A capless multiaxial screw fixation assembly, including: a screw having a threaded portion and a screw head portion positioned at one end thereof; and, a retainer having a first end, a second end opposite the first end, and a bore for receiving the screw threaded portion so that the screw head portion...http://www.google.de/patents/US8029539?utm_source=gb-gplus-sharePatent US8029539 - Offset multiaxial or polyaxial screw, system and assembly
