Reliability of sonography in the assessment of lumbar stabilizer muscles size in healthy subjects and patients with scoliosis

Abstract Objective The purpose of the present study was to compare the reliability of sonography in the evaluation of abdominal and multifidus muscles size between healthy subjects and patients with scoliosis. Methods In this study, 20 healthy males and 20 male patients with scoliosis (20–50 years old) were recruited. Multifidus and abdominal muscles (transversus abdominis, internal and external oblique) size were assessed by sonography. Three images were recorded; the first and second images were taken on the same day with an hour interval to evaluate within-day reliability, and the third image was taken one-week later to assess between-day reliability. Results Intraclass correlation coefficient (ICC = 0.82–0.91) demonstrated high within-day reliability of sonography in the assessment of abdominal muscle thickness in both groups. In addition, high between-day reliability was observed for these muscles in both healthy and patient groups (ICC = 0.80–0.89). Within-day and also between-day reliability of multifidus muscle were shown to be high in the healthy group (ICC = 0.81–0.88) and the patient group (ICC = 0.78–0.85). Overall, within-day reliability was higher than between-day reliability and also the reliability of sonography in healthy subjects was greater than of those suffering from scoliosis. Conclusions According to the results, sonography was shown to be a highly reliable imaging technique for assessment of abdominal and multifidus muscle size in healthy males and those suffering from scoliosis.