Circumferential Decompression Through Posterior Approach for Thoracic OPLL: Technique and Complications

Abstract

In patients with thoracic myelopathy resulting from OPLL in the thoracic spine with a kyphotic curve, anterior spinal cord decompression via OPLL removal or floating is logical and the most effective method for relieving pressure on the spinal cord. Anterior (circumferential) spinal cord decompression through a posterior approach was first reported by Ohtsuka et al. in 1983 and has been used by several surgeons. The disadvantage of this procedure is that anterior decompression and resection of OPLL using an air-drill is mostly performed with a blind procedure. Since 2011, we have employed a surgical technique via a posterolateral approach that allows the surgeon to perform anterior spinal cord decompression more safely and effectively than the conventional procedures. This maneuver includes laminectomies and total resection of the transverse processes and pedicles, which allows space creation bilateral to the dural sac and the targeted OPLL for subsequent anterior decompression. The thoracic nerves at the levels of anterior decompression were ligated bilaterally and lifted to improve the view of the OPLL and the anterolateral aspect of the dural sac. In this procedure, surgeons can perform anterior decompression with adequate recognition of the positions of the OPLL and the whole dural sac at every point in time. Patients with a localized spinal cord compression by a beak-type OPLL with a ≥50% canal occupying ratio in the kyphotic thoracic spine is indicated for anterior decompression via a posterolateral approach. However, the procedure should not be applied for thoracic OPLL with multi-level spinal compressions.