Ultrasonic characterization of the upper trapezius muscle in patients with chronic neck pain

Assessment of the Performance of Ultrasonography for Detecting Myofascial Trigger Points

Needle electromyogram (EMG) research has suggested that endplate noise (EPN) is a characteristic of myofascial trigger points (MTrPs). Although several studies have observed MTrPs through ultrasonography, whether they are hyperechoic or hypoechoic in ultrasound images is still controversial. Therefore, this study determined the echogenicity of MTrP ultrasonography. In stage 1, the MTrP of rat masseter muscle was identified through palpation and marked. Needle EMG was performed to detect the presence of EPN. When EPN was detected, ultrasound scans and indwelling needles were used to identify the nodule with a different grayscale relative to that of its surrounding tissue, and the echogenicity of the identified MTrP was determined. In stage 2, these steps were reversed. An ultrasound scan was performed to detect the nodule at the marked site, and an EMG needle was inserted into the nodule to detect EPN. There were 178 recordings in each stage, obtained from 45 rats. The stage 1 results indicate that the MTrPs in ultrasound images were hypoechoic with a 100% sensitivity of assessment. In stage 2, the accuracy and precision of MTrP detection through ultrasonography were 89.9% and 89.2%, respectively. The results indicate that ultrasonography produces highly accurate and precise MTrP detection results.

Identification of Myofascial Trigger Point Using the Combination of Texture Analysis in B-Mode Ultrasound with Machine Learning Classifiers

Myofascial pain syndrome is a chronic pain disorder characterized by myofascial trigger points (MTrPs). Quantitative ultrasound (US) techniques can be used to discriminate MTrPs from healthy muscle. In this study, 90 B-mode US images of upper trapezius muscles were collected from 63 participants (left and/or right side(s)). Four texture feature approaches (individually and a combination of them) were employed that focused on identifying spots, and edges were used to explore the discrimination between the three groups: active MTrPs (n = 30), latent MTrPs (n = 30), and healthy muscle (n = 30). Machine learning (ML) and one-way analysis of variance were used to investigate the discrimination ability of the different approaches. Statistically significant results were seen in almost all examined features for each texture feature approach, but, in contrast, ML techniques struggled to produce robust discrimination. The ML techniques showed that two texture features (i.e., correlation and mean) within the combination of texture features were most important in classifying the three groups. This discrepancy between traditional statistical analysis and ML techniques prompts the need for further investigation of texture-based approaches in US for the discrimination of MTrPs.

A model for personalized diagnostics for non-specific low back pain: the role of the myofascial unit

Low back pain (LBP) is the leading cause of disability worldwide. Most LBP is non-specific or idiopathic, which is defined as symptoms of unknown origin without a clear specific cause or pathology. Current guidelines for clinical evaluation are based on ruling out underlying serious medical conditions, but not on addressing underlying potential contributors to pain. Although efforts have been made to identify subgroups within this population based on response to treatment, a comprehensive framework to guide assessment is still lacking. In this paper, we propose a model for a personalized mechanism-based assessment based on the available evidence that seeks to identify the underlying pathologies that may initiate and perpetuate central sensitization associated with chronic non-specific low back pain (nsLBP). We propose that central sensitization can have downstream effects on the "myofascial unit", defined as an integrated anatomical and functional structure that includes muscle fibers, fascia (including endomysium, perimysium and epimysium) and its associated innervations (free nerve endings, muscle spindles), lymphatics, and blood vessels. The tissue-level abnormalities can be perpetuated through a vicious cycle of neurogenic inflammation, impaired fascial gliding, and interstitial inflammatory stasis that manifest as the clinical findings for nsLBP. We postulate that our proposed model offers biological plausibility for the complex spectrum of clinical findings, including tissue-level abnormalities, biomechanical dysfunction and postural asymmetry, ecological and psychosocial factors, associated with nsLBP. The model suggests a multi-domain evaluation that is personalized, feasible and helps rule out specific causes for back pain guiding clinically relevant management. It may also provide a roadmap for future research to elucidate mechanisms underlying this ubiquitous and complex problem.

Ultrasonographic Analysis of Trapezius Muscle for Efficient Botulinum Toxin Type A Injection

BACKGROUND

Patients nowadays seek medical reduction of the upper trapezius muscle to achieve aesthetic pleasing necklines. Botulinum toxin type A (BoNT-A), a neurotoxin that reduces the force of muscle contraction, is widely used for shoulder contouring. However, detailed metrical data are lacking to guide clinical injection.

METHODS

Forty healthy young women were enrolled. All subjects were seated for point marking and measuring of trapezius muscle (TM) anatomical data. At marked locations, the thickness of the subcutaneous tissue, the thickness of the TM, the TM's anterior border, and the depth from the skin surface to the middle of TM were measured using a real-time ultrasound scanner. In addition, photos were taken to assess the shoulder area proportion and shoulder angle.

RESULTS

The shoulder area size among participants was 90 ± 15.2 cm2, the average area proportion was 0.55 ± 0.1, and the shoulder angle was 23.12° ± 2.9°. Ultrasonography data reveal that the thickness of the subcutaneous tissue, the thickness of the TM, and the depth from the skin surface to the middle of TM all thickened from the anterior line to the posterior line (P < 0.001). The length of the TM extending forward was 1.47 ± 0.4 cm (range 0.51-1.31 cm). To better evaluate the appearance of the trapezius muscle, we constructed a grading system correlated to shoulder angle.

CONCLUSION

In this study, ultrasonography and photos were applied to assess the TM's anatomical features. Trapezius hypertrophy was described on a scale from 0 to 2 based on the shoulder angle. The findings of the present study provide a practical clinical guidance for precise and efficient BoNT-A administration.

LEVEL OF EVIDENCE IV

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Quantitative ultrasound to assess efficacy of treatment for neck somatic dysfunctions: a feasibility study

CONTEXT

Neck pain is a common complaint in healthcare clinics. Although the pathogenesis of neck pain is often multifactorial, trapezius muscle dysfunction has been commonly linked to neck pain. Osteopathic manipulative treatment (OMT) has been demonstrated to be an effective treatment modality in treating trapezius muscle dysfunction and neck pain. However, there is a current lack of objective, quantitative measures to assess the effectiveness of OMT. Through previous research, ultrasound technology has been shown to be promising in its ability to quantify tissue changes both pre- and post-OMT.

OBJECTIVES

The objectives of this study are to evaluate the feasibility of shear wave elastography (SWE) in assessing upper trapezius muscles with pain and hypertonicity, as well as the changes in these muscles post-OMT for cervical somatic dysfunctions.

METHODS

After obtaining approval from the Rocky Vista University Institutional Review Board and written informed consent from participants, SWE and osteopathic assessments were performed on 22 adult participants with and without cervical spine somatic dysfunction. Participants with positive osteopathic assessments of tissue texture, asymmetry, restricted motion, and/or tenderness (TART) were treated utilizing OMT. Shear wave velocity (SWV, m/s) and shear wave velocity rate [SWVR = (SWV contraction - SWV relaxation)/ SWV relaxation] of the upper trapezius muscles with and without pain and hypertonicity, and before and after OMT, were examined utilizing a two-tailed t-test.

