Patent ID: 8444695

Claim:
A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising: an upper plate having an upper surface which engages a vertebra and an opposite bearing surface; a lower plate having a lower surface which engages a vertebra and an opposite bearing surface; a rigid mobile core having upper and lower bearing surfaces configured to cooperate with the bearing surfaces of the upper and lower plates to allow the upper and lower plates to slide and translate over the core; a peripheral restraining structure located at an outer edge of the bearing surface of only one of the upper and lower plates and integrally formed with the plate, the peripheral restraining structure comprising an inwardly directed annular flange which forms an overhang, wherein the peripheral restraining structure formed integrally with the plate limits motion in each of the anterior, posterior and lateral directions; and wherein the core extends into the overhang during sliding motion of the plates over the core.