Objective sonographic measures for characterizing myofascial trigger points associated with cervical pain

Myofascial trigger point (MTrP) size and elasticity properties can be used to differentiate characteristics of MTrPs in lower back skeletal muscle

Myofascial trigger points (MTrPs) are localized contraction knots that develop after muscle overuse or an acute trauma. Significant work has been done to understand, diagnose, and treat MTrPs in order to improve patients suffering from their effects. However, effective non-invasive diagnostic tools are still a missing gap in both understanding and treating MTrPs. Effective treatments for patients suffering from MTrP mediated pain require a means to measure MTrP properties quantitatively and diagnostically both prior to and during intervention. Further, quantitative measurements of MTrPs are often limited by the availability of equipment and training. Here we develop ultrasound (US) based diagnostic metrics that can be used to distinguish the biophysical properties of MTrPs, and show how those metrics can be used by clinicians during patient diagnosis and treatment. We highlight the advantages and limitations of previous US-based approaches that utilize elasticity theory. To overcome these previous limitations, we use a hierarchical approach to distinguish MTrP properties by patients' reported pain and clinician measured palpation. We show how US-based measurements can characterize MTrPs with this approach. We demonstrate that MTrPs tend to be smaller, stiffer, and deeper in the muscle tissue for patients with pain compared to patients without pain. We provide evidence that more than one MTrP within a single US-image field increases the stiffness of neighboring MTrPs. Finally, we highlight a combination of metrics (depth, thickness, and stiffness) that can be used by clinicians to evaluate individual MTrPs in combination with standard clinical assessments.

Comparison of Dry Needling and Cold-Spray-Stretching Treatments by Ultrasonography and Electrophysiology: Prospective, Randomized Controlled Trial

OBJECTIVES

To compare the efficacy of dry needling (DN) and cold-spray-stretching treatments using surface electromyography (sEMG) and ultrasound (US) in the treatment of patients with myofascial pain syndrome (MPS) with active trigger point (ATrP) in the upper trapezius muscle.

METHODS

This prospective randomized single-blind study included 60 MPS patients aged 18-65 years who have ATrP in the upper trapezius muscle. Patients were randomized into two treatment groups as DN and cold spray stretching. Both treatment groups received 1 treatment per week and totally 3 sessions. Evaluation parameters were pain level assessed by Numeric Rating Scale and algometer, neck range of motion angles, neck disability index (NDI). The effects of the treatments on ATrP were evaluated by sEMG and US histogram. All parameters were evaluated at the beginning of the treatment and at the end. Algometer and sEMG were performed also before and after the first and third sessions.

RESULTS

There was no significant difference between the two groups regarding demographic data. The mean age of the participants was 39.7 ± 11.6 years. Fifty-one patients were female. Significant improvement in terms of pain level, functionality, sEMG, and US histogram were achieved in both groups (P < .05). When comparing the two groups, algometer scores and the NDI score were statistically higher in the cold-spray-stretching group than in the DN group (P < .008 and P < .028, respectively).

CONCLUSION

Both treatment options should be preferred. The efficacy of both treatments was observed via sEMG and US histograms.

Myofascial and discogenic origins of lumbar pain: A critical review

The purpose of this three-part narrative review is to examine the anatomy of, and the research which supports, either the lumbar myofascia or intervertebral disc (IVD) as principal sources of our patient's low back pain. A comprehensive understanding of anatomical lumbar pain generators in combination with the current treatment-based classification system will further improve and enhance clinical decision-making skills. Section I reviews the anatomy of the spinal myofascia, myofascial sources of lumbar pain, and imaging of myofascial tissues. Part II reviews the anatomy of the IVD, examines the IVD as a potential lumbar pain generator, and includes detailed discussion on Nerve Growth Factor, Inflammatory Cytokines, Vertebral End Plates and Modic change, Annular tears, and Discogenic instability. Part III looks at the history of myofascial pain, lab-based research and myofascial pain, and various levels of discogenic pain provocation research including animal, laboratory and human subjects. Our review concludes with author recommendations on developing a comprehensive understanding of altered stress concentrations affecting the posterior annulus fibrosis, neo-innervation of the IVD, inflammatory cytokines, discogenic instability, and how this knowledge can complement use of the Treatment-Based Classification System.

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.

Ischemic compression associated with joint mobilization does not promote additional clinical effects in individuals with rotator cuff related shoulder pain: A randomized clinical trial

OBJECTIVE

The objective of this study was to verify which are the additional effects of the ischemic compression (IC) technique associated with joint mobilization techniques on pain, morphological aspects of myofascial trigger points (MTrPs), function, and psychological aspects in individuals with rotator cuff-related shoulder pain (RCRSP).

METHODS

Sixty individuals with RCRSP were randomly allocated intervention sessions the Mobilization Group (MG, n = 20), only joint mobilizations of the shoulder complex; intervention sessions Compression Group (CG, n = 20), with the same mobilizations associated with the IC over MTrPs; and Placebo Group (PG, n = 20), with the same mobilizations associated with placebo of IC. All interventions performed 2 per week, for 6-weeks. Pain was assessed by Visual Analogue Scale and function by the Disabilities of the Arm, Shoulder and Hand questionnaire. The kinesiophobia, pain catastrophizing, perception of improvement, mobility, pain threshold and area the MTrPs were also evaluated at baseline (week-0), after 6-weeks and after 10-weeks.

RESULTS

There were no between-group difference in pain: CG-MG 0.8 (95% CI 0.4 to 1.2), CG-PG 0.5 (95% CI 0.0 to 0.9), MG-PG -0.3 (95% CI -0.8 to 0.1) after 6-weeks and CG-MG 0.1 (95% CI -0.2 to 0.5), CG-PG -0.7 (95% CI -0.9 to -0,4), MG-PG -0,8 (95% CI -1.07 to 0.5) at 10-weeks. Similar effects were observed on function, characteristics of MTrPs and psychological aspects.

CONCLUSION

The IC technique on the MTrPs of the upper trapezius muscle associated with joint mobilization techniques has no additional effect on pain in individuals with RCRSP.

TRIAL REGISTRATION

RBR-44v8y7.

