Shane L. Koppenhaver

Reliability of Rehabilitative Ultrasound Imaging of the Transversus Abdominis and Lumbar Multifidus Muscles

OBJECTIVES To evaluate the intraexaminer and interexaminer reliability of rehabilitative ultrasound imaging (RUSI) in obtaining thickness measurements of the transversus abdominis (TrA) and lumbar multifidus muscles at rest and during contractions. DESIGN Single-group repeated-measures reliability study. SETTING University and orthopedic physical therapy clinic. PARTICIPANTS A volunteer sample of adults (N=30) with current nonspecific low back pain (LBP) was examined by 2 clinicians with minimal RUSI experience. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Thickness measurements of the TrA and lumbar multifidus muscles at rest and during contractions were obtained by using RUSI during 2 sessions 1 to 3 days apart. Percent thickness change was calculated as thickness(contracted)-thickness(rest)/thickness(rest). Intraclass correlation coefficients (ICC) were used to estimate reliability. RESULTS By using the mean of 2 measures, intraexaminer reliability point estimates (ICC(3,2)) ranged from 0.96 to 0.99 for same-day comparisons and from 0.87 to 0.98 for between-day comparisons. Interexaminer reliability estimates (ICC(2,2)) ranged from 0.88 to 0.94 for within-day comparisons and from 0.80 to 0.92 for between-day comparisons. Reliability estimates comparing measurements by the 2 examiners of the same image (ICC(2,2)) ranged from 0.96 to 0.98. Reliability estimates were lower for percent thickness change measures than the corresponding single thickness measures for all conditions. CONCLUSIONS RUSI thickness measurements of the TrA and lumbar multifidus muscles in patients with LBP, when based on the mean of 2 measures, are highly reliable when taken by a single examiner and adequately reliable when taken by different examiners.

The short-term effects of thoracic spine thrust manipulation on patients with shoulder impingement syndrome

The study was an exploratory, one group pretest/post-test study, with the objective of investigating the short-term effects of thoracic spine thrust manipulations (TSTMs) on patients with shoulder impingement syndrome (SIS). There is evidence that manual physical therapy that includes TSTM and non-thrust manipulation and exercise is effective for the treatment of patients with SIS. However, the relative contributions of specific manual therapy interventions are not known. To date, no published studies address the short-term effects of TSTM in the treatment of SIS. Fifty-six patients (40 males, 16 females; mean age 31.2+/-8.9) with SIS underwent a standardized shoulder examination, immediately followed by TSTM techniques. Outcomes measured were the Numeric Pain and Rating Scale (NPRS) and the Shoulder Pain and Disability Index (SPADI), all collected at baseline and at a 48-h follow-up period. Additionally, the Global Rating of Change Scale (GRCS) was collected at 48-h follow-up to measure patient perceived change. At 48-h follow-up, the NPRS change scores for Neer impingement sign, Hawkins impingement sign, resisted empty can, resisted external rotation, resisted internal rotation, and active abduction were all statistically significant (p<0.01). The reduction in the SPADI score was also statistically significant (p<0.001) and the mean GRCS score=1.4+/-2.5. In conclusion, TSTM provided a statistically significant decrease in self reported pain measures and disability in patients with SIS at 48-h follow-up.

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.

Rehabilitative ultrasound imaging is a valid measure of trunk muscle size and activation during most isometric sub-maximal contractions: a systematic review.

QUESTIONS Is rehabilitative ultrasound imaging a valid measure of trunk muscle size and activation? Are rehabilitative ultrasound imaging measures sensitive to change? DESIGN Systematic review of studies of criterion-related validity, construct validity, and sensitivity to change. PARTICIPANTS People with low back pain and asymptomatic controls. OUTCOME MEASURE Trunk muscle size and activation measured by rehabilitative ultrasound imaging, MRI and/or EMG. RESULTS 37 studies were included. 10 studies investigated criterion-related validity and provided evidence that while ultrasound may be a valid measure of trunk muscle size, the validity of ultrasound to quantify muscle activation is context-dependent, depending on the muscle involved, the contraction strategy utilised, and the intensity of muscle contraction. 23 studies provided evidence of construct validity by demonstrating the ability of ultrasound measurement to differentiate individuals in terms of back pain, anthropometry, and postures. Six studies contained a limited amount of information about sensitivity to change. CONCLUSIONS. It is valid to use rehabilitative ultrasound imaging to measure trunk muscle size and activation during most isometric sub-maximal contractions. Ultrasound measures appear sensitive to both positive and negative change.

