Patent ID: 6485494
Filing Date: 2002-11-26
Classification: A61B,Y10T

Abstract:
A pedicle screw assembly for use in conjunction with a rod for immobilizing bone segments comprising:a screw having a threaded shaft for insertion into a bone segment and an enlarged head; a polyaxial housing having an upper and lower portion, the head of the screw being captured in the lower portion of the housing, the housing being free to rotate and pivot relative to the head of the screw and having a pair of upstanding posts forming the upper portion of the housing, the posts defining a U-shaped slot therebetween to accommodate the rod and having interior threads; a set screw arranged to be threaded into the interior threads of the housing to clamp the assembly to the rod; a cup-shaped cap having two opposing openings which fit over the posts and a cross connector extending across the bottom thereof, the cross connector being positioned within the U-shaped slot, between the set screw and the rod, and defining a concave generally saddle-shaped rod engaging surface for engaging the upper surface of the rod, the rod engaging surface being arranged to clamp against the rod when the set screw is tightened; and a washer positioned within the housing between the rod and the head of the screw, the washer having a concave generally saddle-shaped upper surface for engaging the lower surface of the rod, the lower surface of cross connector and the upper surface of the washer serving to firmly grasp the rod when the set screw is tightened to prevent the rod from rotating or moving longitudinally within the housing.