Assessment of Myofascial Trigger Points via Imaging: A Systematic Review

Efficacy and Safety of Ultrasound-Guided Acupotomy Versus Celecoxib in Patients with Thoracodorsal Myofascial Pain Syndrome: A Randomized Controlled Trial

Objective: To evaluate the efficacy and safety of ultrasound-guided acupotomy (UgA) for the treatment of thoracodorsal myofascial pain syndrome (TDMPS) and monitor its mid-term efficacy at 3 months after treatment. Methods: A 3-week, evaluator-blinded randomized clinical trial was conducted among 100 patients with TDMPS (visual analogue scale [VAS] score > 3) in the outpatient clinic of the Department of Orthopaedics of the Second Affiliated Hospital of Anhui University of Traditional Chinese Medicine, with a 3-month follow-up starting after completion of treatment. These patients were randomly assigned to receive UgA (n = 50) or oral celecoxib (n = 50). Recruitment was conducted between January 2021 and July 2022. The primary outcome was the VAS score, and the secondary outcomes included the Oswestry Disability Index (ODI), Pain Anxiety Symptoms Scale (PASS), and TNF-α and IL-1β levels. Outcome data were collected at baseline, week 3 (post-treatment) and week 15 (follow-up). Results: Compared with that in the celecoxib group, the pain in the UgA group was alleviated more strongly, with an adjusted mean group difference of -0.69 (95% CI,-1.07 to -0.31 after multiple imputation) at week 3 and -1.96 (95% CI,-2.33 to -1.59 after multiple imputation) at week 15 (p < 0.001 for overall group × time interaction). Both groups exhibited improvements in the ODI and PASS scores at weeks 3 and 15, but these improvements were significantly greater in the UgA group (p < 0.05). At week 3, the TNF-α and IL-1 levels were significantly lower in both groups, but celecoxib was more effective (p < 0.05). Results from analyses with multilevel multiple imputation for missingness were similar. Conclusion: UgA led to greater and safer alleviation of pain, dysfunction, and pain anxiety in patients treated with TDMPS than did celecoxib and had a durable 3-month efficacy but was inferior to celecoxib in reducing the level of inflammatory factors. These findings may prompt clinicians to recommend UgA as an alternative and supplementary therapy for pain management in patients with TDMPS.

Exploring transvaginal sonographic characteristics of the levator ani muscle in women with postpartum pelvic floor myofascial pain

BACKGROUND

Pelvic floor myofascial pain is one of the pelvic floor dysfunction diseases disturbing women after delivery. There is a lack of objective standardization for the diagnosis of pelvic floor myofascial pain due to the various symptoms and the dependence on the palpating evaluation. Ultrasound imaging has the advantages of safety, simplicity, economy and high resolution, which makes it an ideal tool for the assistant diagnosis of pelvic floor myofascial pain and evaluation after treatment.

METHODS

This is a retrospective case-control study including women accepting evaluation of pelvic floor function at 6 weeks to 1 year postpartum. They were divided into pelvic floor myofascial pain group and normal control group. A BCL 10-5 biplane transducer was applied to observed their puborectalis. The length, minimum width, area, deficiency, deficiency length, deficiency width, deficiency area, rate of deficiency area, local thickening,angle between the tendinous arch of levator ani muscle and puborectalis of corresponding puborectalis in different groups were observed and measured.

RESULTS

A total of 220 postpartum women participated in the study, with 77 in the pelvic floor myofascial pain group and 143 in the normal control group. The Intraclass correlation coefficient value was over 0.750, and Kappa ranged from 0.600 to 0.800. puborectalis deficiency (adjusted odds ratio = 11.625, 95% confidence interval = 4.557-29.658) and focal thickening (adjusted odds ratio = 16.891, 95% confidence interval = 1.819-156.805) were significantly associated with higher odds of having postpartum pelvic floor myofascial pain. Grayscale or the angle between the arch tendineus levator ani and puborectalis measurements on the pain side tended to be smaller than on the non-pain side in patients with unilateral puborectalis or iliococcygeus pain (P < 0.05).

CONCLUSIONS

This study demonstrated that transvaginal ultrasound was a potentially efficient technique for evaluating postpartum pelvic floor myofascial pain due to its ability to assess various sonographic characteristics of the levator ani muscles.

