Artificial disc prosthesis for replacing a damaged nucleus

摘要

A multi-piece disc replacement implant for replacing a disc removed by a discectomy including an upper plate member, a lower plate member, and an intermediate resilient member providing movement between the two plate members replicating the natural movement of the spine. The plate members are rigid and have orthogonal sidewalls forming an enclosure. The resilient member is an elastic solid or a multi-chamber balloon structure of fluid-filled sacks that collectively define a non-uniform shape such as an oblate spheroid, or a helically coiled string of beads. Such an implant is capable of supporting the compressive and cyclic loads required of a natural disc. The upper and lower plate members are cooperatively formed to selectively limit the allowable range of motion in any given direction and a provided with protrusions to be received in one or more channels cooperatively formed in the vertebrae and secured in place by a bone screw.