An elastic intervertebral disc prosthesis comprising two opposite plates joined together by partitions capable of deforming elastically as a function of the load applied on the prosthesis.

A spinal disk implant comprises a solid body having four faces arranged to define a right-rectangular solid body and two faces that define the ends of the solid body. The faces that define the right-rectangular body include two opposed side faces and two opposed transverse faces. A kit that may be used by a surgeon includes an implant and an implant delivery tool dimensioned to releasably hold the implant. The delivery tool preferably has an implant holder with a pair of flexible opposed arms extending from a base, separated so that the implant can fit between the arms. Optionally, the implant holder may have a breakable release band extending around the implant to hold it in place until a weak link in the release band is intentionally broken during implantation.

A spinal disc prosthesis to replace a damaged spinal disc in a spinal column (16) of a human, includes a body (10) having an upper surface (52) engageable with the upper vertebra (12) and a lower surface (152) engageable with the lower vertebra (14). The body (10) includes a crescent-shaped projection (62, 162) extending from one of the upper and lower surfaces (52, 152) of the body for receipt in a cavity in the adjacent vertebra (12, 14).

A spinal disc prosthesis comprises an upper rigid plate, a lower rigid plate, and an elastomeric core interposed between the plates and adhered to the plates. The elastomeric core has an upper portion with an outer peripheral surface extending substantially perpendicular to the upper plate. A lower portion of the elastomeric core has an outer peripheral surface extending substantially perpendicular to the lower plate. An intermediate portion of the elastomeric core, extending between the upper and lower portions, has a concave outer peripheral surface. Each of the upper and lower plates has a plurality of ribs extending into the elastomeric core to secure the elastomeric core to the upper and lower plates.

A prosthetic nucleus replacement comprises a solid flattened oval disk. The top surface of the disc is domed and has a crest that is about three times higher than the crest on the domed bottom surface. Both top and bottom surfaces are therefore convex. A peg extends down from the middle of the bottom domed surface and is used to pin the disc to the lower of two vertebrae it fits between. Metal markers are inserted into the peg and an outside edge of the disc so that radiographs can be used to determine the disc's in situ position. The prosthetic nucleus replacement is surgically implanted into the hollowed out intervertebral space through a flap cut in the natural annulus fibrosis. The lower vertebrae is prepared to receive the peg by clearing the material covering the top of the bone matrix. Bone cement is used around the peg to ensure a tight fit and immobile attachment of the disc to the lower vertebrae.