Intervertebral disc nucleus implants and methods

Abstract

Nucleus pulposus implants that are resistant to migration in and/or expulsion from an intervertebral disc space are provided. In one form of the invention, an implant includes a load bearing elastic body surrounded in the disc space by an anchoring, preferably resorbable, outer shell. In certain forms of the invention, the elastic body is surrounded by a supporting member, such as a band or jacket, and the supporting member is surrounded by the outer shell. Kits for forming such implants are also provided. In another form of the invention, an implant is provided that has locking features and optional shape memory characteristics. In yet another aspect of the invention, nucleus pulposus implants are provided that have shape memory characteristics and are configured to allow short-term manual, or other deformation without permanent deformation, cracks, tears, breakage or other damage. Methods of forming and implanting the implants are also described.

What is claimed is:  
     
         1 . An intervertebral disc nucleus pulposus implant, comprising: 
 a load bearing elastic body sized for introduction into an intervertebral disc space, said body surrounded by a resorbable shell.    
     
     
         2 . The implant of  claim 1 , wherein said resorbable shell is comprised of an elastic material.  
     
     
         3 . The implant of  claim 1 , wherein said resorbable shell is comprised of a material selected from the group consisting of fibrin, albumin, gelatin, collagen, elastin, silk, demineralized bone matrix, polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polypropylene fumarate and combinations thereof.  
     
     
         4 . The implant of  claim 1 , wherein said elastic body is comprised of a hydrogel material.  
     
     
         5 . The implant of  claim 4 , further including a pharmacological agent associated with said hydrogel material, said resorbable shell, or a combination thereof, said agent selected from the group consisting of growth factors, anti-inflammatory drugs, antibiotics, analgesics, and combinations thereof.  
     
     
         6 . The implant of  claim 5 , wherein said pharmacological agent is a growth factor.  
     
     
         7 . The implant of  claim 6 , wherein said growth factor is selected from the group consisting of transforming growth factor β, bone morphogenetic proteins, fibroblast growth factors, platelet-derived growth factors, insulin-like growth factors and combinations thereof.  
     
     
         8 . The implant of  claim 7 , wherein said growth factor is a recombinant human protein.  
     
     
         9 . The implant of  claim 1 , wherein said elastic body is comprised of a polymer selected from the group consisting of elastomers and hydrogels.  
     
     
         10 . The implant of  claim 1 , wherein the outer surface of said elastic body includes projections extending therefrom, said projections configured for enhancing fixation of said body in said intervertebral space.  
     
     
         11 . The implant of  claim 10 , wherein said projections comprise fiber loops.  
     
     
         12 . The implant of  claim 1 , wherein the outer surface of said elastic body is microtexturized.  
     
     
         13 . The implant of  claim 12 , wherein said microtexturizing is performed by a process selected from the group consisting of bead blasting, plasma etching, chemical etching and combinations thereof.  
     
     
         14 . The implant of  claim 1 , wherein the outer surface of said elastic body includes reactive chemical groups selected from the group consisting of hydroxyl groups, amino groups, carboxyl groups and organofunctional silane groups, said groups enhancing fixation of said elastic body to said resorbable shell.  
     
     
         15 . The implant of  claim 1 , wherein said resorbable shell is formed in-situ.  
     
     
         16 . An intervertebral disc nucleus pulposus implant, comprising: 
 a load bearing elastic body of hydrogel material sized for introduction into an intervertebral disc space, said body surrounded by a resorbable shell.    
     
     
         17 . An intervertebral disc nucleus pulposus implant, comprising: 
 a load bearing elastic body sized for introduction into an intervertebral disc space, said body surrounded by a supporting member, said supporting member surrounded by a resorbable shell.    
     
     
         18 . The implant of  claim 17 , wherein said resorbable shell is comprised of an elastic material.  
     
     
         19 . The implant of  claim 17 , wherein said resorbable shell is comprised of a material selected from the group consisting of fibrin, albumin, gelatin, collagen, elastin, silk, demineralized bone matrix, polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polypropylene fumarate and combinations thereof.  
     
     
         20 . The implant of  claim 17 , wherein said elastic body is comprised of a hydrogel material.  
     
     
         21 . The implant of  claim 17 , wherein said supporting member is comprised of a supporting band.  
     
     
         22 . The implant of  claim 17 , wherein said supporting member is comprised of a jacket.  
     
     
         23 . An intervertebral disc nucleus pulposus implant, comprising: 
 a load bearing elastic body sized for placement into an intervertebral disc space, said body having a first end, a second end, a central portion, and a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold, said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, said body configurable back into said first configuration after said insertion.    
     
     
         24 . The implant of  claim 23 , wherein said inner fold defines an aperture.  
     
     
         25 . The implant of  claim 23 , wherein said elastic body is comprised of a hydrogel material.  
     
     
         26 . The implant of  claim 23 , wherein said elastic body is comprised of an elastomer.  
     
     
         27 . The implant of  claim 26 , wherein said elastomer is selected from the group consisting of silicone, polyurethane, copolymers of silicone and polyurethane, polyolefins, nitrile and combinations thereof.  
     
     
         28 . The implant of  claim 24 , wherein said inner fold has a surface with projections, said projections extending into said aperture.  
     
     
         29 . The implant of  claim 23 , wherein said elastic body has an outer surface, said outer surface having projections extending therefrom, said projections configured for enhancing fixation of said body in said intervertebral disc space.  
     
     
         30 . The implant of  claim 23 , wherein the outer surface of said elastic body is microtexturized.  
     
     
         31 . The implant of  claim 30 , wherein said microtexturizing is performed by a process selected from the group consisting of bead blasting, plasma etching, chemical etching and combinations thereof.  
     
