1448 - The Association of Extensor Muscles and Lumbar Lordosis Angle in Patients with Chronic Low Back Pain

Objectives: The intricate relationship between spinal extensor muscles and lumbar lordosis influences spinal stability, load distribution, and movement patterns. Understanding variations of this relationship in patients with chronic low back pain could advance insights into the biomechanical changes present in chronic pain and inform targeted therapeutic strategies. The objective of this study is to better characterize the relationship between extensor spinal muscle atrophy and lumbar lordosis in patients with chronic low back pain.

Design: The design of this study was a retrospective chart review of 60 patients with chronic low back pain who visited an outpatient spine clinic. Magnetic resonance imaging (MRI) and standing x-ray images of the lumbar spine for all patients were included in the study. The primary outcome measure was total extensor muscle cross sectional area as measured on lumbar spine MRI at L1-S1 and fatty fraction of the extensor muscles.

Results: Linear regression modeling showed that increasing lumbar lordosis angle correlated with decreasing total extensor muscle cross-sectional area (OR 0.877, 95% CI 0.787-0.977, p=0.009) and increasing fatty fraction (OR 1.991, 1.239-3.201, Adjusted R² = 0.2174, p=0.004). There was no relationship between lumbar lordosis and pain scores, sex, patient age, BMI or duration of symptoms.

Conclusions: This study shows that the degree of spinal extensor muscle atrophy is associated with increased lumbar lordosis in patients with chronic low back pain. This relationship differs from that seen in healthy controls and suggests an alteration in the baseline relationship between lumbar lordosis and extensor muscles in patients with chronic low back pain.