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, as are delivery devices and components thereof for delivering the implants.

1 - 28 . (canceled)  
     
     
         29 . A method for implanting an intervertebral disc nucleus pulposus implant in an intervertebral disc space, comprising: 
 (a) preparing said intervertebral 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.    
     
     
         30 . A method for implanting an intervertebral disc nucleus pulposus implant in an intervertebral disc space, comprising: 
 (a) preparing said intervertebral 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.    
     
     
         31 . 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 intervertebral disc space to receive said body; and    (c) positioning said body into said intervertebral disc space after said preparing step.    
     
     
         32 . 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 intervertebral disc space to receive said body;    (c) positioning said body into said intervertebral disc space after said preparing step.    
     
     
         33 - 47 . (canceled)  
     
     
         48 . A method according to  claim 31  wherein said preparing step includes distracting the disc space.  
     
     
         49 . A method according to  claim 48  wherein said distracting of the disc space is accomplished using the tip of an instrument used to position the body in the disc space.  
     
     
         50 . A method according to  claim 31  wherein said preparing step includes removing part or all of the natural disc nucleus pulposus.  
     
     
         51 . A method according to  claim 31  wherein said method further includes the step of making a hole in the disc annulus fibrosis to allow passage of a disc nucleus implant therethrough.  
     
     
         52 . A method according to  claim 31  wherein said positioning step includes inserting a nucleus pulposus implant using either an anterior approach or a posterior approach.  
     
     
         53 . A method according to  claim 31  wherein said positioning step is accomplished using a spinal disc implant delivery device, comprising: 
 (a) an elongated member having a proximal end, a distal end, and a lumen extending longitudinally therethrough, wherein said lumen has a diameter sized to receive a nucleus pulposus implant; and    (b) a plurality of movable members positioned at the distal end of said elongated member, each of said movable members having a proximal end and a distal end, each of said proximal ends of said movable members abutting said distal end of said elongated member, said movable members having a closed configuration defining a cavity in communication with said lumen of said elongated member, wherein said cavity has a diameter smaller than the diameter of said lumen, wherein said movable members are sized and configured such that their distal ends may be inserted in an aperture in an annulus fibrosus when said movable members are in their closed configuration, said movable members further being openable to an open configuration wherein the distal ends of said movable members define a passageway having a diameter at least as large as the diameter of said lumen to allow passage of a nucleus pulposus implant therethrough.    
     
     
         54 . The method of  claim 53  wherein said body is positioned by passing the body through said movable members such that the movable members open to their open configuration by the force of said body passing therethrough.  
     
     
         55 . The method of  claim 54  wherein said opening of said movable members dilates an opening in the annulus fibrosis.  
     
     
         56 . A method of implanting an intervertebral disc nucleus pulposus implant in an intervertebral disc space; said method comprising: 
 (a) providing a spinal disc implant delivery device, comprising: 
 (i) an elongated member having a proximal end, a distal end, and a lumen extending longitudinally therethrough, wherein said lumen has a diameter sized to receive a nucleus pulposus implant; and  
 (ii) a plurality of opening members positioned at the distal end of said elongated member, each of said opening members having a proximal end and a distal end, each of said proximal ends of said opening members abutting said distal end of said elongated member, at least one of said opening members being a movable member, said opening members having a closed configuration defining a cavity in communication with said lumen of said elongated member, wherein said cavity has a proximal end and a distal end, wherein the distal end of said cavity has a diameter smaller than the diameter of said lumen, wherein said opening members are sized and configured such that their distal ends may be inserted in an aperture in an annulus fibrosus when said opening members are in their closed configuration, said opening members further being openable to an open configuration by moving at least one movable member to an open configuration, wherein the distal ends of said opening members define a passageway having a diameter at least as large as the diameter of said lumen when said opening members are in their open configuration to allow passage of a nucleus pulposus implant therethrough;  
   (b) loading into said spinal disc implant delivery device a disc nucleus pulposus implant comprising a load bearing elastic body sized for placement into an intervertebral disc space;    (c) preparing said intervertebral disc space to receive said disc nucleus pulposus implant;    (d) providing an opening in the wall of an annulus fibrosis;    (e) positioning the distal ends of the opening members of the delivery device in the opening in the wall of the annulus fibrosis;    (f) extruding the disc nucleus pulposus implant through the delivery device, wherein the passage of the disc nucleus pulposus implant through the opening members of the delivery device opens the opening members to their open configuration and thus dilates the opening in the annulus fibrosis; and    (g) withdrawing the delivery device from the opening in the annulus fibrosis and allowing the opening to relax back to a size smaller than its fully dilated size such that the disc nucleus pulposus implant is retained within the disc annulus fibrosis.    
     
     
         57 . The method of  claim 56  wherein said plurality of opening members includes at least two movable members.  
     
     
         58 . The method of  claim 56  wherein said plurality of opening members includes at least four movable members.  
     
     
         59 . The method of  claim 56  wherein said disc nucleus pulposus implant comprises a load bearing elastic body having a first end, a second end, a central portion, and a first, folded configuration wherein at least one of said first end and said second end are folded over 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, wherein said body is loaded into said delivery device such that the body is positioned in the deliver device in its straightened configuration, and wherein said load bearing elastic body is extruded through the delivery device while the elastic body is in its straightened configuration.  
     
     
         60 . The method of  claim 59 , and further including the step of allowing said elastic body to assume its folded configuration in the disc nucleus space.  
     
     
         61 . A method according to  claim 56  wherein the opening members of said delivery device are positioned to extend 1 mm to 10 mm past the inner surface of the annulus fibrosis when the delivery instrument is positioned to deliver the elastic body.