US Patent 8394108 Screw driver for a multiaxial bone screw

A screwdriver for driving a multi-axial its distal end for engaging the head of the bone screw for joint rotational movement. The screw driver includes an outer retention sleeve within which the inner shaft rotates freely. The outer retention sleeve releasably attaches to the yoke of the bone screw. In another configuration, the screwdriver comprises a screw engagement member affixed to the shaft for joint rotational movement therewith, the screw engagement member comprising a stop sized to seat within a slot of the bone screw yoke, the stop being configured to rotate the yoke upon rotation shaft. A releasable retention member is provided on the screw engagement member for releasably attaching the screwdriver to the bone screw.