Comprehensive analysis of muscles wasting in disc herniation

Neuromuscular reeducation of the muscles that stabilize the spine is the basis of conservative treatment of disc herniation. Therefore, it is important to investigate how these muscles are affected by disc herniation. The aim of this study was to investigate the effect of disc herniation, herniation severity, patient age, and biomechanics on the lumbar stabilizer muscles. A total of 330 individuals, including 261 patients with disc herniations and 69 without disc herniation participated in this study. The cross-sectional areas (CSAs) of the lumbar stabilizer muscles and the lumbar lordosis angle were evaluated by magnetic resonance imaging (MRI), according to the severity of the disc herniation and the patient’s age. In the patients with disc herniation, the CSAs of the quadratus lumborum (QL) and the multifidus (MF) muscles were decreased. The psoas major (PM) muscle CSA was higher in the patients with sequestered discs than in those with protruded and extruded discs. A negative relationship between the sagittal curve and the PM muscle CSA was found. In addition, MF muscle CSA was found to decrease at age 45 years and over. Although disc herniation negatively affects muscle CSAs, no linear relationship was found between the severity of the herniation and the muscle CSA. In addition, the PM muscle was found to be a strong compensatory muscle in disc herniation.