ENDROPROSTHESIS FOR INTERVERTEBRAL DISCS

摘要

The present invention relates to a multipart endoprothesis of the Nucleus pulposus which is inserted between base plate and cover plate of two adjacent vertibral bodies and is for re-establishing and maintaining the distance in the intervertbral space and permits a mobility in the physiological range. Such an endoprothesis of the Nucleus pulposus has biochemical and biomechanical tolerance, natural stability on absorbing compression and can be inserted without substantial treatment of the adjacent vertebral bodies while excluding a mechanical destruction of the adjoining vertebral bodies. Three embodiments are provided. First, the vertebral disc endoprothesis comprises a pair of symmetrical concave end plates with intervening convex distance piece. End plates and distance piece have a plane guide rim. The end plates have either a bent rim or an annular tee-slot for a torus on the distance piece. Second, the vertebral disc endoprothesis comprises a pair of asymmetrical end plates and a distance piece but the two regions of motion are staggered by 90.degree. relative to each other and are jointing planes of a cylinder. In the third embodiment the two symmetrical end plates are convex and the distance piece is cylindrical and concave at both ends. Furthermore, it has a strong sheath.