Compressive Thoracic Myelopathy Caused by Combined Ossification of the Posterior Longitudinal Ligament and Ossification of the Ligamentum Flavum: A Report of Four Cases and a Literature Review

Abstract

We describe here the rare condition of compressive thoracic myelopathy and its management in four patients with combined thoracic ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum. One of the four patients underwent decompressive laminectomies only, whereas the other three patients had posterolateral fusion with posterior instrumentation (pedicle screws and rods system) in addition to decompressive laminectomies. All four patients developed transient complete paraplegia after surgery. The three patients who received decompressive laminectomies and posterior instrumentation with posterolateral fusion had improved sensation, motor, and sphincter functions compared with their preoperative neurological state. The patient who underwent laminectomy only showed no neurological gain after 7.5 years. A dural tear was noted in two patients and they recovered without complications after intraoperative repair. Posterior instrumentation with posterolateral fusion in addition to decompression laminectomies and excision of the ossification of the ligamentum flavum seems to have a better outcome than simple decompression laminectomies for this rare cause of compressive thoracic myelopathy.