Pictorial Essay on Ultrasound and Magnetic Resonance Imaging of Paraspinal Muscles for Myofascial Pain Syndrome

The paraspinal muscles of the cervical, thoracic, and lumbar spine are important pain generators because muscle strains or myofascial pain syndrome caused by trigger points are common during clinical practice. Ultrasonography is the most convenient imaging tool for evaluating these muscles due to its advantages, such as providing good delineation of soft tissues, easy accessibility, and zero radiation. Additionally, ultrasound can serve as a useful guiding tool for paraspinal muscle intervention to prevent inadvertent injuries to vital axial neurovascular structures. This pictorial essay presents ultrasound scanning protocols for the paraspinal and other associated muscles as well as a discussion of their clinical relevance. Axial magnetic resonance imaging has also been used to elucidate reciprocal anatomy. In conclusion, ultrasound imaging proves to be a valuable tool that facilitates the differentiation of individual paraspinal muscles. This capability significantly enhances the precision of interventions designed to address myofascial pain syndrome.

Innovations in the Assessment of Skeletal Muscle Health: A Glimpse into the Future

Skeletal muscle is the largest organ system in the human body and plays critical roles in athletic performance, mobility, and disease pathogenesis. Despite growing recognition of its importance by major health organizations, significant knowledge gaps remain regarding skeletal muscle health and its crosstalk with nearly every physiological system. Relevant public health challenges like pain, injury, obesity, and sarcopenia underscore the need to accurately assess skeletal muscle health and function. Feasible, non-invasive techniques that reliably evaluate metrics including muscle pain, dynamic structure, contractility, circulatory function, body composition, and emerging biomarkers are imperative to unraveling the complexities of skeletal muscle. Our concise review highlights innovative or overlooked approaches for comprehensively assessing skeletal muscle in vivo. We summarize recent advances in leveraging dynamic ultrasound imaging, muscle echogenicity, tensiomyography, blood flow restriction protocols, molecular techniques, body composition, and pain assessments to gain novel insight into muscle physiology from cellular to whole-body perspectives. Continued development of precise, non-invasive tools to investigate skeletal muscle are critical in informing impactful discoveries in exercise and rehabilitation science.

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.

Up-and-coming Radiotracers for Imaging Pain Generators

Chronic musculoskeletal pain is among the most highly prevalent diseases worldwide. Managing patients with chronic pain remains very challenging because current imaging techniques focus on morphological causes of pain that can be inaccurate and misleading. Moving away from anatomical constructs of disease, molecular imaging has emerged as a method to identify diseases according to their molecular, physiologic, or cellular signatures that can be applied to the variety of biomolecular changes that occur in nociception and pain processing and therefore have tremendous potential for precisely pinpointing the source of a patient's pain. Several molecular imaging approaches to image the painful process are now available, including imaging of voltage-gated sodium channels, calcium channels, hypermetabolic processes, the substance P receptor, the sigma-1 receptor, and imaging of macrophage trafficking. This article provides an overview of promising molecular imaging approaches for the imaging of musculoskeletal pain with a focus on preclinical methods.

Comparative Techniques of Acupuncture and Dry Needling Intersecting with Trigger Point Physiology and Diagnostics: A Cross-Discipline Narrative Review

Background

Pain management is a great burden on society; therefore, cost-effective and nonaddictive treatments for pain are urgently required. Needling of painful spots has been applied in acupuncture along with dry needling

Methods

A narrative review of the literature on TrP physiology, its associated diagnostics, and the techniques of DN and acupuncture was performed.

Results

Diagnostic imagery may benefit the study and treatment of TrPs using needling. Acupuncture and DN techniques are similar in their applications. However, the warm needling technique is established in acupuncture but not in dry needling. Additionally, translational difficulties have inhibited crossdiscipline learning.

Conclusions

Historical evidence suggests a need to examine the use of heat in needling further. Additional research should be conducted on TrP categories to determine if a relationship with the needling technique can be established. Furthermore, interdisciplinary communication would benefit both modalities.

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Key Words

• acupuncture
• dry needling
• myofascial trigger points
• trigger point physiology

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MESH Headings Collapse

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Affiliation(s)

Jordan Barber AOMA Graduate School of Integrative Medicine, Austin, TX, USA
Fabio Lodo So Wen School of Acupuncture, Milan, Italy
Andrew Nugent-Head Association for Traditional Studies, Ashville, NC, USA
Xia Zeng AOMA Graduate School of Integrative Medicine, Austin, TX, USA

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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.

