Digital computed tomography evaluation of spinal canal and dural sac before and after surgical decompression of lumbar stenosis.

INTRODUCTION Advances in digital computed tomography prompted the authors to use this technique to measure correlations between the lumbar spinal canal and the dural sac. The aim of the study was to: 1. Evaluate the value of surgical decompression of neural structures using digital computed tomography. 2. Establish mathematical correlations between the surface area of the dural sac and the narrowed spinal canal before and after the operation. MATERIAL AND METHODS. The analysis involved 33 patients who underwent lumbar stenosis surgery. Complete clinical records and imaging examination reports were available for this group of patients. RESULTS 1. Statistically significant differences in spinal canal height at L4 and L5 were found between the control group (N) and the surgically treated group before and after surgery. L4: Reference--16.85 mm, before surgery--14.10 mm; after surgery--15.8 mm. L5: Reference--17.77 mm, before surgery--15.79 mm; after surgery--15.83 mm. 2. Statistically significant differences were found in the ratio of the surface area of the spinal canal and vertebral body surface area at L4 and L5 between the control group (N) and the operated group before surgery. L4: Reference--19.5%, before surgery--17.7%, after surgery--20.3%. L5: Reference--19.37%, before surgery--14.25%; after surgery--17.93%. 3. Statistically significant differences were found in the ratio of the surface area of the dural sac to the spinal canal surface area at L4 and L5 between the control group (N) and the operated group before surgery. L4: Reference--69.84%, before surgery--51.82%, after surgery--67.36%. L5: Reference--70.31%, before surgery--61.40%; after surgery--69.46%. CONCLUSIONS 1. The ratio of the surface area of the spinal canal to the vertebral body surface area at L4 and L5 after surgery was statistically comparable to the value obtained for a normal spine. 2. The ratio of the surface area of the dural sac to the spinal canal surface area at L4 and L5 after surgery was statistically comparable to the value obtained for a normal spine.