Investigation of abdominal muscle thickness changes after spinal manipulation in patients who meet a clinical prediction rule for lumbar stabilization

Extended field-of-view ultrasound imaging is reliable for measuring Transversus Abdominis muscle size at rest and during contraction

Background

The strength and size of core muscles, including the abdominal muscles, are crucial to proper function in most activities. Therefore, it is important to reliably assess these characteristics. Our primary objective was to determine if the length, thickness and cross-sectional area of the transversus abdominis (TrA) can be visualized independently from the internal and external abdominal oblique muscles using extended field of view ultrasound imaging at rest and with contraction and to establish its intra- and inter-tester reliability.

Methods

Twenty-six individuals were recruited to participate in the study (20 F, 6 M), average age 24.0 years (SD 9.4), height 170.7 cm (SD 8.6) and weight 63.9 kg (SD 9.0). From this total number of participants, two groups of 16 randomly selected participants were assessed to determine intra- and inter-tester reliability respectively. Extended field of view ultrasound images were obtained at three vertebral levels during rest and contraction in the side lying position for both the right and left sides of the trunk.

Results

Excellent intra-tester and inter-tester reliability was seen (ICC range of 0.972 to 0.984). The overall average percent standard error of the measurement for all measurements and locations was approximately 4%. The overall average minimal difference for the thickness measurement for the resting and contraction conditions combined were as follows: intratester 0.056 (0.014) cm and intertester 0.054 (0.017) cm, for area intratester 0.287 (0.086) cm² and intertester 0.289 (0.101) cm² and for length intratester 0.519 (0.097) cm and intertester 0.507 (0.085) cm.

Conclusions

Extended field of view ultrasound imaging is an effective method of reliably capturing clear images of the TrA during rest and contraction. It provides an efficient mechanism for the analysis of muscle morphology by being able to measure the cross-sectional area, thickness, and length on one image. This methodology is recommended for studies investigating TrA function and training.

Pain Catastrophizing Is Related to Static Postural Control Impairment in Patients with Nonspecific Chronic Low Back Pain: A Cross-Sectional Study

Purpose

Pain catastrophizing may contribute to the altered trunk muscle activity in patients with nonspecific chronic low back pain (NSCLBP). It is unclear if pain catastrophizing influences static postural control in patients with NSCLBP. This study aimed to investigate the relationship between pain catastrophizing and static postural control in NSCLBP patients.

Methods

Sixty-eight participants with NSCLBP and 40 healthy participants were recruited. Postural control was assessed by the sway area and the sway length of the center of pressure (COP) during balance tests. Pain catastrophizing in participants with NSCLBP was assessed by the Pain Catastrophizing Scale (PCS). Bilateral transversus abdominis (TrA) activation was evaluated by ultrasound imaging-measured percent change in muscle thickness. Associations between COP parameter and PCS/subscales of PCS were examined by multiple linear regression (MLR).

Results

Our results observed a larger COP sway area in NSCLBP group under eyes-closed condition (p < 0.001) and a lower level of voluntary activation of the bilateral TrA (p < 0.001), compared with the healthy control group. The MLR analyses revealed that the COP area sway under eyes-closed condition was significantly associated with the PCS score/helplessness score of PCS, voluntary activation of the left TrA, and age in participants with NSCLBP (β = 0.222/0.236, 0.341/0.344, and 0.328/0.325; p=0.045/0.033, 0.002, and 0.004, resp.).

Conclusions

Static postural control was associated with pain catastrophizing, voluntary activation of TrA, and age in participants with NSCLBP. This indicated that pain catastrophizing may affect postural control and should be considered when interpreting balance test results and managing NSCLBP.

The Effects of Thrust Joint Manipulation on the Resting and Contraction Thickness of Transversus Abdominis in Patients With Low Back Pain: A Randomized Control Trial

OBJECTIVE

To investigate the immediate changes in resting and contracted thickness of the transversus abdominis (TrA) muscle after application of thrust joint manipulation (TJM) vs sham manipulation in participants with low back pain.

