Patent ID: 8298287

Claim:
A motion disc comprising: a) a first prosthetic vertebral endplate comprising: i) a first outer surface adapted to mate with a first vertebral body, ii) a first inner surface comprising an first peripheral surface and a first articulation surface, iii) a body portion connecting the first inner and outer surfaces, b) a second prosthetic vertebral endplate comprising: i) a second outer surface adapted to mate with a second vertebral body, and ii) a second inner surface comprising a second peripheral surface and a second articulation surface, iii) a body portion connecting the second inner and outer surfaces, c) an articulating core member comprising: i) a first articulation surface adapted for articulation with the first articulation surface of the first endplate, and ii) a second articulation surface adapted for articulation with the first articulation surface of the second endplate, d) a peripheral, helical shock-absorbing component comprising: i) a first end portion contacting the first endplate, and ii) a second end portion contacting the second endplate, and iii) an axial channel, wherein the core member is disposed within the axial channel of the helical shock-absorbing component and oriented therein to produce a first articulation interface between the first articulation surface of the first endplate and the first articulation surface of the core member, and a second articulation interface between the first articulation surface of the second endplate and the second articulation surface of the core member, further comprising a sheath adapted to at least partially enclose the articulation surfaces, wherein the sheath is located between the core and the peripheral, helical shock-absorbing component.