Intervertebral disc prosthesis

A motion preserving disc prosthesis comprising:

• a first endplate including first and second surfaces;
• a second endplate including first and second surfaces;
• and
• a nucleus including first and second surfaces contacting the second surface of the first endplate and the first surface of the second endplate, respectively, wherein the first surface of the nucleus comprises at least one central recess intersecting a plurality of grooves radiating outwardly from the at least one central recess to facilitate engagement of the nucleus relative to the second surface of the first endplate in response to movement by a patient, wherein contacting portions adjacent to the at least one central recess and plurality of grooves are configured to provide a contact area between the first surface of the nucleus and second surface of the first endplate that is substantially equal to a contact area between the second surface of the nucleus and the first surface of the second endplate, whereby constraints applied to the disc prosthesis are absorbed equally by both surfaces of the nucleus, wherein the plurality of grooves are interconnected via the at least one central recess, wherein the contacting portions of the first surface of the nucleus and the second surface of the first endplate are each substantially flat and wherein an angle formed by edges of the at least one central recess relative to a substantially flat contacting portion of the first surface of the nucleus is softened.

A surgical kit, comprising:

• a disc prosthesis comprising:
• a first endplate including first and second surfaces;
• a second endplate including first and second surfaces;
• and
• a nucleus including first and second surfaces engaging the second surface of the first endplate and the first surface of the second endplate, respectively, wherein the first surface of the nucleus comprises at least one central recess intersecting a plurality of grooves radiating outwardly from the at least one central recess to facilitate engagement of the nucleus relative to the second surface of the first endplate in response to movement by a patient, wherein a plurality of engaging portions adjacent to the at least one central recess and plurality of grooves are configured to provide a contact area between the first surface of the nucleus and second surface of the first endplate that is substantially equal to a contact area between the second surface of the nucleus and the first surface of the second endplate, whereby constraints applied to the disc prosthesis are absorbed equally by both surfaces of the nucleus, wherein the plurality of grooves are interconnected via the at least one central recess, wherein the engaging portions of the first surface of the nucleus and the second surface of the first endplate are each substantially flat and wherein each of the plurality of grooves extends from the at least one central recess to a peripheral edge of the engaging portion of the first surface of the nucleus;
• and
• a prosthesis insertion tool to position the disc prosthesis between opposing vertebrae of a patient, the disc prosthesis insertion tool comprising a clip having a U-shaped engaging surface that engages a front of the disc prosthesis, the clip further comprising a plurality of laterally opposed blades, each laterally opposed blade of the clip gripping opposing sides of the disc prosthesis and a center portion of the U-shaped engaging surface engaging the first and second endplates of the disc prosthesis.

A prosthetic intervertebral disc comprising:

• a first endplate;
• a second endplate;
• and
• a compressible core member positioned between said first and second endplates, said compressible core member having at least one engaging surface with a plurality of grooves that are interconnected via at least one dummy hole, wherein the at least one dummy hole passes through only a portion of the compressible core member, wherein the at least one engaging surface of the compressible core member is an upper surface of the compressible core member adjacent to a lower surface of the first endplate, wherein the at least one dummy hole is centrally located on the upper surface of the compressible core member, wherein the compressible core member comprises polyethylene, wherein each of an upper surface of the first endplate and a lower surface of the second endplate comprise a porous biocompatible coating, and wherein the upper surface of the first endplate and the lower surface of the second endplate each comprise plural teeth proximal to opposing edges of the first endplate and the second endplate, respectively, and oriented to prevent sliding of the prosthetic intervertebral disc prior to adhesion of the porous biocompatible coating to osseous tissue of an adjacent vertebrae of a patient, and
• wherein said first endplate and said second endplate are separated by a first distance, and wherein said prosthetic intervertebral disc is expandable between a contracted condition and an expanded condition, said first distance being greater in said expanded condition than in said contracted condition.