SPINAL IMPLANTS WITH COOPERATING ANCHORING SUTURES

Abstract

Spinal implant devices include: (a) a spinal implant; and (b) at least on suture extending through a bone tunnel and attached to the spinal implant to fixate the spinal implant in the body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an anterior view of an implantable spinal disc prosthesis with cooperating sutures in an exemplary spinal position according to embodiments of the present invention.

FIG. 2A is an anterior view of a vertebral body with bone tunnels configured to accept sutures according to embodiments of the present invention.

FIG. 2B is an axial sectional view of the bone tunnels in the vertebral body taken along lines 2B-2B in FIG. 2A.

FIG. 2C is an anterior perspective view of bone tunnels extending a depth (in the posterior direction) into the vertebral body and a keel mortise in a vertebral body according to some embodiments of the present invention.

FIG. 2D is an anterior perspective (transparent) view of a spinal implant attached to the vertebral body shown in FIG. 2C using sutures in bone tunnels according to some embodiments of the present invention.

FIGS. 3A and 3B are lateral views of a portion of bone tunnels in vertebral bone with sutures routed therethrough according to embodiments of the present invention.

FIGS. 3C and 3D are partial sagittal cross sections of another orientation of a bone tunnel according to embodiments of the present invention.

FIG. 4A is an anterior view of a spinal implant between adjacent vertebral bodies to help fixate the implant in position with bone tunnels and sutures according to embodiments of the present invention.

FIG. 4B is an anterior view of a vertebral body with a keel space and a plurality of bone tunnels in one vertebral body that can be used to hold a spinal implant in position according to yet other embodiments of the present invention.

FIG. 4C is an anterior view of a partial implant with an alternate fixation configuration according to embodiments of the present invention.

FIGS. 5A-5C are partial axial section views of different bone tunnel configurations according to some embodiments of the present invention.

FIGS. 6A and 6B are partial axial section views of different suture and implant attachment means according to embodiments of the present invention.

FIG. 7A is an anterior view of a spinal implant residing between adjacent vertebral bodies with a tab attachment material structure using sutures and bone tunnels according to embodiments of the present invention.

FIG. 7B is an anterior view of a spinal implant residing between adjacent vertebral bodies with bone tunnels and sutures in combination with at least one suture anchor and one suture set to help hold the implant in position according to embodiments of the present invention.

FIGS. 8A-8E are sequential views of steps that can be used to position or anchor a spinal implant in the body according to embodiments of the present invention. FIGS. 8A-8C and 8E are lateral views and FIG. 8D is an anterior exploded view.

FIGS. 9A and 9B are lateral views of suture anchors that can be used to anchor spinal implants according to embodiments of the present invention.

FIG. 10 is a schematic illustration of a medical kit according to embodiments of the present invention.

FIG. 11 is an anterior view of a multi-level spinal implant fixation configuration according to some embodiments of the present invention.

FIG. 12 is a side perspective view of a spinal implant with keels according to some embodiments of the present invention.

FIG. 13A is a side view of a portion of the spine illustrating an implant on a spinous process with a cooperating suture anchor according to embodiments of the present invention.

FIG. 13B is a side view of an exemplary spinous process cuff suitable for use with a cooperating suture and bone tunnel according to some embodiments of the present invention.

FIG. 14 is a side view of a spine illustrating a wide range facet prosthesis secured using a cooperating suture in a bone tunnel according to some embodiments of the present invention.

DETAILED DESCRIPTION

The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity. Broken lines illustrate optional features or operations unless specified otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as “between X and Y” and “between about X and Y” should be interpreted to include X and Y. As used herein, phrases such as “between about X and Y” mean “between about X and about Y.” As used herein, phrases such as “from about X to Y” mean “from about X to about Y.”

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.

It will be understood that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. The sequence of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise.

The terms “spinal disc implant” and “spinal disc prosthesis” are used interchangeably herein to designate total disc replacements using an implantable total disc replacement (TDR) prosthesis (rather than a nucleus only) and as such are configured to replace the natural spinal disc of a mammalian subject (for veterinary or medical (human) applications). In contrast, the term “spinal implant” refers to both TDR spinal disc implants and alternative spinal implants, such as, for example, a spinal annulus implant, a spinal nucleus implant, a facet implant, and a spinous process implant as well as implants for other portions of the spine.

The term “suture” refers to a flexible material that joins a spinal structure to a spinal implant to help hold the implant in location in the body. The suture may be resorbable or non-resorbable, synthetic or natural. The suture can be configured to hold the implant in location for at least an initial post-implantation period of at least about 1 week, but may reside permanently in the body or, as noted above, may be substantially resorbable over time. The suture can be a single filament or multi-filament (braided) thread, floss, gut or wire, or combinations thereof that can be used to hold a portion of a spinal implant against target spinal structures, typically vertebral bodies. The suture may comprise a resorbable or non-resorbable biocompatible material. Examples of suture materials include elastomeric materials, such as, for example, polymers, copolymers and/or derivatives thereof, as well as other materials including, for example, NITINOL, and combinations thereof. In particular embodiments, a high strength braided suture comprising UHMWPE, such as the MaxBraid size 2 (metric 5), from Arthrotek, Inc., may be used alone or in combination with another suture in a respective bone tunnel.

The term “keel” means an implant component, feature or member that is configured to be received in a recess or mortise in an adjacent bone to facilitate short and/or long-term fixation and/or to provide twist or torsion resistance in situ.

The term “flexible” means that the member can be flexed or bent. In some embodiments, the implant can include a keel, which may be flexible but has sufficient rigidity to be substantially self-supporting so as to be able to substantially maintain a desired configuration outside of the body. If flexible, the keel can include reinforcement to increase its rigidity.

