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

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.