A prosthesis assembly replaces a cephalad portion of a left natural facet joint on a vertebral body and a cephalad portion of a right natural facet joint on a vertebral body. The prosthesis assembly has a left prosthesis body accommodating fixation to the vertebral body at or near a left pedicle and...http://www.google.de/patents/US8092532?utm_source=gb-gplus-sharePatent US8092532 - Facet arthroplasty devices and methods
