Intrarater Reliability of Diaphragm Excursion and Resting Thickness Using Ultrasound Imaging in Subjects With Nonspecific Chronic Low Back Pain.

Objective: The purpose of this study was to establish within-day intrarater reliability values of ultrasound measurements (excursion and resting thickness). Methods: Seventeen volunteers met the inclusion criteria for this preliminary study. The right and left hemidiaphragm excursion and resting thickness were compared between 2 measurement sessions using M-mode and B-mode real-time ultrasound, respectively (30 min apart). Intraclass coefficients, coefficients of variation, standard errors of measurement, and minimal detectable changes were calculated to determine intrarater reliability. Results: The intraclass coefficients of right hemidiaphragm excursion were 0.91 and 0.94 during quiet and deep breathing, respectively. The intraclass coefficient of left hemidiaphragm excursion was 0.95 during quiet breathing. The intraclass coefficients of diaphragm resting thickness were 0.99 and 0.97 in the right and left hemidiaphragm, respectively, which showed high intrarater reliability for ultrasound measurements of both sides of the diaphragm. Conclusion: This preliminary study suggests that diagnostic ultrasonography could be used as a potential method for measuring the resting thickness and excursion of the right and left hemidiaphragm in people with chronic low back pain. Future research with a larger sample size is needed to confirm these findings.

Diaphragm thickness, thickness change, and excursion in subjects with and without nonspecific low back pain using B-mode and M-mode ultrasonography.

BACKGROUND: Previous studies have demonstrated that respiratory dysfunction has a potential association with low back pain (LBP). Despite the role of the diaphragm for respiration and spinal stability, knowledge of the function of both sides of the diaphragm in subjects with LBP is still limited. OBJECTIVE: This study aimed to compare the structural integrity and function of the right and left hemidiaphragm by ultrasonography (USG) in subjects with and without nonspecific chronic low back pain (NS-CLBP). METHODS: A total of 37 subjects with NS-CLBP and 34 healthy subjects participated in this case-control study. The thickness, thickness change, and excursion of the right and left hemidiaphragm were compared within and between the groups during quiet breathing (QB) and deep breathing (DB) through B-mode and M-mode ultrasound imaging. RESULTS: The LBP group had a significantly smaller degree of right hemidiaphragm thickness change (P = .001) compared with the healthy control group, with a strong effect size. Nevertheless, there was no significant change for diaphragm thickness and excursion between the two groups. The result showed that, in the healthy group, the right hemidiaphragm had a significantly smaller thickness at expiration and larger thickness change compared with the left hemidiaphragm, with a moderate effect size. Based on the multivariate prediction analysis, the right hemidiaphragm thickness change might significantly predict LBP. CONCLUSION: We found that participants with LBP had a smaller degree of right hemidiaphragm thickness change. Also, the right hemidiaphragm thickness change might significantly predict LBP.