STUDY DESIGN: A retrospective study. OBJECTIVE: To evaluate the outcomes of myelopathy caused by atlantoaxial dislocation (AAD). SUMMARY OF BACKGROUND DATA: No reports to date have accurately evaluated the results of surgery for delayed myelopathy for patients with chronic AAD. Thus, the appropriate surgical time and methods of decompression and fusion remain a hot debate. MATERIALS AND METHODS: In our study, 18 patients underwent decompression, fixation, and fusion. Demographic data, operation time, blood loss, and complications were evaluated. The Japanese Orthopedic Association Scale, severity of disability and visual analogue scale were evaluated. The fusion rate, space available for the cord, instability index, cord compression index, and cord decompression rate were also assessed. RESULTS: The average time of operation was 248±50 minutes, and blood loss was 350±200 mL. Five patients in grade I maintained their neurological status, and the others had improved neurological status. With average follow-up time of 15.3±9.6 months, the Japanese Orthopedic Association score improved, the visual analogue scale score decreased, the space available for the cord improved, and the instability index and cord compression index decreased. Cord decompression rate was 65.9%. Fusion rate reached 83%. CONCLUSIONS: There is a high risk of delayed myelopathy for patients with AAD who do not undergo timely surgical treatment. There is no need for complete reduction for treatment of chronic AAD. Whether it can be reduced or not, sufficient decompression and solid fusion for AAD are required. Both C1-C2 fusion for reducible dislocation and occipital-cervical fusion for irreducible dislocation have satisfactory outcomes.
STUDY DESIGN: A retrospective study. OBJECTIVE: To evaluate the outcomes of myelopathy caused by atlantoaxial dislocation (AAD). SUMMARY OF BACKGROUND DATA: No reports to date have accurately evaluated the results of surgery for delayed myelopathy for patients with chronic AAD. Thus, the appropriate surgical time and methods of decompression and fusion remain a hot debate. MATERIALS AND METHODS: In our study, 18 patients underwent decompression, fixation, and fusion. Demographic data, operation time, blood loss, and complications were evaluated. The Japanese Orthopedic Association Scale, severity of disability and visual analogue scale were evaluated. The fusion rate, space available for the cord, instability index, cord compression index, and cord decompression rate were also assessed. RESULTS: The average time of operation was 248±50 minutes, and blood loss was 350±200 mL. Five patients in grade I maintained their neurological status, and the others had improved neurological status. With average follow-up time of 15.3±9.6 months, the Japanese Orthopedic Association score improved, the visual analogue scale score decreased, the space available for the cord improved, and the instability index and cord compression index decreased. Cord decompression rate was 65.9%. Fusion rate reached 83%. CONCLUSIONS: There is a high risk of delayed myelopathy for patients with AAD who do not undergo timely surgical treatment. There is no need for complete reduction for treatment of chronic AAD. Whether it can be reduced or not, sufficient decompression and solid fusion for AAD are required. Both C1-C2 fusion for reducible dislocation and occipital-cervical fusion for irreducible dislocation have satisfactory outcomes.