Effects of Myofascial Induction Therapy on Ankle Range of Motion and Pressure Pain Threshold in Trigger Points of the Gastrocnemius-A Clinical Trial

BACKGROUND

The myofascial induction technique (MIT) has been shown to increase shoulder range of motion (ROM) in breast cancer survivors and decrease pain pressure threshold over the radial nerve in patients with epicondylalgia. To the authors' best knowledge, no study on trigger points and MIT has been published to date. The effect on ROM of latent trigger points is also unknown.

METHODS

A total of 20 twins with one latent trigger point of the gastrocnemius muscle were evaluated pre- and post-MIT in the calf. We measured static footprint variables in a pre-post study.

RESULTS

We found differences in PPT (p = 0.001) and no differences in ROM with knee flexed (p = 0.420) or stretched (p = 0.069).

CONCLUSIONS

After Calf MIT, latent myofascial trigger points improve PPT but no change in ankle dorsiflexion with knee bent or knee flexed were found in non-restriction healthy subjects.

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.

Global Status and Future Trends of Fascia and Pain Research in 2013-2022: Bibliometric Analysis Based on CiteSpace and VOSviewer

Background

Fascial pathological pain is the main type of chronic pain in older adults today, and studying the relationship between fascia and pain can help in the clinical search for effective treatments. However, in the face of the vast amount of research findings, there is no systematic assessment of the relationship between fascia and pain in a bibliometric analysis. Therefore, the purpose of this study is to analyze studies on fascia and pain using CiteSpace and VOSviewer to identify research hotspots and future directions.

Materials and Methods

A total of 744 papers related to fascia and pain from 2013 to 2022 were collected from the core collection database of Web of Science, and the authors, countries, institutions, keyword co-occurrence, keyword clustering, and keyword emergence were analyzed by CiteSpace and VOSviewer to construct a knowledge map.

Results

Literature publication has shown an overall upward trend over the past decade, but there have been some fluctuations. Carmelo Pirri, Caterina Fede, and Raffaele De Caro are the top three authors with the most articles. The United States, China, and Spain are major contributors to fascial and pain research. The University of Padua, Universidad Complutense and Harvard Medical School are leading institutions in this field. However, it is noteworthy that the collaboration between authors, countries and institutions is not active. Keyword analysis showed that hot spots and trends in research on fascia and pain focused on hot diseases, major interventions, and mechanism exploration.

Conclusion

This analysis identifies the most influential authors, institutions, and countries in the field of fascial and pain research and provides a reference for assessing their academic impact. The analysis of keywords and co-cited literature is useful for analyzing research hotspots and their evolution, as well as for predicting future trends.

The Role of Manual Therapies in the Treatment of Headache Disorders

PURPOSE OF REVIEW

A comprehensive headache treatment plan typically requires both medication and non-medication treatment strategies. Manual therapies offer another therapeutic approach to headache treatment. This article reviews the evidence for manual therapies in the treatment of headache disorders.

RECENT FINDINGS

Current evidence shows potential benefit from myofascial trigger point injections, myofascial release, and massage for the treatment of various headache types. There is also evidence for strain counterstrain technique, ischemic compression, and spinal manipulative therapies for cervicogenic headache. Although larger randomized clinical trials are necessary for many of these modalities, recent findings show that manual therapies could be an important tool for the treatment of some headache disorders.

Women with Chronic Pelvic Pain Demonstrate Increased Lumbopelvic Muscle Stiffness Compared to Asymptomatic Controls

Background: Although lumbopelvic muscle stiffness is commonly clinically assessed in women with chronic pelvic pain (CPP), it has not been objectively quantified in this population, and its association with other pain-related impairments has not yet been established. Objective: To compare superficial lumbopelvic muscle stiffness in women with and without CPP. In addition, pressure pain threshold (PPT) was compared between groups and the associations between muscle stiffness and PPT were assessed in women with CPP. Study Design: Case-control. Methods: Muscle stiffness and PPT of 11 lumbopelvic muscles were assessed in 149 women with CPP and 48 asymptomatic women. Subjective outcome measures, including pelvic floor function, health history, and psychosocial outcomes, were collected before muscle stiffness and PPT measurements. Analysis of covariance was used to compare muscle stiffness differences between groups, and independent t-tests were used to compare PPT between groups. Associations between measurements of PPT and muscle stiffness were calculated using correlation analysis. Results: Five of the 11 muscles measured were significantly stiffer in women with CPP than those without CPP (p < 0.05). PPT was significantly decreased in all muscles measured in women with CPP; however, there was not a significant association between muscle stiffness and PPT in women with CPP. Conclusion: The study identified the abdominal lumbopelvic muscles that have increased stiffness in women with CPP compared to asymptomatic women. In addition, muscle stiffness and PPT are two distinct impairments within this population. The results suggest that women with CPP have peripheral muscle impairments, which may be addressed without intravaginal or intrarectal intervention. Clinical Trial Registration: NCT04851730.

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.

Potential Role of Insulin-Like Growth Factors in Myofascial Pain Syndrome: A Narrative Review

ABSTRACT

Insulin-like growth factors have diverse functions in skeletal muscles by acting through multiple signaling pathways, including growth regulation and differentiation, anti-inflammation, and antioxidation. Insulin-like growth factors have anti-inflammatory effects and also play roles in nociceptive pathways, determining pain sensitivity, in addition to their protective role against ischemic injury in both the nervous system and skeletal muscle. In skeletal muscle, insulin-like growth factors maintain homeostasis, playing key roles in maintenance, accelerating muscle regeneration, and repair processes. As part of their maintenance role, increased levels of insulin-like growth factors may be required for the repair mechanisms after exercise. Although the role of insulin-like growth factors in myofascial pain syndrome is not completely understood, there is evidence from a recent study that insulin-like growth factor 2 levels in patients with myofascial pain syndrome are lower than those of healthy individuals and are associated with increased levels of inflammatory biomarkers. Importantly, higher insulin-like growth factor 2 levels are associated with increased pain severity in myofascial pain syndrome patients. This may suggest that too low or high insulin-like growth factor levels may contribute to musculoskeletal disorder process, whereas a midrange levels may optimize healing without contributing to pain hypersensitivity. Future studies are required to address the mechanisms of insulin-like growth factor 2 in myofascial pain syndrome and the optimal level as a therapeutic agent.

