Reliability of B-mode ultrasonography for abdominal muscles in asymptomatic and patients with acute low back pain

Protocol and reference values for minimal detectable change of MyotonPRO and ultrasound imaging measurements of muscle and subcutaneous tissue

The assessment of muscle health is of paramount importance, as the loss of muscle mass and strength can affect performance. Two non-invasive tools that have been found to be useful in this are the MyotonPRO and rehabilitative ultrasound imaging, both have shown to be reliable in previous studies many of which conducted by the research team. This study aims to determine the reliability of previously unassessed local body structures and to determine their minimal detectable changes (MDC) to support both researchers and clinicians. Twenty healthy participants were recruited to determine the reliability of seven skin positions out of a previously established protocol. Reliability was determined between three independent raters, and day to day reliability was assessed with one rater a week apart. Intraclass Correlation Coefficients (ICC) between raters and between days for tissue stiffness, tone and elasticity range from moderate to excellent (ICC 0.52–0.97), with most good or excellent. ICCs for subcutaneous thickness between days was good or excellent (ICC 0.86–0.91) and moderate to excellent between raters (ICC 0.72–0.96), in muscles it was moderate to excellent between raters and days (ICC 0.71–0.95). The protocol in this study is repeatable with overall good reliability, it also provides established MDC values for several measurement points.

The Effect of Stabilization Exercises Along With Self-care Training on Transverse Abdominal Activity, Pain, and Disability in Mothers With Low Back Pain Having Children With Cerebral Palsy: A Randomized Controlled Trial

OBJECTIVE

Many mothers of children with cerebral palsy experience low back pain, so the purpose of this study was to investigate the effect of stabilization exercises along with self-care training on transverse abdominal muscle activity, pain, disability, and depression in them.

DESIGN

In this single-blinded randomized clinical trial, 32 mothers with cerebral palsy children were selected were randomly divided into two groups. Both groups received self-care training individually. For the experimental group, in addition to the self-care training, 24 sessions of stabilization exercises were held. Outcome measures included visual analog scale, Roland-Morris Disability Questionnaire, Persian version of Beck Depression Inventory-II, and ultrasonography.

RESULTS

In the experimental group, the transverse abdominal muscle activity during abdominal hollowing exercises was significantly increased (P < 0.05). There was no significant difference between the two groups in pain, disability, and depression (P > 0.05).

CONCLUSIONS

Stabilization exercises could improve the voluntary activity of transverse abdominal muscle of mothers of children with cerebral palsy.

Effect of corporal suspension and pendulum exercises on neuromuscular properties and functionality in patients with medullar thoracic injury

BACKGROUND

Traumatic spinal cord injury (TSCI) is one of the most devastating injuries that has a physical impact on patients. The CHORDATA® method involves suspension and pendulous exercises and has been clinically used to treat patients with TSCI. Although empirically used to treat neurological patients, there is no scientific evidence of the efficacy of this method.

PURPOSE

To evaluate the chronic effects of CHORDATA® method on torque, muscle activation, muscle thickness, and functionality in patients with traumatic spinal cord injury.

METHODS

Twenty-six male patients with medullar thoracic injury were randomly categorised into two groups: intervention group (n = 14) and control group (n = 12). Rehabilitation program comprised of 16 sessions of body suspension and pendulum exercises (twice/week). The maximal voluntary isometric trunk flexion and extension torques, muscle activation and thickness (external and internal oblique, rectus and transversus abdominis, longissimus, and multifidus muscles), and functionality (adapted reach test) were evaluated before and after of rehabilitation program.

FINDINGS

A significant increase was observed in maximal voluntary isometric torque (flexion, 58%; extension, 76%), muscle activation of the rectus abdominis muscle, and muscle thickness of all intervention group muscles, without changes in the control group. Compared to the pre-intervention period, the intervention group also showed improvement in functionality at post-intervention, but no such differences were noted in the control group.

INTERPRETATION

The corporal suspension and pendulum exercises training improved rectus abdominis muscle activation, trunk muscles structure and strength, and reaching capacity in medullar thoracic injury patients.

Ultrasound Assessment of Abdominal Muscle Thickness in Women With and Without Low Back Pain During Pregnancy

OBJECTIVE

The aim of this preliminary study was to determine the differences in abdominal musculature thickness, within 1 month of delivery, in women who experienced back pain during pregnancy compared with those who did not.

