Modulation in Elastic Properties of Upper Trapezius with Varying Neck Angle

Ultrasound elastography of back muscle biomechanical properties: a systematic review and meta-analysis of current methods

OBJECTIVES

To report the current elastography methods used to quantify back muscles' biomechanical characteristics in patients with musculoskeletal disorders (MSKd) and inform on their reliability, validity, and responsiveness.

METHODS

MEDLINE, Embase, CINAHL, Cochrane library and grey literature were consulted. Predefined criteria allowed for study selection and data extraction. The quality of evidence was rated using the COSMIN tool. Data were meta-analyzed in terms of pooled intraclass correlation coefficient (pICC) for reliability and pooled standardized mean difference (pSMD) for validity and responsiveness. Heterogeneity was assessed.

RESULTS

Seventy-nine studies were included in the meta-analysis (total number of participants N = 3178). Three elastography methods were identified: strain imaging (SI; number of cohorts M = 26), shear wave imaging (SWI; M = 50), and vibration sonoelastography (VSE; M = 3). Strain imaging and SWI studies reported good reliability measurement properties (pICC > 0.70) and a medium pSMD (0.58 for SI and 0.60 for SWI; p ≤ 0.020) in discriminating MSKd from controls' condition (validity). Strain imaging studies reported a medium pSMD (0.64; p = 0.005) in detecting within-group changes over time, whereas SWI pSMD was very high (1.24; p = 0.005). Only SWI reported significant but small pSMD (0.30; p = 0.003) in detecting between-group changes over time. The small number of VSE studies could not be meta-analyzed. Heterogeneity was high (I-squared > 90%; p < 0.001).

CONCLUSIONS

Elastography presents good reliability results and a medium pSMD in discriminating MSKd from control conditions. Responsiveness data suggest detectable changes within groups over time using SI and SWI, calling for long-term longitudinal studies. Assessing changes between groups over time using elastography still needs to be proven. Highly significant heterogeneity limits meta-analytic results.

CRITICAL RELEVANCE STATEMENT

While still in its early-stage exploration phase, musculoskeletal ultrasound elastography may reliably quantify back muscles' biomechanics in asymptomatic individuals, moderately discriminate back musculoskeletal disorders and detect biomechanical changes over time in these conditions, calling for long-term longitudinal studies.

KEY POINTS

Ultrasound elastography is reviewed for back pain and related musculoskeletal disorder assessments. Growing literature supports good reproducibility, some validity and responsiveness. Back muscle elastography considers assumptions calling for standardized protocols.

Scapular muscle dynamic stiffness of asymptomatic subjects and subjects with chronic shoulder pain, at rest and isometric contraction conditions

Muscle stiffness had a crucial role in joint stability, particularly, at the shoulder complex. Although changes in upper trapezius muscle stiffness have been described for shoulder pain, contradictory findings have been obtained. Also, existing data regarding scapular muscles are, majorly, about trapezius. Myotonometry is a method used to assess stiffness; however, the reliability values of scapular muscle stiffness through this method have not been assessed in shoulder pain conditions. The present study aims to compare scapular muscles' stiffness (trapezius, serratus anterior, and levator scapulae) between subjects with and without chronic shoulder pain and to evaluate the related test-retest reliability. Twenty-two symptomatic and twenty-two asymptomatic subjects participated in a cross-sectional study. The dynamic muscular stiffness of scapular muscles, at rest and during an isometric contraction, was measured bilaterally with myotonometry, in two moments. The differences in bilateral averaged values between symptomatic and asymptomatic subjects and the effect of the group (group presenting pain in the dominant or non-dominant side, and asymptomatic group) and of the limb (unilateral painful or asymptomatic limb, and bilateral asymptomatic limbs) were investigated. Test-retest intra-rater reliability was determined. An effect of the group was observed at rest, for middle trapezius stiffness, and during contraction, for middle and lower trapezius stiffness. For middle trapezius, increased values were observed in the group presenting pain in non-dominant side comparing to both groups or to group presenting pain in dominant side. The intraclass correlation coefficient, majorly, ranged between 0.775 and 0.989. Participants with pain in the non-dominant side presented an increased middle trapezius' stiffness. Globally, high reliability was observed for scapular muscles dynamic stiffness.

