Clinical Results and Complications of Circumferential Spinal Cord Decompression Through a Single Posterior Approach for Thoracic Myelopathy Caused by Ossification of Posterior Longitudinal Ligament

Abstract

A retrospective review. This study examined the clinical outcomes of circumferential spinal cord decompression through a posterior approach for thoracic ossification of posterior longitudinal ligament (OPLL), to determine the efficacy of this procedure and the incidence of complications. Since posterior decompressive laminectomy is not always effective in the treatment of thoracic myelopathy caused by OPLL, circumferential spinal cord decompression through a single posterior approach seems to offer an effective treatment option. However, this procedure is technically demanding and has a high risk of postoperative neurologic deterioration. Long-term clinical outcome data and complication rates of this procedure are not well covered in the literature. Medical records of sequentially treated 30 patients, who had undergone circumferential spinal cord decompression through a single posterior approach, were reviewed to determine demographic data, neurologic examination, imaging findings, surgical procedure, and follow-up data. The Japanese Orthopedic Association (JOA) score was used to assess physical dysfunction and neurologic impairment. The mean follow-up period was 8 years; the average operative time was 389 minutes; the mean blood loss was 1883 mL. An average of 4-level spinal cord decompression was performed on all 30 patients. Posterior spinal fusion was performed on 26 of the 30 patients. The mean preoperative JOA score was 3.4/11, and it improved to an average of 7.1/11 at final evaluation. Clinical symptoms and the JOA score improved in 24 patients, but were unchanged or worsened in the other 6 patients compared to the preoperative conditions. Surgical complications included dural tear in 12 patients (40%), deep infection in 3 (10%), and postoperative neurologic deterioration in 10 (33%). Statistical analysis showed that a risk factor associated with the unfavorable surgical outcomes was multiple level circumferential spinal cord decompression of 5 or more vertebral levels. Despite circumferential spinal cord decompression through posterior approach for thoracic OPLL providing effective neurologic recovery, there was a high rate of complications such as postoperative neurologic deterioration. Risk factor analysis shows that multiple level circumferential decompression of 5 or more vertebral levels to be associated with unfavorable surgical outcome.