METHODS

B-mode ultrasound imaging was used to measure abdominal muscle thickness on 76 postpartum participants who participated in a larger study; 47 women experienced back pain during pregnancy, and 29 did not. Participant data were stratified by group, and primary comparisons were based on these grouping across the abdominal muscles, including rectus abdominis (upper and lower fibers), external oblique, internal oblique, and transversus abdominis. Means and standard deviations were also used to set parameters for future studies.

RESULTS

In the present study, there was no difference in any abdominal muscle thickness between groups. Women with low back pain were significantly shorter (165.19 ± 6.64 cm) than women who did not have from back pain during pregnancy (169.38 ± 7.58 cm). All other demographics, such as age, weight, and date tested postpartum, were not significantly different between groups.

CONCLUSION

The results of this study showed no variation in abdominal muscle thickness in women who had back pain during pregnancy and those who did not.

Ultrasound Measurement of Abdominal Muscle Thickness With and Without Transducer Fixation During Standing Postural Tasks in Participants With and Without Chronic Low Back Pain: Intrasession and Intersession Reliability

BACKGROUND

Ultrasound (US) imaging can be used for the measurement of trunk muscle activity. The displacements of US transducer, especially during more dynamic situations, however, may disturb the measurement results. To control this variable, some studies have used transducer fixator (TF), but no study evaluated the effect of using TF on US reliability in dynamic situations. The present study discriminated this issue.

OBJECTIVE

To investigate the intrasession and intersession reliability of lateral abdominal muscle thickness measurement in dynamic standing postural tasks by using US with and without TF in participants with and without chronic low back pain (CLBP).

DESIGN

An intersession and intrasession reliability study.

SETTING

Biomechanics laboratory, Neuromuscular Rehabilitation Research Center, Semnan University of Medical Sciences, Semnan, Iran.

PARTICIPANTS

Twenty-three patients with CLBP and 23 healthy matched individuals.

METHODS

Abdominal muscle thickness of all the subjects was evaluated with use of US imaging with the patient in the supine position and double-leg stance at different levels of platform stability of BBS (static, levels 6 and 3), with and without using TF. Intraclass correlation coefficients (ICCs), standard errors of measurement, minimal metrically detectable changes, and coefficients of variation were calculated to determine intersession and intrasession reliability of muscle activity measure.

MAIN OUTCOME MEASUREMENTS

Lateral abdominal muscle thickness.

RESULTS

The intersession ICCs in the conditions with TF ranged from 0.93 to 0.98 and 0.97 to 0.99 in CLBP and healthy individuals, respectively. The intersession ICCs in the conditions without TF ranged from 0.67 to 0.79 and 0.7 to 0.86 in CLBP and healthy groups, respectively. In addition, smaller standard errors of measurement and minimal metrically detectable change values were observed with US measurement in both the groups when TF was used.

CONCLUSION

US imaging appears to have acceptable reliability for the assessment of abdominal muscle thickness during dynamic standing tasks in individuals with and without CLBP. The use of TF results in greater levels of reliability during US measurement of abdominal muscle.

LEVEL OF EVIDENCE

III.

Ultrasound Assessment of Abdominal Muscle Thickness in Postpartum vs Nulliparous Women

OBJECTIVE

The purpose of this study was to determine the effect size in measurable change of abdominal musculature morphology using ultrasonography in postpartum women within 1 month of a healthy, vaginal delivery.

METHODS

One hundred fifty-six participants were recruited for this study. B-mode ultrasound imaging was used to measure abdominal muscle thickness on 80 nulliparous women and 76 mothers who had delivered within the past 4 weeks. Measures were taken for the upper and lower rectus abdominus, external and internal obliques, and transversus abdominus at rest.