     
         32 . The implant of  claim 23 , wherein said body further comprises a reinforcing material at said inner fold surface.  
     
     
         33 . The implant of  claim 32 , wherein said reinforcing material comprises fibers.  
     
     
         34 . The implant of  claim 23 , wherein said elastic body is comprised of a hydrogel material, said material having at least one growth factor dispersed therein.  
     
     
         35 . The implant of  claim 34 , wherein said growth factor is selected from the group consisting of transforming growth factor β, bone morphogenetic proteins, fibroblast growth factors, platelet-derived growth factors, insulin-like growth factors and combinations thereof.  
     
     
         36 . The implant of  claim 34 , wherein said growth factor comprises a recombinant protein.  
     
     
         37 . The implant of  claim 36 , wherein said recombinant protein is a human protein.  
     
     
         38 . An intervertebral disc nucleus pulposus implant, comprising: 
 a load bearing elastic body sized for placement into an intervertebral disc space, said body having a first end and a second end, said first end and said second end configured for mating engagement with each other, said elastic body having a first configuration wherein said first end and said second end are matingly engaged to each other, said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, said body configurable back into said first configuration after said insertion.    
     
     
         39 . The implant of  claim 38 , wherein one of said ends defines an internal channel, said other end interlockingly disposed within said channel.  
     
     
         40 . The implant of  claim 39 , wherein said other end is configured to conform to the shape of said internal channel.  
     
     
         41 . The implant of  claim 38 , wherein said elastic body is annular-shaped.  
     
     
         42 . The implant of  claim 38 , wherein said elastic body is comprised of a hydrogel material, said material having a growth factor dispersed therein.  
     
     
         43 . The implant of  claim 42 , wherein said growth factor is selected from the group consisting of transforming growth factor β, bone morphogenetic proteins, fibroblast growth factors, platelet-derived growth factors, insulin-like growth factors and combinations thereof.  
     
     
         44 . A kit for forming an intervertebral disc nucleus pulposus implant, comprising a load bearing elastic body sized for introduction into an intervertebral disc space and a container of material to form a resorbable shell around said body.  
     
     
         45 . The kit of  claim 44 , wherein said material is curable.  
     
     
         46 . The kit of  claim 44 , wherein said resorbable shell is comprised of an elastic material.  
     
     
         47 . The kit of  claim 44 , wherein said resorbable shell is comprised of a material selected from the group consisting of fibrin, albumin, gelatin, collagen, elastin, silk, demineralized bone matrix, polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polypropylene fumarate and combinations thereof.  
     
     
         48 . The kit of  claim 44 , wherein said elastic body is comprised of a hydrogel material.  
     
     
         49 . The kit of  claim 44 , wherein said elastic body is comprised of a polymer selected from the group consisting of elastomers and hydrogels.  
     
     
         50 . A kit for forming an intervertebral disc nucleus pulposus implant, comprising a load bearing elastic body sized for introduction into an intervertebral disc space, a supporting member to surround said body and a container of material to form a resorbable shell around said supporting member.  
     
     
         51 . A method for implanting an intervertebral disc nucleus pulposus implant in an intervertebral disc space, comprising: 
 (a) preparing said intervertebal disc space to receive said implant; and    (b) introducing a load bearing elastic body into said disc space, said body surrounded in said disc space by a resorbable shell.    
     
     
         52 . The method of  claim 51 , comprising introducing said resorbable shell into said intervertebral disc space prior to introducing said elastic body into said intervertebral disc space.  
     
     
         53 . The method of  claim 51 , comprising introducing said resorbable shell into said intervertebral disc space after introducing said elastic body into said intervertebral disc space.  
     
     
         54 . The method of  claim 51 , comprising introducing said resorbable shell into said intervertebral disc space at the same time as introducing said elastic body into said intervertebral disc space.  
     
     
         55 . The method of  claim 51 , comprising surrounding said elastic body with said resorbable shell prior to introducing said elastic body into said disc space.  
     
     
         56 . The method of  claim 51 , wherein said resorbable shell is formed from a resorbable material in an uncured state and is cured to form said outer shell.  
     
     
         57 . A method for implanting an intervertebral disc nucleus pulposus implant in an intervertebral disc space, comprising: 
 (a) preparing said intervertebal disc space to receive said implant; and    (b) introducing a load bearing elastic body into said disc space, said body surrounded by a supporting member, said supporting member surrounded in said disc space by a resorbable shell.    
     
     
         58 . The implant of  claim 57 , wherein said supporting member is comprised of a supporting band.  
     
     
         59 . The implant of  claim 57 , wherein said supporting member is comprised of a jacket.  
     
     
         60 . A method for implanting an intervertebral disc nucleus pulposus implant in an intervertebral disc space, comprising: 
 (a) providing a load bearing elastic body sized for placement into an intervertebral disc space, said body having a first end, a second end, a central portion, and a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold, said elastic body configurable into a second, straightened configuration for insertion through an opening in said annulus fibrosis, said body configurable back into said first configuration after said insertion;    (b) preparing said intervertebal disc space to receive said body; and    (c) positioning said body into said intervertebral disc space after said preparing step.    
     
     
         61 . The method of  claim 60 , wherein said method further comprises configuring said body at least partially into said second, straightened configuration prior to said placing step.  
     
     
         62 . A method for implanting an intervertebral disc nucleus pulposus implant in an intervertebral disc space, comprising: 
 (a) providing a load bearing elastic body sized for placement into an intervertebral disc space, said body having a first end and a second end, said first end and said second end configured for mating engagement with each other, said elastic body having a first configuration wherein said first end and said second end are matingly engaged to each other, said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, said body configurable back into said first configuration after said insertion;    (b) preparing said intervertebal disc space to receive said body;    (c) positioning said body into said intervertebral disc space after said preparing step.