Patent ID: 8679182

Claim:
An artificial disc replacement (ADR) configured for positioning between vertebral bodies, said artificial disc replacement comprising: a first saddle-shaped component having a first articulating surface and a first vertebral contact surface for contacting a first vertebral body, the first vertebral contact surface including at least one projection for engaging the first vertebral body, and the first articulating surface including first and second lateral edges and a toroidal region extending between the first lateral edge and the second lateral edge; and a second saddle-shaped component having a second articulating surface directly engaged with the first articulating surface and a second vertebral contact surface for contacting a second vertebral body, the second vertebral contact surface including at least one projection for engaging the second vertebral body, and the second articulating surface including third and fourth lateral edges and a toroidal region extending between the third lateral edge and the fourth lateral edge, wherein the toroidal regions of the first and second articulating surfaces, respectively, are defined by continuous curves, wherein the first articulating surface is defined by a concave arc having a radius of curvature A about a first axis, and a convex arc having a radius of curvature B about a second axis perpendicular to the first axis, and the second articulating surface is defined by a convex arc having a radius of curvature C about a third axis, and a concave arc having a radius of curvature D about a fourth axis perpendicular to the third axis, the radius of curvature A, D of at least one of the concave arcs being different than the radius of curvature B, C of at least one of the convex arcs, wherein the first and second saddle-shaped components are configured to facilitate normal spinal flexion, extension, and lateral bending, while limiting axial rotation.