RESULTS

Statistically significant differences were found in the thickness of the rectus abdominus muscle at both sites; upper (P < .0001) and lower (P < .0001) as well as the internal oblique (P < .0001). All 3 muscles were thinner in postpartum participants (8.29 ± 1.83 mm, 8.89 ± 2.29 mm, and 7.06 ± 1.82 mm, respectively) within the first month of delivery than in controls (10.82 ± 1.93 mm, 11.13 ± 2.38 mm, and 8.36 ± 1.87 mm, respectively). Large effect sizes were found for the influence of pregnancy on the rectus muscle segments (1.35 for the upper rectus abdominus and 1.00 for the lower rectus abdominus) and a medium effect size for the internal oblique (0.71). No significant differences were observed in the remaining 2 muscles.

CONCLUSION

This study showed that there are differences in morphology of the abdominal muscles in pregnant women vs nonpregnant controls. The large effect sizes reported may provide the basis for future studies examining relationships between morphology, functional change, and back pain during pregnancy.

Reliability of rehabilitative ultrasonography to measure transverse abdominis and multifidus muscle dimensions

BACKGROUND

Lumbar paraspinal muscles play an important role in providing both mobility and stability during dynamic tasks. Among paraspinal muscles, transverse abdominis and lumbar multifidus have been of particular interest as active stabilizers of the lumbar spine. These muscles may become dysfunctional in chronic low back pain (CLBP). Low back injury can result in muscle inhibition and control loss that cannot recover spontaneously, and specific exercises are required to stimulate their recovery.

OBJECTIVES

The purpose of this study was to test the reliability of ultrasonography to measure muscle dimensions and to present a reliable method for measuring transverse abdominis and lumbar multifidus as stabilizing muscles of the lumbar spine.

SUBJECTS AND METHODS

Fifteen healthy participants (18-55 year olds) were evaluated by a radiologist using ultrasonography (ES500) with two probes (50mm linear 7.5 MHZ and 70 mm curvilinear 3.5 MHz). The muscle thickness of transverse abdominis and the anterior-posterior diameter and cross sectional area of the LMF were measured. To determine within and between days reliabilities, second and third measurements were repeated with half an hour and one week intervals, respectively.

RESULTS

Intraclass correlation coefficient for left and right showed good to high reliability for the cross sectional area of lumbar multifidi (0.74 and 0.88, respectively) as well as the anterior-posterior dimensions of lumbar multifidi (0.89 and 0.91, respectively) and transverse abdomini thickness (0.73 and 0.85, respectively).

CONCLUSIONS

Rehabilitative ultrasonography is a reliable and non-invasive instrument to measure muscle thickness. The method used in this study is a reliable way to measure lumbar stabilizing muscles.

Reliability of B-mode sonography of the abdominal muscles in healthy adolescents in different body positions

OBJECTIVES

The primary aim of this study was to determine the reliability of abdominal sonographic measurements in adolescents. The secondary aim was to determine whether age, sex, or body position had an impact on the reliability of abdominal muscle sonographic measurements in adolescents.

METHODS

Sixty-nine asymptomatic participants aged 10 to 15 years without any postural faults participated in the study. The participants were divided into 3 age groups: 10 to 11, 12 to 13, and 14 to 15 years, according to their sex. All participants underwent 3 measurements of the thickness of the transversus abdominis, internal oblique, and external oblique muscles on both sides of the body in the supine, sitting, and standing positions. The participants' measurements were taken at the end of normal exhalation, and the values were recorded in millimeters.

RESULTS

Regardless of the participant's age, sex, and body position, the results for the 3 measurements (intraclass correlation coefficient [ICC(3,3)]) for the transversus abdominis and internal oblique ranged from 0.81 to 0.99. With reference to the external oblique, intraexaminer reliability (ICC(3,3)) in the supine position ranged from 0.81 to 0.98, whereas in the sitting and standing positions, it fluctuated from 0.63 to 0.96.

CONCLUSIONS

Sonography for assessment of the internal oblique and transversus abdominis muscles in different body positions in healthy adolescents aged 10 to 15 years was found to have reliability. To obtain high measurement reliability for the transversus abdominis and internal oblique at rest, at least 2 measurements should be performed, regardless of age, sex, or resting body position. Performing 3 measurements of the external oblique guarantees satisfactory reliability only in the supine position.

