POLYAXIAL BONE ANCHORS WITH POP-ON SHANK, FRICTION FIT FULLY RESTRAINED RETAINER, INSERT AND TOOL RECEIVING FEATURES

摘要

A polyaxial bone screw assembly includes a threaded shank body having an integral upper portion receivable in an integral receiver, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. The receiver can have crimp tabs, but is devoid of spring tabs and collet¬ like flexible structures. A down-loadable compression insert (some with lock and release feature), a down¬ loadable friction fit split retaining ring and an up- loadable shank upper portion cooperate to provide for pop- or snap-on assembly of the shank with the receiver either prior to or after implantation of the shank into a vertebra. The shank and receiver once assembled cannot be disassembled. The receiver and insert include aligned tool receiving apertures for lock and release of the polyaxial mechanism.