Ultrasound Imaging and Guidance for Cervical Myofascial Pain: A Narrative Review

Cervical myofascial pain is a very common clinical condition in the daily practice of musculoskeletal physicians. Physical examination is currently the cornerstone for evaluating the cervical muscles and identifying the eventual presence of myofascial trigger points. Herein, the role of ultrasound assessment in precisely localizing them is progressively mounting in the pertinent literature. Moreover, using ultrasound, not only the muscle tissue but also the fascial and neural elements can be accurately located/evaluated. Indeed, several potential pain generators, in addition to paraspinal muscles, can be involved in the clinical scenario of cervical myofascial pain syndrome. In this article, the authors extensively reviewed the sonographic approach for cervical myofascial pain in order to better diagnose or guide different procedures that can be performed in the clinical practice of musculoskeletal physicians.

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.

Case study: Treating infraspinatus and supraspinatus trigger points and supraspinatus tendinopathy utilizing piezoelectric shockwave

Two individual case studies demonstrate piezoelectric shockwave treatment for the resolution of a supraspinatus tendinopathy and supraspinatus and infraspinatus myofascial trigger points (MTPs) via musculoskeletal ultrasound. This is the first documentation of improvement of both tendon and muscle fiber patterns in canine patients treated with piezoelectric shockwave. These cases validate the use of piezoelectric shockwave during the rehabilitation of common canine shoulder injuries.

Contracture Knots vs. Trigger Points. Comment on Ball et al. Ultrasound Confirmation of the Multiple Loci Hypothesis of the Myofascial Trigger Point and the Diagnostic Importance of Specificity in the Elicitation of the Local Twitch Response. Diagnostics 2022, 12, 321

A recent study published in Diagnostics attempted to visualize trigger points and contracture knots with high-definition ultrasound. Based on their findings, the authors reversed the commonly understood meaning of the two terms. However, they did so without providing any convincing evidence. The authors maintained that their sonography images represented trigger points within contracture knots, supporting the multiple loci hypothesis. On review of the paper, both conclusions seem premature and rather speculative.

Efficacy of Dry Needling Under EMG Guidance for Myofascial Neck and Shoulder Pain: A Randomized Clinical Trial

Purpose

To determine the difference in maintenance of improvement of pain and disability for dry needling (DN) under needle electromyography (EMG) guidance technique in myofascial neck and shoulder pain patients, compared with DN alone.

Patients and Methods

In this randomized single-blind clinical trial, 30 participants with myofascial pain in the neck and shoulder were randomly allocated to two groups: myofascial trigger points (MTrPs) DN with EMG guided (DN-EMG) group and MTrPs DN without EMG (DN) group. Needling treatment lasted for 2 weeks, twice a week. The primary outcome was pain intensity as assessed by visual analogue scale (VAS) and neck disability index (NDI). A number of mappings referred to pain and spontaneous muscle activity (SEA) were considered secondary outcomes. VAS and NDI were measured before treatment, after 2 weeks of intervention and at 4-, 6- and 12-week follow-up periods after the intervention. Secondary outcomes were assessed before each treatment (T1–T4). Data were analysed using mixed-model analyses of variance (ANOVA) with time as a within-subject variable and groups as between-subject variables followed by Bonferroni’s post-hoc test.

Results

Mixed-model ANOVA revealed significant time-by-group interaction effects (F = 3.49, P = 0.01) for VAS. Post-hoc analysis showed a significant decrease in VAS and NDI after 2 weeks of intervention and at all follow-up periods compared with baseline in both groups (p < 0.01). The DN-EMG group exhibited higher improvements in VAS at 6- and 12-week follow-up period than the DN group (p < 0.05). In the SEA of MTrPs, we found positive sharp waves, fibrillation and fascicular potentials. DN-EMG group exhibited lower amplitudes at T2–T4 and frequencies at T2 and T3.

Conclusion

DN under needle EMG guidance technique exhibited greater improvements in maintenance of improvement of pain and lower SEA value than the DN group due to sufficient MTrPs inactivation.