The term “mesh” means any biocompatible flexible material in any form including, for example, any knotted, braided, extruded, stamped, pressed, knitted, woven or otherwise, including felt or other flexible material, and may include a material with a substantially regular foramination pattern and/or irregular foramination patterns with pores of any size.

The term “macropores” refers to apertures having at least about a 0.1 mm diameter or width size, typically a diameter or width that is between about 0.1 mm to about 3 mm, and more typically a diameter or width that is between about 1 mm to about 1.5 mm (the width dimension referring to non-circular apertures). Where mesh keels are used, the macropores are larger than the openings or foramina of the mesh substrate. The macropores may promote bony through-growth for increased fixation and/or stabilization over time.

The term “loop” refers to a shape in the affected material that has a closed or nearly closed turn or figure. For example, the loop can have its uppermost portion merge into two contacting lower portions or into two proximately spaced apart lower portions. The term “fold” means to bend and the bend of the fold may have a sharp or rounded edge. The terms “pleat” or “fold” refer to doubling material on itself (with or without sharp edges). The term “attachment point” and derivatives thereof refers to a common attachment location and is not meant to restrict the attachment to a geometric point.

Referring now to the figures, FIG. 1 illustrates an example of a spinal implant 10 with a plurality of spaced apart cooperating sutures 22 that can be tied in a knot 22t or otherwise secured to reside proximate to, typically snugly against, a surface of the spinal implant 10. Thus, in lieu of, or with, the knot 22t, the ends of the sutures 22 may be attached to the implant 10 via other attachment means. For example, the two end portions of the suture 22 can be separately or jointly adhesively attached to the implant 10 such with an adhesive, heat-melt process, staple, clip or other anchor member.

As shown in FIG. 1, the implant 10 can include a bone attachment member or material 11 that receives the suture 22. That is, the suture 22 penetrates or extends through the bone attachment material 11 with leading and trailing edge portions 22e (FIG. 2A) secured against an outer surface of the material 11 and while a medial portion 22m (FIG. 2A) of the suture resides in a bone tunnel 122 (FIGS. 2A, 2B) formed in the (vertebral) bone 25. As shown, the bone attachment material 11 can extend above and below the primary body 10b of the implant 10. However, the bone attachment material 11 may be configured to reside only above, only below, or to be substantially coextensive with the primary implant body (not shown).

Each suture 22 can be closed together so that the respective knot 22t or other attaching means resides against or proximate an exterior surface of the bone attachment material 11, above or below the primary body of the implant 10. In other embodiments, as shown for example in FIG. 4C, one leg 22, of a first suture 22a in one bone tunnel 122₁ can be tied to a leg 22₂ of another suture 22b in a different bone tunnel 122₂. The remaining leg of each suture may be attached by a knot or anchor 22a or otherwise held against the bone attachment material 11. Alternatively, or additionally, one leg of a suture 22 in a bone tunnel 122 can be anchored by a bone anchor 20b (FIGS. 6, 9A, 9B) with a respective suture or suture set 22s, rather than to the same suture in the respective bone tunnel 122. Multiple sutures may also reside in one or more of the bone tunnels 122 and tied or otherwise secured to the bone attachment material 11 for additional stability (not shown).

In some embodiments a unitary layer of bone attachment material can form a skirt that defines both an upper and lower bone attachment material 11. The bone attachment material 11 can comprise any biocompatible material suitable to provide the attachment and/or stabilization. The bone attachment material 11 may comprise a flexible substrate. In some embodiments, the bone attachment material 11 comprises a mesh substrate. The mesh can be metallic, fabric, polymeric or comprise combinations of these or other materials.

The bone attachment material 11 can include pre-marked with alignment indicia 125 (FIG. 8D) for reliable positional placement of the sutures in or against the implant 10. The bone attachment material 11 may also include one or more relatively small preformed apertures (not shown) or structurally reinforced regions at the respective target indicia markings 122 that can be sized and configured to receive an end portion of the suture, typically using a needle 23 attached or holding the suture 22. The suture may be an atraumatic suture, with a swaged needle, but is not required to be such. In some embodiments, such as with wire or sutures with metal, including, for example, NITINOL, needles may not be required to position the suture 22 in the bone tunnel 122 and/or through the substrate of the bone attachment member or material 11 as the suture itself may have sufficient rigidity and/or sharpness to penetrate the material 11. Where used, the preformed apertures may be scored, molded in or introduced at a manufacturing site to reduce clinician preparation time. Alternatively, the substrate can be configured to allow the needle to be inserted through the substrate in the target attachment regions in situ without requiring preformed apertures.

The bone attachment material 11 can be between about 0.25 mm to about 20 mm thick, and is more typically between about 0.5 mm to about 5 mm thick. In some embodiments, the mesh comprises a DACRON mesh of about 0.7 mm thick available as Fablok Mills Mesh #9464 from Fablok Mills, Inc., located in Murray Hill, N.J. The mesh may comprise cryogel material to increase rigidity.

FIG. 1 illustrates that the implant 10 is secured using a plurality of sutures 22, some above and some below the implant 10. Although shown as four sutures 22 with respective bone tunnels 122 (FIGS. 2A, 2B) two in a first vertebral body 25 and two in a second adjacent vertebral body on opposing sides of the TDR region, additional or lesser numbers of the sutures 22 and/or bone tunnels 122 may be used.