Intramuscular Electrical Stimulation to Trigger Points: Insights into Mechanisms and Clinical Applications—A Scoping Review

Intramuscular electrical stimulation (IMES) is a modality used by clinicians to treat myofascial pain. Recent studies have shown positive results for the use of IMES on pain outcomes, yet studies investigating the potential mechanisms of IMES directly to trigger points (TrPs) are lacking. We performed a scoping review of the literature to summarize the current evidence from human and animal studies on the mechanisms of IMES to the TrP location, and to identify gaps in the existing literature. Electronic literature searches were conducted across five databases from inception to 15 August 2022, including PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED), Scopus and Cochrane Register of Controlled Trials. Four studies met our full criteria for inclusion in this review. Three studies assessed the effects of IMES to TrPs on human subjects with MPS, and only one study used an animal model with experimentally generated TrPs. Based on the results of the included studies, IMES within a TrP region was reported to normalize muscle blood flow, decrease endplate noise of the TrP and elicit antinociceptive effects, at least partially, through engaging supraspinal descending pain inhibitory systems. At present, no clinical implications can be determined on the use of IMES to TrPs due to the limited amount and quality of the available evidence. Further studies investigating the clinical effectiveness and also underlying mechanisms of IMES to TrPs are clearly needed.

Effects of Repeated Injection of 1% Lidocaine vs. Radial Extracorporeal Shock Wave Therapy for Treating Myofascial Trigger Points: A Randomized Controlled Trial

Background and Objectives: This study tested the hypothesis that treatment of myofascial trigger points (MTrPs) in the upper trapezius muscle (UTM) with repeated injection of 1% lidocaine results in better alleviation of muscular stiffness and soreness as well as improved metabolism in the hypercontracted MTrP area than treatment with radial extracorporeal shock wave therapy (rESWT). Materials and Methods: A single-blinded, prospective, randomized controlled trial was conducted on patients suffering from MTrPs in the UTM. Thirty patients were treated with repeated injection of 2 mL of 1% lidocaine (three injections; one injection per week). Another 30 patients were treated with rESWT (three treatment sessions; one treatment session per week; 2000 radial extracorporeal shock waves per treatment session; positive energy flux density = 0.10 mJ/mm2). The primary outcome measure was pain severity using the VAS score. The secondary outcome measures included muscle elasticity index, pressure pain threshold and neck disability index. Evaluation was performed at baseline (T1), 15−30 min after the first treatment in order to register immediate treatment effects (T2), before the second treatment (i.e., one week after baseline) (T3) and one week after the third treatment (i.e., four weeks after baseline) (T4). Results: There were no statistically significant differences in the primary and secondary outcome measures between the patients in the lidocaine arm and the patients in the rESWT arm at T1 and T4. Within the arms, the mean differences of all outcomes were statistically significant (p < 0.001) when comparing the data obtained at T1 with the data obtained at T3 and the data obtained at T4. Conclusions: The results of this pilot study suggest that the use of rESWT in patients with MTrPs in the UTM is safe and leads to reduced pain and improved muscle elasticity, pressure pain threshold and neck disability index, without adverse effects. Larger trials are necessary to verify this. Clinicians should consider rESWT instead of injections of lidocaine in the treatment of MTrPs in the UTM.

Trigger point injections and dry needling can be effective in treating long COVID syndrome-related myalgia: a case report

INTRODUCTION

Myofascial pain is a complex health condition that affects the majority of the general population. Myalgia has been recognized as a symptom of long COVID syndrome. The treatment for long COVID syndrome-related myalgia lacks research. Dry needling is a technique that involves the insertion of a needle into the tissue of, or overlaying, a pain point. Wet needling is the addition of an injection of an analgesic substance such as lidocaine while performing needling. Both dry and wet needling have are practiced as treatment modalities for myofascial pain. Limited literature exists to define long COVID syndrome-related myalgia and its relation to myofascial pain, or to examine the utility of needling techniques for this pain. We report a case of dry and wet needling as effective treatments for long COVID-related myofascial pain.

CASE PRESENTATION

A 59-year-old, previously healthy Hispanic male with no comorbid conditions was diagnosed with COVID-19 pneumonia. The patient suffered moderate disease without hypoxia and was never hospitalized. Three months later, the patient continued to suffer from symptoms such as exertional dyspnea, "brain fog," and myalgia. An extensive multisystem workup revealed normal cardiac, pulmonary, and end organ functions. The patient was then diagnosed with long COVID syndrome. The nature and chronicity of the patient's myalgia meet the criteria for myofascial pain. Both wet and dry needling were used to treat the patient's myofascial pain, with good short- and long-term therapeutic effects.

CONCLUSIONS

COVID-19 infection has been shown to exacerbate preexisting myofascial pain syndrome. Our case report indicates that long COVID syndrome-related myalgia is likely a form of new-onset myofascial pain. Additionally, both wet and dry needling can be utilized as an effective treatment modality for this pain syndrome, with short- and long-term benefits.

Combined effectiveness of extracorporeal radial shockwave therapy and ultrasound-guided trigger point injection of lidocaine in upper trapezius myofascial pain syndrome

OBJECTIVE

Myofascial pain syndrome (MPS) is a major musculoskeletal problem and a leading cause of disability worldwide. Extracorporeal shockwave therapy (ESWT) and trigger point injection (TPI) have shown positive results for MPS but no previous study has investigated the combined effects of radial shockwave and trigger point injection of lidocaine for upper trapezius myofascial pain syndrome.

METHOD

For this purpose, forty-five participants were randomly divided into shockwave (n = 15), shockwave with ultrasound-guided trigger point injection (combined; n = 15), and control (standard care; n = 15) groups. Participants were assessed at baseline, one week and four weeks by using the visual analog scale, neck disability index, electromyography, infrared thermography, and sonoelastography.

RESULTS

Compared with control group, both shockwave and combined groups showed a statistically significant reduction in pain (P<0.01), functional disability (P<0.01), skin temperature (P<0.01), and elastic stiffness, with greater reduction in the combined group (P<0.01) than shockwave group (P<0.05) at four weeks. However, no significant difference was found in electrical activity between the groups (P>0.05). The combined group also showed significant differences in pain (P<0.05) and elastic stiffness (P<0.01) compared with shockwave group at four weeks.