Reliability of ultrasound measurement of automatic activity of the abdominal muscle in participants with and without chronic low back pain

Background

Ultrasound (US) imaging has been considered as a non-invasive technique to measure thickness and estimate relative abdominal muscle activity. Although some studies have assessed the reliability of US imaging, no study has assessed the reliability of US measurement of automatic activity of abdominal muscles in positions with different levels of stability in participants with chronic low back pain (cLBP). The purpose of this study was to investigate within-day and between-days reliability of US thickness measurements of automatic activity of the abdominal muscles in asymptomatic participants and within-day reliability in those with cLBP.

Methods

A total of 20 participants (10 with cLBP, 10 healthy) participated in the study. The reliability of US thickness measurements at supine lying and sitting positions (sitting on a chair, sitting on a gym ball with both feet on the ground or lifting one foot off the floor) were assessed. We evaluated within-day reliability in all participants and between-days reliability in asymptomatic participants.

Results

We found high ICC scores (0.85-0.95) and also small SEM and MDC scores in both groups. The reliability of the measurements was comparable between participants with and without LBP in each position but the SEMs and MDCs was slightly higher in patient group compared with healthy group. It indicates high intra-tester reliability for the US measurement of the thickness of abdominal muscles in all positions.

Conclusion

US imaging can be used as a reliable method for assessment of automatic activity of abdominal muscles in positions with low levels of stability in participants with and without LBP.

Rehabilitative ultrasound imaging of the supraspinatus muscle: Intra- and interrater reliability of thickness and cross-sectional area

OBJECTIVE

To examine intra- and interrater reliability of thickness and cross-sectional area (CSA) measurements of the supraspinatus muscle using rehabilitative ultrasound imaging (RUSI).

METHODS

Two physical therapists acquired b-mode images of the supraspinatus muscles in twenty-five healthy subjects. Thickness and CSA were measured. Intra- and interrater reliability were examined.

RESULTS

Intrarater reliability for thickness was high, (ICC1.1 0.91) for rater 1 and (ICC1.1 0.92) for rater 2. Intrarater reliability for CSA was also high, (ICC1.1 0.90) for rater 1 and (ICC1.1 0.85) for rater 2. Interrater reliability for the thickness was high, (ICC3.1 0.86). For CSA, interrater reliability was moderate, (ICC3.1 0.70).

CONCLUSION

Supraspinatus muscle thickness and CSA can be reliably measured by physical therapists in healthy subjects. These findings confirm that RUSI has an interesting potential for physiotherapy clinical practice, especially to assess morphometric changes in skeletal muscles. Further research is needed in subjects with shoulder disorders.

Reliability of real-time ultrasound measurement of transversus abdominis thickness in healthy trained subjects

PURPOSE

To investigate intra- and inter-rater reliability of the ultrasound measurement of transversus abdominis (TrA) thickness and thickness change (difference between thickness at rest and during contraction) in asymptomatic, trained subjects. To define the number of repeated measurements that provide acceptable level of reliability. To investigate variability of the measurements over time of 5 days and the reliability of duplicate analysis of images.

METHODS

A single-group repeated-measures design was used to assess reliability. Healthy volunteers (n = 10) were subjected to 1-week training in voluntary activation of TrA. Real-time ultrasound imaging and subsequent measurement of the TrA thickness at rest and during voluntary contraction were repeated on Monday, Wednesday and Friday of the next week.

RESULTS

Using a single repeated measurement, intraclass correlation coefficients (ICCs) for TrA thickness were: 0.86-0.95 (intra-rater), 0.86-0.92 (inter-rater); and for TrA thickness change: 0.34-0.56 (intra-rater), 0.47-0.61 (inter-rater). Using the mean of three repeated measurements respective values were: 0.97, 0.96-0.98; and 0.81-0.84, 0.80-0.90. No significant differences were found between mean values of TrA thickness as well as thickness change obtained on three consecutive measurement days. Duplicate analysis of the images was highly reliable with ICCs of 0.89-0.99.

CONCLUSIONS

Two repeated measurements for TrA thickness and at least three measurements for TrA thickness change are needed to achieve acceptable levels of intra- and inter-rater reliability. In healthy trained volunteers TrA thickness and thickness change are relatively stable parameters over a 5-day period. Duplicate analysis of the same images by two blinded observers is reliable.

