MRI-Based Assessment of Trunk and Hip Muscle Morphology and Strength in Chronic Low Back Pain

BACKGROUND Low back pain (LBP) is a leading cause of disability worldwide, yet the relationship between muscle morphology, strength imbalances, and chronic LBP remains incompletely understood. This study investigated cross-sectional area (CSA) and strength differences in trunk and hip muscles between chronic LBP patients and healthy controls. MATERIAL AND METHODS Fifty patients with chronic LBP (age 53±13.5) and 30 (age 42.3±8.3) healthy controls underwent lumbosacral magnetic resonance imaging to measure CSA of paravertebral (psoas major, quadratus lumborum, erector spinae, multifidus), abdominal (rectus abdominis), and hip muscles (iliacus, gluteus maximus). Isokinetic dynamometry assessed trunk and hip flexor/extensor strength. Statistical analyses included t tests confirmed with Cohen's d and Pearson correlations. RESULTS Patients with LBP showed smaller psoas major CSA at L2/L5 and rectus abdominis CSA at S2/S3 than controls (all P