Comparison of the effect of 3 different approaches to the lumbar spinal canal on postoperative paraspinal muscle damage

Background: To assess the effect of 3 different surgical approaches on paraspinal muscle atrophy in patients undergoing lumbar back surgery, we compared their pre- and postoperative CT scans and their serum Hb, CRP, and CPK levels. Methods: The study population consisted of 71 patients who had undergone lumbar back surgery with microscopic posterior decompression without fusion. We examined the effect on paraspinal muscle atrophy of 3 different approaches to the spinal canal. Group 1 (n = 19) underwent unilateral paraspinal dissection from the spinous process with cutting of the spinous process. In group 2 (n = 24), we used modified bilateral decompression via hemilaminectomy, and group 3 (n = 28) was treated by modified bilateral decompression via spinous process splitting. We measured the levels of CPK, Hb, and CRP preoperatively and on the first postoperative day, and compared the preoperative volume of the paraspinal muscle with the volume measured I year after the operation. Results: Age, sex, operative time, and CRP and Hb levels were not statistically different among the 3 groups. The postoperative elevation of CPK was significantly lower in groups 2 and 3 than in group 1. Group 3 manifested a significantly lower degree of atrophic changes of the paraspinal muscle than groups 1 and 2. Conclusions: We found that among the 3 approaches evaluated, modified bilateral decompression via spinous process splitting is less invasive, facilitates preservation of the paraspinal muscle, and is a useful approach to posterior spinal elements resulting in decreased muscle damage. (C) 2008 Elsevier Inc. All rights reserved.