Postoperative Cervical Sagittal Realignment Improves Patient-Reported Outcomes in Chronic Atlantoaxial Anterior Dislocation.

BACKGROUND: Chronic atlantoaxial anterior dislocation (AAD) not only results in myelopathy, but dislocation-related kyphosis also results in cervical malalignment, which permanently affects neck function and patient-reported outcomes (PROs). OBJECTIVE: To investigate the effect of kyphotic correction on realigning cervical spine and independent cervical alignment parameters, which may be correlated with an improvement of PROs. METHODS: The study included 21 patients with chronic AAD-related kyphosis who underwent C1-2 reduction and correction surgery. Radiographic parameters were measured to assess cervical realignment preoperatively and postoperatively. Neck disability index (NDI), short form 12 physical component summary (SF-12 PCS), and Japanese Orthopaedic Association (JOA) scores were recorded to reveal changes in PROs. The independent parameters correlated with the improvements of PROs were analyzed. RESULTS: Of the radiographic parameters, the C1-2 Cobb angle, the C2-7 Cobb angle, thoracic inlet angle, cervical tilt, and T1 slopewere significantly changed from -4.0 degrees +/- 16.2 degrees, -29.2 degrees +/- 11.2 degrees, 73.1 degrees +/- 13.3 degrees, 30.4 degrees +/- 8.5 degrees, and 29.1 degrees +/- 8.8 degrees preoperatively to -13.5 degrees +/- 8.1 degrees (P = .005),-18.0 degrees +/- 12.0 degrees (P <. 001), 67.1 degrees +/- 11.6 degrees (P = .042), 23.1 degrees +/- 10.3 degrees (P = .007), and 24.0 degrees +/- 7.0 degrees (P = .011) at last follow-up, respectively. NDI, JOA, and SF-12 PCS scores were significantly improved postoperatively. The C1-2 Cobb angle was an independent parameter correlated with the improvements in SF-12 PCS, NDI, and JOA scores. CONCLUSION: Correction and reduction surgery can realign cervical spine in chronic AAD patients. The C1-2 Cobb angle was an independent parameter correlated with the improvements of PROs.