Surgical Strategy for Multilevel Severe Ossification of Posterior Longitudinal Ligament in the Cervical Spine

Study Design: A retrospective clinical study was conducted. Objective: To compare surgical outcome of anterior approach (corpectomy and fusion) with that of posterior approach (laminoplasty or laminectomy and instrumented fusion) for the treatment of multilevel severe ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, and simultaneously to investigate the potential benefits of instrumented fusion after laminectomy by comparing it with laminoplasty. Summary of Background Data: Surgical strategy for multilevel severe OPLL in the cervical spine still remains controversial. Although the advantages of anterior decompression and fusion have been reported earlier, it becomes more technically demanding and risky with the increasing narrowing rate and extent of ossification. Laminoplasty has been used to relieve cord decompression posteriorly, but results are not always good. It also has potential risks of ossification progression and kyphotic deformity after operation. Methods: A total of 75 cervical patients with multilevel severe OPLL were included in this study. Twenty-two patients underwent anterior corpectomy and fusion. Among the patients undergoing posterior approach, laminectomy and instrumented fusion was performed on 28 patients and laminoplasty on 25 patients. The radiologic findings including plain radiographs, computed tomography scan, and magnetic resonance images were reviewed, and surgical outcome was assessed using the Japanese Orthopedic Association scoring system. The radiologic and clinical data were compared between 3 groups of different surgical processes. Results: Radiologic studies showed preoperative cervical lordosis, occupying rate and extent of OPLL were comparable between 3 groups in this study, but the postoperative cervical lordosis after anterior corpectomy or laminectomy and instrumented fusion was significantly larger than that of after laminoplasty. Postoperative Japanese Orthopedic Association score and improvement rate of neurologic function after anterior corpectomy were significantly higher than those after laminoplasty, and the results after laminectomy and instrumented fusion were in the middle of results of above 2 processes. The main complication after anterior decompression was cerebrospinal fluid leakage, whereas posterior approach was complicated with a high incidence of C5 palsy and axial pain. Conclusions: Anterior corpectomy and fusion was significantly more effective for multilevel severe OPLL when compared with posterior laminoplasty in the cervical spine. If having technical difficulties and posterior decompression was alternatively performed, instrumented fusion was recommended to help to restore cervical lordosis and produce better results according to this study.