Posterior Hybrid Technique for Ossification of the Posterior Longitudinal Ligament Associated With Segmental Instability in the Cervical Spine

Abstract

Retrospective case series. To discuss the indications for a posterior hybrid technique for ossification of the posterior longitudinal ligament (OPLL) associated with segmental instability in the cervical spine and evaluate its effectiveness and safety. Dynamic factors have been shown to play an important role in the progression of ossification and OPLL myelopathy. Laminoplasty has been widely used to treat cervical OPLL, but progressive kyphosis and progression of ossified lesions are often detected in long-term follow-up. Fifteen patients were treated by a posterior hybrid technique including laminoplasty and lateral mass screw fixation at unstable levels. Preoperatively, the extent and type of OPLL, spinal cord compression, and presence of high-intensity zones were investigated by x-ray, computed tomography, and magnetic resonance imaging. Segmental instability in the cervical spine was investigated by dynamic x-ray. Postoperatively, clinical outcomes were evaluated with the Japanese Orthopedic Association scoring system and visual analog scale scores for neck pain. Radiologic results included cervical alignment and progression of OPLL. A total of 17 intervertebral levels in 15 patients (11 mixed-type and 4 continuous-type OPLL) had segmental instability, which was consistent with the presence of high-intensity zone levels in 10 (66.7%) patients. Neurological function as evaluated by the Japanese Orthopedic Association scores was significantly improved 6 months postoperatively and well maintained 4 years postoperatively. Neck pain was significantly improved 4 years postoperatively. No patients developed progressive kyphosis or progression of ossified lesions during the follow-up. Only 1 patient developed unilateral C5 palsy and completely recovered 2 months later. This hybrid posterior technique seems to be effective and safe in the treatment of selected patients with OPLL associated with segmental instability. The potential benefits of this technique include a stable environment for spinal cord recovery and prevention of progressive kyphosis and OPLL.