Further, although the sutures 22 and bone tunnels 122 are shown as being substantially aligned (side to side and vertically) in proximate vertebral bone and in the bone attachment material 11, the sutures 22 may be arranged asymmetrically. In addition, sutures with bone anchors 20b or bone screws or other devices may be used with one or more of the sutures 22 with bone tunnels 122 (not shown). The implant 10 can be attached to bone 25 using the cooperating sutures 22 in a manner that allows substantially normal, or at least not unduly restrictive, spinal movement.

FIGS. 2A-2C illustrate examples of bone tunnels 122 that can be used to receive the sutures 22 as discussed above. FIG. 2C also illustrates that a keel mortise 26 may be formed in the vertebral body 25. FIG. 2D illustrates an exemplary suture 22 arrangement in the bone tunnels 122 shown in FIG. 2C with an implant 10 in position and a flexible keel 126 in the mortise 26. The bone tunnels 122 can be formed using known bone tunneling drill devices, such as, for example, the CurvTek® bone tunneling system from Arthrotek, Inc., located in Warsaw, Ind., and Ontario, CA. The bone tunnels 122 may be curvilinear and position the ingress and egress portions 122i, 122e of the tunnels spaced apart at between about 0.25 mm to about 20 mm, and may have a depth into the bone of between about 2 to about 20 mm, typically between about 4-8 mm. At least one suture 22 with at least one bone tunnel 122 can provide a relatively strong attachment of the spinal implant 10 to the adjacent vertebral body 25 through the bone attachment material 11 (typically a skirt) and avoid any metal components for that purpose. As such, scattering/noise can be reduced when conducting CT and MRI imaging and/or such an attachment technique avoids attendant risks of loosening of metal elements (screws or pins) that may cause complications/adverse events. This attachment technique can be configured to rely primarily on the strength of the cortical layer of bone and only some on the cancellous structure, which is typically not as strong.

The CurvTek® system includes a pneumatic handpiece on which is attached a disposable cartridge that incorporates the flexible drill bits and that conventionally comes in three different diameters (tunnel curvature diameters): 7, 12 and 22 mm. Below is a summary of the tunnel dimensions, conventional size tools may be used or custom tools developed to provide the desired intervertebral tunnels.

	Bone bridge	7	mm	12	mm	22	mm
	Total Depth	4.7	mm	5.2	mm	7.8	mm
	Tunnel size	2	mm	2	mm	2	mm

To advance the sutures 22, circular needles or suture passers, that have a diameter substantially matching the one of the bone bridge (tunnel curvature diameter), can be used to insert the suture through the tunnel 122.

It is noted that the ingress portions 122i of the tunnel 122 are interchangeable with the egress portions 122e, which are labeled in FIGS. 2B-2D for ease of discussion. The tunnels 122 may be formed substantially horizontally or may be angled upward or downward (not shown), combinations of different tunnel orientations may also be used. The tunnels 122 may be relatively small, sized and configured to allow at least one suture 22 to be threaded therethrough, typically between about 1 mm to about 3 mm. A suture 22 can be placed after the tunnel 122 is formed or can be pulled through using the drilling tool while the tunnel is being formed.

FIG. 3A illustrates that the bone tunnel 122 can extend substantially horizontally a distance “L” into the vertebral body 25 with the ingress and egress portions residing recessed into or substantially flush with the natural boundary of the vertebral bone 25. FIG. 3B illustrates the bone tunnel 122 can be angled upward through the cortical layer and may extend to cancellous bone.

FIGS. 3C and 3D illustrate a sagittal cross section of another orientation of a bone tunnel 122 and suture 22 which can take advantage of the stronger cortical bone to anchor or hold the implant 10 in the body.

FIG. 4A illustrates that the bone tunnels 122 may reside above or below the target bone attachment region and material 11, rather than substantially behind it as shown in FIG. 1. FIG. 4B illustrates that some bone tunnels 122a may reside behind the material 11 while some above 122b (or below) and each may be configured to attach to the material 11. FIG. 4C is an anterior view of a partial implant with an alternate fixation configuration with discrete anchors 22a and spaced apart bone tunnels 122₁, 122₂ with a suture exiting the respective tunnels and crossing and tied 22t over the material 11 according to embodiments of the present invention.

FIGS. 5A-5C illustrate that different numbers and sizes of tunnels 122 may be used to secure the implant. FIG. 5A illustrates three (3) tunnels 122 of smaller tunnel curvature (diameter), while FIG. 5B illustrates two (2) tunnels 122 and FIG. 5C illustrates a single, larger diameter (curvature) tunnel 122. FIGS. 6A and 6B illustrate exemplary securing means. FIG. 6A illustrates the two ends of the suture can be joined such as with a knot 22t which may be particularly suitable for small diameter sutures, while FIG. 6B illustrates the two end portions may include discrete anchors 22a, and can be separately secured such as via crimping, swaging or knotting with the anchor 22. One end of the suture may be pre-knotted, crimped, swaged or otherwise pre or post-attached to a fixation anchor 22a while the other is threaded through the tunnel 122 or each may be attached or formed with the anchor after placement through the tunnel 122.

FIG. 7A illustrates that the bone attachment material 11 can be configured with discrete tabs 11t spaced apart laterally; each tab 11t can engage at least one suture 22. FIG. 7B illustrates that the upper bone attachment material 11 may be configured differently from the lower bone attachment material. FIG. 7B also illustrates that a bone anchor 20b (see also, FIGS. 9A, 9B) with an attached suture or suture set may be used in combination with the suture 22 and bone tunnel 122. As shown, the bone anchor 20b can reside above the bone attachment material 11 while the bone tunnels 122 and sutures 22 may reside substantially behind the bone attachment material 11. Other embodiments can reverse the arrangement or use other combination arrangements of bone tunnels and bone anchors.

