Reproducibility of the Ultrasonography in Measuring the Cross-section of the Longus Colli in Patients With Non-specific Neck Pain

Purpose: Ultrasonography (US) can be used to measure the dimensions and the cross-section of muscles. This study aims to investigate the intra- and inter-tester reproducibility of the US measures of the cross-section of the longus colli (LC) muscle at rest and in contraction states in patients with chronic non-specific neck pain (CNSNP) and healthy individuals. Methods: This cross-sectional study was conducted on seven healthy individuals and seven patients with chronic non-specific pains. The cross-section of the LC muscle was measured at rest and in contraction states at the C5-6 vertebrae by two raters using the US on two consecutive days. The data were analyzed by the Pearson correlation coefficient (ICC). Results: The intra-tester reproducibility was excellent in the healthy (ICC 0.97) and patient (ICC 0.95) groups at rest and in contraction. The inter-tester reproducibility was great in the healthy group (ICC 0.97) in both states and at rest (ICC=0.98) and in the contraction (ICC 0.95) in the patient group. Conclusion: The results revealed that the US demonstrated higher agreement in measuring the cross-section of the LC in healthy subjects and patients with CNSNP. Thus, this method is reliable and can be used to measure the cross-section of the muscles.