Comparison of Radiography and Computed Tomography in Evaluating Posterior Indirect Reduction of Spinal Canal Bone Fragment

Abstract

This article describes a retrospective study of patients who underwent posterior indirect reduction procedures for thoracolumbar burst fractures. The goal of this study was to explore a simple and effective method for evaluating the reduction of spinal canal fragments during posterior indirect reduction procedures. Sixty-four burst fractures with retropulsed bone fragments encroaching the spinal canal at the thoracolumbar junction were performed. C-arm fluoroscopy was used to evaluate the spinal canal fragments' reduction. A standard lateral view of the thoracolumbar spine was set up. When a continuous and smooth posterior vertebral body line of the injured vertebrae appeared, similar to below and above the vertebrae, the spinal canal bone fragment was considered to be satisfactorily reduced. The midsagittal diameter of the injured segment was measured on preoperative and postoperative computed tomography (CT) scans. Narrowing of the midsagittal diameter of the injured segment was improved from 41.4%±15.9% to 13.7%±9.7%. The correction value was 27.6%±15.6%. All pre- and postoperative outcome variables had statistical significance ( P <.01). Forty-two patients experienced a restored posterior vertebral body line with a continuous and smooth vertical line, indicating that the fragment reduction was satisfactory. Post-operative CT showed that the spinal canal compromise was <10% (range, 0%–9.8%; mean, 6.1%±2.9%). Continuous and smooth posterior vertebral body line imaging is a simple and effective method to judge the reduction of a bone fragment retropulsed into the spinal canal. It can provide evidence as to whether a laminotomy and pushing the bone fragment are necessary during posterior surgery.