Association between radiculopathy and lumbar multifidus atrophy in magnetic resonance imaging

BACKGROUND AND OBJECTIVES: Many studies have evaluated factors related to lumbar multifidus (MF) muscle atrophy. However, few studies have investigated radiculopathy and the MF muscle. In this study, the association between radiculopathy and lumbar MF muscle atrophy in magnetic resonance imaging (MRI) was evaluated. MATERIALS AND METHODS: In total, 100 patients with low back pain or radiating leg pain were examined. Their lumbar MRIs were visually analyzed semi-quantitatively for signs of lumbar MF muscle atrophy. The severity and extent of MF atrophy were compared between non-radiculopathy (Non-rad) and radiculopathy (Rad) groups. Asymmetry of MF atrophy was also compared between unilateral radiculopathy (UniR) and bilateral radiculopathy (BiR) groups. RESULTS: Significantly more severe and extensive MF atrophy was observed in the Rad group than in the Non-rad group (p < 0.01). However, no difference in the asymmetry of MF atrophy was found between the UniR and BiR groups (p > 0.05). CONCLUSION: More severe and extensive atrophy in the lumbar MF muscle was associated with radiculopathy. Thus, we might consider the presence of radiculopathy when severe and extensive multi-level involvement of MF atrophy is seen in MRI.