Determining Optimal C2 Pedicle Screw Placement and Length in Patients with Axis Traumatic Spondylolisthesis: A Case Series

We sought to determine the optimal placement and screw length for C2 pedicle screw fixation to compare with recommendations in literature. Nine patients were included in this study and underwent C2 pedicle instrumentation either for a hangman's fracture as part of C2 pedicle–C3 lateral mass fixation or for C2–C3 subluxation. All nine patients had good postoperative improvement with satisfactory fracture consolidation. Mediolateral and rostrocaudal angulations of the inserted screws were not consistent with the traditional angulations of 20 degrees in each plane due to the fracture lines and the anatomical variations. Because the frequent observation of the bony anatomical variations and the lines of fractures brought about by trauma, a shift from the classic 20 degrees of angulation in both trajectories has been concluded. But still fixed angles of angulations cannot be generalized. As a consequence, accurate preoperative planning can be obtained by computed tomography with three-dimensional images so that it gives the surgeon a good prediction of the best length of utilized screws in the procedure and the best angulations for safety of the neighboring neurovascular structures.