Discriminative and reliability analyses of ultrasound measurement of abdominal muscles recruitment

Rehabilitative ultrasound imaging has a great potential to be used as a tool in the assessment of trunk muscle function in patients with low back pain (LBP). However, a further investigation of the discriminative ability of this tool as well as the effect of operators' levels of training on reliability is warranted. Discriminative analysis of ultrasound and electromyography (EMG) measurements of transversus abdominus (TrA), obliquus internus (OI), and obliquus externus (OE) muscles function between people with and without LBP and the effect of operator's training on reliability of TrA muscle function of chronic LBP patients were conducted. For the discriminative study, measurements were collected from 10 subjects with LBP and 10 matched controls during isometric low load tasks with their limbs suspended. For the reliability study, in stage 1 the reliability of single ultrasonographic static images involved 4 operators (1 trained and 3 non-trained), whereas, in stage 2, two operators (1 trained and 1 non-trained) were used to determine the reliability of TrA thickness change. Methods used in the statistical analysis were pearson correlation and receiver operating characteristic curve for the discriminative study and intraclass correlation coefficient (ICC) for the reliability study. While ultrasound measures of OE muscle function showed poor association with EMG (r = 0.28, p = 0.22), TrA and OI function showed moderate to excellent association (TrA: r = 0.74, p < 0.000; OI: r = 0.85, p < 0.000). Ultrasound and EMG measures of TrA and OI function discriminated LBP patients from controls. Reliability of the assessment of TrA function with a trained operator (ICC = 0.92; 95% CI: 0.81-0.97) was substantially higher than a non-trained one (ICC = 0.44; 95% CI: -0.41-0.78). In conclusion, ultrasound measures of deep trunk function is a valid discriminative tool in LBP but highly dependent on operator's level of training.

Application of rehabilitative ultrasound in the assessment of low back pain: a literature review

Low back pain (LBP) is one of the most common work-related conditions affecting all populations both in industrialized and non-industrialized countries, with reported high prevalence and incidence rates and huge direct and indirect costs. Among various suggested causes of LBP, dysfunction of back muscles, particularly lumbar multifidus and transverse abdominis, has been the subject of considerable research during last decades. Of the available imaging techniques, ultrasound (US) imaging technique is increasingly used to assess muscle dimensions and function as a valid, reliable and non-invasive approach. The purpose of the present study was to review the previously published studies (1990-2009) concerning the merit of US imaging of lumbar and abdominal muscles with particular attention to its clinical application in patients with LBP. Studies showed wide variation in terms of methodology, sample size, procedure, definition of LBP, heterogeneous sample, method of analyzing US imaging, US imaging parameters, etc. However, a convincing body of evidence was identified that supports US imaging as a reliable and valid tool both to differentiate patients with LBP from normal subjects and to monitor the effect of rehabilitation programs.

Abdominal hollowing and lateral abdominal wall muscles' activity in both healthy men & women: An ultrasonic assessment in supine and standing positions

The objective of this study was to investigate the effects of Abdominal Hollowing (AH) maneuver on External Oblique (EO), Internal Oblique (IO) and Transversus Abdominis (TrA) muscles in both healthy men and women during the two postures of supine and upright standing. The study was conducted on 43 asymptomatic volunteers (22 males and 21 females) aged 19-44 (27.8±6.4) years. Rehabilitative Ultrasonic Imaging (RUSI) was simultaneously performed to measure muscle thickness in both rest and during AH maneuvers while activation of the TrA during AH was controlled by Pressure Biofeedback (PBF) device. Mixed-model ANOVA with repeated measures design, and Pearson correlation tests were used to analyze the data. Muscle thickness of all muscles was significantly higher for male subjects (F>6.2, p<0.017). The interaction effect of gender and muscle status was significant only for IO (F=7.458, p=0.009) indicating that AH maneuver increased the thickness of IO in men. Interaction effect of posture and muscle status on muscular thickness indicated that changing position only affects the resting thickness of TrA (F=5.617, p=0.023). Standing posture significantly affected the TrA contraction ratio (t=3.122, p=0.003) and TrA preferential activation ratio (t=2.76, p=0.008). There was no relationship between age and muscle thickness (r=0.262, p=0.09). The PBF has been introduced as a clinical and available device for monitoring TrA activity, while RUSI showed that both TrA and IO muscles had activated after AH maneuver. We recommend performing further investigations using electromyography and RUSI simultaneously at more functional postures such as upright standing.

