Safety Trial of Patient Specific Guides for Lumbar Fusion

This is a single centre, non-blinded safety trial. Patients undergoing lumbar fusion will be treated using patient specific guides (PSG) or navigation. Patients requiring lumbar fusion will be treated using conventional surgical methods except when inserting pedicle screws, where half of the patients will be having screws inserted using PSGs. The conventional method of navigation and intraoperative imaging will be used in conjunction with PSGs, to confirm the safety of the guide trajectory. The primary outcome will be screw accuracy measured in degrees from planned trajectory and mm from the planned entry point.