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

Characteristics of patients with myofascial pain syndrome of the low back

The objective of this study is to determine characteristics of patients with myofascial pain syndrome (MPS) of the low back and the degree to which the low back pain in the patients examined can be attributed to MPS. Twenty-five subjects with myofascial trigger point(s) [MTrP(s)] on the low back participated in this cross-sectional study. The location, number, and type of selected MTrPs were identified by palpation and verified by ultrasound. Pain pressure threshold, physical function, and other self-reported outcomes were measured. Significant differences were found in Group 1 (Active), 2 (Latent), 3 (Atypical, no twitching but with spontaneous pain), and 4 (Atypical, no twitching and no spontaneous pain) of participants in the number of MTrPs, current pain, and worst pain in the past 24 h (p = .001-.01). There were interaction effects between spontaneous pain and twitching response on reports of physical function, current pain, and worst pain (p = .002-.04). Participants in Group 3 reported lower levels of physical function, and higher levels of current pain and worst pain compared to those in Group 4. Participants in Group 1 and 2 had similar levels of physical function, current pain, and worst pain. The number of MTrPs is most closely associated with the level of pain. Spontaneous pain report seems to be a decisive factor associated with poor physical function; however, twitching response is not.

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.

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.

Comparative effects of Bowen therapy and tennis ball technique on pain and functional disability in patients with thoracic myofascial pain syndrome

BACKGROUND

Thoracic myofascial pain syndrome is a clinical problem arising from the muscles and soft tissues of thoracic region, which include the mid and upper back area. Risk factors associated with myofascial pain syndrome are muscle overuse and repetitive strain, poor posture, trauma or injury, emotional and psychological stresses. The management of myofascial pain syndrome (MPS) typically involves a multidimensional approach that focuses on relieving pain, reducing muscle tension, and improving muscle function. Bowen therapy and tennis ball technique are also recommended for treating myofascial pain syndrome.

OBJECTIVE

The objective of this study was to compare the effects of Bowen therapy and tennis ball technique on pain and functional disability in patients with thoracic myofascial pain syndrome.

METHODS

It was a randomized clinical trial conducted on thirty patients. It was carried out in physiotherapy outpatient department of D.H.Q Hospital, Kasur. Non-probability convenience sampling technique was used. Data collection was done from the patients of thoracic myofascial pain syndrome by using Numeric Pain Rating Scale (NPRS) for pain and Pain Disability Questionnaire (PDQ) for functional disability. Participants were randomly allocated into two groups using computer generated random number method. Group A received Bowen therapy, and group B received tennis ball technique. Outcome measures were measured at baseline, after second week treatment session and after fourth week with three sessions in a week on alternate days. Data analysis was done by using Statistical Package for the Social Sciences (SPSS) version 26.

RESULTS

There was significant difference between the mean values of NPRS and PDQ in both groups at baseline, second week and fourth week with p value < 0.05. The results indicated that both treatments were significant but Bowen therapy is more effective treatment than tennis ball technique. Within-group difference calculated with repeated-measure ANOVA indicated that there was significant difference from pre- to post-values of both groups.

CONCLUSION

This study concluded that Bowen therapy produced statistically significant and clinically relavant results for all the outcome measures.

TRIAL REGISTRATION

(IRCT20190717044238N7).

Preclinical efficacy of TZG in myofascial pain syndrome by impairing PI3K-RAC2 signaling-mediated neutrophil extracellular traps

Tianhe Zhuifeng Gao (TZG) shows a satisfying therapeutic efficacy in treating arthromyodynia, which shares similar etiology to myofascial pain syndrome (MPS). We herein aim to explore whether TZG could be a potential prescription for MPS therapy. An MPS rat model was successfully established presenting with reduced pain thresholds, abnormal local switch responses, etc., which was effectively reversed by TZG treatment externally. A transcriptome sequencing based on the active MTrPs samples of rats, combined with network analysis revealed that TZG might ameliorate the progression of MPS by impairing neutrophil extracellular traps (NETs) release through inhibiting PI3K-RAC2 signaling to reduce NADPH oxidase-originated ROS. Experimentally, the expression levels of inducers, biomarkers of NETs formation and vessel injury, and p-PI3K, p-P47, and RAC2 proteins were all significantly up-regulated in affected tissues, which were markedly reversed by TZG. Our results not only shed light into broadening the clinical indications of TZG, but benefit MPS therapy.

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.

Identifying chronic low back pain phenotypic domains and characteristics accounting for individual variation: a systematic review

ABSTRACT

Interpatient variability is frequently observed among individuals with chronic low back pain (cLBP). This review aimed at identifying phenotypic domains and characteristics that account for interpatient variability in cLBP. We searched MEDLINE ALL (through Ovid), Embase Classic and EMBASE (through Ovid), Scopus, and CINAHL Complete (through EBSCOhost) databases. Studies that aimed to identify or predict cLBP different phenotypes were included. We excluded studies that focused on specific treatments. The methodological quality was assessed using an adaptation of the Downs and Black tool. Forty-three studies were included. Although the patient and pain-related characteristics used to identify phenotypes varied considerably across studies, the following were among the most identified phenotypic domains and characteristics that account for interpatient variability in cLBP: pain-related characteristics (including location, severity, qualities, and duration) and pain impact (including disability, sleep, and fatigue), psychological domains (including anxiety and depression), behavioral domains (including coping, somatization, fear avoidance, and catastrophizing), social domains (including employment and social support), and sensory profiling (including pain sensitivity and sensitization). Despite these findings, our review showed that the evidence on pain phenotyping still requires further investigation. The assessment of the methodological quality revealed several limitations. We recommend adopting a standard methodology to enhance the generalizability of the results and the implementation of a comprehensive and feasible assessment framework to facilitate personalized treatments in clinical settings.