FIGS. 8A-8E illustrate one optional sequence of steps that can be used to attach a spinal implant to cooperating sutures 22 in situ. As shown in FIG. 8A, the primary implant body 10b can be positioned in an intervertebral space. The bone attachment material 11 can be pulled, pushed or folded back as shown in FIG. 8B and a bone tunnel 122 formed (of course the bone tunnel 122 can be formed before the implant is placed in the target space). Then, as shown in FIG. 8C, the suture 22 can be introduced into the target vertebral bone 25 proximate the implant 10. As shown in FIG. 8D, in an exploded view for clarity, a suture 22 can be pulled through the material 11. That is, the needles 23 can be inserted from one side of the material (i.e., flexible skirt) from the posterior (inner) to the anterior (outer) side. The suture 22 can be pulled substantially taut and tied together to form a knot 22t against the outer surface of the material 11 while the suture 22 remains in the tunnel 122 in the vertebral bone 25 to tighten the material 11 against the vertebral body 25. The incision can then be closed with the knot 22t inside the incision (not pulled through the skin).

Other sequences of steps may be used to attach the implant to the vertebral bodies such as, but not limited to:

• • Drill tunnels, insert disc, fold skirt open to visualize location of the tunnel, insert suture through attachment material (such as a skirt or tabs) (using needle), through the tunnel, through the skirt again and secure the suture around the skirt or tab (using a knot for the small diameter, or an anchoring/crimping system for the larger tunnel curvature diameter in order to avoid having the suture loosening/tearing through the thin layer of cortical bone when tightening the knot and applying force to the sutures).
  • Drill tunnels, insert disc (the skirt or tab in this case may have reinforced pre-holes), insert suture in bone tunnel (through pre-holes in the skirt) and secure the suture around the skirt
  • Insert disc, drill tunnel through skirt or tab and vertebral body at the same time, insert suture and secure.

FIG. 9A illustrates a threaded bone anchor 20b with an attached suture set 22s in position in a vertebral body 25. As shown, a suture 22 is held by a head portion 20h of the bone anchor 20b. The head 20h can be recessed into or be substantially flush with the natural boundary of the vertebral bone 25. For recessed configurations, bone chips or other void filling (bone growth) material may be inserted in the cavity between the material 11 and the bone anchor head 20h. The material can be provided as part of a medical kit 500 (FIG. 10). Typically, the head 20h includes an aperture 21 and a length of suture 22 is threaded through the aperture 21 to form a suture set 22s with a pair of legs 22L. The opposing end portions of the suture legs 22L (the end portion away from the head 21) can include/merge into a needle 23 (FIG. 8D). In use, after inserting the needle 23 through the bone attachment material 11, the corresponding suture leg 22L can be pulled through the material 11 and the suture set 22s can be tied or stitched together proximate an outside surface of the material 11.

FIG. 9B illustrates that the bone anchor 20b can be inserted through the cortical layer such that at least a tip portion thereof resides in cancellous bone. It is contemplated that the bone anchor 20b may have improved pullout strength if the threads of the bone anchor 20b bear on cortical bone. As shown, the bone anchor 20b can angularly reside in the bone 25 (rather than be substantially horizontal as shown in FIG. 9A). Combinations of these and other orientations may also be used.

A paper or flexible disposable template 300 (FIG. 10) may also be provided to help a clinician mark locations on vertebral bodies for the tunnels 122, sutures 22 and/or bone anchor 20b to help provide proper seating and alignment. The bone attachment material 11 may also include needle insertion indicia 125 (FIG. 10) to provide visual references that a clinician can use to attach the suture 22 to the implant 10 and location. The indicia 125 may also be color coded to the suture for that location.

The bone anchor 20b can be self-tapping and/or self-drilling. The bone anchor 20b may be implanted into a prior formed bore. The threads of the bone anchor 20b can be adapted to the porosity of the vertebral cancellous bone (which may be less dense than in other regions). The bone anchor 20b may have a largest diameter of between about 3-10 mm, typically between about 5-8 mm. The bone anchor 20b may have a length between about 8-30 mm, typically between about 10-20 mm.

As shown in FIG. 8D, the needle 23 may be swaged, threaded or otherwise attached to the suture 22. The needle 23 may be straight or curved. As shown, the needle 23 is curved and may also include a substantially blunt tip. Where a mesh is used to form the material 11, the blunt tip 23b may inhibit damage to mesh or other sensitive or susceptible fibers when suturing mesh material 11 to the bone. The suture can have lengths between about 5-20 cm. The needle 23 is typically removed from the suture 22 after pulling the suture leg through the bone attachment material 11, and the suture 22 can be tied or otherwise secured to the material 11 and the surplus lengths thereof can be removed (cut).

FIG. 10 illustrates a medical kit 500 that can provide the sutures 22. The kit 500 can include at least one implant 10 and a plurality of sutures 22 and may optionally include one or more bone anchors 20b with suture(s) (not shown). The kit 500 can also include the template 300 that may include indicia for the bone tunnel or suture entry location 301 and may optionally include needle indicia 322 that can align with indicia on an interior surface of the bone attachment material 11 proximate the indicia 125 that can be placed on the outside surface of the material 11 (for indicating a target needle exit location). The template 300 may be configured so that each target bone tunnel 122 location is color-coded to sutures 22 and/or a location on material 11. A similar or different template 300 can be provided for attachment to a lower location or an upper location, or a combination template can be provided with both sets of alignment/target location indicia (not shown). The kit may also include a bone tunneling device 510 and/or reamers or tunneling tools 511 particularly sized and configured to form the vertebral bone tunnels 122.