The Effect of Averaging Multiple Trials on Measurement Error During Ultrasound Imaging of Transversus Abdominis and Lumbar Multifidus Muscles in Individuals With Low Back Pain

STUDY DESIGN Clinical measurement, reliability study. OBJECTIVES To investigate the improvements in precision when averaging multiple measurements of percent change in muscle thickness of the transversus abdominis (TrA) and lumbar multifidus (LM) muscles. BACKGROUND Although the reliability of TrA and LM muscle thickness measurements using rehabilitative ultrasound imaging (RUSI) is good, measurement error is often large relative to mean muscle thickness. Additionally, percent thickness change measures incorporate measurement error from both resting and contracted conditions. METHODS Thirty volunteers with nonspecific low back pain participated. Thickness measurements of the TrA and LM muscles were obtained using RUSI at rest and during standardized tasks. Percent thickness change was calculated with the formula thickness(contracted) - thickness(rest)/thickness(rest). Standard error of measurement (SEM) quantified precision when using 1 or a mean of 2 to 6 consecutive measurements. RESULTS Compared to when using a single measurement, SEM of both the TrA and LM decreased by nearly 25% when using a mean of 2 measures, and by 50% when using the mean of 3 measures. Little precision was gained by averaging more than 3 measurements. CONCLUSION When using RUSI to determine percent change in TrA and LM muscle thickness, intra examiner measurement precision appears to be optimized by using an average of 3 consecutive measurements.

Preliminary Investigation of the Mechanisms Underlying the Effects of Manipulation: Exploration of a Multivariate Model Including Spinal Stiffness, Multifidus Recruitment, and Clinical Findings

Study Design. Prospective case series. Objective. To examine spinal stiffness in patients with low back pain (LBP) receiving spinal manipulative therapy (SMT), evaluate associations between stiffness characteristics and clinical outcome, and explore a multivariate model of SMT mechanisms as related to effects on stiffness, lumbar multifidus (LM) recruitment, and status on a clinical prediction rule (CPR) for SMT outcomes. Summary of Background Data. Mechanisms underlying the clinical effects of SMT are poorly understood. Many explanations have been proposed, but few studies have related potential mechanisms to clinical outcomes or considered multiple mechanisms concurrently. Methods. Patients with LBP were treated with two SMT sessions over 1 week. CPR status was assessed at baseline. Clinical outcome was based on the Oswestry disability index (ODI). Mechanized indentation measures of spinal stiffness and ultrasonic measures of LM recruitment were taken before and after each SMT, and after 1 week. Global and terminal stiffness were calculated. Multivariate regression was used to evaluate the relationship between stiffness variables and percentage ODI improvement. Zero-order correlations among stiffness variables, LM recruitment changes, CPR status, and clinical outcome were examined. A path analysis was used to evaluate a multivariate model of SMT effects. Results. Forty-eight patients (54% women) had complete stiffness data. Significant immediate decreases in global and terminal stiffness occurred post-SMT regardless of outcome. ODI improvement was related to greater immediate decrease in global stiffness (P = 0.025), and less initial terminal stiffness (P = 0.01). Zero-order correlations and path analysis supported a multivariate model suggesting that clinical outcome of SMT is mediated by improvements in LM recruitment and immediate decrease in global stiffness. Initial terminal stiffness and CPR status may relate to outcome though their relationship with LM recruitment. Conclusion. The underlying mechanisms explaining the benefits of SMT appear to be multifactorial. Both spinal stiffness characteristics and LM recruitment changes appear to play a role.

Beyond minimally important change: Defining a successful outcome of physical therapy for patients with low back pain

Study Design. Prospective, longitudinal cohort study Objective. To examine the validity of a threshold that has been used to define a successful outcome for patients with low back pain (LBP), undergoing nonsurgical rehabilitation based on a 50% improvement on the Modified Oswestry disability index (ODI). Summary of Background Data. Making research findings interpretable is a goal of evidence-based practice. One attempt to improve interpretability is reporting treatment results as the percentage of patients achieving a threshold level of improvement within treatment groups along with mean between-group differences. The most recommended threshold is the minimum clinically important difference of the outcome tool. For clinical conditions with favorable natural histories such as LBP, thresholds requiring more than minimal improvement may be preferable for defining success. Methods. Patients with LBP receiving 4 weeks of physical therapy were examined. The ODI and measures of pain, fear-avoidance beliefs, and demographic characteristics were recorded at baseline and after treatment. A 15-point global rating of change was also completed after treatment. The percent ODI change with treatment was computed and compared between groups known to have different prognoses. The percent ODI change was compared to the global rating of change to determine the accuracy of various thresholds of success based on the percent ODI change. Results. A total of 243 subjects (mean age 37.2 ± 11.4 years, 44.9% female) were included. Mean percent ODI change was 43.1% (±40.5), and 109 subjects (44.9%) had a successful outcome (≥50% ODI improvement). As hypothesized, baseline factors with known prognostic importance were less likely to be present in subjects with a successful outcome. The 50% ODI improvement threshold for success had high sensitivity (0.84; 95% CI: 0.79, 0.88) and specificity (0.89; 95% CI: 0.85, 0.93) when compared with success based on the global rating of change. No other percent improvement threshold for the ODI had a higher accuracy than the 50% threshold when compared to the global rating of change. Conclusion. A threshold of 50% improvement on the ODI may be a valid measure for defining a successful outcome for patients with LBP.

