A prosthesis replaces all or a portion of a natural facet joint on a vertebral body. The prosthesis has a prosthesis body accommodating fixation to the vertebral body at or near a pedicle and without support by a lamina. The prosthesis body has a fastening element installed within the vertebral body...http://www.google.de/patents/US20040049275?utm_source=gb-gplus-sharePatent US20040049275 - Facet arthroplasty devices and methods
