LONG-TERM FOLLOW-UP-STUDY OF ANTERIOR DECOMPRESSION AND FUSION FOR THORACIC MYELOPATHY RESULTING FROM OSSIFICATION OF THE POSTERIOR LONGITUDINAL LIGAMENT

Study Design. This was a retrospective study of the results of anterio r decompression and fusion in patients with thoracic myelopathy second ary to ossification of the posterior longitudinal ligament with a mini mum follow-up time of 5 years. Objectives. To clarify the effectivenes s and limits of anterior decompression and fusion for thoracic ossific ation of the posterior longitudinal ligament. Summary of Background Da ta. Posterior decompression for the surgical management of thoracic os sification of the posterior longitudinal ligament has had an uncertain success record. Anterior decompression and fusion have been considere d the treatment of choice; however, there are few reports describing t he long-term results. Methods. The participants in this investigation were 33 patients whose cases were followed for an average period of 8 years and 2 months. The factors that were investigated included change s in the Japanese Orthopedic Association score and-in recovery rates, postoperative complications, and radiographic findings of bone union a nd progression of ossification of the posterior longitudinal ligament within the area of anterior decompression. Results. Although the recov ery rates were relatively stable from 1-5 years after surgery, the rat es declined thereafter. The average recovery rate at the final follow- up visit was 53.2%. Postoperative complications included th ree cases of deterioration of thoracic myelopathy thy and four cases of extra pl eural cerebrospinal fluid leakage. Except for the one case of deterior ation of thoracic myelopathy, the remainder of the complications were transient. Conclusions. Anterior decompression and fusion is an effect ive surgical procedure for thoracic ossification of the posterior long itudinal ligament with good, stable, long-term results; when thoracic ossification of the posterior longitudinal ligament Was extensive coin cident with ossification of the intraspinal ligament, however, the res ults were not as predictable.