Background: Changes in paraspinal muscle cross-sectional surface area (CSA) have been shown to occur in patients with chronic and acute low back pain. Numerous factors can affect muscle density; however, the relationship between metabolic disease, such as type II diabetes mellitus (DM) and lumbar paraspinal morphometry, has not been examined. Therefore, we set out to compare paraspinal CSA in diabetic patients undergoing lumbar fusion to patients without diabetes.
Methods: A retrospective review of 101 patients, who underwent posterior lumbar fusion for degenerative spondylolisthesis, was performed. Data collected included preoperative Oswestry Disability Index, SF-12 physical and mental health scores, and visual analog scale for back pain. Utilizing standard measurement software for the iliocostalis, longissimus, multifidus, and psoas muscles, individual paraspinal muscle CSA was measured on preoperative magnetic resonance imaging. Average CSA measurements were then compared between diabetic and non-diabetic patients utilizing Student’s t-test.
Results: Thirteen patients were included in the DM group while 88 composed the non-DM group. There were no differences in age or body mass index between the groups. There were no significant differences in preoperative health-related outcome scores. Average psoas muscle iliocostalis as well as multifidus CSA were not significantly different between the non-DM and DM groups (p=0.09, 0.263, 0.458). The longissimus CSA was significantly decreased in the DM group compared to the non-DM (p=0.004).
Conclusions: This study shows that type II DM is associated with decreased paraspinal muscle CSA, but this finding was specific to the longissimus muscle. Our findings suggest that metabolic factors may play an important role in the maintenance of paraspinal muscle balance.