A prospective study on CT scan outcomes after conservative decompression surgery for lumbar spinal stenosis

This is a prospective study analyzing CT scan imaging outcomes after conservative decompression in patients with lumbar spinal stenosis. Forty patients (18 males and 22 females) initially underwent a laminarthrectomy surgical procedure to decompress the central canal as well as the neuroforamina and nerve root canals while respecting the integrity of the neural arches, facet joints, and most muscle attachments. Morphologic features of preoperative CT scan images were compared with postoperative CT scans of the operative levels, obtained for 36 patients (17 males and 19 females) after a minimum follow-up of 1 year (mean 1.7 years). Successful surgical outcome was defined as an improvement in at least three of the following four criteria: self-reported pain on a visual analog scale, self-reported functional status measured by LBOS, reduction of pain while walking, and reduction of leg pain. Fifty-five percent of patients met the successful surgical outcome criteria, including 14 subjects who met all four success criteria. Overall, there was a statistically significant increase in the interfacet bony canal diameter of the operated levels (3.9 mm, p < 001). However, patients categorized as successful surgical outcomes had a substantially, but not significantly, lower interfacet canal diameter increase postsurgically (mean 3.41 mm) in comparison with patients categorized as failures (mean postoperative increase 4.52 mm). Midsagittal canal diameters remained unchanged in the failure group but increased in the success group. The CT scan canal measures used in this study cannot be advocated for evaluation of outcome in conservative lumbar spinal canal decompression.