Artificial intervertebral disc with lower height

An intervertebral disc comprising:

• an upper plate having:
• an upper vertebra contacting portion and a lower bearing surface portion, wherein the upper vertebra contacting portion of the upper plate includes:
• a convex central portion,
• an anchoring element formed integrally with and extending outward from an upper surface of the convex central portion to define a height above the upper surface, wherein the lower bearing surface portion has a concavity disposed opposite the convex central portion and wherein the convex central portion and the concavity have nesting curvatures, and
• a transverse hole extending at least partially through a width of the anchoring element, and sized for bone ingrowth;
• a lower plate having a lower vertebra contacting surface and an upper bearing surface;
• and, wherein the lower vertebra contacting surface of the lower plate has a convex central portion, and wherein the upper bearing surface has a concavity disposed opposite the convex central portion and wherein the convex central portion and the concavity have nesting curvatures;
• and
• a rigid core positioned between the upper and lower plates, the core having rigid upper and lower convex surfaces configured to slide and translate over the bearing surfaces of the upper and lower plates, wherein a centerline axis of the core is substantially aligned with the anchoring element,
• wherein the convex central portion of the upper plate is raised relative to a generally planar peripheral portion of the upper plate.

A method of implanting an artificial intervertebral disc between adjacent spinal vertebrae in place of a damaged disc, the method comprising:

• providing an artificial intervertebral disc comprising:
• an upper plate having:
• an upper vertebra contacting portion and a lower bearing surface portion, wherein the upper vertebra contacting portion of the upper plate includes:
• a convex central portion,
• a fin formed integrally with and extending outward from an upper surface of the convex central portion to define a height above the upper surface, the height being greater than a width of the fin, wherein the lower bearing surface portion has a concavity disposed opposite the convex central portion and wherein the convex central portion and the concavity have nesting curvatures, and
• a transverse hole extending at least partially through the width of the fin, and sized for bone ingrowth;
• a lower plate having a lower vertebra contacting surface and an upper bearing surface,
• wherein the lower vertebra contacting surface of the lower plate has a convex central portion, and wherein the upper bearing surface has a concavity disposed opposite the convex central portion, and the convex central portion and the concavity have nesting curvatures;
• and
• a rigid core positioned between the upper and lower plates, the core having rigid upper and lower convex surfaces;
• inserting the artificial intervertebral disc including the upper and lower plates and core together into a space between the adjacent spinal vertebrae;
• and
• allowing the upper and lower plates to slide and translate over the rigid upper and lower convex surfaces of the core,
• wherein the convex central portion of the upper plate is raised relative to a generally planar peripheral portion of the upper plate.