Prostheses, systems, and methods are provided for replacement of natural facet joints between adjacent vertebrae using polyaxial attachment mechanisms for securing the prostheses to the vertebrae. A cephalad prosthesis attached to a superior adjacent vertebra replaces the inferior half of a natural facet...http://www.google.de/patents/US20080177332?utm_source=gb-gplus-sharePatent US20080177332 - POLYAXIAL ADJUSTMENT OF FACET JOINT PROSTHESES
