Intervertebral implant comprising dome-shaped joint surfaces

An intervertebral implant comprising:

• a top part having a top apposed surface for contacting an upper vertebra;
• a bottom part having a bottom apposed surface for contacting a lower vertebra;
• a convex joint part having a first articular surface, the convex joint part operatively coupled to one of the top and bottom parts;
• and
• a joint shell having a second articular surface, the joint shell operatively coupled to the other of the top and bottom parts,
• wherein the first and second articular surfaces are coated with an amorphous diamond-like carbon (ADLC) coating, the ADLC coating on the second articular surface of the joint shell slidably contacting the ADLC coating on the first articular surface of the convex joint part such that the top part is articulatable with respect to the bottom part about at least one axis of rotation;
• and
• wherein the top and bottom parts are manufactured from a metal and the convex joint part and the joint shell are manufactured from a plastic;
• wherein the convex joint part includes an inner hollow space, the implant further comprising an anchoring element including a disc-shaped extension located in the hollow space and a pin connected to the extension and passing through the joint part, through the joint shell and into engagement with one of the top and bottom parts so that the top part, the bottom part, the convex joint part and the joint shell are held together during implantation, the anchoring element enabling the joint shell and the joint part to be separatable by an axial clearance;
• wherein the pin passes through the first articular surface and the ADLC coating thereon and through the second articular surface and the ADLC coating thereon, and wherein the axial clearance is sufficiently large to allow sliding articulation between the ADLC coating on the first articular surface, the ADLC coating on the second articular surface and formation of a lubricating film therebetween.