Computed tomography evaluation of fat infiltration ratio of the multifidus muscle in chronic low back pain patients

Background and objectives: Fat infiltration of multifidus muscle is an important parameter to assess the efficacy of spinal stabilization training in chronic low back pain (LBP) patients. As a CT scan shows a specific attenuation value for fat, it can be used as a ratio to evaluate fat infiltration of the muscle relative to its cross-sectional area. This study aims to compare the fat infiltration ratio of multifidus muscle between subjects with and without chronic LBP in Indonesia. Methods: Comparative cross-sectional study of 20 subjects with chronic LBP and 20 subjects without LBP. Fat infiltration ratio calculation of the multifidus muscle was obtained from the database of abdominal CT at the level of the superior and inferior endplate of L4 and L5 vertebral body. Results: The fat infiltration ratio of multifidus muscle in the chronic LBP subjects group was significantly higher than the subjects group without NPB (p < 0.05). The cut-off value of the fat infiltration ratio at the level of the inferior endplate of L4 was 0.125 (75 % sensitivity and 80 % specificity). Conclusion: The calculation of the multifidus muscle fat infiltration ratio at the inferior endplate L4 using CT is a potential method to evaluate multifidus muscle quality in chronic LBP patients.