CONCLUSION

Our study revealed that extracorporeal radial shockwave therapy combined with trigger point injection of lidocaine was more effective for decreasing pain and elastic stiffness in upper trapezius myofascial pain syndrome at four weeks.

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.

Is Shear-Wave Elastography a Clinical Severity Indicator of Myofascial Pain Syndrome? An Observational Study

Since manual palpation is a subjective procedure for identifying and differentiate Myofascial Trigger Points -MTrPs-, the use of Shear Wave Elastography -SWE- as an objective alternative is increasing. This study aimed to analyze pain pressure thresholds -PPTs- and SWE differences between active MTrPs, latent MTrPs and control points located in the upper trapezius to analyze the association of SWE features with clinical severity indicators (e.g., pain extension area, PPTs, neck pain and neck disability). An observational study was conducted to calculate the correlation and to analyze the differences of sociodemographic, clinical and SWE features on 34 asymptomatic subjects with latent MTrPs and 19 patients with neck pain and active MTrPs. Significant PPT differences between active with latent MTrPs (p < 0.001) and control points (p < 0.001) were found, but no differences between latent MTrPs and control points (p > 0.05). No stiffness differences were found between active MTrPs with latent MTrPs or control points (p > 0.05). However, significant control point stiffness differences between-samples were found (p < 0.05). SWE showed no significant correlation with clinical severity indicators (p > 0.05). No stiffness differences between active and latent MTrPs were found. Neck pain patients showed increased control point stiffness compared with asymptomatic subjects. SWE showed no association with clinical severity indicators.

Combined T2 Mapping and Diffusion Tensor Imaging: A Sensitive Tool to Assess Myofascial Trigger Points in a Rat Model

Background

Myofascial trigger points (MTrPs) are defined as very small and hypersensitive points in skeletal muscle that are palpable, and produce localized pain on compression. The aim of this study was to explore the feasibility of combining T2 mapping with diffusion tensor imaging (DTI) for assessing MTrPs in a rat model and to investigate properties of the pathophysiological mechanisms.

Methods

Twenty-four Sprague-Dawley rats (model group, n = 14; control group, n = 10) underwent a magnetic resonance imaging (MRI) examination on a 3 T-MRI-scanner with a protocol consisting of T2 mapping and DTI. The MTrPs were established by blunt strike in combination with eccentric exercise. Enzyme-linked immunosorbent assays (ELISAs) were used to detect the levels of interleukin-1ß (IL-1ß) and interleukin-2 (IL-2) and their results were correlated with T2 values. Parameters from MRI including T2 values, fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) were compared between the two groups. Histological analysis was applied to provide an additional supply for MRI findings.

Results

The MTrPs of rats displayed significantly increased T2 values and FA (= 0.000) compared with normal controls, whereas MD and RD values were significantly lower (P= 0.031, = 0.000, respectively). There was no statistically significant difference in AD between the two groups (P= 0.400). These differences were accompanied by elevated levels of IL-1ß and interleukin-2 IL-2 in the MTrP group compared with controls. T2 values were positively correlated with elevated IL-1ß levels (r = 0.543, P < 0.05) but were not correlated with IL-2 levels (P > 0.05).

Conclusion

Combining T2 and DTI sequences creates a sensitive tool to assess MTrPs in a rat model. These data clarify a hypothesis that a trigger point is a chronic and mild muscle injury with inflammation.

Properties of muscle nodules recognized by manual physical therapy practitioners

[Purpose] The purpose of this study was to describe the properties of muscle nodules (kinkoketsu) recognized by manual physical therapy practitioners. [Participants and Methods] A total of one hundred and thirty-three physical therapists, occupational therapists, judo therapists, and acupuncturists participated in this study. The shape, size, direction, depth, and hardness of muscle nodules, often treated in the buttocks, were investigated through the completion of a questionnaire. [Results] A total of 124 answer sheets were completed; 112 of these described the shape of muscle nodules as ellipsoidal. Of these 112 sheets, 97 effective sheets were analyzed. The results showed that the mean long axis length, short axis length, and thickness of the muscle nodules were 30.9 mm, 16.2 mm, and 9.3 mm, respectively. The most common responses on the long axis direction, depth, and hardness of the muscle nodules were the craniocaudal orientation, the second shallowest layer of 5 divisions, and the eraser level, respectively. [Conclusion] The typical muscle nodule found in the buttocks by manual physical therapy practitioners is roughly the shape of a large almond.

Effectiveness of Deep Dry Needling vs Ischemic Compression in the Latent Myofascial Trigger Points of the Shortened Triceps Surae from Triathletes on Ankle Dorsiflexion, Dynamic, and Static Plantar Pressure Distribution: A Clinical Trial

OBJECTIVE

To determine the immediate efficacy of a single session of deep dry needling (DDN) vs ischemic compression (ICT) in a latent myofascial trigger point (MTrP) of the shortened triceps surae from triathletes for ankle dorsiflexion and redistribution of plantar pressures and stability.

DESIGN

A randomized simple blind clinical trial (NCT03273985).

SETTING

An outpatient clinic.

SUBJECTS

Thirty-four triathletes with a latent MTrP in the shortened gastrocnemius.

METHODS

Triathletes were randomized to receive a single session of DDN (N = 17) or ICT (N = 17) in a latent MTrP of the shortened triceps surae. The primary outcome was ankle dorsiflexion range of motion (ROM) by a universal goniometer. Secondary objectives were distribution of dynamic and static plantar pressures by T-Plate platform pressure, with measurements both before and after five, 10, 15, 20, and 25 minutes of treatment.

RESULTS

There were no statistically significant differences (P > 0.05) for ankle dorsiflexion ROM or dynamic and static plantar pressures between the experimental group treated with DDN and the control group treated with ICT before and after treatment.

CONCLUSIONS

DDN vs ICT carried out in latent MTrPs of the shortened gastrocnemius of triathletes did not present differences in terms of dorsiflexion ROM of the tibiofibular-talar joint or in static and dynamic plantar pressure changes before and immediately after treatment.