FIG. 11 illustrates three different exemplary mounting configurations for sutures 20 (alone or with suture anchors 20b) that may be used to attach to spinal implants 10. As shown, two TDR implants 10 are in position in respective intervertebral spaces. The upper implant 10₁ includes a single level multi-attachment point suture anchor 20sm with sutures 22 and respective tunnels 122. The lower portion of the upper implant 10₁ and the upper portion of the lower implant 10₂ illustrate a double level multi-attachment point suture anchor 20dm. That is, sutures 22 from respective bone anchors 20b extend to different levels (above and below the bone anchors 20b). The lower level of the second implant 10₂ illustrates a single level, single attachment point suture anchor 20ss also with sutures 22 and bone tunnels 122.

Referring to FIG. 12, in some embodiments, the shape of the implant 10 can be described as a three-dimensional structure that provides a desired anatomical shape, shock absorbency and mechanical support. In some embodiments, the anatomical shape can have an irregular solid volume to fill a target intervertebral disc space. The coordinates of the body can be described using the anatomic directions of superior (toward the head), inferior (toward the feet), lateral (away from the midline), medial (toward the midline), posterior (toward the back), and anterior (toward the front). From a superior view, the implanted device has a kidney shape with the hilum toward the posterior direction. The margins of the device in sagittal section are generally contained within the vertebral column dimensions. The term “primary surface” refers to one of the superior or inferior surfaces.

FIG. 12 illustrates one embodiment of spinal disc implant 10. The implant 10 can include at least one keel 126 on at least one primary surface. As shown, the implant 10 includes at least one flexible keel 126. In this embodiment, the flexible keel 126 is an anterior/posterior keel. In the embodiment shown in FIG. 12, the implant 10 includes both upper and lower keels 126 on respective superior and inferior primary surfaces. In other embodiments, the keel 126 can be oriented to extend substantially laterally. The keel 126 can be defined by a fold in a unitary layer of flexible material.

The size of the prosthetic spinal disc 10 can vary for different individuals. A typical size of an adult lumbar disc is 3-5 cm in the minor axis, 5 cm in the major axis, and 1.5 cm in thickness, but each of these dimensions can vary. It is contemplated that the implant 10 can be provided in a range of predetermined sizes to allow a clinician to choose an appropriate size for the patient. That is, the implant 10 can be provided in at least two different sizes with substantially the same shape. In some embodiments, the implant 10 can be provided in small, medium and large sizes. Further, the sizes can be configured according to the implant position—i.e., an L3-L4 implant may have a different size from an L4-L5 implant. In some embodiments, an implant 10 can be customized (sized) for each respective patient.

The implant 10 can be configured as a flexible elastomeric MRI and CT compatible implant of a shape generally similar to that of a spinal intervertebral disc. The implant 10 can have a solid elastomeric body with mechanical compressive and/or tensile elasticity that is typically less than about 100 MPa (and typically greater than 1 MPa), with an ultimate strength in tension generally greater than about 100 kPa, that can exhibit the flexibility to allow at least 2 degrees of rotation between the top and bottom faces with torsions greater than 0.01 N-m without failing. The implant 10 can be configured to withstand a compressive load greater than about 1 MPa.

The implant 10 can be made from any suitable elastomer capable of providing the desired shape, elasticity, biocompatibility, and strength parameters. The implant 10 can be configured with a single, uniform average durometer material and/or may have non-linear elasticity (i.e., it is not constant). The implant 10 may optionally be configured with a plurality of durometers, such as a dual durometer implant. The implant 10 can be configured to be stiffer in the middle, or stiffer on the outside perimeter. In some embodiments, the implant 10 can be configured to have a continuous stiffness change, instead of two distinct durometers. A lower durometer corresponds to a lower stiffness than the higher durometer area. For example, one region may have a compressive modulus that is between about 11-100 MPa, while the other region may have a compressive modulus that is between 1-10 MPa.

The implant 10 can have a tangent modulus of elasticity that is about 1-10 MPa, typically about 3-5 MPa, and a water content of between about 30-60%, typically about 50%.

Some embodiments of the implantable spinal disc 10 can comprise polyurethane, silicone, hydrogels, collagens, hyalurons, proteins and other synthetic polymers that are configured to have a desired range of elastomeric mechanical properties, such as a suitable compressive elastic stiffness and/or elastic modulus. Polymers such as silicone and polyurethane are generally known to have (compressive strength) elastic modulus values of less than 100 MPa. Hydrogels and collagens can also be made with compressive elasticity values less than 20 MPa and greater than 1.0 MPa. Silicone, polyurethane and some cryogels typically have an ultimate tensile strength greater than about 100 or 200 kiloPascals. Materials of this type can typically withstand torsions greater than 0.01 N-m without failing.

As shown in FIG. 12, the spinal disc body 10 may have a circumferential surface 14, a superior surface 12, and an inferior surface 13. The superior and inferior surfaces 13, 12 may be substantially convex to mate with concave vertebral bones. One or more of the surfaces may also be substantially planar or concave. The circumferential surface 14 of spinal disc body 10 corresponds to the annulus fibrosis (“annulus”) of the natural disc and can be described as the annulus surface 14. The superior surface 12 and the inferior surface 13 of spinal disc body 10 correspond to vertebral end plates (“end plates”) in the natural disc. The medial interior of spinal disc body 10 corresponds to the nucleus pulposus (“nucleus”) of the natural disc.

