Ultrasound assessment of transversus abdominis muscle contraction ratio during abdominal hollowing: a useful tool to distinguish between patients with chronic low back pain and healthy controls?

Abstract

Spine stabilisation exercises, in which patients are taught to preferentially activate the transversus abdominus (TrA) during ''abdominal hollowing'' (AH), are a popular treatment for chronic low back pain (cLBP). The present study investigated whether performance during AH differed between cLBP patients and controls to an extent that would render it useful diagnostic tool. 50 patients with cLBP (46.3 ± 12.5 years) and 50 healthy controls (43.6 ± 12.7 years) participated in this case-control study. They performed AH in hook-lying. Using M-mode ultrasound, thicknesses of TrA, and obliquus internus and externus were determined at rest and during 5 s AH (5 measures each body side). The TrA contraction-ratio (TrA-CR) (TrA contracted/rest) and the ability to sustain the contraction [standard deviation (SD) of TrA thickness during the stable phase of the hold] were investigated. There were no significant group differences for the absolute muscle thicknesses at rest or during AH, or for the SD of TrA thickness. There was a small but significant difference between the groups for TrA-CR: cLBP 1.35 ± 0.14, controls 1.44 ± 0.24 (p \ 0.05). However, Receiver Operator Characteristics (ROC) analysis revealed a poor and non-significant ability of TrA-CR to discriminate between cLBP patients and controls on an individual basis (ROC area under the curve, 0.60 [95% CI 0.495; 0.695], p = 0.08). In the patient group, TrA-CR showed a low but significant correlation with Roland Morris score (Spearman Rho = 0.328; p = 0.02). In conclusion, the difference in group mean values for TrA-CR was small and of uncertain clinical relevance. Moreover, TrA-CR showed a poor ability to discriminate between control and cLBP subjects on an individual basis. We conclude that the TrA-CR during abdominal hollowing does not distinguish well between patients with chronic low back pain and healthy controls.

Comparison of the Sonographic Features of the Abdominal Wall Muscles and Connective Tissues in Individuals With and Without Lumbopelvic Pain

“…21,37,49,56 As USI is noninvasive, relatively inexpensive, and portable, its use has become more widespread to assess the morphology (form and size) of muscle 57,58 and connective tissues. 31 As muscles and connective tissues remodel in response to loading, their morphological characteristics can provide insight into their loading history.…”

Clinimetric Analysis of Pressure Biofeedback and Transversus Abdominis Function in Individuals With Stabilization Classification Low Back Pain

“…24,32 Selecting a TrA activation cutoff for the ability to contract the TrA effectively during the ADIM was difficult, due to the variance in reported values. 4,27,36,44,54,66,67 One study reported that LBP patients could achieve a TrA activation of above 2.0 with minimal training. 66 Others have found TrA activations of healthy individuals to be around 1.4.…”

“…22 These investigators found agreement between EMG amplitude and ultrasound data but did not complete a formal analysis. 22 Regardless, ultrasound imaging has been utilized in a number of studies investigating abdominal muscle thickness change as an indicator of muscle activation between groups of individuals with lumbar spine pathology, 2,4,15,27,28,30,44,54,59,66 healthy individuals, 4,6,7,31,36,44,54,64,67 and as an intervention outcome. 25,28,31,59 Activation of the TrA may be quantified by examining the ratio of muscle thickness during contraction to muscle thickness at rest, which is known as the TrA activation ratio (TrA contracted thickness/TrA relaxed thickness).…”

“…We chose 1.5 because TrA activation values less than 1.5 are typical for individuals with LBP who meet stabilization classification criteria, 44 as well as in nonspecific LBP. 15,54,67 Values found in healthy individuals are typically greater than 1.5, ranging from 1.5 to greater than 2.0. 4,15,27,44,67 An investigator blinded to the ultrasound image results measured pressure readings.…”

Methodological consistency and measurement reliability of transversus abdominis real time ultrasound imaging in chronic low back pain populations: a systematic review

“…11,[32][33][34] Q ualSyst scores ranged from 0.19 to 1. Most studies were found to have m oderate to high quality, 11,13,[32][33][34][35][36][37][38][39][40][41][42][43][44] with only 5 studies scoring below 0.75 31,[45][46][47][48] (Table 1 ). Results of the Q AREL ranged from three to seven (Table 2 ).…”