RESULTS

SWV in muscle contraction and SWVR were significantly lower in muscles with pain compared to muscles without pain (p≤0.01). SWV in muscle contraction was also significantly lower in hypertonic muscles compared to normotonic muscles (p<0.01). Following OMT, SWV in muscle contraction and SWVR in muscles with pain and hypertonic increased significantly (p≤0.01). Overall TART score of all muscles with somatic dysfunction (SD) after OMT significantly decreased (p<0.01). SWV in muscle contraction and SWVR in hypertonic muscles were also significantly increased (p≤0.03), with an improvement index of 0.11 and 0.20.

CONCLUSIONS

This study's results demonstrate the feasibility of utilizing SWE to evaluate somatic dysfunctions of the upper trapezius musculature and the efficacy of OMT for neck somatic dysfunctions.

The importance of myofascial trigger points in chronic neck pain: An ultrasonography preliminary study

BACKGROUND

Ultrasonographic evaluation of trigger points detected by physical examination in patients with myofascial pain syndrome is being used more frequently in clinical care. However, the sonographic appearance of trigger points, in association with pain and disability, has not been adequately described.

OBJECTIVE

To reveal the presence of trigger points with ultrasonography in those with myofascial pain syndrome and to determine if ultrasound images can help discriminate between demographic and disease characteristics.

METHODS

Fifty-two participants with chronic neck pain (NP) were in this cross-sectional study. The pain intensity was evaluated using a 0-10 cm visual analog scale (VAS). The neck disability index measured the NP-induced disability status of the participants. Ultrasonography was used to measure the thicknesses of the paraspinal muscles and the presence of hypoechoic areas within these muscles.

RESULTS

There was a positive correlation between the VAS scores of the participants and the ultrasonographic detection of myofascial trigger points (MTPs) in the multifidus and middle trapezius muscles (right/left r = .30, p = .027; r = .29, p = .029; r = .32, p = .009, r = .30, p = .011, respectively). These features correlated with the disability levels of the participants and the MTPs on both the right and left sides of the splenius, multifidus, upper trapezius, and middle trapezius (r = .32, p = .028; r = .38, p = .013, r = .25, p = .027; r = .33, p = .016; r = .25, p = .025, r = .32, p = .018, r = .28, p = .013, r = .29, p = .016, respectively). A significant correlation was present between the detection of MTP at ultrasonography and decreased muscle thickness in the relevant muscles (between p = .001 and p = .034).

CONCLUSION

The detection of MTPs with ultrasonography is associated with the severity of pain and disability in those with chronic NP. Features on ultrasound include hypoechoic changes within muscle and reduced muscle thickness associated with MTPs.

From Histoanatomy to Sonography in Myofascial Pain Syndrome: A EURO-MUSCULUS/USPRM Approach

ABSTRACT

Myofascial pain is a common clinical condition, whereby accurate physical examination is usually considered as the cornerstone to identify/diagnose the "trigger point complex," that is, the characteristic finding of this syndrome. Considering the emerging role of ultrasound examination as the natural extension of physical assessment for musculoskeletal disorders, we briefly revise the histological/anatomical features of trigger points and propose a standardized, multistep sonographic approach to myofascial pain. We also imply that the integrated clinical-ultrasound evaluation could be considered as a potential tool to discriminate different phases/subsets of this challenging pathology.

Demonstration of kinesio taping effect by ultrasonography in neck pain

OBJECTIVE

This study aimed to demonstrate the effectiveness of kinesio taping in nonspecific neck pain and to assess whether ultrasonographic parameters of the upper trapezius muscle can be used in the follow-up of kinesio taping treatment.

METHODS

This was a single-blind, prospective, randomized controlled trial study involving 60 participants with nonspecific neck pain. The participants were randomly assigned into two groups. Kinesio taping group (n=29) received a 4-week neck exercise program, with kinesio taping applied twice a week for a total of four times, and the exercise group (n=28) received a 4-week neck exercise program. Participants were evaluated according to pain intensity (Visual Analog Scale), cervical range of motion, and disability (Neck Disability Index). Also, trigger point diameter and upper trapezius muscle thickness were evaluated with ultrasonography. Before and after the therapy, as well as the first month, all measures were taken by an investigator other than the practitioner of the treatment program.

RESULTS

The results showed that the Visual Analog Scale and Neck Disability Index scores in the kinesio taping group were statistically significantly improved when compared to the exercise group (p<0.05). In addition, the thickness of the upper trapezius muscle and the diameter of the trapezius muscle trigger point were statistically significantly improved in the kinesio taping group compared to the exercise group (p<0.05). In the kinesio taping group, there was no statistical significance in cervical range of motion as compared to the exercise group.

CONCLUSION

The combination of kinesio taping and exercise therapy was effective in reducing nonspecific neck pain and neck disability. Also, this study showed that ultrasonographic evaluation of the trapezius muscle could be used in the follow-up of kinesio taping therapy.

Diagnostic Applications of Ultrasonography in Myofascial Trigger Points: A Scoping Review and Critical Appraisal of Literature

Objective:

Myofascial trigger points (MTrPs) are pathognomonic of myofascial pain syndrome. The detection ability of MTrPs via ultrasonography is underreported and the characteristics of MTrPs are not sufficiently standardized. The objective was to summarize the characteristics and diagnostic abilities of ultrasonography for MTrP investigations.

Materials and Methods:

A multi-database, and bibliography hand-search was implemented. Studies of ≥10 patients, published after 1980, appraising ultrasonography as a diagnostic aid for myofascial pain syndrome were included. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool was used to evaluate the diagnostic accuracy of the included studies.

Results:

Six cross-sectional studies met the inclusion criteria. The back and trapezius muscles were the most studied locations. The diagnostic studies were of low-medium risk of bias. The studies reported a large range of diagnostic metrics (accuracy 58%–100%, sensitivity 33%–91%, specificity 75%–100%, positive predictive value 91%–100%, negative predictive value 47%–97%, positive likelihood ratio 3.6, and negative likelihood ratio 0.12–0.67).

Conclusion:

This review found low-medium risk of bias evidence in support of ultrasonography for MTrP investigations. The clinical studies identified in the scoping review used gray-scale ultrasound equipment systems with a 5 to 14 MHz transducer to diagnose MTrPs and the local twitch response, and MTrPs were visualized mostly as hypoechoic nodules.

Myofascial pain in temporomandibular disorders: Updates on etiopathogenesis and management

OBJECTIVES

Temporomandibular disorders (TMDs) are an umbrella term encompassing disorders of both the temporomandibular joint (TMJD) and masticatory musculature (MMD). The objective of this review is to provide an overview of the etiopathogenesis, clinical features and diagnosis of MMD, and to summarize the current trends in the therapeutic management.

METHODS

A review of the literature was performed from 1985 to 2020. The keywords included were "temporomandibular disorders OR temporomandibular joint disorders" AND "myofascial pain OR masticatory myofascial pain OR trigger point". A total of 983 articles were screened with abstracts and approximately 500 full text articles were included in the review based on their relevance to the topic.