A critical overview of the current myofascial pain literature - January 2021

Myofascial pain syndrome (MPS), trigger points (TrPs), and dry needling (DN) continue to be of interest to researchers and clinicians worldwide. In this quarterly overview, we included studies from 19 countries, including Pakistan, Iran, Spain, Israel, the US, Australia, Turkey, the UK, China, Italy, Germany, Brazil, Denmark, Canada, Saudi Arabia, Egypt, India, New Zealand, and Thailand. As encouraging as it may be that myofascial pain is being considered worldwide, it is frustrating how many studies do not include a proper control group making them not very useful. It is not clear why researchers would go through the trouble of setting up a study, which requires many hours of work and dedication, and not produce a meaningful paper for clinicians and researchers alike. Fortunately, several papers are high quality studies. This overview covers 39 basic research studies, systematic reviews and meta-analyses, clinical studies, and a few case reports.

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.

Assessment of the effects of ischaemia/ hypoxia on angiogenesis in rat myofascial trigger points using colour Doppler flow imaging

Background & Aims

Myofascial pain syndrome (MPS) is a common non-articular disorder of the musculoskeletal system that is characterized by the presence of myofascial trigger points (MTrPs). Despite the high prevalence of MPS, its pathogenesis, which induces the onset and maintenance of MTrPs, is still not completely understood. To date, no studies have investigated the changes in the biochemical milieu caused by ischaemia/hypoxia in the MTrP regions of muscle that are proposed in the integrated hypothesis. Therefore, this study investigated whether ischaemic/hypoxic conditions participate in the formation of active MTrPs and affect angiogenesis using colour Doppler flow imaging (CDFI).

Methods

Twenty-five Sprague-Dawley rats were randomly divided into a model group and a normal control group. A model of active MTrPs was established by a blunt strike combined with eccentric exercise. Enzyme-linked immunosorbent assays (ELISAs) were employed to detect the levels of HIF-1α and VEGF. Microvessel density (MVD) was evaluated using immunohistochemistry. CDFI was applied to observe the blood flow signals in the MTrPs, which were classified into four grades based on their strengths.

Results

Compared with the control group, the active MTrP group exhibited significantly higher HIF-1α and VEGF levels and MVD values. These differences were accompanied by increased blood flow signals. In the active MTrP group, the blood flow signal grade was positively correlated with the MVD (P < 0.05) and independently correlated with the VEGF level (P < 0.05) but was not correlated with the expression of HIF-1α (P > 0.05).

Conclusion

Ischaemic/hypoxic conditions may be involved in the formation of MTrPs. CDFI is useful for detection of the features of angiogenesis in or surrounding MTrPs via assessment of blood flow signals.

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.

Increased substance P-like immunoreactivities in parabrachial and amygdaloid nuclei in a rat model with masticatory myofascial pain

This study explores the involvement of substance P (SP) in the parabrachial nucleus (PBN) and central amygdaloid nucleus (CeA) in the nociception-emotion link and of rats with masticatory myofascial pain (MMP) induced by chronic tetanic eccentric muscle contraction. A total of 18 rats were randomly and equally assigned for MMP (MMP group) and sham-MMP induction (sMMP group). MMP was induced by electrical-stimulated repetitive tetanic eccentric contraction of the masseter muscle for 14 consecutive days. Myofascial trigger points in the masseter muscle were identified by palpable taut bands, increased prevalence of endplate noise (EPN), focal hypoechoic nodules on ultrasound and restricted jaw opening. All animals were killed for morphological and SP immunohistochemical analyses. Chronic tetanic eccentric contraction induced significantly thicker masseter muscle confirmed by hypoechogenicity, increased prevalence and amplitudes of EPN, and limited jaw opening. Immunohistochemically, the SP-like positive neurons increased significantly in PBN and CeA of the MMP group. Our results suggested that MMP increases the SP protein levels in PBN and CeA, which play important roles in MMP-mediated chronic pain processing as well as MMP-related emotional processes.

Interrater and Intrarater Reliability and Minimum Detectable Change of Ultrasound for Active Myofascial Trigger Points in Upper Trapezius Muscle in Individuals With Shoulder Pain

OBJECTIVE

We sought to investigate the interrater and intrarater reliability of ultrasound and the minimum detectable change (MDC) for the trigger points (TrPs) active in the upper trapezius (UT) muscle in individuals with shoulder pain.

METHODS

Forty individuals with shoulder pain were investigated for the presence of active TrPs in the UT muscle by means of ultrasound for the parameters of gray scale, muscle thickness of UT muscle at rest, and contraction and area of TrPs. The intrarater reliability was performed on 2 days, and interrater reliability on the same day. For the gray scale, the reliability was evaluated using the kappa coefficient (κ), while the other parameters were measured by the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and MDC.

RESULTS

For the gray scale, the intrarater agreement was almost perfect (κ = 1.00) and the interrater agreement was substantial (κ = 0.75). The intrarater and interrater reliability were excellent for most of the parameters, except for the area of TrPs (intrarater: ICC = 0.71, substantial; interrater: ICC = 0.52, substantial). The MDC for intrarater reliability varied between 0.04 and 0.05 (SEM% between 2.4% and 38.87%), and that for interrater reliability ranged from 0.05 to 0.07 (SEM% between 3.18% and 55.10%), with a higher value for area.

CONCLUSION

Parameters such as gray scale, resting muscle thickness, and muscle contraction of the UT muscle, obtained through ultrasound, showed excellent intrarater and interrater reliability with low SEM%. The intrarater and interrater reliability for the area deserves a caveat regarding their use.

Theory and usage of tensiomyography and the analysis method for the patient with low back pain

Tensiomyography (TMG) is an injury detecting tool for muscle group imbalances and/or side-to-side asymmetries. It is liable to detect to measure contractile properties and mechanical responses based on muscle belly displacement. Although other previous papers have well suggested the methods for examining the several muscle groups using TMG, a detecting method for the imbalances in low back muscles has not been investigated, and no review papers have been compiled. Therefore, this study aimed to synthesize the theories of the previous studies observed using TMG and to briefly summarize its usefulness by performing simple experiments on the left and right regions of the erector spinae muscles, which may be a problem using TMG for patients with low back pain.