The implant 10 can include a porous covering, typically a mesh material layer, 12c, 13c on each of the superior and inferior primary surfaces 12, 13, respectively. As shown, the implant 10 can also include a porous, typically mesh, material layer 14c on the annulus surface 14. The annulus cover layer 14e can be formed as a continuous or seamed ring to inhibit lateral expansion. In other embodiments, the annulus cover layer 14c can be discontinuous. As also shown, the three coverings 12c, 13c, 14c can meet at respective edges thereof to encase the implant body 10. In other embodiments, the coverings 12c, 13c, 14c may not meet or may cover only a portion of their respective surfaces 12, 13, 14.

FIG. 12 illustrates that the annulus cover 14c, the superior cover 12c, and or the inferior cover 13c can be oversized to extend beyond the bounds of the implant body 10b above or below an anterior portion of the implant body 10b to define the attachment material 11 that can cooperate with sutures 22 in bone tunnels 122. The material 11 can extend above or below the body 10b with a height between about 2-35 mm, typically 5-15 mm.

The implant 10 may be configured to allow vertical passive expansion or growth of between about 1-40% in situ as the implant 10 absorbs or intakes liquid due to the presence of body fluids. The passive growth can be measured outside the body by placing an implant in saline at room temperature and pressure for 5-7 days, while held in a simulated spinal column in an intervertebrate space between two simulated vertebrates. It is noted that the passive expansion can vary depending, for example, on the type of covering or mesh employed and the implant material. For example, in some embodiments, the mesh coverings 14c, 12c, 13c along with a weight percentage of (PVA) used to form the implant body are configured to have between about 1-5% expansion in situ.

In addition, in some embodiments, the mesh may comprise a biocompatible coating or additional material on an outer and/or inner surface that can increase the stiffness. The stiffening coating or material can include PVA cryogel. The annulus cover 14C (also described as a “skirt”) can be a continuous skirt that defines the bone attachment material 11 and may include stiffening or reinforcement means.

Some embodiments of the spinal disc implant 10 are configured so that they can mechanically function as a substantially normal (natural) spinal disc and can attach to endplates of the adjacent vertebral bodies. As shown in FIG. 12, the primary spinal disc body 10b is generally of kidney shape when observed from the superior, or top, view, having an extended oval surface and an indented portion. The anterior portion of spinal disc 10 can have greater height than the posterior portion 10p of spinal disc 10 in the sagittal plane. The implant 10 can be configured with a mechanical compressive modulus of elasticity of about 1.0 MPa, ultimate stretch of greater than 15%, and ultimate strength of about 5 MPa. The device can support over 1200 N of force. Further description of an exemplary flexible implant is described in co-pending U.S. Patent Application Publication No. 20050055099, the contents of which are hereby incorporated by reference as if recited in full herein.

Elastomers useful in the practice of the invention include silicone rubber, polyurethane, polyvinyl alcohol (PVA) hydrogels, polyvinyl pyrrolidone, poly HEMA, HYPAN™ and Salubria® biomaterial. Methods for preparation of these polymers and copolymers are well known in the art. Examples of known processes for fabricating elastomeric cryogel material is described in U.S. Pat. Nos. 5,981,826 and 6,231,605, the contents of which are hereby incorporated by reference. See also, Peppas, Poly (vinyl alcohol) hydrogels prepared by freezing—thawing cyclic processing. Polymer, v. 33, pp. 3932-3936 (1992); Shauna R. Stauffer and Nikolaos A. Peppas.

In some embodiments, the implant body 10 is a substantially solid PVA hydrogel having a unitary body shaped to correspond to a natural spinal disc. An exemplary hydrogel suitable for forming a spinal implant is (highly) hydrolyzed crystalline poly (vinyl alcohol) (PVA). PVA cryogels may be prepared from commercially available PVA material, typically comprising powder, crystals or pellets, by any suitable methods known to those of skill in the art. Other materials may also be used, depending, for example, on the application and desired functionality. Additional reinforcing materials or coverings, radiopaque markers, calcium salt or other materials or components can be molded on and/or into the molded body. Alternatively, the implant can consist essentially of only the molded PVA body.

In some embodiments, the attachment material 11 is integrally attached to a moldable implant material via a molding process. The moldable primary implant material can be placed in a mold. The moldable material comprises an irrigant and/or solvent and about 20 to 70% (by weight) PVA powder crystals. The PVA powder crystals can have a MW of between about 124,000 to about 165,000, with about a 99.3-100% hydrolysis. The irrigant or solvent can be a solution of about 0.9% sodium chloride. The PVA crystals can be placed in the mold before the irrigant (no pre-mixing is required). The mold has the desired 3-D implant body shape. A lid can be used to close the mold. The closed mold can be evacuated or otherwise processed to remove air bubbles from the interior cavity. For example, the irrigant can be overfilled such that, when the lid is placed on (clamped or secured to) the mold, the excess liquid is forced out thereby removing air bubbles. In other embodiments, a vacuum can be in fluid communication with the mold cavity to lower the pressure in the chamber and remove the air bubbles. The PVA crystals and irrigant can be mixed once in the mold before and/or after the lid is closed. Alternatively, the mixing can occur naturally without active mechanical action during the heating process.

Typically, the mold with the moldable material is heated to a temperature of between about 80° C. to about 200° C. for a time sufficient to form a solid molded body. The temperature of the mold can be measured on an external surface. The mold can be heated to at least about 80-200° C. for at least about 5 minutes and less than about 8 hours, typically between about 10 minutes to about 4 hours. The (average or max and min) temperature can be measured in several external mold locations. The mold can also be placed in an oven and held in the oven for a desired time at a temperature sufficient to bring the mold and the moldable material to suitable temperatures. In some embodiments, the mold(s) can be held in an oven at between about 50-200° C. for a target period of time, typically between about 100-200° C. for about 2-6 hours; the higher range may be used when several molds are placed therein or lower temperatures are used, but different times and temperatures may be used depending on the heat source, such as the oven, the oven temperature, the configuration of the mold, and the number of items being heated.