RESULTS

MMD's present significant challenges in diagnosis and treatment. Effective treatment requires a clear diagnosis based on an understanding of pathophysiologic mechanisms, a detailed history with assessment of predisposing local and systemic factors, perpetuating factors, a comprehensive clinical evaluation and a diagnostic workup.

CONCLUSION

A thorough history and clinical examination are the gold standards for diagnosis of MMD. Serological testing may help identify underlying co-morbidities. Recent diagnostic modalities including ultrasound sonoelastography and magnetic resonance elastography (MRE) have shown promising results. The treatment goals for MMD are to control pain, restore mandibular function and facilitate the return to normal daily activity and improve the overall quality of life of a patient. Conservative modalities including home care regimens, pharmacotherapy, intraoral appliance therapy, local anesthetic trigger point injections, physiotherapy and complementary modalities may be beneficial in patients with MMD's.

Quantitative Ultrasound Texture Feature Changes With Conservative Treatment of the Trapezius Muscle in Female Patients With Myofascial Pain Syndrome

OBJECTIVE

We set out to assess whether quantitative ultrasound could be used to assess changes that occur after physical therapy in patients experiencing myofascial pain syndrome.

METHODS

We consecutively recruited female subjects experiencing myofascial pain syndrome of the neck and shoulder region and provided 10 sessions of conservative physical therapy. A control group was recruited for textural analyses. We measured change in pain ratings, range of motion, and ultrasound texture features before and after the intervention and after 3 mos.

RESULTS

We recruited 63 female myofascial pain syndrome subjects and 20 healthy controls. After treatment, the mean blob size (an ultrasound texture feature) value for each subject decreased from 30.84 ± 5.00 to 25.86 ± 5.67 on the right and decreased from 31.70 ± 5.51 to 28.08 ± 5.53 on the left (P < 0.0005). The blob count showed a significant increase only on the left side (P < 0.01). Corresponding to this were reductions in pain and disability scores after treatment and at 3 mos compared with retreatment (P < 0.0005 for all checkpoints). Cervical range of motion values were significantly increased only at 3 mos compared with pretreatment except for mean flexion range of motion.

CONCLUSIONS

Ultrasound texture feature of blob size and count changes correspond to routine clinical outcomes after conservative physical therapy of myofascial pain syndrome in female individuals.

Assessment of Myofascial Trigger Points via Imaging: A Systematic Review

ABSTRACT

This study systematically reviewed the published literature on the objective characterization of myofascial pain syndrome and myofascial trigger points using imaging methods. PubMed, Embase, Ovid, and the Cochrane Library databases were used, whereas citation searching was conducted in Scopus. Citations were restricted to those published in English and in peer-reviewed journals between 2000 and 2021. Of 1762 abstracts screened, 69 articles underwent full-text review, and 33 were included. Imaging data assessing myofascial trigger points or myofascial pain syndrome were extracted, and important qualitative and quantitative information on general study methodologies, study populations, sample sizes, and myofascial trigger point/myofascial pain syndrome evaluation were tabulated. Methodological quality of eligible studies was assessed based on the Quality Assessment of Diagnostic Accuracy Studies criteria. Biomechanical properties and blood flow of active and latent myofascial trigger points assessed via imaging were found to be quantifiably distinct from those of healthy tissue. Although these studies show promise, more studies are needed. Future studies should focus on assessing diagnostic test accuracy and testing the reproducibility of results to establish the best performing methods. Increasing methodological consistency would further motivate implementing imaging methods in larger clinical studies. Considering the evidence on efficacy, cost, ease of use and time constraints, ultrasound-based methods are currently the imaging modalities of choice for myofascial pain syndrome/myofascial trigger point assessment.

Re-Examining Myofascial Pain Syndrome: Toward Biomarker Development and Mechanism-Based Diagnostic Criteria

PURPOSE OF REVIEW

We discuss the need for a mechanism-based diagnostic framework with a focus on the development of objective measures (e.g., biomarkers) that can potentially be added to the diagnostic criteria of the syndrome. Potential biomarkers are discussed in relation to current knowledge on the pathophysiology of myofascial pain syndrome (MPS), including alterations in redox status, inflammation, and the myofascial trigger point (MTrP) biochemical milieu, as well as imaging and neurophysiological outcomes. Finally, we discuss the long-term goal of conducting a Delphi survey, to assess the influence of putative MPS biomarkers on clinician opinion, in order to ultimately develop new criteria for the diagnosis of MPS.

RECENT FINDINGS

Myofascial pain syndrome (MPS) is a prevalent healthcare condition associated with muscle weakness, impaired mood, and reduced quality of life. MPS is characterized by the presence of myofascial trigger points (MTrPs): stiff and discrete nodules located within taut bands of skeletal muscle that are painful upon palpation. However, physical examination of MTrPs often yields inconsistent results, and there is no gold standard by which to diagnose MPS. The current MPS diagnostic paradigm has an inherent subjectivity and the absence of correlation with the underlying pathophysiology. Recent advancements in ultrasound imaging, systemic biomarkers, MTrP-specific biomarkers, and the assessment of dysfunction in the somatosensorial system may all contribute to improved diagnostic effectiveness of MPS.

Quantitative Shear Wave Speed Assessment for Muscles with the Diagnosis of Taut Bands and/or Myofascial Trigger Points Using Probe Oscillation Shear Wave Elastography: A Pilot Study

OBJECTIVE

To use probe oscillation shear wave elastography (PROSE) with two vibration sources to generate two shear waves in the imaging plane to quantitatively assess the shear wave speeds (SWSs) of muscles with and without the diagnosis of taut bands (TB) and/or myofascial trigger points (MTrPs).

METHODS

Thirty-three patients were scanned with the PROSE technique. Shear waves were generated through continuous vibration of the ultrasound probe, while the shear wave motions were detected using the same probe. SWSs for the sides with and without TBs and/or MTrPs were computed and compared. The pressure pain thresholds (PPTs) were measured as an indicator of maximum pain tolerance of patients. The statistical differences between the SWSs with and without TBs and/or MTrPs with different PPT values were analyzed using the nonparametric Wilcoxon rank-sum test.

RESULTS

The mean SWSs for the sides with TBs and/or MTrPs are faster than that of the contralateral side without TBs and/or MTrPs. A significant difference was observed between mean SWSs with and without TBs and/or MTrPs without any information of PPT, with rank-sum test P <  .005. Additionally, with the information of PPT, a significant difference was observed between mean SWSs for the sides with and without TBs and/or MTrPs, for PPT values between 0 and 50 N/cm² (P <  .005), but for PPT values between 50 and 90 N/cm² , it was difficult to differentiate mean SWSs with and without TBs and/or MTrPs.

CONCLUSION

Our preliminary results show that SWSs measured from patients had a significant difference between the mean SWSs with and without TBs and/or MTrPs.