The effect of focused extracorporeal shock wave therapy on myofascial pain syndrome of trapezius: A systematic review and meta-analysis

BACKGROUND

Myofascial pain syndrome (MPS) is commonly seen in clinical settings and negatively influences a patient's daily life. Recently, the application of extracorporeal shock wave therapy (ESWT) has been utilized as one of the treatment methods for MPS. The aim of this systematic review and meta-analysis was to summarize the current evidence for the short-term effect of ESWT on MPS of trapezius.

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials were searched from the database inception to March 2019. Two reviewers independently screened articles, evaluated methodological quality, and extracted data. The primary outcome was post-interventional pain intensity.

RESULTS

Randomized controlled trials (RCTs) were conducted to determine whether ESWT was used as the main treatment on MPS. The 5 studies reviewed in this meta-analysis were evaluated for changes in pain intensity. Compared with other treatments, focused ESWT in MPS was more effective in reducing the scores of visual analog scale (VAS) (standardized mean difference [SMD] = -0.48, 95% CI -0.74 to -0.22).

CONCLUSIONS

There is very low level evidence that focused ESWT is effective for short-term relief of neck pain in MPS. The limited sample size and poor quality of these studies highlight and support the need for large scale, good quality placebo controlled trials in this area.

The effects of shock wave and dry needling on active trigger points of upper trapezius muscle in patients with non-specific neck pain: A randomized clinical trial

BACKGROUND

Chronic neck pain is associated with various myofascial trigger points (MTrPs).

OBJECTIVE

A single-blind randomized clinical trial was designed to compare the effects of extracorporeal shock wave therapy (ESWT) with dry needling (DN) techniques on the upper trapezius muscle trigger point in patients with non-specific neck pain (NSNP).

METHODS

Seventy patients with NSNP and active MTrPs of the upper trapezius muscle were randomly divided into two groups: an ESWT group (n= 35) and a DN group (n= 35). Treatment sessions were performed for three weeks and all participants received related intervention once a week. The outcome measures were pain intensity, measured by a numeric pain rating scale (NPRS), pain pressure threshold (PPT), measured with a digital algometer, and functional disability, evaluated by using the neck disability index (NDI).

RESULTS

NPRS and NDI were significantly decreased in the DN group and ESWT group (P< 0.05). Also, the PPT was significantly increased in the DN group and ESWT. However, there was no significant difference in pain intensity, NDI, and the PPT between the two groups (P⩾ 0.05).

CONCLUSION

Both ESWT and DN can be employed to treat MTrPs of the upper trapezius muscle in patients with NSNP.

Effectiveness between Dry Needling and Ischemic Compression in the Triceps Surae Latent Myofascial Trigger Points of Triathletes on Pressure Pain Threshold and Thermography: A Single Blinded Randomized Clinical Trial

BACKGROUND

Deep dry needling (DDN) and ischemic compression technic (ICT) may be considered as interventions used for the treatment of Myofascial Pain Syndrome (MPS) in latent myofascial trigger points (MTrPs). The immediate effectiveness of both DDN and ICT on pressure pain threshold (PPT) and skin temperature of the latent MTrPs of the triceps surae has not yet been determined, especially in athletes due to their treatment requirements during training and competition.

OBJECTIVE

To compare the immediate efficacy between DDN and ICT in the latent MTrPs of triathletes considering PPT and thermography measurements.

METHOD

A total sample of 34 triathletes was divided into two groups: DDN and ICT. The triathletes only received a treatment session of DDN (n = 17) or ICT (n = 17). PPT and skin temperature of the selected latent MTrPs were assessed before and after treatment.

RESULTS

Statistically significant differences between both groups were shown after treatment, showing a PPT reduction (p < 0.05) in the DDN group, while PPT values were maintained in the ICT group. There were not statistically significant differences (p > 0.05) for thermographic values before and treatment for both interventions.

CONCLUSIONS

Findings of this study suggested that ICT could be more advisable than DDN regarding latent MTrPs local mechanosensitivity immediately after treatment due to the requirements of training and competition in athletes' population. Nevertheless, further studies comparing both interventions in the long term should be carried out in this specific population due to the possible influence of delayed onset muscle soreness and muscle damage on PPT and thermography values secondary to the high level of training and competition.

New insights into pathways of the dorsal scapular nerve and artery for selective dorsal scapular nerve blockade

Background

The aim of this study was to clarify the topographical relationships between the dorsal scapular nerve (DSN) and the dorsal scapular artery (DSA) in the interscapular region to identify safe and convenient injection points related to DSN blockade.

Methods

Thirty shoulders of embalmed Korean cadavers and 50 live subjects were used for dissection and ultrasound (US) analysis.

Results

The running patterns of the DSA and DSN in the interscapular region were classified into 3 types. Type I was defined as nerves that were medial to the artery and parallel without changing location (80.0% of specimens). In type II (13.3%), the nerve and artery traversed one another only one time over their entire length. In type III (6.7%), the nerve and artery traversed one another, resembling a twist. Above the level of the scapular spine, the nerve was always medial to the artery. Below the scapular spine, the number of arteries was obviously decreased. Most of the arteries were lateral to the medial border of the scapula, except at the level of the superior angle of the scapula artery (SA). The positional tendency of the DSN toward the medial or lateral sides from the medial border of the scapula was similar. In US imaging of live subjects, the DSA was most observed at the level of the SA (94.0%).

Conclusions

Results of this study enhance the current knowledge regarding the pathway of the DSN and DSA and provide helpful information for selective diagnostic nerve blocks in the interscapular region.

Stiffness and echogenicity: Development of a stiffness-echogenicity matrix for clinical problem solving

The assessment of soft tissue stiffness is important to evaluate many neuromusculoskeletal conditions. Several tools have been proposed for the assessment of stiffness, but ultrasonography appears to be most practical. The reflection of ultrasound waves as it travels through tissue enables assessment of tissue echogenicity, which is influenced by the characteristics of the sound wave as well as the characteristics of the tissue through which it passes, such as the amount of fat and fibrous tissue. However, tissue stiffness is not directly proportional to its echogenicity. Hence evaluation of echogenicity, as a stand-alone technique, is inadequate to describe its mechanical properties. The aim of this manuscript is to present a method of combining echogenicity evaluation by ultrasound and stiffness evaluation by palpation to better describe the mechanical properties of muscle using a stiffness-echogenicity matrix.

