Human spinal disc prothesis with hinges

Abstract

The invention relates to a spinal disc endoprosthesis. The endoprosthesis has a resilient body formed of one or more materials which may vary in stiffness from a relatively stiff exterior annular gasket portion to a relatively supple central nucleus portion. Concaval-convex elements at least partly surround that nucleus portion so as to retain the nucleus portion and gasket between adjacent vertebral bodies in a patient's spine. Assemblies of endoprosthetic discs, endoprosthetic vertebral bodies, and endoprosthetic longitudinal ligaments may be constructed. To implant this endoprosthesis assembly, information is obtained regarding the size, shape, and nature of a patient's damaged spine. Thereafter, one or more prosthetic vertebral bodies and disc units are constructed in conformity with that information. Finally, the completed and conformed vertebral body and disc assembly is implanted in the patient's spine.

Description

[0001]This is a continuation-in-part of U.S. patent application Ser. No. 08 / 681,230, filed Jul. 22, 1996, now U.S. Pat. No. 5,674,296 and which is a continuation-in-part of U.S. patent application Ser. No. 08 / 339,490, filed Nov. 14, 1994, which is abandoned.BACKGROUND OF THE INVENTION [0002]This invention relates generally to human prostheses, and especially to spinal column vertebralintervertebral disc prostheses. The invention also relates to surgical procedures for preparing the patient to receive a vertebralan intervertebral disc endoprosthesis, and for implanting that endoprosthesis in the patient's spine.[0003]The herniation of a spinal disc and the often resultant symptoms of intractable pain, weakness, sensory loss, incontinence and progressive arthritis are among the most common of debilitating processes affecting mankind. If a patient's condition does not improve after conservative treatment, and if clear physical evidence of nerve root or spinal cord compression is appare...

AI Technical Summary

Benefits of technology

[0015]To accomplish these objects, the invention comprises a resilient body formed of a material varying in stiffness from a relatively stiff exterior portion to a relatively supple central portion. A concaval-convex means at least partly surrounds that resilient body so as to retain the resilient body between adjacent vertebral bodies of a patient's spine. If medical considerations so indicate, several disc endoprostheses can be combined with one or more endoprosthetic vertebral bodies in an entire assembly.

Problems solved by technology

Statistics suggest that present surgical techniques are likely to result in short-term relief, but will not prevent the progressive deterioration of the patient's condition in the long run.

But it has become clear that unless the removed disc is replaced or the spine is otherwise properly supported, further degeneration of the patient's condition will almost certainly occur.

However, it has become increasingly apparent that unfused vertebral segments at the levels above and below the fused segment degenerate at accelerated rates as a direct result of this fusion.

None provide for a patient's return to near-normal functioning.

Though these procedures may solve a short-term problem, they can cause other, longer term, problems.

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