Using Bidimensional Multiscale Entropy Analysis of Ultrasound Images to Assess the Effect of Various Walking Intensities on Plantar Soft Tissues

Walking performance is usually assessed by linear analysis of walking outcome measures. However, human movements consist of both linear and nonlinear complexity components. The purpose of this study was to use bidimensional multiscale entropy analysis of ultrasound images to evaluate the effects of various walking intensities on plantar soft tissues. Twelve participants were recruited to perform six walking protocols, consisting of three speeds (slow at 1.8 mph, moderate at 3.6 mph, and fast at 5.4 mph) for two durations (10 and 20 min). A B-mode ultrasound was used to assess plantar soft tissues before and after six walking protocols. Bidimensional multiscale entropy (MSE_2D) and the Complexity Index (CI) were used to quantify the changes in irregularity of the ultrasound images of the plantar soft tissues. The results showed that the CI of ultrasound images after 20 min walking increased when compared to before walking (CI₄: 0.39 vs. 0.35; CI₅: 0.48 vs. 0.43, p < 0.05). When comparing 20 and 10 min walking protocols at 3.6 mph, the CI was higher after 20 min walking than after 10 min walking (CI₄: 0.39 vs. 0.36, p < 0.05; and CI₅: 0.48 vs. 0.44, p < 0.05). This is the first study to use bidimensional multiscale entropy analysis of ultrasound images to assess plantar soft tissues after various walking intensities.

A sonographic comparison of the effect of dry needling and ischemic compression on the active trigger point of the sternocleidomastoid muscle associated with cervicogenic headache: A randomized trial

BACKGROUND

Cervicogenic headache (CeH) is among the common types of headache which has an undesirable influence on the quality of life. The myofascial trigger point (MTrP) within the sternocleidomastoid (SCM) muscle is one of the most important causes of CeH.

OBJECTIVE

The purpose of this study was to compare the effect of dry needling (DN) and ischemic compression (IC) on the headache symptoms as well as MTrP-related features in subjects with CeH originating from MTrPs of the SCM muscle using a sonographic method.

METHODS

A total of 29 female subjects aged 35.34 ± 12.19 on average with a clinical diagnosis of CeH originating from MTrP in the SCM muscle were randomly divided into the DN, IC, and control groups. Both DN and IC groups received 4 treatment sessions. Headache intensity, duration, frequency, MTrP elastic modulus, MTrP area, and pressure pain threshold (PPT) were assessed 2 weeks before and after treatments.

RESULTS

In both DN and IC groups, a significant improvement was found in the headache intensity, duration, frequency, PPT, and MTrP area (P< 0.05). No significant differences were observed between DN and IC (P> 0.05). Pearson correlation revealed a significant correlation between headache intensity and the MTrP elastic modulus (P< 0.05).

CONCLUSIONS

Both interventions could reduce headache symptoms, PPT, and MTrP area. Neither intervention was found to be superior to the other in short-term follow-up. IC may be preferred since it has fewer unwanted side effects compared to DN. Based on the data, it may be concluded that some MTrP biomechanical features such as stiffness may influence the produced headache symptoms.

Quantitative Ultrasound Texture Analysis to Assess the Spastic Muscles in Stroke Patients

This study aimed to investigate the feasibility of sonoelastography for determining echotexture in post-stroke patients. Moreover, the relationships of muscle echotexture features, muscle stiffness, and functional performance in spastic muscle were explored. The study population comprised 22 males with stroke. The echotexture features (entropy and energy) of the biceps brachii muscles (BBM) in both arms were extracted by local binary pattern (LBP) from ultrasound images, whereas the stiffness of BBM was assessed by shear wave velocity (SWV) in the transverse and longitudinal planes. The Fugl–Meyer assessment (FMA) was used to assess the functional performance of the upper arm. The results showed that echotexture was more inhomogeneous in the paretic BBM than in the non-paretic BBM. SWV was significantly faster in paretic BBM than in non-paretic BBM. Both echotexture features were significantly correlated with SWV in the longitudinal plane. The feature of energy was significantly negatively correlated with FMA in the longitudinal plane and was significantly positively correlated with the duration from stroke onset in the transverse plane. The echotexture extracted by LBP may be a promising approach for quantitative assessment of the spastic BBM in post-stroke patients.

Ultrasound-guided interventional procedures for myofascial trigger points: a systematic review

Myofascial pain syndrome (MPS) is characterized by the presence of clinically detected myofascial trigger points (MTrPs). Diagnostic ultrasound (US) has been proposed as a method to strengthen the reliability of MTrP localization, thus potentially improving the efficacy and safety profile of interventional procedures. The objective is to evaluate the benefit and safety profile of any US-guided interventional procedure for MPS. Medline, Embase, PubMed, the Allied and Complementary Medicine Database (AMED), and Web of Science were systematically searched from their inception to May 2020 for any randomized controlled trial that evaluated treatment benefit and safety of any US-guided interventional procedure for MPS. The primary outcome of interest was pain severity. Additional outcomes of interest were function and adverse effects. The risk of bias was assessed using the Risk of Bias V.2.0 tool. eleven studies met all inclusion and exclusion criteria. Two studies (n=174) with a high risk of bias revealed some evidence supporting US guidance over blinded interventions for improvement in pain and function. Eight studies (n=483) with varying risks of bias were of head-to-head comparisons of different US modalities. These studies revealed that US-guided local anesthetic injections were inferior to US-guided pulse radiofrequency and US-guided dry needling (DN). US-guided DN was also found to be superior to US-guided platelet-rich-plasma injections but inferior to US-guided miniscalpel. Meanwhile, one study (n=21) with some concerns of bias found that US-guided local anesthetic injections were superior to non-steroidal anti-inflammatory drugs for pain outcomes and fewer adverse events. All US-guided procedures resulted in zero or minimal self-limited adverse events. Issues with clinical relevance, limited sample sizes, and small point estimates warrant more high-quality research to better characterize the possible value of US-guided injections.

Skeletal Muscle Fatigue State Evaluation with Ultrasound Image Entropy

Muscle fatigue often occurs over a long period of exercise, and it can increase the risk of muscle injury. Evaluating the state of muscle fatigue can avoid unnecessary overtraining and injury of the muscle. Ultrasound imaging can non-invasively visualize muscle tissue in real-time. Image entropy is commonly used to characterize the texture of an image. In this study, we evaluated changes in the ultrasound image entropy (USIE) during the fatigue process. Twelve volunteers performed static sustained contractions of biceps brachii at four different intensities (20%, 30%, 40%, and 50% of maximal voluntary contraction torque). The ultrasound images and surface electromyography (sEMG) signals were acquired during exercise to fatigue. We found that (1) the root-mean-square of the sEMG signal increased, the USIE decreased significantly with time during the sustained contractions; (2) the maximum endurance time (MET) and the decline percentage of USIE were significantly different (p < .05) among the four contraction intensities; (3) the decline slope of USIE of the same volunteer was basically the same at different contraction intensities. The USIE could be a new method for the evaluation of skeletal muscle fatigue state.

Eccentric Training Changes the Pressure Pain and Stiffness Maps of the Upper Trapezius in Females with Chronic Neck-Shoulder Pain: A Preliminary Study

OBJECTIVE

Between 50% and 67% of adults suffer from neck-shoulder pain, which may be associated with increased stiffness of neck muscles. We assessed pressure pain sensitivity and muscle stiffness maps of the upper trapezius in female computer users with and without chronic neck-shoulder pain and investigated the effects of eccentric training on females with neck-shoulder pain.

