Patent ID: 8246685

Claim:
A vertebral disc prosthesis for cervical vertebrae comprising: a first component and a second component intended to be connected to respective vertebral plates which are jointed to each other, wherein the first component comprises a bottom, a peripheral wall and, at a distance from said bottom, an edge extending inwards, which delimit between them a single central housing, said bottom forming a first articular surface, and said edge forming, on the side opposite to said bottom, a peripheral supporting surface and, on a side turned towards said bottom, a second articular surface; wherein the second component comprises a plate intended to come into contact with the vertebral plate of the relevant vertebra and a single central pin with a widened head, this head forming, at a free end, a third articular surface able to cooperate with said first articular surface, and, on a side turned to the side of said plate, a fourth articular surface able to cooperate with said second articular surface; wherein said housing and said head are mutually dimensioned so that the first component and the second component are mobile relative to each other, sideways, perpendicularly to the axis of said central pin, and axially relative to each other, along the axis of this central pin; and wherein the prosthesis comprises at least one third component made of an elastically deformable material, interposed between said peripheral supporting surface of the first component and said plate of the second component, each third component maintains said second and fourth articular surfaces in contact with each other, each third component being able to be compressed so that said first and third articular surfaces come into contact with each other; when a force is exerted axially on a first side of the prosthesis, each third component is only compressed on the first side of the prosthesis allowing the first and the third articular surfaces to come into contact on the first side of the prosthesis and the second and fourth articular surfaces to come into contact on a second side of the prosthesis; and when the force tends to displace the first component or the second component in a translation relative to the other component in a transverse direction relative to the vertebrae, each third component allows the second and fourth articular surfaces to slide on each other on the side opposite to the one on which said force is exerted, while allowing contact of the first and the third articular surfaces on the side on which said force is exerted.