Patent ID: 8016890

Claim:
A spinal disc implant, comprising: a pair of end plates for affixation to adjacent vertebral bodies, said pair of end plates respectively including a pair of bearing components formed therein, said pair of bearing components respectively defining a pair of elongated, generally part-cylindrical convex bearing surfaces extending generally on orthogonal axes relative to each other, said bearing surfaces facing each other; and an insert having opposed and generally concave recessed bearing seats defined thereon and disposed generally on orthogonal axes relative to each other for respective articulation with said part-cylindrical bearing surfaces; wherein one of said part-cylindrical bearing surfaces extends generally in an anterior-posterior direction, and the other of said part-cylindrical bearing surfaces extends generally in a medial-lateral direction; wherein at least one of said generally concave recessed bearing seats has a cross sectional shape defined by laterally spaced-apart, offset radii to include a generally flattened base segment interposed between a pair of curved sides.