Objective Methods of Muscle Tone Diagnosis and Their Application-A Critical Review

"Muscle tone" is a clinically important and widely used term and palpation is a crucial skill for its diagnosis. However, the term is defined rather vaguely, and palpation is not measurable objectively. Therefore, several methods have been developed to measure muscle tone objectively, in terms of biomechanical properties of the muscle. This article aims to summarize these approaches. Through database searches, we identified those studies related to objective muscle tone measurement in vivo, in situ. Based on them, we described existing methods and devices and compared their reliability. Furthermore, we presented an extensive list of the use of these methods in different fields of research. Although it is believed by some authors that palpation cannot be replaced by a mechanical device, several methods have already proved their utility in muscle biomechanical property diagnosis. There appear to be two issues preventing wider usage of these objective methods in clinical practice. Firstly, a high variability of their reliability, and secondly, a lack of valid mathematical models that would provide the observed mechanical characteristics with a clear physical significance and allow the results to be compared with each other.

The Effect of Vibration Massage on Fatigue of the Upper Trapezius Muscle during Different Tasks

Background: Vibratory massage is now widely used to alleviate muscle fatigue. The effects of different vibration massage intensities on left and right upper trapezius (UT) fatigue have not been examined. Therefore, the present study first examined whether a vibration massage intervention had an effect on UT muscles and second compared the effects of 2 different levels (36 Hz and 46 Hz) of vibratory massage on the right and left oblique muscles under 3 different fatigue conditions. Methods: A total of 23 participants (12 female, 11 male; age: 26.5 ± 3.9 year, height: 170.5 ± 1.6 cm, mass: 57.5 ± 1.5 kg, BMI: 24.3 ± 1.6 kg/m2) were randomly divided into intervention and control groups. The 2 groups of subjects completed isometric contraction fatigue tasks of 30 s of fatigue, 60 s of fatigue and 90 s of fatigue in turn. The specific task of isotonic contraction was performed by subjects holding a 1 kg dumbbell in each hand and performing a straight arm weighted lateral supination exercise. After each exercise, the intervention group was randomized to apply a massage device with a vibration intensity of 36 Hz or 46 Hz on the left and right UT muscles for 5 min each. The control group did not receive any treatment. Both groups then repeated the same fatigue task as before. Then, the effects of different vibration massage interventions on UT muscles were derived by analyzing the changes in maximal voluntary contraction percentage (MVC%) of surface electromyography (sEMG) signals before and after the intervention, and the most effective vibration massage program for relieving left and right UT fatigue was summarized. Then, four classification algorithms were used to label and classify the collected sEMG data, and finally a UT muscle fatigue identification and vibration massage model was constructed. Results: After using the vibration massage level 1 (36 Hz) intervention, the MVC% of the right UT muscle showed significant reductions in the 30 s fatigue task, the 60 s fatigue task and the 90 s fatigue task (R1: p = 0.022, R2: p = 0.005, R3: p = 0.049). After using the vibration massage level 3 (46 Hz) intervention, the MVC% of the right UT muscle showed a significant decrease in both the 60 s fatigue task and the 90 s fatigue task (R2: p = 0.033, R3: p = 0.028). Significant decreases in MVC% for the left UT muscle were found only in the 90 s fatigue task (L3: p = 0.040). Then, by comparing the different performances of four commonly used classification algorithms, it was found that the bagging (accuracy = 0.860) algorithm had higher accuracy. Therefore, the bagging algorithm was used for the UT fatigue identification and vibration massage models. Conclusions: This was the first study to show the impacts of different levels of vibration massage on fatigue alleviation in the left and right UT muscles. Furthermore, the bilateral UT fatigue identification and vibration massage model developed in this study can help people to choose the most appropriate massage protocol for quick relief and relaxation of the UT muscles under three different fatigue tasks.

Scapular Dynamic Muscular Stiffness Assessed through Myotonometry: A Narrative Review

Several tools have been used to assess muscular stiffness. Myotonometry stands out as an accessible, handheld, and easy to use tool. The purpose of this review was to summarize the psychometric properties and methodological considerations of myotonometry and its applicability in assessing scapular muscles. Myotonometry seems to be a reliable method to assess several muscles stiffness, as trapezius. This method has been demonstrated fair to moderate correlation with passive stiffness measured by shear wave elastography for several muscles, as well as with level of muscle contraction, pinch and muscle strength, Action Research Arm Test score and muscle or subcutaneous thickness. Myotonometry can detect scapular muscles stiffness differences between pre- and post-intervention in painful conditions and, sometimes, between symptomatic and asymptomatic subjects.