The liners 14c, 12c, 13c can be placed in the mold to integrally attach to the molded implant body during the molding process. In some embodiments, osteoconductive material, such as, for example, calcium salt can be placed on the inner or outer surfaces of the covering layers 14c, 12c, 13c, and/or the inner mold surfaces (wall, ceiling, floor) to coat and/or impregnate the mesh material to provide osteoconductive, tissue-growth promoting coatings.

After heating, the implant body can be cooled passively or actively and/or frozen and thawed a plurality of times until a solid crystalline implant is formed with the desired mechanical properties. The molded implant body can be removed from the mold prior to the freezing and thawing or the freezing and thawing can be carried out with the implant in the mold. Alternatively, some of the freeze and thaw steps (such as, but not limited to, between about 0-10 cycles) can be carried out while the implant is in the mold, then others (such as, but not limited to, between about 5-20 cycles) can be carried out with the implant out of the mold.

Before, during and/or after freezing and thawing (but typically after demolding), the molded implant can be placed in water or saline (or both or, in some embodiments, neither). The device can be partially or completely dehydrated for implantation. The resulting prosthesis can have an elastic modulus of at least about 2 MPa and a mechanical ultimate strength in tension and compression of at least 1 MPa, preferably about 10 MPa, and under about 100 MPa. The prosthesis may allow for between about 1-10 degrees of rotation between the top and bottom faces with torsions of at least about 1 N-m without failing. The implant can be a single solid elastomeric material that is biocompatible by cytotoxicity and sensitivity testing specified by ISO (ISO 10993-5 1999: Biological evaluation of medical devices—Part 5: Tests for in vitro cytotoxicity and ISO 10993-10 2002: Biological Evaluation of medical devices-Part 10: Tests for irritation and delayed-type hypersensitivity).

The testing parameters used to evaluate the compressive tangential modulus of a material specimen can include:

Test type: unconfined compression

Fixtures: flat platens, at least 30 mm diameter

Rate: 25.4 mm/sec to 40% strain

Temperature: room temp (˜22° C.)

Bath: samples stored in saline or water until immediately before test

Samples: cylinders, 9.8±0.1 mm height, 9.05±0.03 mm diameter

Compressive Tangential Modulus calculated at 15, 20, and 35% strain

Embodiments of the instant invention employ sutures 22 with tunnels 122 to attach any suitable prosthesis and the present invention is not limited to spinal implants. In some embodiments, the suture anchors can be used to attach or affix implants comprising PVA cryogel material. The PVA cryogel implants can be manufactured to be mechanically strong, or to possess various levels of strength among other physical properties with a high water content, which provides desirable properties in numerous applications. For example, the cryogel tissue replacement construct is especially useful in surgical and other medical applications as an artificial material for replacing and reconstructing soft tissues or as orthopedic implants in humans and other mammals.

FIGS. 13A and 13B illustrate that sutures 22 and bone tunnels 122 can be used to secure other implants in the body. As shown in FIG. 13A, a spinous process sleeve or cuff implant 210 is in position on the spinous process 35 in the body. The suture 22 is attached to the implant 210. That is, the bone tunnel 122 resides in the spinous process 35 while the suture 22 is tied 22t to the implant 210. FIG. 13B illustrates that attachment extensions 211 (such as tabs or a skirt) can be used to secure the sutures 22. The extensions 211 can include the needle indicia 125. FIG. 13A illustrates that the sutures 22 may be attached directly to the cuff body. The cuff body may include reinforced regions (i.e., PVA cryogel with polymeric mesh fabric, laminated layers of mesh fabric and the like) with increased rigidity or strength that inhibits tearing that define the attachment zones.

FIG. 14 illustrates a synthetic wide range facet implant 310 secured in position in the spine using a cooperating suture 22 in bone tunnel 122. The implant 310 is configured as a “spinal facet joint”. This term refers to the location at which vertebral bodies meet at a rear portion of the spine. The shape of facet joints change along the length of the spine. The facet joint includes bone, cartilage, synovial tissue, and menisci. The implant 310 can be an elastic body that is configured to substantially conformably reside on an outer surface of the bone in a manner that allows a relatively wide range of motion between the bones forming the joint.

The implants 310 and 210 can be substantially “conformal” so as to have sufficient flexibility to substantially conform to a target structure's shape.

The facet implant or prosthesis can be applied to one surface (one side) of the facet joint (the bone is resurfaced by the implant) or to both surfaces of the joint, and/or may reside therebetween as a spacer to compress in response to loads introduced by the cooperating bones at the facet joint and still allow motion therebetween.

The spinal facet joint implant 310 can be configured to provide “wide range motion”; this phrase refers to the substantially natural motion of the bones in the facet joint which typically include all ranges of motion (torsion, lateral and vertical). The implant 310 can have a thickness that is less than about 6 mm, typically between about 0.001-3 mm, and may be between about 0.01 mm to about 0.5 mm. The target structure's shape can be either the upper portion of the lower bone or the lower portion of the upper bone (one of the two vertebral bones) that meet at the rear of the spine.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims

1. A spinal implant with at least one cooperating suture, comprising: a spinal implant; andat least one suture, wherein, in position, the at least one suture extends through a bone tunnel in a vertebral body and attaches to the spinal implant.