DESIGN

Cross-sectional (part 1) and open-label (part 2) study.

SETTING

University.

SUBJECTS

Twenty females with neck-shoulder pain were compared with 20 controls (part 1). In part 2, neck-shoulder pain participants followed a five-week unilateral upper trapezius eccentric training program.

METHODS

Topographical maps of pressure pain thresholds (pressure algometer) and muscle stiffness (myotonometer), using a 15-point grid covering myotendinous and muscle belly sites, and shoulder elevation force and range of elevation (dynamometer) were assessed at baseline and after training.

RESULTS

There were no differences in pressure pain thresholds between sites (P = 0.243) or groups (P = 0.068), and there were significant differences in stiffness between myotendinous and muscle belly sites (P < 0.001) but not groups (P = 0.273). After training, pressure pain thresholds increased, stiffness decreased (P < 0.005), and shoulder elevation force and range of elevation improved (P < 0.001).

CONCLUSIONS

The lack of differences in upper trapezius pressure pain sensitivity and stiffness between females with or without neck-shoulder pain confirms no clear etiology among computer users reporting neck-shoulder pain. A five-week eccentric training protocol showed positive effects on pressure pain sensitivity, stiffness, shoulder force, and range of motion.

Effect of Neighbourhood Size in Entropy Mapping of Ultrasound Images

Image filtering is a technique that can create additional visual representations of the original image. Entropy filtering is a specific application that can be used to highlight randomness of pixel grayscale intensities within an image. These image map created from filtering are based on the number of surrounding neighbourhood of pixels considered. However, there is no standard procedure for determining the correct "neighbourhood size" to use. We investigated the effects of neighbourhood size on the entropy calculation and provide a standardized approach for determining an appropriate neighbourhood size in entropy filtering in a musculoskeletal application. Ten healthy subjects showing no symptoms related to neuromuscular disease were recruited and ultrasound images of their trapezius muscle were acquired. The muscle regions in the images were manually isolated and regions of interest with varying neighbourhood sizes (increasing by 2 pixels) from 3x3 to 61X61 pixels were extracted. The entropy, relative signal entropy over noise entropy, statistical effect size as well as the percentage change of the effect size and instantaneous slope of the effect size was examined. The analysis showed that a neighbourhood size within the range of 21-25 pixels provides the maximum amount of information gained and coincides with a percentage change of the effect size of less than 5% and instantaneous slopes < 0.05.

[Efficacy of dry needling in neck pain compared with other physiotherapy techniques: A systematic review]

OBJECTIVE

To determine the efficacy of dry needling (DN) in the treatment of myofascial trigger points (MTrP) compared to other methods of physical therapy in the treatment of neck pain.

METHOD

A systematic search was carried out in the MEDLINE Complete (EBSCO), Pubmed, PEDro and Scopus databases. The quality of the studies was assessed using the standard of biases of the Cochrane Collaboration.

RESULTS

Eleven articles met the eligibility criteria. The characteristics of the participants and the results of the comparison of the application of DN with ultrasound, TENS, manual therapy techniques (passive stretching, strain-counterstrain, ischaemic pressure) and kinesiotape bandage are described.

CONCLUSION

DN was a useful technique in reducing neck pain. However, its efficacy in the treatment of cervicalgia could not be determined in comparison with other physiotherapy approaches.

Feasibility of a Support Vector Machine Classifier for Myofascial Pain Syndrome: Diagnostic Case-Control Study

OBJECTIVES

Myofascial pain syndrome (MPS) is the most common cause of chronic pain worldwide. The diagnosis of MPS is subjective, which has created a need for a robust quantitative method of diagnosing MPS. We propose that using a support vector machine (SVM) along with ultrasound (US) texture features can differentiate between healthy and MPS-affected skeletal muscle.

METHODS

B-mode US video data were collected in the upper trapezius muscle of healthy (29) participants and patients with active (21) and latent (19) MPS, using an acquisition method outlined in previous works. Regions of interest were extracted and filtered to obtain a unique set of 917 images where texture features were extracted from each region of interest to characterize each image. These texture features were then used to train 4 separate binary SVM classifiers using nested cross-validation to implement feature selection and hyperparameter tuning. The performance of each kernel was estimated on the data and validated through testing on a final holdout set.

RESULTS

The radial basis function kernel classifier had the greatest Matthews correlation coefficient performance estimate of 0.627 ± 0.073 (mean ± SD) along with the largest area under the curve of 91.0% ± 3.0%. The final holdout test for the radial basis function classifier resulted in 86.96 accuracy, a Matthews correlation coefficient of 0.724, 88% sensitivity, and 86% specificity, validating our earlier performance estimates.

CONCLUSIONS

We have demonstrated that specific US texture features that have been used in other computer-aided diagnostic literature are feasible to use for the classification of healthy and MPS muscle using a binary SVM classifier.

Influence of Forward Head Posture on Myotonometric Measurements of Superficial Neck Muscle Tone, Elasticity, and Stiffness in Asymptomatic Individuals With Sedentary Jobs

OBJECTIVE

The objective of the study was to assess the influence of forward head posture on the mechanical parameters and pressure pain threshold of superficial neck muscles in clinically nonsymptomatic individuals with sedentary jobs.

METHODS

Twenty-five office workers with forward head posture and 25 office workers with normal head posture were matched for sex, age, body mass index, and the nature and duration of their work and were compared at a single point. The study participants were divided into study groups on the basis of photometric craniovertebral angle measurements. The upper trapezius, sternocleidomastoid, and splenius capitis mechanical properties were assessed in the sitting position. Primary outcome measures were muscle stiffness (N/m), muscle tone (Hz), and muscle elasticity. The secondary variable was perceived pain threshold.

RESULTS

No significant differences between the groups were found for biomechanical properties and perceived pain threshold in the studied muscles.

CONCLUSION

Forward head posture has no impact on muscle stiffness, tone, and elasticity, nor does it increase the pressure sensitivity of superficial neck muscles in healthy, mildly symptomatic office workers. It is most likely that not incorrect posture of the cervical spine, but probably other factors combined with forward head posture, like comorbid acute and chronic cervical pain and musculoskeletal disorders or prolonged sitting, contribute to changes in active myofascial tone and tensegrity as well as increased pressure sensitivity of neck muscles.

Effect of aerobic exercise in the treatment of myofascial pain: a systematic review

Myofascial pain is prevalent chronic pain disorder that is comorbid with many conditions. Strengthening and stretching exercises are capable of inducing hypoalgesic effects in people with myofascial pain syndrome. The goal of this systematic review was to summarize the effects of aerobic exercise on the management of myofascial pain. A comprehensive database search was conducted. A total of 1,331 articles were identified for review. One article was eligible for inclusion after full screening. Risk of bias was assessed using the Downs and Black quality assessment questionnaire (1998). Mean difference scores were calculated for continuous variables. The identified study had a low risk of bias. It was a randomized controlled trial assessing the influence of an 8-week water aerobic exercise program on myofascial pain in breast cancer patients. Visual analogue scale pain intensity ratings and the number of myofascial trigger points present in the neck and shoulder/axillary area of participants significantly decreased in the exercise group compared to those in the control group. Pain pressure thresholds significantly increased in muscle areas of the cervical spine in the water exercise group. Aerobic exercise presents a potential treatment modality for managing myofascial pain. Additional research is necessary.

