Modular pedicle screw assembly

Abstract

A modular pedicle screw assembly having a pedicle screw shank with an insertion end for vertebral engagement and a connector end with a conical outer surface and an internal driver receptacle. A spherical collet with compression slits is mounted on the connector end, the collet having upper and lower openings for driver tool access. A split ring with a chamfered lower inner edge and an overlying cap are positioned over the collet. A saddle coupled to the collet defines a U-shaped channel for receiving a spinal rod and a threaded section for a set screw. Tightening the set screw compresses the cap and split ring to lock the rod and saddle while enabling the collet to provide a polyaxial or uniplanar connection between the screw shank and the rod. The modular configuration allows insertion through minimal incisions, improves surgical and provides secure, adjustable fixation for spinal stabilization.