Total intervertebral disc prosthesis has one plate with curved inner surface guide for sliding intermediate element

摘要

The prosthesis, consisting of upper (1) and lower (2) plates, e.g. of titanium or chrome/cobalt alloy, and an intermediate element (3), has at least one of the plates made with a guide groove or rib (9) on its inner surface along which the intermediate element can slide in a curved trajectory to permit natural rotation of the vertebral joint about its vertical axis. The outer surface (4, 10) of at least one of the plates has a projection that matches the shape of the vertebra in contact with it.