Quantitative ultrasound of trapezius muscle involvement in myofascial pain: comparison of clinical and healthy population using texture analysis

PURPOSE

Ultrasound is a non-invasive quantitative method to characterize sonographic textures of skeletal muscles. To date, there is no information available on the trapezius muscle. This study assessed the trapezius muscles of patients with myofascial pain compared with normal healthy participants.

METHODS

The trapezius muscles of 15 healthy and 17 myofascial pain participants were assessed using B-mode ultrasound to obtain 120 images for healthy and 162 images from myofascial pain participants. Texture features such as blob area, count and local binary patterns (LBP) were calculated. Multi-feature classification and analysis were performed using principal component analysis (PCA) and MANOVA to determine whether there were statistical differences.

RESULTS

We demonstrate the two principal components composed of a combination of LBP and blob parameters which explain 92.55% of the cumulative variance of our data set. In addition, blob characteristics were significantly different between healthy and myofascial pain participants.

CONCLUSION

Our study provides evidence that texture analysis techniques can differentiate between healthy and myofascial pain affected trapezius muscles. Further research is necessary to evaluate the nature of these differences.

Experimental myofascial trigger point creation in rodents

Myofascial pain syndrome is one of the most common forms of muscle pain. In this syndrome, pain is originated by the so-called trigger points, which consists of a set of palpable contraction knots in the muscle. It has been proposed that a high, spontaneous neurotransmission may be involved in the generation of these contraction knots. To confirm this hypothesis, we exposed mouse muscles to an anticholinesterasic agent to increase the neurotransmision in the synaptic cleft in two different conditions, in vivo and ex vivo experiments. Using intracellular recordings, a sharp increase in the spontaneous neurotransmission in the levator auris longus muscle and a lower increase in the diaphragm muscle could be seen. Likewise, electromyography recordings reveal an elevated endplate noise in gastrocnemius muscle of treated animals. These changes are associated with structural changes such as abundant neuromuscular contracted zones observed by rhodaminated α-bungarotoxin and the presence of abundant glycosaminoglycans around the contraction knots, as shown by Alcian PAS staining. In a second set of experiments, we aimed at demonstrating that the increases in the neurotransmission reproduced most of the clinical signs associated to a trigger point. We exposed rats to the anticholinesterase agent neostigmine, and 30 min afterward we observed the presence of palpable taut bands, the echocardiographic presence of contraction knots, and local twitch responses upon needle stimulation. In summary, we demonstrated that increased neurotransmission induced trigger points in both rats and mice, as evidenced by glycosaminoglycans around the contraction zones as a novel hallmark of this pathology. NEW & NOTEWORTHY In rodents, when neostigmine was injected subcutaneously, the neuromuscular neurotransmission increased, and several changes can be observed: an elevated endplate noise compared with normal endplate noise, as evidenced by electromyographyc recording; many muscular fibers with contraction knots (narrower sarcomeres and locally thickened muscle fiber) surrounded by infiltration of connective tissue like glycosaminoglycans molecules; and palpable taut bands and local twitch responses upon needle stimulation. Several of these signs are also observed in humans with muscle pain.

Quantification of Muscle Tissue Properties by Modeling the Statistics of Ultrasound Image Intensities Using a Mixture of Gamma Distributions in Children With and Without Cerebral Palsy

OBJECTIVES

To investigate whether quantitative ultrasound (US) imaging, based on the envelope statistics of the backscattered US signal, can describe muscle properties in typically developing children and those with cerebral palsy (CP).

METHODS

Radiofrequency US data were acquired from the rectus femoris muscle of children with CP (n = 22) and an age-matched cohort without CP (n = 14) at rest and during maximal voluntary isometric contraction. A mixture of gamma distributions was used to model the histogram of the echo intensities within a region of interest in the muscle.

RESULTS

Muscle in CP had a heterogeneous echo texture that was significantly different from that in healthy controls (P < .001), with larger deviations from Rayleigh scattering. A mixture of 2 gamma distributions showed an excellent fit to the US intensity, and the shape and rate parameters were significantly different between CP and control groups (P < .05). The rate parameters for both the single gamma distribution and mixture of gamma distributions were significantly higher for contracted muscles compared to resting muscles, but there was no significant interaction between these factors (CP and muscle contraction) for a mixed-model analysis of variance.

CONCLUSIONS

Ultrasound tissue characterization indicates a more disorganized architecture and increased echogenicity in muscles in CP, consistent with previously documented increases in fibrous infiltration and connective tissue changes in this population. Our results indicate that quantitative US can be used to objectively differentiate muscle architecture and tissue properties.

Electrical impedance of the torso is associated with the pressure pain threshold on myofascial trigger points in patients with chronic neck pain: A cross-sectional study

BACKGROUND

Myofascial trigger points are dysfunctional structures present in skeletal muscles and are related to sensory, motor, and autonomic changes. Despite scientific advances in recent decades in the measurement of musculoskeletal pain, evaluation of this clinical phenomenon is supported with instruments that, although valid and reliable, have a considerable degree of subjectivity.

OBJECTIVE

To correlate electrical impedance of the upper limbs and torso with pain intensity, functional capacity, catastrophizing, pressure pain threshold, and skin temperature on myofascial trigger points in the upper trapezius muscle of patients with neck pain.

METHODS

A single-blind cross-sectional study. Twenty-eight volunteers of both genders were included in the study, were aged 18-45 years, and had chronic neck pain and myofascial trigger points in the upper trapezius. The volunteers were assessed using the Numeric Rating Scale, the Neck Disability Index, the Pain-Related Self-Statement Scale, algometry, infrared thermography, and electrical bioimpedance.

RESULTS

The following significant results were observed: a negative association between the pressure pain threshold on myofascial trigger point in the right upper trapezius and electrical impedance of the torso at 5 kHz (rs=-0.392, p= 0.032), 50 kHz (rs=-0.406, p= 0.026), 250 kHz (rs=-0.388, p= 0.034), and to the frequency 500 kHz (rs=-0.444, p= 0.014).

CONCLUSION

Electrical impedance of the torso is associated with the pressure pain threshold of myofascial trigger points on the upper trapezius of individuals with neck pain. Thus, individuals with a lower pressure pain threshold have higher electrical impedance values of the torso and vice versa.

Accessory nerve distribution for aesthetic botulinum toxin injections into the upper trapezius muscle: anatomical study and clinical trial : Reproducible BoNT injection sites for upper trapezius

PURPOSE

The descending part of the trapezius muscle is clinically associated with neck pain and aesthetic applications. The innervation of the trapezius muscle is not well described in the medical literature for clinicians. The aim of study was to analyze the perforating branch pattern of the accessory nerve in the descending part of the trapezius muscle with the aim of describing the most efficient and reproducible BoNT injection sites for aesthetic treatment of shoulder contouring.