METHODS

A pretest-posttest randomized controlled trial design was performed. Consecutive subjects satisfying eligibility criteria completed patient-report outcome baseline measures, pretreatment rehabilitative ultrasound imaging (RUSI) measurements, followed by the randomly assigned intervention then, post-treatment RUSI measurements, and post-treatment & final patient-reported outcome measures. To compare the outcomes of TJM and sham manipulation on the TrA muscle thickness, a 2-by-2 analysis of variance (treatment [TJM and sham manipulation]) by time (pretreatment and post-treatment) was completed for both the TrA muscle thickness at rest and muscle thickness during contraction. Descriptive statistics including independent-sample t tests for continuous variables and χ² tests for categorical variables were used to analyze differences in patient-reported outcome measures between groups.

RESULTS

Sixty-seven eligible participants agreed to participate. No significant interactions were identified for either muscle thickness at rest or contraction.

CONCLUSION

This study did not support the hypothesis that manipulation would result in greater changes in TrA thickness at rest or during contraction in participants with low back pain. Based on prior research that identified subgroups of participants likely to respond to manipulation, future research should include participants more likely to respond favorably to TJM. This study was a priori registered with clinicaltrails.gov (NCT02558855).

Psychometric Properties of the Deep Muscle Contraction Scale for Assessment of the Drawing-in Maneuver in Patients With Chronic Nonspecific Low Back Pain

Study Design A prospective cohort study. Background Motor control dysfunctions have been commonly reported in patients with chronic nonspecific low back pain (LBP). Physical therapists need clinical tools with adequate psychometric properties to assess such patients in clinical practice. The deep muscle contraction (DMC) scale is a clinical rating scale for assessing patients' ability to voluntarily contract deep abdominal muscles. Objectives To investigate the intrarater reliability, floor and ceiling effects, internal and external responsiveness, and correlation analysis (with ultrasound measures) of the DMC scale in patients with chronic nonspecific LBP undergoing a lumbar stabilization exercise program. Methods Sixty-two patients with chronic nonspecific LBP were included. At baseline, self-report questionnaires were administered to patients and a trained assessor evaluated abdominal muscle recruitment with the DMC scale and ultrasound imaging. Four ratios of the change in abdominal muscle thickness between the resting and contracted states were calculated through the ultrasound measures. After 1 week, the same ultrasound measures and DMC scale were collected again for the reliability analysis. The proportions of patients with the lowest and highest scores on the DMC scale were calculated to investigate floor and ceiling effects. All patients underwent a lumbar stabilization program, administered twice a week for 8 weeks. After the treatment period, all measures were collected again, with the addition of the global perceived effect scale, to assess the internal and external responsiveness of the measures. Correlation coefficients between ultrasound ratios and DMC scale total and subscale scores were also calculated. Results The intrarater reliability of the DMC scale and the 4 ratios of abdominal muscle thickness varied from moderate to excellent. The DMC scale showed no floor or ceiling effects. Results for internal responsiveness of the DMC scale showed large effect sizes (2.26; 84% confidence interval [CI]: 2.06, 2.45), whereas the external responsiveness was below the proposed threshold (area under the curve = 0.54; 95% CI: 0.39, 0.68). Fair and significant correlations between some ultrasound ratios and DMC subscales were found. Conclusion The DMC scale was demonstrated to be a reliable tool, with no ceiling and floor effects, and to detect change in the ability to contract the deep abdominal muscles after a lumbar stabilization exercise program, but with low accuracy for estimating patient-perceived clinical outcome. J Orthop Sports Phys Ther 2017;47(6):432-441. doi:10.2519/jospt.2017.7140.

Associations between low back pain, urinary incontinence, and abdominal muscle recruitment as assessed via ultrasonography in the elderly

BACKGROUND

Low back pain (LBP) and urinary incontinence (UI) are highly prevalent among elderly individuals. In young adults, changes in trunk muscle recruitment, as assessed via ultrasound imaging, may be associated with lumbar spine stability.

