Intervertebral disc prosthesis

Abstract

The invention relates to an intervertebral disc prosthesis comprising at least two plates, namely first and second plates, articulated about each other by means of a curved surface, namely articulation, of at least one of the plates, each of the plates comprising a surface known as a contact surface, intended to be in contact with a vertebral plate of one of the vertebrae between which the prosthesis is intended to be inserted, this contact surface for each of the plates comprising a geometrical centre at equal distance from at least two diametrically opposite points located on the periphery of the plate, in which the geometric centres of the plates are not vertically aligned, this off-setting of the geometrical centres of the plates engendering an off-setting of the edges of the plates in at least one direction perpendicular to the vertical axis of the spinal column.

Description

technical field [0001] [0001] The present invention relates to intervertebral disc prostheses that are replaced with fibrocartilaginous discs that provide coupling between the vertebrae of the spine. Background technique [0002] [0002] Various types of intervertebral disc prostheses are known in the art. Various prostheses, such as those described in patent applications WO 02 089 701 and WO 2004 / 041129, consist of lower and upper plates forming a cage hinged around a central core. Other prostheses, such as those disclosed in US Pat. No. 5,676,701 and application WO 03 / 059212 A1, comprise only a lower and an upper plate articulated about themselves by means of articular surfaces. These hinged prostheses have the advantage of allowing free movement of the patient using the prosthesis by allowing the plates to tilt and / or rotate relative to each other. A prosthesis comprising a central core movable between the plates has the added advantage of allowing the core to be spontan...

AI Technical Summary

Problems solved by technology

The difference in plate size causes the offset of the edge of the plate, but also has the inconvenience of causing the offset of the joint axis of the plate

Moreover, this type of prosthesis has the inconvenience that one of its plates may end up being larger than the vertebral plate, or conversely, the other plate may be smaller than the vertebral plate, thus not leaning against the vertebral plate periphery but on the smaller on the solid part of the prosthesis, so there is a risk of damage to the lamina of the prosthesis

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