2. An implant according to claim 1, wherein the spinal implant is a total disc replacement spinal implant with attachment material attached thereto, the spinal implant having a primary implant body with a boundary substantially coextensive with a target natural spinal disc replacement location, wherein the attachment material extends in at least one of a superior or inferior direction beyond the bounds of the primary implant body with opposing end portions of the at least one suture extending through the attachment material while a medial portion of the suture resides in the bone tunnel in the vertebral body.

3. An implant according to claim 1, wherein, during implantation, the suture includes at least one needle, wherein the needle is curved with a substantially blunt tip.

4. An implant according to claim 1, wherein the spinal implant comprises attachment material, wherein the at least one suture is configured so that a length of suture forms two outwardly extending legs with a medial portion therebetween, and wherein, in position, the two legs of the suture define a suture knot that reside tightly against an outer surface of the attachment material with the medial portion in the bone tunnel in the vertebral body.

5. An implant according to claim 4, wherein the at least one suture is a plurality of sutures for multi-point attachment to the attachment material of the spinal implant.

6. An implant according to claim 1, wherein the at least one suture extends through a bone tunnel formed in vertebral cancellous bone.

7. An implant according to claim 1, wherein the at least one suture is resorbable.

8. An implant according to claim 2, wherein the primary body is a non-articulating unitary elastomeric body.

9. An implant according to claim 2, wherein the attachment material comprises a porous material.

10. An implant according to claim 2, wherein the attachment material comprises a mesh skirt extending over at least a major portion of an annulus outer surface of the primary implant body with upwardly and downwardly extending pliant segments, and wherein the at least one suture is at least two spaced apart sutures that are secured to the mesh skirt via tied suture knots, wherein the tied suture knots snugly abut an outer surface of the pliant segments forcing the attachment material against the vertebral body.

11. An implant according to claim 1, further comprising at least one threaded bone anchor with an associated suture attached to the bone attachment material in a location that is spaced apart from the at least one suture.

12. An implant according to claim 2, wherein the primary body comprises a crystalline polyvinylalcohol hydrogel, wherein the bone attachment material comprises a mesh skirt with attachment segments that extend above and below a superior and inferior surface of the primary body, and wherein the at least one suture is at least four sutures, a respective one attached to spaced apart portions of the attachment segments of the mesh skirt with the suture sets from the bone anchors tied in knots tightly against an outer surface of the mesh skirt.

13. A medical spinal implant kit, comprising; a total disc replacement (TDR) spinal implant comprising a bone attachment material; anda plurality of sutures configured to reside against an outer surface of the bone attachment material with the respective sutures configured and sized to reside in at least one bone tunnel in a vertebral body above and/or below the TDR implant to secure the TDR implant in position.

14. A medical kit according to claim 13, wherein each of the plurality of sutures comprise a needle or a substantially rigid sharp leading edge portion configured to be able to penetrate the bone attachment material, and wherein, in position the edges of the sutures define suture knots that reside against the outer surface of the bone attachment material.

15. A medical kit according to claim 13, wherein the bone attachment material comprises at least one of needle, suture or bone tunnel alignment indicia to allow a clinician to visually identify target suture positions.

16. A medical kit according to claim 13, further comprising a bone tunneling drill configured to form a bone tunnel in a vertebral body.

17. A medical kit according to claim 13, further comprising at least one suture anchor with a threaded bone anchor body and an associated at least one suture.

18. A medical kit according to claim 13, wherein the bone attachment material comprises mesh.

19. A medical kit according to claim 13, further comprising a bone tunnel template for defining target bone tunnel ingress and egress positions in a vertebral body.

20. A method of attaching a total disc replacement (TDR) implant to at least one vertebral body, comprising; implanting a TDR;forming at least one bone tunnel in at least one vertebral body proximate the TDR;inserting at least one suture through the at least one bone tunnel; andaffixing the inserted at least one suture to the TDR to thereby secure the TDR in position in the body.

21. A method according to claim 20, wherein the forming step is carried out after the implanting step.

22. A method according to claim 20, wherein the implanting step is carried out before the inserting step.

23. A method according to claim 20, wherein the implanting step is carried out after the forming and inserting steps.

24. A method according to claim 20, wherein the affixing step comprises tying the at least one suture to form a knot.

25. A method according to claim 20, wherein the TDR comprises a porous bone attachment material extending upwardly and/or downwardly beyond the bounds of a primary implant body, wherein the method further comprises: pushing or pulling the porous bone attachment material away from the proximate vertebral body during the inserting step; andpushing or pulling at least one needle attached to the at least one suture through the porous bone attachment material before the affixing step.

26. A method according to claim 20, wherein the TDR implant comprises an elastomeric primary body with mesh bone attachment material integrally attached thereto, wherein the affixing step comprises tying a plurality of spaced apart sutures tightly against mesh material extending from the TDR implant to hold the implant in position in a patient's body.

27. A method according to claim 20, wherein the affixing step comprises anchoring the TDR to a vertebral body using the at least one suture extending through a bone tunnel that extends into cancellous bone.

28. A method according to claim 20, wherein the at least one suture is a plurality of sutures, and wherein the at least one bone tunnel is a plurality of bone tunnels, the inserting step comprises inserting at least one suture into at least two spaced apart bone tunnels in an upper vertebral body and inserting at least one suture into at least two spaced apart bone tunnels in a lower vertebral body with the TDR therebetween, and wherein the affixing step comprises tying the at least four sutures, to the TDR to thereby secure the TDR in position in the body.

29. A method according to claim 20, further comprising placing a template of target ingress and egress locations of a bone tunnel over a selected vertebral body, then marking the target ingress and egress locations of a bone tunnel on vertebral bone using the template.