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.

Subgrouping Patients With Low Back Pain: A Treatment-Based Approach to Classification

Context: Low back pain (LBP) is a prevalent condition imposing a large socioeconomic burden. Despite intensive research aimed at the efficacy of various therapies for patients with LBP, most evidence has failed to identify a superior treatment approach. One proposed solution to this dilemma is to identify subgroups of patients with LBP and match them with targeted therapies. Among the subgrouping approaches, the system of treatment-based classification (TBC) is promoted as a means of increasing the effectiveness of conservative interventions for patients with LBP. Evidence acquisition: MEDLINE and PubMed databases were searched from 1985 through 2010, along with the references of selected articles. Results: TBC uses a standardized approach to categorize patients into 1 of 4 subgroups: spinal manipulation, stabilization exercise, end-range loading exercise, and traction. Although the TBC subgroups are in various stages of development, recent research lends support to the effectiveness of this approach. Conclusions: While additional research is required to better elucidate this method, the TBC approach enhances clinical decision making, as evidenced by the improved clinical outcomes experienced by patients with LBP.

Rehabilitative ultrasound imaging

UNLABELLED Neuromuscular deficits have been linked with chronic musculoskeletal conditions. The use of ultrasound imaging(USI) to aid rehabilitation of neuromusculoskeletal disorders has been called rehabilitative ultrasound imaging (RUSI)and defined as ‘a procedure used by physical therapists to evaluate muscle and related soft tissue morphology and function during exercise and physical tasks. RUSI is used to assist in the application of therapeutic interventions,providing feedback to the patient and physical therapist (Teyhen 2006). Brightness mode (b-mode) USI is the most common form used by physical therapists and will be the focus of this summary. CLINICAL UTILITY USI can distinguish between healthy adults and those with low back pain (LBP). Those with LBP have decreased muscle thickness, side-to-side asymmetry,and decreased ability to thicken the muscles during a contraction (Teyhen et al 2009). Moreover, when measured by USI, lumbar multifidus muscle asymmetry appears to be predictive of future episode of LBP up to three years later(Hides et al 2001). Finally, USI can distinguish between changes in muscle thickness during common LBP exercises when performed by healthy adults (Teyhen et al 2008) and is preliminarily supported as a biofeedback tool to enhance exercise effectiveness (Henry and Teyhan 2007). CRITERION-RELATED VALIDITY: In a recent systematic review Koppenhaver et al (2009a) concluded that b-mode USI when applied in a rehabilitative setting is a valid tool to measure trunk muscle size and muscle activation during most submaximal contracted states. When comparing muscle thickness obtained by magnetic resonance imaging and USI, researchers have demonstrated substantial agreement(ICC 0.84 to –0.95) with only minimal differences between the modalities (0.03 to 0.21 cm2) (Hides et al 1995, 2006). Although comparisons between electromyography and change in muscle thickness obtained by USI have most often demonstrated a curvilinear relationship (Hodges et al 2003), the ability of USI to measure muscle activation is likely context-dependent and is based on the muscle being measured, the task performed, and the intensity of the contraction (Koppenhaver et al 2009a). RESPONSIVENESS TO CHANGE: Motor control training has been demonstrated to increase multifidus cross sectional area (p = 0.004), decrease side-to-side asymmetry, and was associated with a 50% reduction in pain (Hides et al 2008b).Additionally, recent evidence suggests increased contracted thickness of the lumbar multifidus one week after a spinal manipulation was predictive of larger improvements in low back pain-related disability (Koppenhaver et al 2011).The minimal amount of change associated with clinical improvement has yet to be determined. RELIABILITY In a recent systematic review Hebert et al (2009)concluded that the majority of high quality studies indicated that RUSI has good intrarater and inter-rater reliability (ICC> 0.90). The standard error of measurement was decreased by nearly 25% when using a mean of two measures and by 50% when using a mean of three measures (Koppenhaver et al 2009b). Novice raters, when properly trained, can assess the trunk muscles reliably (ICC 0.86 to 0.94) (Teyhen et al 2011). INFLUENCE OF SEX AND BODY MASS INDEX: Muscle thickness and cross sectional area is greater in males than females and is associated with increased body mass index (Teyhenet al 2007).