OBJECTIVE

To assess the associations between LBP, UI, and the pattern of transversus abdominis (TrA), internal (IO), and external oblique (EO) muscle recruitment in the elderly as evaluated by ultrasound imaging.

METHOD

Fifty-four elderly individuals (mean age: 72±5.2 years) who complained of LBP and/or UI as assessed by the McGill Pain Questionnaire, Incontinence Questionnaire-Short Form, and ultrasound imaging were included in the study. The statistical analysis comprised a multiple linear regression model, and a p-value <0.05 was considered significant.

RESULTS

The regression models for the TrA, IO, and EO muscle thickness levels explained 2.0% (R2=0.02; F=0.47; p=0.628), 10.6% (R2=0.106; F=3.03; p=0.057), and 10.1% (R2=0.101; F=2.70; p=0.077) of the variability, respectively. None of the regression models developed for the abdominal muscles exhibited statistical significance. A significant and negative association (p=0.018; β=-0.0343) was observed only between UI and IO recruitment.

CONCLUSION

These results suggest that age-related factors may have interfered with the findings of the study, thus emphasizing the need to perform ultrasound imaging-based studies to measure abdominal muscle recruitment in the elderly.

A clinical prediction rule to identify patients with low back pain who are likely to experience short-term success following lumbar stabilization exercises: a randomized controlled validation study

STUDY DESIGN

Randomized controlled trial.

OBJECTIVE

To determine the validity of a previously suggested clinical prediction rule (CPR) for identifying patients most likely to experience short-term success following lumbar stabilization exercise (LSE). Background Although LSE is commonly used by physical therapists in the management of low back pain, it does not seem to be more effective than other interventions. A 4-item CPR for identifying patients most likely to benefit from LSE has been previously suggested but has yet to be validated.

METHODS

One hundred five patients with low back pain underwent a baseline examination to determine their status on the CPR (positive or negative). Patients were stratified by CPR status and then randomized to receive an LSE program or an intervention consisting of manual therapy (MT) and range-of-motion/flexibility exercises. Both interventions included 11 treatment sessions delivered over 8 weeks. Low back pain-related disability was measured by the modified version of the Oswestry Disability Index at baseline and upon completion of treatment.

RESULTS

The statistical significance for the 2-way interaction between treatment group and CPR status for the level of disability at the end of the intervention was P = .17. However, among patients receiving LSE, those with a positive CPR status experienced less disability by the end of treatment compared with those with a negative CPR status (P = .02). Also, among patients with a positive CPR status, those receiving LSE experienced less disability by the end of treatment compared with those receiving MT (P = .03). In addition, there were main effects for treatment and CPR status. Patients receiving LSE experienced less disability by the end of treatment compared to patients receiving MT (P = .05), and patients with a positive CPR status experienced less disability by the end of treatment compared to patients with a negative CPR status, regardless of the treatment received (P = .04). When a modified version of the CPR (mCPR) containing only the presence of aberrant movement and a positive prone instability test was used, a significant interaction with treatment was found for final disability (P = .02). Of the patients who received LSE, those with a positive mCPR status experienced less disability by the end of treatment compared to those with a negative mCPR status (P = .02), and among patients with a positive mCPR status, those who received LSE experienced less disability by the end of treatment compared to those who received MT (P = .005).

CONCLUSION

The previously suggested CPR for identifying patients likely to benefit from LSE could not be validated in this study. However, due to its relatively low level of power, this study could not invalidate the CPR, either. A modified version of the CPR that contains only 2 items may possess a better predictive validity to identify those most likely to succeed with an LSE program. Because this modified version was established through post hoc testing, an additional study is recommended to prospectively test its predictive validity.

LEVEL OF EVIDENCE

Prognosis, level 1b-.

Reliability of a treatment-based classification system for subgrouping people with low back pain

STUDY DESIGN

Observational, cross-sectional reliability study.