[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.

Randomized Trial on Comparison of the Efficacy of Extracorporeal Shock Wave Therapy and Dry Needling in Myofascial Trigger Points

OBJECTIVE

The aim of the study was to compare the efficacy of radial extracorporeal shock wave therapy and dry needling in the treatment of myofascial trigger points in the upper trapezius muscle.

DESIGN

A total of 65 patients with myofascial trigger points were randomly divided into extracorporeal shock wave therapy group (n = 32) and dry needling group (n = 33). Patients received 3 wks of treatment at 1-wk intervals (in both groups). Visual analog scale, pressure pain threshold, Neck Disability Index, and shear modulus were evaluated before treatment, immediately after the first therapy, 1 mo, and 3 mos after the completion of the third therapy.

RESULTS

Significant improvements of visual analog scale, pressure pain threshold, and Neck Disability Index scores were observed at all time points after treatment (P < 0.01) in both treatment groups. The shear modulus of myofascial trigger points was reduced in both dry needling group (P < 0.05) and extracorporeal shock wave therapy group (P < 0.01) immediately after the first treatment. Significant reductions in shear modulus were maintained up to 3-mo posttreatment in both groups (P < 0.01). There were no significant differences between the radial extracorporeal shock wave therapy group and dry needling group.

CONCLUSIONS

The extracorporeal shock wave therapy is as effective as dry needling for relieving pain, improving function, and reducing shear modulus for patients with myofascial trigger points after a series of three treatments.

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.

Automatic ROI Placement in the Upper Trapezius Muscle in B-mode Ultrasound Images

Research involving B-mode ultrasound imaging often requires user defined regions of interest (ROIs) for analysis, traditionally drawn/selected by a trained operator. This manual process is incredibly time consuming and subjective. Here, we propose a fast and simple method of detecting the average location of aponeurosis layers in ultrasound images of the upper trapezius to place a rectangular ROI for quantitative image analysis. A total of 56 B-mode ultrasound images were analyzed, where rectangular ROIs were manually placed in the skeletal muscle by two trained operators. Interoperator agreement was determined between the ROI border locations using intercorrelation coefficient (ICC). Next, our automatic algorithm was applied (image thresholding, binary masking, and pixel intensity peak detection), estimating the mean position of both aponeurosis layers for rectangular ROI placement. The automatic estimation method was compared with the manual (visual) method by various statistics ( t test, linear correlation, Bland-Altman plot). The performance was also evaluated under additive noise conditions (Speckle). Finally, agreement of the overlapping ROI area between the manual and automatic methods was also computed. Performance of the automatic method compared with manual placement was excellent for both the superficial and deep ROI borders, performing consistently even with additive noise (error <0.674 ± 1.69 mm). Manual measurements indicated excellent consensus (ICC = 0.902) between operators. The overlapping area between the manual and automatic measurements demonstrated good agreement (90.65 ± 11.3%). With constraints, our method is robust even under large levels of noise addition making the automatic algorithm an acceptable replacement for manual ROI placement in the upper trapezius.

Ultrasound imaging for sarcopenia, spasticity and painful muscle syndromes

PURPOSE OF REVIEW

On the basis of its various advantages and the relevant awareness of physicians, ultrasound imaging has overwhelmingly taken its place in the scientific arena. This is true both from the side of daily clinical applications and also from the side of research. Yet, ultrasound provides real-time (diagnostic) imaging and (interventional) guidance for a wide spectrum of muscle disorders. In this regard, this review aims to discuss the potential/actual utility of ultrasound imaging in particular muscle disorders, that is, sarcopenia, spasticity and fibromyalgia/myofascial pain syndrome.

RECENT FINDINGS

Due to the aging population worldwide and the importance of functionality in the older population, mounting interest has been given to the diagnosis and management of sarcopenia in the recent literature. Likewise, several articles started to report that ultrasound imaging can be used conveniently and effectively in the early diagnosis and quantification of sarcopenia.For spasticity, aside from ultrasound-guided botulinum toxin injections, intriguing attention has been paid to sonographic evaluation of muscle architecture, echogenicity and elasticity in the follow-up of these chronic conditions.As regards painful muscle syndromes, quantitative ultrasound techniques have been shown to detect statistically significant differences between healthy controls and patients with myofascial pain syndrome.

SUMMARY

Ultrasound imaging seems to be a promising tool that indisputably deserves further research in the management of a wide range of muscle disorders. VIDEO ABSTRACT: http://links.lww.com/COSPC/A17.

Widespread Pressure Pain Sensitivity and Referred Pain from Trigger Points in Patients with Upper Thoracic Spine Pain

Objectives

The presence of trigger points (MTrPs) and pressure pain sensitivity has been well documented in subjects with neck and back pain; however, it has yet to be examined in people with upper thoracic spine pain. The purpose of this study was to investigate the presence of MTrPs and mechanical pain sensitivity in individuals with upper thoracic spine pain.

Methods

Seventeen subjects with upper thoracic spine pain and 17 pain-free controls without spine pain participated. MTrPs were examined bilaterally in the upper trapezius, rhomboid, iliocostalis thoracic, levator scapulae, infraspinatus, and anterior and middle scalene muscles. Pressure pain thresholds (PPTs) were assessed over T2, the C5-C6 zygapophyseal joint, the second metacarpal, and the tibialis anterior.

Results

The numbers of MTrPs between both groups were significantly different (P < 0.001) between patients and controls. The number of MTrPs for each patient with upper thoracic spine pain was 12.4 ± 2.8 (5.7 ± 4.0 active TrPs, 6.7 ± 3.4 latent TrPs). The distribution of MTrPs was significantly different between groups, and active MTrPs within the rhomboid (75%), anterior scalene (65%), and middle scalene (47%) were the most prevalent in patients with upper thoracic spine pain. A higher number of active MTrPs was associated with greater pain intensity and longer duration of pain history.

Conclusions

This study identified active MTrPs and widespread pain hypersensitivity in subjects with upper thoracic spine pain compared with asymptomatic people. Identifying proper treatment strategies might be able to reduce pain and improve function in individuals with upper thoracic spine pain. However, future studies are needed to examine this.