Four weeks of exercise regimen for sedentary workers with rounded shoulder posture: a randomized controlled study

BACKGROUND

Rounded shoulder (RS) posture causes neck and shoulder pathologies. Mechanical correction taping (MCT) is often incorporated into postural corrective therapies; however, its effects on muscle stiffness are unclear.

OBJECTIVE

We investigated the effect of MCT with different tape fabrics, along with exercise, on upper trapezius and pectoralis minor muscle stiffness and the posture of sedentary workers.

DESIGN AND SETTING

A randomized controlled study was performed at Aydın Adnan Menderes University, Aydın, Turkey.

METHODS

The study included 39 workers with RS posture. Two intervention groups (performance tape: PT and classic tape: CT) were taped twice a week and administered a home exercise program for 4 weeks. The control (C) group performed only home exercises. RS was measured using an acromion-testing table (AT), stiffness using shear wave elastography ultrasound, and shoulder angle (SA) using a smartphone application at baseline and 4 weeks. Time and group interactions were determined using 3 × 2 mixed analysis of variance.

RESULTS

Intragroup analyses revealed a significant main effect of time on AT distance (η2 = 0.445) and SA (η2 = 0.325) in the PT and C groups (P < 0.05) and left upper trapezius stiffness (η2 = 0.287) in the CT and C groups (P < 0.05). In the post hoc analyses, no difference was noted between the groups from baseline to 4 weeks (P > 0.05).

CONCLUSION

Scapular MCT added to postural exercises did not show any difference between the intervention groups and controls in terms of muscle stiffness and posture in sedentary workers.

Neck Disability Index Is Better in Classification of Recovery after Whiplash Injury in Comparison with Ultrasound Shear Wave Elastography of Trapezius Muscle

A prospective observational study comparing shear wave elastography (SWE) of trapezius muscle with Neck Disability Index (NDI) in a prediction model of health status six months after a whiplash injury. Both SWE values, measured by two radiologists, and NDI scores were obtained at baseline and after physical therapy (PT) (6-month period). Those values were compared with a 3-point Likert scale (no, partial or full recovery). Twenty-two subjects completed the study. A decrease in trapezius stiffness was detected by both radiologists, statistically significant for one (Δ10.1 kPa; p = 0.04) but not for the second radiologist (Δ8.63 kPa; p = 0.07). The measurements showed excellent intra-observer (ICC 0.75–0.94) and inter-observer (ICC 0.78–0.88) reliability. After six months, fully recovered patients showed lower NDI scores than partially recovered patients (Δ22.98; p < 0.001). SWE values did not differ with the recovery status (55.6 ± 9.7 vs. 57 ± 15.8, Δ1.45; p = 0.82). The single most accurate variable in classifying health status six months after whiplash injury was the relative change of NDI, and it showed the highest accuracy (73.9%) and low Akaike information criterion (AIC = 39.2). Overall, the most accurate classification was obtained when combining NDI and SWE after physical therapy with an accuracy of 77.3% and a decrease in AIC (32.8).

Effects of body postures on the shear modulus of thoracolumbar fascia: a shear wave elastography study

This study is aimed to use shear wave elastography (SWE) to study the relationship between shear modulus and different body postures of the thoracolumbar fascia (TLF) and acquire physiologically meaningful information from the stiffness-posture graph to better quantify passive flexion responses. Seven passive postures were defined to evaluate the shear modulus of right side TLF at the third and fourth lumbar vertebra levels (L3 and L4) in twenty healthy male subjects. The TLF stiffness was significantly different among different postures (p < 0.001), and the TLF stiffness at L3 was always less than that at L4 (p < 0.001). As the forward tilt increased from 0 to 60°, the TLF stiffness increased in sitting and standing postures by 54.01% and 192.84%. In the neutral postures, the TLF stiffness in standing and sitting postures was 66.98% and 165.48% higher than that in rest posture. The above results show that the elastic properties of TLF play an important role in maintaining body static posture and that the forward tilt and sitting postures are likely to induce low back pain (LBP). In conclusion, this study provides preliminary in vivo data for the relationship between body postures and TLF stiffness.