OBJECTIVES

To examine the interrater reliability of novice raters in their use of the treatment-based classification (TBC) system for low back pain and to explore the patterns of disagreement in classification errors.

BACKGROUND

Although the interrater reliability of individual test items in the TBC system is moderate to good, some error persists in classification decision making. Understanding which classification errors are common could direct further refinement of the TBC system.

METHODS

Using previously recorded patient data (n = 24), 12 novice raters classified patients according to the TBC schema. These classification results were combined with those of 7 other raters, allowing examination of the overall agreement using the kappa statistic, as well as agreement/disagreement among pairwise comparisons in classification assignments. A chi-square test examined differences in percent agreement between the novice and more experienced raters and differences in classification distributions between these 2 groups of raters.

RESULTS

Among 12 novice raters, there was 80.9% agreement in the pairs of classification (κ = 0.62; 95% confidence interval: 0.59, 0.65) and an overall 75.5% agreement (κ = 0.57; 95% confidence interval: 0.55, 0.69) for the combined data set. Raters were least likely to agree on a classification of stabilization (77.5% agreement). The overall percentage of pairwise classification judgments that disagreed was 24.5%, with the most common disagreement being between manipulation and stabilization (11.0%), followed by a mismatch between stabilization and specific exercise (8.2%).

CONCLUSION

Additional refinement is needed to reduce rater disagreement that persists in the TBC decision-making algorithm, particularly in the stabilization category. J Orthop Sports Phys Ther 2012;42(9):797-805, Epub 7 June 2012. doi:10.2519/jospt.2012.4078.

Continued recovery in an adult with cerebellar ataxia

BACKGROUND AND PURPOSE

The authors previously reported on the functional recovery of an adult with chronic, severe ataxia secondary to traumatic brain injury (TBI) after 28 sessions of trunk stabilization and locomotor training (LT). The purpose of this case report is to describe this individual's functional abilities 3.5 years after the intervention.

CASE DESCRIPTION

Thirteen months post-TBI and not expected to be a functional ambulator, an adult male participated in a trunk stabilization and LT intervention. After the intervention, he continued to exercise in a hospital-based fitness program and received additional physical therapy. Evaluation of balance, gait, trunk performance, self-reported function, and quality of life was performed at 6 weeks (baseline), 1 year, and 3.5 years after completing the intervention.

OUTCOMES

Balance, gait, and function improved. Resting left transverse abdominis thickness, measured using ultrasound imaging, increased as did left-side bridge and trunk flexion endurance. He increased community participation and expressed general satisfaction with his overall quality of life.

DISCUSSION AND CONCLUSION

In the 3.5 years after participation in an intervention of trunk stabilization and LT this adult became an independent limited community ambulator. Persons with severe ataxia secondary to TBI may continue to improve many years after injury.

Association between history and physical examination factors and change in lumbar multifidus muscle thickness after spinal manipulation in patients with low back pain

Understanding the clinical characteristics of patients with low back pain (LBP) who display improved lumbar multifidus (LM) muscle function after spinal manipulative therapy (SMT) may provide insight into a potentially synergistic interaction between SMT and exercise. Therefore, the purpose of this study was to identify the baseline historical and physical examination factors associated with increased contracted LM muscle thickness one week after SMT. Eighty-one participants with LBP underwent a baseline physical examination and ultrasound imaging assessment of the LM muscle during submaximal contraction before and one week after SMT. The relationship between baseline examination variables and 1-week change in contracted LM thickness was assessed using correlation analysis and hierarchical multiple linear regression. Four variables best predicted the magnitude of increases in contracted LM muscle thickness after SMT. When combined, these variables suggest that patients with LBP, (1) that are fairly acute, (2) have at least a moderately good prognosis without focal and irritable symptoms, and (3) exhibit signs of spinal instability, may be the best candidates for a combined SMT and lumbar stabilization exercise (LSE) treatment approach.