Facet joint prosthesis for vertebra of spinal column, has joint surfaces formed such that surfaces guide upper vertebra with respect to lower vertebra independent of displacement and tilting of upper vertebra with respect to lower vertebra

摘要

The prosthesis has two pairs of joint bodies (10, 20), and a pair of joint surfaces (30) with a shape of an ellipsoid arranged such that a longitudinal axis of the ellipsoid is aligned parallel to a longitudinal axis of a spinal column. Another pair of joint surfaces (40) is formed such that the latter joint surfaces guide an upper vertebra with respect to a lower vertebra independent of displacement of the upper vertebra with respect to the lower vertebra in a transverse plane and independent of tilting of the upper vertebra with respect to the lower vertebra about a right-left axis.