Patent ID: 6113601
Filing Date: 2000-09-05
Classification: A61B

Abstract:
A polyaxial pedicle screw for use with rod implantation apparatus, comprising:a bone screw having a shaft and a curvate head, said curvate head including an annular recess formed therein;a body element including an axial interior passage extending through the element from a proximal upper end to a distal lower end, said distal lower end having an inwardly tapered surface defining a socket wherein said curvate head may be polyaxially mounted such that said shaft may extend out from said lower end of said body and polyaxially rotate through a range of angles relative to said body element, said range of angles including non-axially parallel ones, said proximal upper end including a rod receiving channel and a pair of upwardly extending members having a threading disposed thereon;a compression element having a curvate upper exterior surface and a concave interior surface, said concave interior surface being curvate and being rotationally seatable on the curvate head of said bone screw, said concave interior surface further including an annular recess;means for loosely coupling said compression element to said curvate head of said bone screw, said means being positionable within said annular recesses of said curvate head and said compression element, wherein said means includes a snap ring; anda locking nut, mateable with the threading on the upwardly extending members of the body element, for compressing a rod into the channel of the body, and onto the compression element, thereby imparting a compression force onto the head of the screw which rigidly locked the head against the inwardly tapered surface at the distal lower end of the body element.