US Patent 6964686 Intervertebral disc replacement prosthesis

An intervertebral disc prosthesis that comprises a deformable flexure with an axial cavity, the axial cavity extending along the axis of the flexure, and a slit defined in the perimeter surface of the flexure to provide flexibility to the disc member, the slit having a slit thickness. The slit may be in the form of a coil to impart a spring-like appearance and function. The intervertebral disc prosthesis further comprises a lower disc support housed in the axial cavity and an upper disc support housed in the axial cavity; with the lower and upper disc supports communicating with one another to provide support to the disc. The lower or upper disc support may alternatively be incorporated into the flexure.