Patent ID: 7887590
Filing Date: 2011-02-15
Classification: A61F

Abstract:
1. An intervertebral disc prosthesis comprising: an upper plate, a lower plate having a substantially flat support surface, an intermediate element comprising a base having a rim and surmounted by a spherical cap, the upper plate having an indentation having exactly the same radius of curvature as the spherical cap and coming into contact with said cap so as to define a ball and socket joint between the upper plate and the intermediate element, the base of the intermediate element coming into contact with the support surface, the lower plate having a guide which is a closed recess in the lower plate, said guide comprising an anterior edge and a posterior edge facing each other, maintaining between them a substantially constant distance and holding between them the intermediate element, the rim of the base coming into contact with at least one of the anterior edge and posterior edge, wherein the rim is a circle in cross-section and is suited to allow the movement by rolling of the intermediate element along the anterior edge and posterior edge; wherein the edges of the guide have a non-circular conic type shape, so as to guide the intermediate element along a conic-type trajectory; wherein the edges of the guide have a parabolic shape.