 610 according to one embodiment of the invention. Here, a bow-like anterior projection 612 extends outwardly from a posterior support member 614 (e.g., a patch, barrier or mesh). The projection 612 can be connected at each end of the posterior support member 614 along its horizontal axis. The projection 612 can be attached at any point along the vertical axis of the end including its midline, ends, or its entirety. The projection 612 may be integral to the posterior support member 614 such that the posterior support member 614 is simply formed as a band or attached separately. As shown the implant 610 can be shaped like a bow. The bow can be a gentle arc, curved, re-curved one or more times, triangular, rectangular, octagonal, linked multiple sided, oval or circular. Though in some embodiments, an arc or smooth bow may be advantageous for transferring loads evenly, a rigid mid-section portion or a comparatively flexible hinge-like mid-section along the bow is also presented. The mid-section of the bow projection can have a different height than the remainder of the bow and be the same or different (less than or greater than) height than the midsection patch or biocompatible support member portion of the device.
Various embodiments of the bow or arcurate member or projection 612 can act like a spring to aid in holding the ends of the patch open and against the anulus wall. Similarly, in one embodiment, the profile of the projection 612 can provide resistance to anterior travel of the implant through the nucleus or through the opposite wall of the anulus. In another embodiment of the invention, the projection or stabilizer 612 can also provide torsional resistance to the barrier 614. Finally, because the projection or bow 612 extends across the endplates it creates an elongated profile functioning as a lever arm and thus resists rotation along the anulus wall within the disc.
The projection, bow or band portion 612 of the implant 610 can be tubular, wire-like, flat, mesh-like, curvilinear, bent, comprised of one or more rails, or contain voids. The bow can define concavities facing inward or outward and be opposite or the same as the concavities defined by the biocompatible support member portion 614 of the implant 610. The projection 612 can simply be angled projections of the biocompatible support member and be made of the same material and have the same properties. Alternatively the projection can have different properties such as less flexibility or more rigidity along one or more axes. Although one projection is shown in FIG. 76, more than one bow-like projections may be used.
Different bow or loop projection profiles may be useful for retaining nucleus tissue within the area bounded by the implant, soft anchoring to the nucleus or at least resisting travel through or along the nucleus, or for mechanically displacing nucleus tissue. Mechanical displacement (through pinching or pressing) of the nucleus can increase disc height and serve to more uniformly load the anulus and improve the performance of the implant. Also, the gap within the disc created by the bow or projection can be left vacant or filled in with suitable nucleus augmentation either through, or around a periphery of the implant. The bow projection 612 can also act as a piston or shock absorber that deforms under compressive loading of the disc relieving some of the load on the anulus caused by the nucleus being compressed between the endplates.
The stabilizing projection 612 can be made of the same material as the biocompatible support member 614 (e.g., barrier, patch or mesh). In one embodiment, the stabilizing projection 612 is an off-angle projection of the biocompatible support member 614 and forms a continuous loop or band. In another embodiment, the stabilizing projection 612 can be made of a different biocompatible material, including polymers, metals, bio-materials, and grafts.
FIGS. 77A-H show various cross-sectional side views of an implant 610 along a horizontal axis according to one or more embodiments of the invention. Accordingly, a bow, band or projection can be uniform in height or non-uniform. It can be the same height, shorter or taller than the patch portion of the implant. For example, in one embodiment, a projection is narrow at the point where it connects to the posterior support member component of the implant and then flairs near the midline of the anterior bow until its height exceeds the posterior member height. Such a configuration might be favorable between cupped or concave vertebral endplates when the posterior member portion of the implant is positioned against the posterior anulus. Further, in one or more embodiments of the invention, a projection can have different mechanical properties than the support member or patch section of the implant. For example, in one embodiment, a projection is more or less flexible along one or more axes compared to the patch or biocompatible support member portion of the implant. In another embodiments, a projection can be concave along one or more axes, or can have variable regions of concavity along the same axis.
FIGS. 78A-J show various cross-sectional top views of implants 610 along a vertical axis according to some embodiments of the invention. For example, FIG. 78G shows an implant (e.g., an anulus augmentation device such as a mesh) that has a puckered bow-like projection that is well-suited for disc morphology.
FIGS. 79A-F show a frontal view of a portion of various embodiments of projections according to one or more embodiments of the invention.
FIGS. 80A-D show various cross-sections of projection 612, according to some embodiments of the invention.
FIGS. 81A-D show looped or bent bow-type projections 612 that are contiguous or integral with, or are connected to the biocompatible support member 614 at two or more points along a vertical or horizontal axis. FIG. 81A shows a criss-cross loop projection. FIG. 81B shows a strap-like projection. FIG. 81C shows a projection that is integral with the support member such that the implant forms a circular band that serves to stabilize the device. FIG. 81D shows a box-frame type projection.
One skilled in the art will appreciate that any of the above procedures involving nuclear augmentation and/or anulus augmentation may be performed with or without the removal of any or all of the autologous nucleus. Further, the nuclear augmentation materials and/or the anulus augmentation device may be designed to be safely and efficiently removed from the intervertebral disc in the event they are no longer required.
Referenced byCiting PatentFiling datePublication dateApplicantTitleUS20120083659 *Oct 5, 2010Apr 5, 2012Caballero Gerardo AFoam Surgical Retractor* Cited by examinerClassifications U.S. Classification623/17.16International ClassificationA61F2/44, A61B17/00, A61F2/28, A61F2/46, A61B17/34, A61B17/70, A61B17/32, A61F2/00, A61F2/30, A61B5/107, A61B17/22, A61B19/00, A61F2/02Cooperative ClassificationA61F2/2846, A61F2/30723, A61F2002/30576, A61F2230/0091, A61F2210/0061, A61F2002/30177, A61B2019/461, A61F2310/0097, A61F2/4657, A61B5/1076, A61F2310/00365, A61F2310/00017, A61F2002/30601, A61F2002/4635, A61F2002/2817, A61F2002/30261, A61F2002/4658, A61B2017/00261, A61F2230/0069, A61F2002/30092, A61F2002/4662, A61F2002/30289, A61F2310/00023, A61F2002/30785, A61F2/441, A61F2/4601, A61F2002/30571, A61F2230/0056, A61F2230/0034, A61F2230/0028, A61F2002/30589, A61F2002/30172, A61F2002/30075, A61F2002/30187, A61F2002/30014, A61F2210/0004, A61F2002/30909, A61F2002/30224, A61F2230/0013, A61F2310/00029, A61F2002/4627, A61B5/4514, A61F2230/0052, A61F2/442, A61F2230/0004, A61F2002/30971, A61F2002/30583, A61F2230/0082, A61F2250/0018, A61B2017/22077, A61F2002/30131, A61F2002/30777, A61F2310/00161, A61B2017/320044, A61F2002/4661, A61F2002/30062, A61B17/320708, A61F2002/448, A61F2002/30291, A61B2017/3445, A61B2019/462, A61F2002/30228, A61F2210/0085, A61F2002/4435, A61F2230/0065, A61F2002/302, A61F2310/00976, A61F2002/30136, A61F2310/00293, A61F2/4611, A61F2002/30566, A61F2002/30166, A61F2002/30462, A61F2002/444, A61F2210/0014, A61F2220/0075, A61F2/30907, A61F2002/30677European ClassificationA61F2/44D, A61B17/3207C, A61B5/107J, A61F2/46M, A61F2/44B, A61F2/46B7RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services