Surgical Treatment of Traumatic Type II Odontoid Fracture Using Polyaxial C1 Lateral Mass and C2 Pedicle Screws Fixation

Background Data: Posterior atlantoaxial fixation is indicated for C1-C2 instability or painful osteoarthritis. Different techniques were designed for atlantoaxial fixation as sublaminar wiring, transarticular screw fixation, and, recently, C1 lateral mass and C2 pedicle polyaxial screws and rod system. Purpose: To investigate the safety, advantages, and complications of posterior atlantoaxial fixation with polyaxial C1 lateral mass and C2 pedicle screws in C1-C2 instability. Study Design: A retrospective clinical case series. Patients and Methods: Fourteen consecutive patients, ten males and four females, with a mean age of 40.8±9.6 years were reported. All had traumatic C1-2 instability due to type II odontoid fractures and underwent posterior fixation with polyaxial C1 lateral mass and C2 pedicle screws. Nine patients suffered from motor vehicle accident (MVA) and 5 suffered from falls. All patients were neurologically intact except four patients who had neurological deficits. We used Japanese Orthopedic Association Score (JOA) for their functional evaluation. The average follow-up was 17±1.96 (range, 12–20 months). Operative time, operative blood loss, screw trajectory, screw length, and injury of neurovascular structures were reported. Fusion and construct stability were evaluated by plain radiography and/or CT. Visual Analogue Scale (VAS) of neck pain and JOA were used to evaluate the functional outcome. Results: The mean duration of surgery was 175.3±12.3 min. The mean blood loss was 553.6±106.5 ml and two patients required transfusion of one unit of blood. The mean length of C1 lateral mass and C2 pedicle screws were 30±1.6 mm and 16.4±1.8 mm, respectively. Correct screw placement and good stability were reported in all patients (100%) at the last follow-up. Mean neck pain on VAS was 2.8±0.8 and 2.3±0.5 at 6 and 12 months, respectively. The complications included moderate pain at iliac graft site for 3 months in 2 patients, pain and dysesthesia in C2 dermatome for 4 months in 3 patients, and superficial wound infection in 2 patients. Conclusion: Posterior atlantoaxial fixation with polyaxial C1 lateral mass and C2 pedicle screws is a safe and effective method in the treatment of traumatic atlantoaxial subluxation due to type II odontoid fractures. (2019ESJ176)