Novel pedicle screw system development for osteoporotic incidents

Pedicle screw fixations are widely seen on vertebral fractures, tumor or scoliosis incidents as decompression surgery. Post operation screw loosening influences patients healing period in a negative manner. Bone mineral density is one of the most important factor that affects screw-bone interface, thus screw loosening are widely seen on osteoporotic incidents. A novel pedicle screw fixation system was developed as the scope of this thesis statement. This novel system maintained by a Ti6Al4V screw and an expandable PEEK shell which acts as a fixing plug into the bone. PEEK shell absorbs vibrations sourced by physiologic movements of body, thereby improves fusion and provides high pullout strength by the aid of expansion mechanism. Differing from the conventional expandable pedicle screw systems, in this novel system, Ti alloy screw can be replaced while PEEK shell remains into the bone either if a revision operation is necessary. As a result, this unique system maintains that revision operations can be done without severely deforming the vertebral body. In vitro biomechanical tests were conducted after iterative design and manufactures were completed. The novel system was considered as successful comparing to the conventional pedicle screw fixation systems according to biomechanical test evaluations.