Reliability of measuring abductor hallucis muscle parameters using two different diagnostic ultrasound machines

Background

Diagnostic ultrasound provides a method of analysing soft tissue structures of the musculoskeletal system effectively and reliably. The aim of this study was to evaluate within and between session reliability of measuring muscle dorso-plantar thickness, medio-lateral length and cross-sectional area, of the abductor hallucis muscle using two different ultrasound machines, a higher end Philips HD11 Ultrasound machine and clinically orientated Chison 8300 Deluxe Digital Portable Ultrasound System.

Methods

The abductor hallucis muscle of both the left and right feet of thirty asymptomatic participants was imaged and then measured using both ultrasound machines. Interclass correlation coefficients (ICC) with 95% confidence intervals (CI) were used to calculate both within and between session intra-tester reliability. Standard error of the measurement (SEM) calculations were undertaken to assess difference between the actual measured score across trials and the smallest real difference (SRD) was calculated from the SEM to indicate the degree of change that would exceed the expected trial to trial variability.

Results

The ICCs, SEM and SRD for dorso-plantar thickness and medial-lateral length were shown to have excellent to high within and between-session reliability for both ultrasound machines. The between-session reliability indices for cross-sectional area were acceptable for both ultrasound machines.

Conclusion

The results of the current study suggest that regardless of the type ultrasound machine, intra-tester reliability for the measurement the abductor hallucis muscle parameters is very high.

Induced transducer orientation during ultrasound imaging: effects on abdominal muscle thickness and bladder position

The use of ultrasound imaging (USI) by physiotherapists to assess muscle behavior in clinical settings is increasing. However, there is relatively little evidence of whether the clinical environment is conducive to valid and reliable measurements. Accurate USI measurements depend on maintaining a relatively stationary transducer position, because motion may distort the image and lead to erroneous conclusions. This would seem particularly important during dynamic studies typical of a physiotherapy assessment. What is not known is how much transducer motion can occur before error is introduced. The aim of this study is to shed some light on this question. Eight healthy volunteers (19 to 52 y) participated. USI images were taken of the lateral abdominal wall (LAW) and bladder base (midline suprapubic) at various manually induced transducer orientations (approximately -10 to 10 degrees about 3 axes of rotation), which were quantified by a digital optical motion capture system. Measurements of transversus abdominis (TrA) thickness and bladder base position (cranial /caudal and anterior/posterior) were calculated. Repeated measures analysis of variance was performed to determine if the measurements obtained at the induced transducer orientations were statistically different (p<0.05) from an image corresponding to a reference or starting transducer orientation. Motion analysis data corresponding to measurements that did not differ from reference image measurements were summarized to provide a range of acceptable transducer motion (relative to the pelvis) for clockwise (CW)/counter-clockwise (CCW) rotation, cranial/caudal tilting, medial/lateral tilting and inward/outward displacement. There were no significant changes in TrA thickness measurements if CW/CCW transducer motion was <9 degrees and cranial/caudal or medial/lateral transducer tilting was <5 degrees . Further, there were no significant changes in measurements of bladder base position if CW/CCW transducer motion was <10 degrees , cranial/caudal or medial/lateral transducer tilting was <10 degrees and 8 degrees , respectively and inward/outward motion was <8 mm. These findings provide guidance on acceptable amounts of transducer motion relative to the pelvis when generating measurements of TrA thickness and bladder base position. Future sonographic studies and clinical assessment investigating these parameters could take these findings into account to improve imaging technique reliability.

A systematic review of the reliability of rehabilitative ultrasound imaging for the quantitative assessment of the abdominal and lumbar trunk muscles

STUDY DESIGN

Systematic review.

OBJECTIVE

To systematically review the literature on the rater reliability of Rehabilitative Ultrasound Imaging (RUSI) measurements to assess the morphology of the abdominal and lumbar trunk musculature.

SUMMARY OF BACKGROUND DATA

RUSI is an increasingly popular method of evaluating the morphology and function of muscles with real-time ultrasound. Conclusions regarding the reliability of measurements obtained by RUSI, need to be established before recommending its wider use.

