Paraspinal muscles and gluteus medius fat infiltration are both associated with lumbar disc herniation

OBJECTIVES: To quantitatively assess the degeneration of paraspinal and pelvic muscles in patients with lumbar disc herniation (LDH) using MRI q-Dixon and to explore their potential association with LDH. MATERIALS AND METHODS: The cross-sectional area (CSA) and proton density fat fraction (PDFF) of the multifidus (MF), erector spinae (ES), psoas major (PM), and gluteus medius (GM), as well as the vertebral bone marrow fat fraction (BMFF), lumbar lordosis (LL), and sacral slope (SS), were measured in both LDH and control groups. RESULTS: remained statistically significant (p < 0.05). Although bilateral muscle asymmetry was observed in several muscles, these differences were no longer significant after adjustment (p > 0.05). No significant differences in VBFF, LL, or SS were found (all p > 0.05). CONCLUSIONS: LDH patients exhibit increased fat infiltration in the MF, ES, PM, and GM compared to controls, suggesting a potential association between pelvic and paraspinal muscle degeneration and LDH. CRITICAL RELEVANCE STATEMENT: The MRI q-Dixon technique effectively and noninvasively detects early degeneration of the paraspinal muscles and GM, indicating their potential association with LDH and enabling more targeted rehabilitation strategies. KEY POINTS: Spine and muscle changes affect LDH, but their relationship remains unclear. Fat infiltration is more sensitive than CSA for detecting muscle degeneration. LDH patients exhibit greater paraspinal muscle and GM degeneration.