Reliability of ultrasound to measure the distance between lumbar interspinous processes

OBJECTIVES: This study aimed to determine the reliability of ultrasound to measure the distance between interspinous processes of the lumbar spine at the segmental level (i.e., L1-L2, L2-L3, L3-L4, and L4-L5). METHODS: Ten men with no history of orthopedic diseases or dysfunctions were included in this study. In total, 720 images of the lumbar spines of participants were analyzed (10 participants, 4 segments, 3 trials, 3 positions, 2 examiners). With participants in three different positions, images of each segment specifically focused on the distance between lumbar interspinous processes. Bland-Altman analysis (BAA) was used to determine intra- and inter-rater reliability. RESULTS: Intra-rater intraclass correlation coefficient (ICC) values (1, 1) were found to range from 0.840 to 0.988, whereas inter-rater ICC values (2, 1) ranged from 0.605 to 0.876. BAA results confirmed a fixed bias regarding the L4-L5 of the lumbar spine segment in the flexion position. CONCLUSIONS: Inter-rater reliability decreased throughout this study; however, results showed that using ultrasound to measure the distance between lumbar segmental interspinous processes could be applied in clinical settings to evaluate lumbar segmental mobility.