METHODS

A systematic approach to searching and identifying original research articles reporting quantitative RUSI measurements was undertaken. Reliability data were extracted and methodologic quality was evaluated by 2 independent reviewers.

RESULTS

Of the 24 studies included, 6 were deemed to be of high methodologic quality. Among high quality studies, some reported the measurement error associated with performing repeated measurements of the same image (intraimage analysis), whereas others reported the reliability of obtaining and measuring unique RUSI images (interimage analysis). Intraimage measurements demonstrated good intrarater and interrater reliability (ICC: >0.93). Interimage measurements demonstrated good reliability between raters (ICC: >0.90). Interimage, intrarater correlation coefficients were more variable with ICC values ranging from 0.62 to 0.97.

CONCLUSION

The methodologic quality of research investigating the reliability of RUSI to measure the abdominal and lumbar trunk muscles needs to be improved. The majority of results of high quality studies indicate that RUSI has good levels of rater reliability. Improved reliability was observed among studies examining muscle thickness, and when using mean measurement values obtained by more experienced examiners.

Reproducibility of rehabilitative ultrasound imaging for the measurement of abdominal muscle activity: a systematic review

BACKGROUND

Rehabilitative ultrasound imaging (RUSI) measures of abdominal wall muscles are used to indirectly measure muscle activity. These measures are used to identify suitable patients and to monitor progress of motor control exercise treatment of people with low back pain.

PURPOSE

The purpose of this study was to systematically review reproducibility studies of RUSI for measuring thickness of abdominal wall muscles.

DATA SOURCES

Eligible studies were identified via searches of MEDLINE, EMBASE, and CINAHL. The authors also searched personal files and tracked references of the retrieved studies via the Web of Science Index.

STUDY SELECTION

Studies involving any type of reliability and or agreement of any type of ultrasound measurements (B or M mode) for any of the abdominal wall muscles were selected.

DATA EXTRACTION

Two independent reviewers extracted data and assessed methodological quality.

DATA SYNTHESIS

Due to heterogeneity of the studies' designs, pooling the data for a meta-analysis was not possible. Twenty-one studies were included, and these studies were typically of low quality and studied subjects who were healthy rather than people seeking care for low back pain. The studies reported good to excellent reliability for single measures of thickness and poor to good reliability for measures of thickness change (reflecting the muscle activity). Interestingly, no studies checked reliability of measures of the difference in thickness changes over time (representing improvement or deterioration in muscle activity).

CONCLUSIONS

The current evidence of the reproducibility of RUSI for measuring abdominal muscle activity is based mainly on studies with suboptimal designs and the study of people who were healthy. The critical question of whether RUSI provides reliable measures of improvement in abdominal muscle activity remains to be evaluated.

An investigation of the reproducibility of ultrasound measures of abdominal muscle activation in patients with chronic non-specific low back pain

Ultrasound (US) measures are used by clinicians and researchers to evaluate improvements in activity of the abdominal muscles in patients with low back pain. Studies evaluating the reproducibility of these US measures provide some information; however, little is known about the reproducibility of these US measures over time in patients with low back pain. The objectives of this study were to estimate the reproducibility of ultrasound measurements of automatic activation of the lateral abdominal wall muscles using a leg force task in patients with chronic low back pain. Thirty-five participants from an existing randomised, blinded, placebo-controlled trial participated in the study. A reproducibility analysis was undertaken from all patients using data collected at baseline and after treatment. The reproducibility of measurements of thickness, muscle activation (thickness changes) and muscle improvement/deterioration after intervention (differences in thickness changes from single images made before and after treatment) was analysed. The reproducibility of static images (thickness) was excellent (ICC(2,1) = 0.97, 95% CI = 0.96-0.97, standard error of the measurement (SEM) = 0.04 cm, smallest detectable change (SDC) = 0.11 cm), the reproducibility of thickness changes was moderate (ICC(2,1) = 0.72, 95% CI 0.65-0.76, SEM = 15%, SDC 41%), while the reproducibility of differences in thickness changes from single images with statistical adjustment for duplicate measures was poor (ICC(2,1) = 0.44, 95% CI 0.33-0.58, SEM = 21%, SDC = 66.5%). Improvements in the testing protocol must be performed in order to enhance reproducibility of US as an outcome measure for abdominal muscle activation.