A posterior spinal fusion system may include pedicle screws and one or more segments designed to be attached to the implanted pedicle screws via nuts to fuse spinal motion segments in a modular fashion. The pedicle screws may have semispherical receiving surfaces, and each segment may have mounting portions...http://www.google.com.au/patents/US7766943?utm_source=gb-gplus-sharePatent US7766943 - Modular percutaneous spinal fusion system and method
