Intervertebral disc replacement

Abstract

An intervertebral disc prosthesis in a preferred embodiment has a matrix of bioincorporable fabric, and a nuclear core centrally mixed into the matrix. The core is formed by impregnating the fabric substrate centrally with a polymer, preferably of liquid form that cures into a viscoelastic solid, in which each component—polymer and fabric—reinforces the other against tearing, shearing and weakening under stress. The core is a hybrid composite adapted for elastic deformation centrally of the matrix, in which the polymer is mixed with the fabric, and is surrounded by the outer bioincorporable fabric margin of the matrix. In another embodiment, the nuclear core is separated from an outer sheath of the bioincorporable fabric by an intermediate ligament encasement that surrounds the purely polymeric core In either embodiment, each edge of the outer fabric that interfaces a vertebral end plate is impregnated with an agent to stimulate osseus incorporation and anchoring. An adjunct anchoring system with penetration of bone of adjacent vertebra may be used to for attachment until and after bioincorporation occurs.

1 - 29 . (canceled)  
   
   
       30 . In combination with an intervertebral disc prosthesis, said prosthesis having an elastically deformable central core, and a fabric matrix intimately surrounding said central core, said prosthesis being adapted for replacement of a designated disc in the vertebral column of a patient, 
 an anchoring system comprising fixation means adapted to cooperate with said fabric matrix of the prosthesis for stabilizing said prosthesis relative to adjacent vertebrae at either side thereof when the prosthesis is implanted in the vertebral columnar space vacated by said designated disc being replaced, said fixation means including at least one fastener adapted for manual penetration of bone of an adjacent vertebra to secure said fabric matrix and, thereby, said prosthesis to said adjacent vertebra, so as to avoid interfering with elastic deformation of said central core of the implanted prosthesis under compressive force exerted thereon along the vertebral column.    
   
   
       31 . The combination according to  claim 30 , wherein said fabric matrix comprises a sheath surrounding the central core of said intervertebral disc prosthesis, said sheath having integral fabric extensions projecting from either side of the prosthesis adapted to confront said adjacent vertebrae when the prosthesis is implanted, each of said extensions constituting part of said fixation means and adapted to be secured to bone of an adjacent vertebra by a respective said at least one fastener.  
   
   
       32 . The combination according to  claim 30 , wherein said fabric matrix has fibers running through said central core and an integral fabric margin of said matrix surrounding the core, said margin having integral fabric extensions projecting from either side of the prosthesis adapted to confront said adjacent vertebrae when the prosthesis is implanted, each of said extensions constituting part of said fixation means and adapted to be secured to bone of an adjacent vertebra by a respective said at least one fastener.  
   
   
       33 . The combination according to  claim 30 , wherein 
 said fabric matrix has a distinctive contour at either side of the intervertebral disc prosthesis adapted to confront said adjacent vertebrae end plates, and    said fixation means includes at least two anchoring plates, each having a distinctive contour adapted to mate with the distinctive contour of the fabric matrix at a respective side of said prosthesis, each of said plates having passages therein to accommodate projections of said fabric matrix side contour.    
   
   
       34 . The combination according to  claim 33 , wherein 
 said distinctive contour of the sides of said fabric matrix includes at least one semicircular hump spanning the prosthesis at each side of the fabric matrix, with projections located on each respective hump adapted to extend through respective passages of the associated anchoring plate to promote osseus incorporation from marrow and cancellous bone exposed at regions of said adjacent vertebrae arranged to accommodate nesting of the hump and associated anchoring plate upon implantation of said prosthesis.    
   
   
       35 . The combination according to  claim 33 , wherein each of said anchoring plates includes a fastener portion for securing the respective plate to bone exposed at the adjacent vertebra.