METHODS

Twenty-six specimens (five male and eight female) from embalmed Korean cadavers were used in this study. The trapezius muscle was dissected scrupulously and then reflected to enable examination of the locations of the perforating points. The thickness of trapezius muscle was measured in 13 volunteers using a diagnostic ultrasonography system. BoNT was injected into the trapezius muscle bilaterally. Injections were performed at 6 points separated by 2 cm. The muscle thicknesses were measured three times using ultrasonography: before the injection and at 4 and 12 weeks after the injection.

RESULTS

The dense arborization of the perforating accessory nerve branches was confined mostly to section b (66.7%, 54/81) and section c (33.3%, 27/81). The mean muscle thickness at 4 and 12 weeks consistently decreased 0.68-0.63 cm  in conventional method and 0.65-0.61 cm in new method (NDM) respectively (right and left).

CONCLUSION

To optimize the outcome of BoNT injection, we recommended injecting into six points separated by 2 cm in sections b and c of the upper trapezius muscle. It is significant that it is easier to apply to anyone than to apply unstructured techniques.

Myofascial Pelvic Pain and Related Disorders

Myofascial pelvic pain refers to pain in the pelvic floor muscles, the pelvic floor connective tissue, and the surrounding fascia. The cause is often multifactorial and requires treatment that encompasses multiple modalities. This type of pain is often associated with other abdominopelvic disorders, so providers in these specialties need to be aware of these connections. A comprehensive musculoskeletal examination, including evaluation of the pelvic floor muscles, and history are key to diagnosing myofascial pelvic pain. Treatments include physical therapy, muscle relaxers, oral neuromodulators, cognitive-behavioral therapy, and pelvic floor muscle injections.

Evidence of Generalized Muscle Stiffness in the Presence of Latent Trigger Points Within Infraspinatus

OBJECTIVE

To evaluate stiffness of infraspinatus muscle tissue, both with and without latent trigger points, using ultrasound shear wave elastography (SWE). The primary hypothesis is that muscle with a latent trigger point will demonstrate a discrete region of increased shear wave speed. The secondary hypothesis is that shear wave speed (SWS) in the region with the trigger point will be higher in patients compared with controls, and will be similar between the two groups in the uninvolved regions.

DESIGN

Case-control.

SETTING

Hospital-based outpatient physical therapy center.

PARTICIPANTS

Convenience sample (N=18) of patients (6 female, 3 male, mean age=44) (range=31-61y) diagnosed with latent trigger points in infraspinatus and matched controls without trigger points.

MAIN OUTCOME MEASURES

Shear wave speed (m/s).

RESULTS

SWS of the latent trigger point (mean=4.09±SD1.4 m/s) did not differ from the adjacent muscle tissue (3.92±1.6 m/s, P>.05), but was elevated compared to corresponding tissue in controls (2.8±0.75 m/s, P=.02). SWS was generally greater in patients' uninvolved tissue (3.83±1.6 m/s) when compared to corresponding tissue in controls (2.62±0.2 m/s, P=.05).

CONCLUSION

Although discrete regions of increased SWS corresponding to the trigger point were not observed in patients, evidence of generally increased muscle stiffness in infraspinatus was exhibited compared to healthy controls. Further study of additional muscles with SWE is warranted.

Quantitative Ultrasound Assessment of Myofascial Pain Syndrome Affecting the Trapezius: A Reliability Study

OBJECTIVES

Myofascial pain syndrome is one of the most common causes of chronic pain and is highlighted by the presence of myofascial trigger points. The current practice of diagnosing myofascial pain syndrome among clinicians involves manual detection of myofascial trigger points, which can be inconsistent. However, the detection process can be strengthened with the assistance of ultrasound (US). Therefore, this study aimed to characterize the upper trapezius by using quantitative techniques in healthy asymptomatic individuals with neck pain.

METHODS

Study participants were recruited on the basis of the inclusion and exclusion criteria established, and US images of the trapezius, along the axial and longitudinal orientations, were obtained. Each set was obtained by 2 investigators: experienced and inexperienced personnel.

RESULTS

Fifteen participants were recruited. The mean gray scale US echo intensity distribution obtained was 41.9. A paired t test of the global mean echo intensity value obtained for each image from the US operators did not show any significant difference (P = .77). A t test was performed, comparing the echo intensity of the group of patients with neck pain and healthy control participants, and the difference was found to be significant (P = .052). The median blob area was 2.71. The quartile range for the blob area was 1.72 for the 25th percentile to 4.90 for the 75th percentile.

CONCLUSIONS

This study demonstrated that quantitative analysis of the echo intensity of US images can provide important information. However, further research is necessary to explore the relationships among sex, age, blob area, count, body mass index, regional anatomy, and extent of training or exercise of the particular muscle.

Assessing the viscoelastic properties of upper trapezius muscle: Intra- and inter-tester reliability and the effect of shoulder elevation

BACKGROUND

Increasing stiffness in the upper trapezius muscle may contribute to imbalance of scapular motion, and result in shoulder and neck discomfort during shoulder flexion. Therefore, it is essential to quantify upper trapezius stiffness in various shoulder positions in order to aid in the prevention of these disorders and to optimize rehabilitation.

OBJECTIVES

The objectives of the present study were to examine the intra and inter-tester reliability of MyotonPRO device in measuring upper trapezius stiffness and its ability to determine changes in stiffness during shoulder flexion.

METHODS

Twenty healthy male subjects (mean age: 28.3±4.8 years) were studied. The stiffness of upper trapezius was quantified using the MyotonPRO device.

RESULTS

The results revealed excellent intra and inter-tester reliability for measuring upper trapezius stiffness with the shoulder in a neutral position, and also found a 14.2% increase in stiffness upon shoulder flexion between 0° and 60° of flexion. Minimal detectable change (MDC) was 26.3 N/m.

CONCLUSIONS

Our findings indicate that MyotonPRO device is a feasible tool to quantify upper trapezius stiffness as well as changes in muscle stiffness. Thus, it is important to assess the changes in upper trapezius muscle stiffness due to pathology or treatments for future studies.

Reliability of the Upper Trapezius Muscle and Fascia Thickness and Strain Ratio Measures by Ultrasonography and Sonoelastography in Participants With Myofascial Pain Syndrome

Objective

The purpose of this study was to assess the intra- and interexaminer reliability of the upper trapezius muscle and fascia thickness measured by ultrasonography imaging and strain ratio by sonoelastography in participants with myofascial pain syndrome.

Methods

Thirty-two upper trapezius muscles were assessed. Two examiners measured the upper trapezius thickness and strain ratio 3 times by ultrasonography and sonoelastography independently in the test session. The retest session was completed 6 to 8 days later.

Results

A total of 87.5% of participants had trigger points on the right side, and 22.5% had trigger points on the left side. For the test session, the average upper trapezius thickness, fascia thickness, and strain ratio measured by first and second examiners were 11.86 mm and 11.56 mm, 1.23 mm and 1.25 mm, and 0.94 and 0.99, respectively. For the retest session, the previously mentioned parameters obtained by first and second examiners were 11.76 mm and 11.39 mm, 1.27 mm and 1.29 mm, and 0.96 and 0.99, respectively. The intraclass correlation coefficients indicated good to excellent reliability for both within-intraexaminer (0.78-0.96) and between-intraexaminer (0.75-0.98) measurements. Also, the intraclass correlation coefficients and standard errors of measurement of interexaminer reliability ranged between 0.88 to 0.93 and 0.05 to 0.44 for both muscle and fascia thickness and 0.70 to 0.75 and 0.04 to 0.20 for strain ratio of upper trapezius, respectively.

