Journal of Spine

The Availability of the Screw Guide Template System for the Insertion of Mid-Cervical Pedicle Screw –Technical Note

Abstract

Shuichi Kaneyama, Taku Sugawara, Naoki Higashiyama, Masato Takabatake, Masatoshi Sumi and Kazuo Mizoi

Abstract Study background: Although cervical pedicle screw method is the most stable instrumentation, which is useful for reconstruction of unstable or deformed cervical spine, to insert cervical pedicle screw accurately is sometimes challenging at the risk of the neurovascular injuries due to the anatomical features of cervical pedicles. The purpose of this study is to introduce our Screw Guide Template (SGT) system developed to insert mid-cervical pedicle screws accurately and safely with less risk. Method: Preoperatively, the bone image on CT was analyzed by the multiplanar imaging software and then the trajectory and the depth of the screws were designed three-dimensionally. Three types of transparent templates were created for each lamina: location template, drill guide template and screw guide template. During the operations, after engaging the templates directly with the laminae, three steps; drilling, tapping, and screwing were performed with each template. The screws were inserted accurately as we planned, which was confirmed by postoperative CT. Case presentation: Three cases underwent posterior spinal fusion surgeries with mid-cervical pedicle screw insertion using the SGT system. The location of all screws were perfectly matched the trajectory planned preoperatively in Case 1 and 2. While, the improper templates engagement due to inadequate par spinal muscle retraction lead to the mal-positions of two screws in Case 3. Conclusion: We demonstrated the availability of the SGT system as intraoperative screw navigation for cervical pedicle screw insertion in mid-cervical spine. Proper engaging templates and adequate muscles traction play an important role for the SGT system through the procedure.