Patent ID: 7857832

Claim:
A spinal stabilization device, comprising: an elongate body, having a longitudinal axis, a proximal end and a distal end; a distal anchor on the distal end of the elongate body; a retention structure on the elongate body, proximal to the distal anchor; and a proximal anchor, moveably carried by the elongate body, the proximal anchor having an articular process contacting surface facing in a direction that is transverse to the longitudinal axis, the articular process contacting surface having a length in the axial direction, at least a portion of the articular process contacting surface having an elastic modulus that is lower than titanium and forming a smooth and substantially cylindrical portion; and at least one complementary retention structure on the proximal anchor configured for permitting proximal movement of the elongate body with respect to the proximal anchor but resisting distal movement of the elongate body with respect the proximal anchor; wherein the articular process contacting surface of the proximal anchor has a sufficient axial length to abut an inferior articular process of a superior adjacent vertebrae when the distal anchor is positioned in an inferior adjacent vertebrae to limit at least downward movement of the superior vertebrae with respect to the inferior vertebrae; wherein the proximal anchor comprises an inner member that carries the at least one complementary retention structure and an outer member that forms in part the articular process contacting surface, the inner member including a proximal flange that extends radially outward from the inner member such that a proximal end of the outer member is positioned distally of the proximal flange, the proximal flange having a higher elastic modulus than the articular process contacting surface.