Conclusion

Upper trapezius thickness measurements by ultrasonography and strain ratio by sonoelastography are reliable methods in participants with myofascial pain syndrome.

Measurements of the trapezius and erector spinae muscles using virtual touch imaging quantification ultrasound-Elastography: a cross section study

Background

This study uses virtual touch imaging quantification (VTIQ) technology for the first time to conduct measurements of the trapezius and erector spinae muscles in a large study population. The significance of various influencing factors, such as age and sex, are also examined.

Method

The study population comprised 278 subjects. The Siemens Acuson S3000 and VTIQ technology were used for measurements of the trapezius and erector spinae muscles (Siemens Healthcare, Erlangen, Germany).

Results

The following mean values ± standard deviation were calculated: left trapezius: males 2.89 ± 0.38 m/s, females 2.71 ± 0.37 m/s; right trapezius: males 2.84 ± 0.41 m/s, females 2.70 ± 0.38 m/s; left erector spinae: males 2.97 ± 0.50 m/s, females 2.81 ± 0.57 m/s; right erector spinae: males 3.00 ± 0.52 m/s, females 2.77 ± 0.59 m/s. A significant difference between male and female subjects was demonstrated both for the shear wave velocities of the trapezius and erector spinae as well as for the thickness of the trapezius muscle (p < 0.05). There was also a significant difference in muscle elasticity between subjects over 60 years of age and those under 60 (p < 0.05). Furthermore, the results indicate that regular physical activity has an effect on muscle elasticity.

Conclusions

Our results demonstrate significantly different results between male and female subjects and between under- and over-sixty-year-old subjects. This means that sex-related and age-adapted considerations are obviously needed for further studies.

Novel method to measure active myofascial trigger point stiffness using ultrasound imaging

INTRODUCTION

Myofascial trigger points (MTrPs) are one of the most common and important causes of musculoskeletal pain. Ultrasound is a useful modality in examining musculoskeletal disorders. By applying compressive stress and observing changes in ultrasound images, the elastic modulus (Young's modulus) can be calculated. Our objective was to develop a novel method to distinguish MTrPs from normal tissues.

METHODS

A total of 29 subjects with MTrP in the sternocleidomastoid muscle were assessed. A force gauge was attached to a transducer to obtain stress levels. To obtain strain, images were recorded in both with stress and without stress states. By dividing the stress level by the measured strain, the elastic modulus was determined.

RESULTS

Elastic modulus in MTrPs and the normal part of the muscle were measured to be 13379.57 ± 1069.75Pa and 7078.24 ± 482.92Pa, respectively (P = 0.001). This indicated that MTrPs were stiffer than normal parts of the muscle.

CONCLUSION

This study presents a new method for the quantitative measurement of the elastic modulus of MTrP, thereby distinguishing MTrPs from normal adjacent muscular tissue, with more simplicity and lower cost, compared to other ultrasound methods.

A narrative review of new trends in the diagnosis of myofascial trigger points: diagnostic ultrasound imaging and biomarkers

Myofascial pain syndrome (MPS) is one of the most common conditions of chronic musculoskeletal pain encountered by primary healthcare practitioners on a daily basis. It is generally accepted amongst the broad profile of healthcare practitioners treating MPS that the presence of discrete, palpable and tender nodules within the muscle, known as myofascial trigger points (MTrP), is necessary to confirm the diagnosis of MPS. Manual palpation is currently the most common technique used to detect MTrP, however, previous research has shown that the reliability of manual palpation for detecting MTrP is poor, and in our opinion unacceptably poor, leading to inconsistent diagnosis of MPS and poor patient outcomes. There are currently no objective accepted diagnostic criteria for the clinical detection of MTrP, nor are there standardized diagnostic criteria for MPS. Two promising areas of research with potential for enhancing the diagnosis of MPS include the use of diagnostic ultrasound and biomarkers. Further research is needed to advance the development of composite diagnostic criteria employing ultrasound imaging, biomarker assessments and physical assessment to enhance the accuracy and objectivity of MTrP detection and diagnosis of chronic MPS disorder.

Laryngeal myofascial pain syndrome as a new diagnostic entity of dysphonia

OBJECTIVE

To consider the feasibility of diagnosing intrinsic laryngeal muscle myofascial pain syndrome (MPS) in dysphonic patients who demonstrated immediate symptom and stroboscopic finding improvement after laryngeal electromyography (LEMG) without further treatment.

METHODS

A chart review of patients who showed subtle vocal fold movement abnormalities on a stroboscopic examination and underwent ultrasonography (US)-guided LEMG was performed. Patients with vocal fold paralysis, mucosal lesions, spasmodic dysphonia, and vocal tremor on stroboscopic examination were excluded. Among them, patients with normal EMG findings were included in this study. The patients who reported voice symptom improvement after LEMG without further treatment were placed in laryngeal MPS (LMPS) group and the other patients were placed in non-laryngeal MPS (non-MPS) group. Predisposing factors, voice symptom, symptom-duration, and stroboscopic findings of these patients were reviewed.

RESULTS

Among the 16 patients, LEMG findings were normal, five (31%) were included in the LMPS group and the other 11 patients (69%) were included in the non-MPS group. All LMPS group patients had a history of voice abuse and reported odynophonia. The Korean Voice Handicap Index-10 score decreased significantly after US-guided LEMG without additional treatment in the LMPS group. The stroboscopic findings revealed that vocal fold hypomobility was the most common finding in the LMPS group, and two patients showed a muscle tension dysphonia pattern. The LMPS groups showed improvement of vocal fold mobility on 1-week stroboscopic evaluation.

CONCLUSION

LMPS is a potential diagnosis for patients with vocal fold hypomobility finding on stroboscopic findings but with normal EMG results. Diagnosis of LMPS could be considered in patients who showed symptom and vocal fold movement improvement after LEMG.

A critical overview of the current myofascial pain literature - January 2016

Reflecting on the past year, the number of publications on myofascial pain continues to increase in a steady rate. The current review includes 30 basic and clinical studies, case reports, reviews, and reports from fifteen different countries about trigger points (TrP), myofascial pain (MP), dry needling (DN) and other related interventions. We are pleased that during 2015 this article made the top 15 of most downloaded articles as many as three times! In general, the quality of published papers is improving as well. Nevertheless, several papers included in this overview, mention the application of "ischemic compression", which is a questionable concept in the context of TrP inactivation. As we have outlined previously, in the current thinking about myofascial pain, TrPs feature significant hypoxia and a lowered pH (Ballyns et al., 2011; Shah and Gilliams, 2008), and attempts to induce more ischemia would be counterproductive. Already in 1999, Simons, Travell and Simons changed the terminology from ischemic compression to TrP compression (Simons et al., 1999) and we recommend that contemporary researchers and clinicians adopt the new terminology and stop using the term "ischemic compression."