Intervertebral Disc Replacement
An implantable intervertebral disc prosthesis that comprises a disc member having an upper surface, a lower surface, and a perimeter surface. The disc includes an axis at least one slit defined in the perimeter surface; the slit being of sufficient depth and thickness to provide flexure. The slit terminates in a perimeter opening larger than the slit thickness. The perimeter opening (i.e., hole) acts as a pivot point and relieves stress. The disc prosthesis optionally comprises a cavity with an upper seat defined on the lower surface, a lower disc having an upper and lower surface and a lower seat defined on the upper surface, and a support ball. The support ball engages the seat on the upper disc and the seat on the lower disc.