A modular polyaxial pedicle screw and orthopaedic rod implant device including same includes a shaft portion, a cuff, a stem portion, and a rod coupling sub-assembly. The shaft portion is designed to be inserted into the pedicle, has a hemispherical upper portion, and includes a second threading...http://www.google.se/patents/US5725528?utm_source=gb-gplus-sharePatent US5725528 - Modular polyaxial locking pedicle screw