A critical overview of the current myofascial pain literature - February 2019

This edition of the overview of current myofascial pain literature features several interesting and important publications. From Australia, Braithwaite and colleagues completed an outstanding systematic review of blinding procedures used in dry needling (DN) studies. Other papers tackled the interrater reliability of the identification of trigger points (TrP), the presence of muscle hardness related to latent TrPs, pelvic floor examination techniques, and the links between TrPs, headaches and shoulder pain. Israeli researchers developed a theoretical model challenging the contributions of the Cinderella Hypothesis to the development of TrPs. As in almost all issues, we included many DN, injection and acupuncture studies, which continue to be the focus of researchers all over the world.

The Effect of Electric Stimulation Techniques on Pain and Tenderness at the Myofascial Trigger Point: A Systematic Review

Background

Myofascial pain is a prevalent chronic pain disorder, affecting a large proportion of the general population. Electric stimulation techniques such as transcutaneous electric stimulation (TENS) and electroacupuncture have been shown to be effective for managing chronic pain conditions including myofascial pain. The goal of this study was to review the literature on the effectiveness of electric stimulation techniques on myofascial pain.

Methods

A comprehensive systematic search of three databases—Medline, EMBASE, and Cochrane CENTRAL—was conducted using key words related to myofascial pain and trigger points, as well as various electric stimulation techniques. A total of 15 articles passed the inclusion and exclusion criteria for the study. Data were extracted from these studies and assessed qualitatively and quantitatively. Standardized mean differences (SMDs) were computed from pain intensity measures extracted from these studies. Subgroup analyses were performed to assess the effectiveness of treatment modality, number of treatment sessions, frequency of stimulation, location of treatment, and duration of treatment.

Results

The SMD for electric stimulation techniques on reported pain intensity was significant (P = 0.03), as was the SMD for the electroacupuncture subgroup (P = 0.02); the TENS subgroups’ effect was not significant (P = 0.17). The subgroup analyses tentatively suggest that frequency and number of treatments do not influence pain intensity, whereas the duration of treatment may have an effect. The qualitative results of this study revealed variability in the results among studies delivering TENS treatments.

Conclusions

Electric stimulation is effective at mitigating reported pain intensity at the location of the trigger point. Electroacupuncture presented with significant and larger effect sizes of improvement relative to TENS for reported pain intensity. Given that this review included a small number of studies, there is a need for additional research to confirm its findings. Additionally, studies assessing the parameters and physiological location of treatment are needed to inform the clinical use and recommendations of electric stimulation treatments.

Quantitative magnetic resonance imaging of the upper trapezius muscles - assessment of myofascial trigger points in patients with migraine

Background

Research in migraine points towards central-peripheral complexity with a widespread pattern of structures involved. Migraine-associated neck and shoulder muscle pain has clinically been conceptualized as myofascial trigger points (mTrPs). However, concepts remain controversial, and the identification of mTrPs is mostly restricted to manual palpation in clinical routine. This study investigates a more objective, quantitative assessment of mTrPs by means of magnetic resonance imaging (MRI) with T2 mapping.

Methods

Ten subjects (nine females, 25.6 ± 5.2 years) with a diagnosis of migraine according to ICHD-3 underwent bilateral manual palpation of the upper trapezius muscles to localize mTrPs. Capsules were attached to the skin adjacent to the palpated mTrPs for marking. MRI of the neck and shoulder region was performed at 3 T, including a T2-prepared, three-dimensional (3D) turbo spin echo (TSE) sequence. The T2-prepared 3D TSE sequence was used to generate T2 maps, followed by manual placement of regions of interest (ROIs) covering the trapezius muscles of both sides and signal alterations attributable to mTrPs.

Results

The trapezius muscles showed an average T2 value of 27.7 ± 1.4 ms for the right and an average T2 value of 28.7 ± 1.0 ms for the left side (p = 0.1055). Concerning signal alterations in T2 maps attributed to mTrPs, nine values were obtained for the right (32.3 ± 2.5 ms) and left side (33.0 ± 1.5 ms), respectively (p = 0.0781). When comparing the T2 values of the trapezius muscles to the T2 values extracted from the signal alterations attributed to the mTrPs of the ipsilateral side, we observed a statistically significant difference (p = 0.0039). T2 hyperintensities according to visual image inspection were only reported in four subjects for the right and in two subjects for the left side.

Conclusions

Our approach enables the identification of mTrPs and their quantification in terms of T2 mapping even in the absence of qualitative signal alterations. Thus, it (1) might potentially challenge the current gold-standard method of physical examination of mTrPs, (2) could allow for more targeted and objectively verifiable interventions, and (3) could add valuable models to understand better central-peripheral mechanisms in migraine.

International Consensus on Diagnostic Criteria and Clinical Considerations of Myofascial Trigger Points: A Delphi Study

Objective

There is no consensus on the essential diagnostic criteria for diagnosing a trigger point (TrP). In fact, a variety of diagnostic criteria are currently being used. Our aim was to conduct a Delphi panel to achieve an international consensus on the cluster of criteria needed for the TrP diagnosis to reach a consensus on the definition of active and latent TrPs and to clarify different clinical considerations about TrPs.

Methods

Following international guidelines, an international three-round Delphi survey was conducted. Questions were created based on a systematic literature search of the diagnostic criteria for TrPs.

Results

Sixty experts from 12 countries completed all rounds of the survey. A cluster of three diagnostic criteria was proposed as essential for the TrP diagnosis: a taut band, a hypersensitive spot, and referred pain. Eighty percent of the experts agreed that the referred pain elicited by a TrP can include different sensory sensations and not just pain, that is, pain spreading to a distant area, deep pain, dull ache, tingling, or burning pain. Eighty-four percent of the international experts consistently answered that the main clinical differences between active and latent TrPs are the reproduction of any of the symptoms experienced by a patient and the recognition of pain. No specific location of the pain referral area and TrP location should be expected.

Conclusions

This Delphi panel has produced an expert-based standardized definition of a TrP with a discussion of the clinical components, including the definition of referred pain and the difference between active and latent TrPs, thereby providing a foundation for future research in MPS.

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.

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.