Evaluation of the Efficacy of Titanium Mesh Cages with Posterior C1 Lateral Mass and C2 Pedicle Screw Fixation in Patients with Atlantoaxial Instability

BACKGROUND: Atlantoaxial fusion is a surgical technique that is performed for the treatment of atlantoaxial instability. The standard surgical procedure is fixation of the atlantoaxial complex via a C1 lateral mass and C2 pedicle screw with posterior wiring. Bone grafting material may still be biomechanically suboptimal, such as autologous bone obtained from osteoporotic patients, and may result in collapse and loosening of posterior wiring. METHODS: Fourteen patients with C1 lateral mass and C2 pedicle fixation as a result of atlantoaxial instability were included in this study. All patients were treated by a single surgeon using a titanium mesh cage with demineralized bone matrix packing. Patient clinical history, imaging data, and medical records were reviewed. To evaluate bony fusion, measurement of the atlantodental interval and computed tomography were performed in the preoperative period, immediate postoperative period, and at 1, 3, 6, and 12 months postoperatively. The Wilcoxon signed-rank test was used to compare differences in the radiologic evaluation at 1 and 12 months postoperatively. RESULTS: Bone fusion was achieved in all patients (100%). Of the 14 patients, 11 had rheumatoid arthritis and 3 had trauma. The mean atlantodental interval of patients with rheumatoid arthritis was 1.85 mm in the immediate postoperative period, 1.96 mm at 1 month postoperatively, 1.98 mm at 3 months postoperatively, 1.96 mm at 6 months, and 1.93 mm at 12 months. Hardware failure and other complications were not observed. CONCLUSIONS: The titanium mesh cage has several advantages compared with bone autografts, including reduced donor-site morbidity, immediate rigid fixation, and successful bone fusion.