Efficacy and Effectiveness of Extracorporeal Shockwave Therapy in Patients with Myofascial Pain or Fibromyalgia: A Scoping Review

Myofascial pain syndrome (MPS) and fibromyalgia (FM) are underestimated painful musculoskeletal conditions that could impact function and quality of life. A consensus about the most appropriate therapeutic approach is still not reached. Considering the long course of the diseases, prolonged assumption of drugs, such as NSAIDs and pain killers, could increase the risk of adverse events, often leading affected patients and physicians to prefer non-pharmacological approaches. Among these, radial and focused extracorporeal shock waves therapies (ESWT) are widely used in the management of painful musculoskeletal conditions, despite the fact that the mechanisms of action in the context of pain modulation should be further clarified. We performed a scoping review on PubMed using Mesh terms for analyzing the current evidence about the efficacy and effectiveness of ESWT for patients with MPS or FM. We included 19 clinical studies (randomized controlled trials and observational studies); 12 used radial ESWT, and 7 used focused ESWT for MPS. Qualitative analysis suggests a beneficial role of ESWT for improving clinical and functional outcomes in people with MPS, whereas no evidence was found for FM. Considering this research gap, we finally suggested a therapeutic protocol for this latter condition according to the most recent diagnostic criteria.

Ultrasound Confirmation of the Multiple Loci Hypothesis of the Myofascial Trigger Point and the Diagnostic Importance of Specificity in the Elicitation of the Local Twitch Response

The literature has hypothesized that a trigger point (TrP) area consists of a hyperperfused contracture knot with smaller hypoperfused TrPs within the contracture knot. By contrast, the only published ultrasound image of a TrP has it labeled hypoechoic (i.e., hyperperfused) with no commentary regarding smaller speckles of hypoperfusion within. Furthermore, the lack of clarity in objective definition of the terms associated with the TrP (namely, the palpable “contracture knot” and smaller nonpalpable “trigger point”) has led to unnecessary communication difficulties between and among clinicians and researchers. In this case series of three muscles across two patients, by using high-definition musculoskeletal ultrasound imaging technology, we present what we believe to be the first reliable capture of palpable hypoechoic (e.g., hypoperfused) contracture knots (previously mislabeled as a hypoechoic TrP), and a visual support of the multiple loci hypothesis first proposed by Hong and Simons—the first reliable confirmation of the hyperechoic (i.e., hypoperfused) TrP within. Initially proposed by a histological study and supported by microdialysis study, this case series lends further support for the multiple loci hypothesis through visual confirmation of palpable hypoechoic contracture knots, with smaller hypoechoic TrPs “speckles” within.

The ischemic model of chronic muscle spasm and pain

This article was not intended to be a complete review of the electromyography of pathological muscle states, but it was written to illustrate how the “Coletti Method of EMG ChemoDenervation” (CMECD^©) protocol for the treatment of chronic pain resulting from chronic muscle spasm was developed and established. That process led to an unexpected understanding of the underlying pathophysiology of chronic muscle spasm, which represents a paradigm shift in our understanding and ultimately in our treatment of muscle spasm-induced chronic pain. Other investigators had brought to light the presence of spontaneous electrical activity (SEA) in states of muscle spasm. Those findings were all but ignored by standard EMG/Nerve conduction studies in clinical practice. Starting with a simple EMG device I experimented with various medications to treat patients with chronic pain associated with chronic muscle spasm. Suppression of SEA with long-acting medications resolved both the chronic spasm and chronic pain. A successful protocol using phenoxybenzamine was established and clinical outcomes were followed. More than 200 patients were successfully treated during last 12 years. Correlating known exercise muscle physiology with the development of the pathological state of chronic muscle spasm as seen by electromyography led to the postulation of the ischemic model of chronic muscle spasm. Light microscopy pathophysiologic supportive findings are presented and discussed. Predictions from this model to various aspects of treatment were supportive. Implications regarding treatment by the CMECD^© procedure, as well as other standard therapies, are discussed. Application of the ischemic model to other pain conditions was explored with implications of therapeutic modification. Recommendations for changes in rehabilitation therapy are discussed.

Fascia Mobility, Proprioception, and Myofascial Pain

The network of fasciae is an important part of the musculoskeletal system that is often overlooked. Fascia mobility, especially along shear planes separating muscles, is critical for musculoskeletal function and may play an important, but little studied, role in proprioception. Fasciae, especially the deep epimysium and aponeuroses, have recently been recognized as highly innervated with small diameter fibers that can transmit nociceptive signals, especially in the presence of inflammation. Patients with connective tissue hyper- and hypo-mobility disorders suffer in large number from musculoskeletal pain, and many have abnormal proprioception. The relationships among fascia mobility, proprioception, and myofascial pain are largely unstudied, but a better understanding of these areas could result in improved care for many patients with musculoskeletal pain.