Patent ID: 7485145

Claim:
An artificial intervertebral disc assembly adapted to be implanted adjacent end plates of vertebral bodies following the removal of a diseased or damaged intervertebral disc, said assembly comprising: an upper end plate; a lower end plate, said upper and lower end plates each defining an inner surface and an outer vertebral body engaging surface; an expandable bladder carried by said upper and lower end plates and circumscribing a fluid containment area therebetween; a biocompatible fluid disposed within said containment area between said upper and lower end plates; a cylinder projecting from said inner surface of said lower end plate into said containment area and having an open upper end; a piston reciprocally moveable within said cylinder and projecting from said open end thereof, said piston defining a curvilinear upper surface; a projection depending from said inner surface of said upper end plate into said containment area, said projection defining a curvilinear lower surface for mating with said upper surface of said piston so as to allow relative rotational movement of said upper and lower end plates and into and out of parallel alignment and a plurality of fluid flow apertures disposed in said cylinder below said piston.