Posteroanterior Segmental Displacement of the Lumbar Spine: Assessment Using Ultrasound in Asymptomatic Men

Abstract Objective This study aimed to assess posteroanterior (PA) segmental displacement of the lumbar spine using ultrasound (US). Methods Eight asymptomatic male participants (20.1 ± 0.4 years) were included in this study. The relative depth between the tip of the L4 and L3 spinous processes from the US probe (mm) was measured using US in the following 7 conditions, which were without PA force, applying PA force of 9.8 newton (N), 19.6 N, 29.4 N, 39.2 N, 49.0 N, and 58.8 N to both sides of the L4 costal processes. The measurements were repeated twice within a day. The intraclass correlation coefficient, standard error of measurement (SEM), and minimal detectable change (MDC) were calculated. A repeated-measures analysis of variance was also used to determine the influence of PA force on the relative depth. Results The intraclass correlation coefficients for the intrarater reliability of the 7 conditions were 0.95 (SEM: 0.43 mm, MDC: 1.19 mm), 0.93 (SEM: 0.45 mm, MDC: 1.25 mm), 0.93 (SEM: 0.47 mm, MDC: 1.30 mm), 0.95 (SEM: 0.37 mm, MDC: 1.02 mm), 0.95 (SEM: 0.40 mm, MDC: 1.10 mm), 0.96 (SEM: 0.38 mm, MDC: 1.04 mm), and 0.95 (SEM: 0.42 mm, MDC: 1.15 mm), respectively. The intrarater reliability of the relative depth using US was reliable. There was no significant change in the relative depth among the 7 conditions (F = 0.88, P = .41). Incrementally greater PA force was not related to greater intersegmental translation. Conclusion Our US method could not detect PA segmental displacement of the lumbar spine.