Reliability of shear-wave elastography in assessing thoracolumbar fascia elasticity in healthy male

The objectives of this study were to examine the intra and inter-operator reliability of shear wave elastography (SWE) device in quantifying the shear modulus of thoracolumbar fascia (TLF) and the device’s abilities to examine the shear modulus of the TLF during upper body forward. Twenty healthy male subjects participated in this study (mean age: 18.4 ± 0.7 years). Two independent operators performed the shear modulus of TLF during upper body forward using SWE, and interclass correlation coefficient (ICC) and minimum detectable change (MDC) were calculated. The shear modulus of the TLF was quantified by operator A using SWE at upper body forward 60°. The intra-operator (ICC = 0.860–0.938) and inter-operator (ICC = 0.904–0.944) reliabilities for measuring the shear modulus of the TLF with the upper body forward 0° were rated as both excellent, and the MDC was 4.71 kPa. The TLF shear modulus of upper body forward 60°was increased 45.5% (L3) and 55.0% (L4) than that of upper body forward 0°. The results indicate that the SWE is a dependable tool to quantify the shear modulus of TLF and monitor its dynamic changes. Therefore, this device can be used for biomechanical study and intervention experiments of TLF.

The Rolf Method of Structural Integration on Fascial Tissue Stiffness, Elasticity, and Superficial Blood Perfusion in Healthy Individuals: The Prospective, Interventional Study

Introduction: There are multiple theories surrounding the physiological impact of structural integration (SI) with little evidence or research corroborating any of these. The aim of the study was to assess the effectiveness of 10 sessions of SI on fascial tissue (FT) superficial blood perfusion, stiffness, and elasticity in 13 healthy women.

Methods: This was a prospective, interventional study. The primary outcome measures were FTs’ superficial blood perfusion, stiffness, and elasticity of bilateral selected FT points on the body. Data were collected before and after 10 sessions of SI intervention. Statistical analysis was performed using the non-parametric Wilcoxon test (intragroup comparison).

Results: The superficial blood perfusion increased significantly in the most selected FT points on the body (p < 0.05). SI interventions produced significant decreases in selected points (brachioradialis, biceps brachii, and trapezius; p < 0.05) of FT stiffness and significant increases in elasticity (brachioradialis, biceps brachii, triceps surae, and trapezius; p < 0.05), especially in the FT of the right (dominant) upper limb.

Conclusion: A 10-session of SI demonstrated positive effects on increasing superficial blood perfusion contributed to a decrease in FT stiffness and an increase in elasticity properties in the dominant upper limb. Data collection for this study is currently underway, and the trial is registered at ISRCTN.com with the identifier: ISRCTN46707309.

Eccentric Exercise Reduces Upper Trapezius Muscle Stiffness Assessed by Shear Wave Elastography and Myotonometry

In this study, we tested the hypotheses that unaccustomed eccentric exercise (ECC) would reduce the elastic modulus and dynamic stiffness of the upper trapezius muscle and that these changes would correlate with increases in muscle thickness, reflecting muscle edema. Shear wave elastography was used to measure elastic modulus, dynamic stiffness was assessed using myotonometry, and muscle thickness was measured using ultrasonography. All measurements were performed at four locations over the upper trapezius before and 24 h after a single bout of ECC. Fourteen healthy participants (11 males and 3 females; 23.2 ± 3.0 years; height 175.1 ± 10.4 cm; body mass 73.8 ± 11.3 kg) took part in the study. Overall, ECC resulted in decreased elastic modulus (from 45.8 ± 1.6 to 39.4 ± 1.2 kPa, p < 0.01) and dynamic muscle stiffness (from 369.0 ± 7.3 to 302.6 ± 6.0 N/m, p < 0.01). Additionally, ECC resulted in increased muscle thickness (from 6.9 ± 0.4 to 7.3 ± 0.4 mm, p < 0.01). Spatial changes (across the four locations) were found for elastic modulus, stiffness and thickness. No significant correlations were found between changes in measures of muscle stiffness, or between changes in stiffness and changes in thickness. In conclusion, the present pilot study showed that ECC altered biomechanical muscle properties, reflected by decreased elastic modulus and dynamic muscle stiffness 24 h after ECC.