Which is the most affected muscle in lumbar back pain - multifidus or erector spinae?

Purpose: The purpose of this study is to evaluate the relationship between lumbar back pain, lumbar disc herniation, and erector spinae and multifidus muscle lipomatous degeneration.

Material And Methods: After receiving approval from the clinical studies Ethics Committee, magnetic resonance imaging (MRI) studies of patients who had physical examination in orthopaedic, neurology, neurosurgery, physical medicine and rehabilitation clinics were evaluated. Their pre-diagnoses were 'herniated nucleus pulposus' or 'lumbar disc herniation' or 'back pain' and their age range was between 18 and 64 years. Patients who had vertebral fracture, spondylitis-spondylodiscitis, tumours, structural anomalies such as spondylolisthesis, scoliosis and vertebral segmentation anomalies and previous surgery in the lumbar area were excluded. There were 205 patients in the case group who had lumbar disc herniation between L1-S1 level and there were 187 patients in the control group who had no lumbar disc herniation. In the study, patient age, sex, herniation level and erector spinae and multifidus muscle lipomatous degeneration were compared. Muscle lipomatous degeneration were evaluated with a visual scale.

Results: There were 105 men and 100 women in the case group and 88 men and 99 women in the control group. In the case group, lumbar disc herniation was detected mostly at L4-5 and L5-S1 levels. There was no significant difference between case and control groups with regard to erector spinae and multifidus muscle lipomatous degeneration. In the case group, lipomatous degeneration of the erector spinae was higher compared to that of the multifidus muscle.

Conclusions: Patients with low back pain may have fatty degeneration in erector spina and multifidus muscles with or without LDH, but LDH accelerates this process rather than being a result of it. In patients with LDH, fatty degeneration in the erector spina is more pronounced than in multifidus, and the erector spina is more affected by the LDH process.