Change in the dimensions of the lumbar area muscles after surgery: MRI analysis

OBJECTIVE: This study aims to assess the change in the dimensions of the lumbar muscles in patients with chronic lower back pain using Magnetic Resonance Imaging (MRI) and to determine pre/post effects of surgery. METHODS: We enrolled 28 individuals (13F/15M; age: 45.39±11.56 years) whose L2–S1 muscle measurements were obtained using MRI, before and at follow-up 6–12 months after surgery. The control group comprising 37 individuals (18F/19M; age: 34.41±10.72 years) who had no lumbar pathology but for whom retrospective archive images were available. In the axial MRI analysis, the cross-sections of m.multifidus, mm.erector spinae and m.psoas major on both sides were measured with the ‘closed polygon’ technique. RESULTS: The L2–3 and L4–5 levels of the m.multifidus on the right side, the L2–3, L4–5 and L5–S1 levels of the m.multifidus and the L5–S1 levels of the mm. erector spinae on the left side cross-sectional areas were significantly lower than the control group (p<0.05). The right-side m.multifidus and the left-side mm.erector spinae sectional areas were significantly lower than the pre-surgery values at the L5–S1 levels (p<0.05). CONCLUSION: This study demonstrated that chronic lower back pain causes atrophy in the lumbar muscles and established the existence and continuity of atrophy after surgery.