Long-term Outcomes of Multilevel Anterior Cervical Osteotomy and Posterior Instrumentation for OPLL-Induced Myelopathy With Cervical Kyphosis

Objective: To analyze long-term clinical and radiological outcomes after multilevel anterior osteotomy with posterior instrumentation in patients with ossification of posterior longitudinal ligament (OPLL)-induced myelopathy and cervical kyphosis.Methods: Patients who underwent multilevel anterior osteotomy with posterior instrumentation for OPLL-induced myelopathy and cervical kyphosis and had a minimum of 5-year follow-up were included. Clinical outcomes (Japanese Orthopaedic Association score system for cervical myelopathy [C-JOA], 12-item Short Form health survey [SF-12], Neck Disability Index [NDI]) and radiological parameters (C2–7 lordosis, center of gravity of the head [CGH]-C7 sagittal vertical axis [SVA], T1 slope) were analyzed at the preoperative, immediate postoperative, and latest follow-up timepoints.Results: Twenty-eight patients were included. The average follow-up period was 66.4 months. All clinical outcome parameters showed significant improvement. C-JOA, SF-12, and NDI showed significant improvement at latest follow-up (p<0.001). C2–7 lordosis increased significantly immediately postoperatively (-6.0°±10.4°) compared to preoperatively (+9.2°±9.6°), and was largely maintained at latest follow-up (-5.7°±9.4°). T1 slope significantly increased between the immediate postoperative timepoint (21.9°±7.7°) and latest follow-up (24.2°±9.5°) (p=0.046). CGH-C7 SVA significantly increased between the immediate postoperative timepoint (22.7±14.8 mm) and latest follow-up (32.2±22.6 mm) (p=0.046).Conclusion: Multilevel anterior osteotomy with posterior instrumentation is a safe and effective surgical option for OPLL-induced myelopathy with kyphotic cervical alignment. Future studies are required to investigate the forward tilting of cervical spine over time after surgery.