Artificial spinal disk

Abstract

An artificial spinal disk comprises a central capsule that is configured to slide laterally within the disk space with one or more of flexion, extension, and lateral bending of the spine so as to shift an instantaneous center of rotation of the artificial disk. In one embodiment, the invention comprises an artificial spinal disk comprising a first plate having an inwardly directed surface, a second plate having an inwardly directed surface facing generally toward the inwardly directed surface of the first plate, and a central capsule with outwardly directed opposed faces that slidably mate with the inwardly directed surfaces of the first and second plates.

1 - 9 . (canceled)  
   
   
       10 . An artificial spinal disk configured to allow relative vertebral motion after installation in a disk space, said artificial spinal disk comprising a plurality of separate pieces, wherein said separate pieces are configured and sized to be placed in the disk space separate from one another, wherein said pieces comprise a pair of bone plates and a central capsule, and wherein said bone plates and said central capsule comprise tongue and groove couplers such that said central capsule forms a slidable engagement with said bone plates after installation of said bone plates into a disk space to form a completed artificial disk only after installation within the disk space.  
   
   
       11 - 12 . (canceled)  
   
   
       13 . The artificial disk of  claim 10 , wherein at least one bone plate comprises two or more coupled segments.  
   
   
       14 - 20 . (canceled)