In vivo analysis of cervical range of motion after revised C1-C2 pedicle screw technique for pediatric atlantoaxial instability.

ABSTRACT

OBJECTIVE: The purpose of this study was to analyze the cervical range of motion (ROM) after revised C1-C2 pedicle screw fixation for pediatric patients with atlantoaxial instability. METHODS: 17 pediatric patients (age range 5-14 years; mean 8.3 years) underwent the revised C1-C2 pedicle screw technique. Pre- and postoperative cervical ROM during flexion/extension, rotation and lateral bending were measured using a head-mounted motion goniometer. Plain radiographs, CT scans and MRI were performed to assess spinal cord compression, the accuracy of screw placement, and bone fusion. The American Spinal Injury Association classification was used to evaluate neurological function. RESULTS: Revised atlantoaxial pedicle screw fixation was successfully performed in all 17 pediatric patients. There were no perioperative complications. All cases showed evidence of bone fusion 6 months after surgery by CT scan. During the follow-up period (24-92 months), of 6 patients with preoperative myelopathy, 3 improved from grade D to grade E and 3 from grade C to grade D. The final follow-up cervical ROM was significantly greater than the preoperative and 6-month postoperative ROM. There was a statistically significant difference between preoperative and 6-month postoperative ROM for flexion, extension, and left and right axial rotation movements. CONCLUSION: As a short-segmental fixation technique, revised C1-C2 pedicle screw fixation can provide effective biomechanical stability. Final follow-up cervical ROM is significantly increased through alleviating cervical pain and symptoms of myelopathy after surgery and possible subaxial compensation.