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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Myofascial pain syndrome in the oncologic patient: general considerations

This article aims to make visible a common non-oncologic pain condition in cancer patients. Myofascial pain syndrome can generate an increase in the symptomatic burden of the oncologic patient, increase the demand for opioid medication, and decrease the quality of life. We consider that health professionals involved in the care of cancer patients in its different stages should be aware of it, diagnose it, and treat it early to avoid processes of pain chronification, peripheral tissue modification, and deterioration of the functional condition of patients with oncologic diseases.

Myofascial Temporomandibular Disorders at a Turning Point: Pragmatic or Evidence-Based Management?

Unvalidated theories have been proposed for the etiopathogenesis of masticatory myofascial temporomandibular disorders (mTMD). Modalities such as cone-beam computed tomography/computed tomography and MRI contributes little to the diagnosis of mTMD. Diagnosing mTMD is based on the recognition of "familiar pain" presentation in the masticatory myofascial tissue. This assessment tool contributes little our understanding of the underlying disease process. Thus, management of mTMD is empirical and arbitrary. Exploring emerging technologies to identify biomarkers and objectively assess myofascial tissue physiology in disease and health may be key in moving the diagnosis of mTMD from the pragmatic paradigm to an evidence-based paradigm.

Myofascial Pain as an Unseen Comorbidity in Osteoarthritis: A Scoping Review

OBJECTIVE

This review aimed to identify, summarize, and appraise the evidence supporting the coexistence of myofascial pain (MPS) and trigger points (MTrP) in osteoarthritis (OA), and the effectiveness of MTrPs treatments in OA-related pain and physical function outcomes.

METHODS

Three databases were searched from inception to June 2022. We included observational and experimental studies to fulfill our 2 study aims. Two independent reviewers conducted 2-phase screening procedures and risk of bias using checklist tools for cross-sectional, quasi-experimental, and randomized control trials. Patient characteristics, findings of active and latent MTrPs in relevant muscles, treatments, and pain and physical function outcomes were extracted from low-risk bias studies.

RESULTS

The literature search yielded 2898 articles, of which 6 observational and 7 experimental studies had a low bias risk and the data extracted. Active MTrPs in knee OA patients was more evident in the quadriceps and hamstring muscles than in healthy individuals. Dry needling on active MTrPs improved pain and physical function in the short term compared with sham treatment in hip OA patients. In knee OA, dry needling on latent or active MTrPs improved pain and functional outcomes compared with sham needling but did not result in better pain and physical outcomes when combined with a physical exercise program.

DISCUSSION

The presence of active versus latent MTrPs seems to be a more sensitive discriminating feature of OA given that latent is often present in OA and healthy individuals. Dry needling on active MTrPs improved pain and physical function in the short term compared with sham treatment in hip OA patients. However, the small sample size and the few number of studies limit any firm recommendation on the treatment.

REGISTRY

The study protocol was prospectively registered in Open Science Framework (https://doi.org/10.17605/OSF.IO/8DVU3).

Myofascial Pain Syndrome: A Nociceptive Condition Comorbid with Neuropathic or Nociplastic Pain

Myofascial pain syndrome is featured by the presence of myofascial trigger points (TrPs). Whether TrPs are primary or secondary phenomena or if they relate to central or peripheral nervous system disorders is controversial. Referred pain, a cardinal sign of TrPs, is a central phenomenon driven by peripheral input. In 2021, the International Association for the Study of Pain (IASP) proposed a clinical criteria and grading system for classifying patients with pain on nociceptive, neuropathic, or nociplastic phenotypes. Myofascial TrP pain has been traditionally categorized as a nociceptive phenotype; however, increasing evidence supports that this condition could be present in patients with predominantly nociplastic pain, particularly when it is associated with an underlying medical condition. The clinical response of some therapeutic approaches for managing TrPs remains unclear. Accordingly, the ability to classify myofascial TrP pain into one of these phenotypes would likely be critical for producing more successful clinical treatment outcomes by a precision medicine approach. This consensus paper presents evidence supporting the possibility of subgrouping individuals with myofascial TrP pain into nociceptive, nociplastic, or mixed-type phenotype. It is concluded that myofascial pain caused by TrPs is primarily a nociceptive pain condition, is unlikely to be classified as neuropathic or nociplastic, but can be present in patients with predominantly neuropathic or nociplastic pain. In the latter cases, management of the predominant central pain problem should be a major treatment goal, but the peripheral drive from TrPs should not be ignored, since TrP treatment has been shown to reduce sensitization-associated symptomatology in nociplastic pain conditions, e.g., fibromyalgia.

Successful Treatment of Myofascial Pain Syndrome (MPS) with Surgical Cauterization of Temporalis Muscle Trigger Points: A Case Report

For patients suffering from myofascial pain syndrome (MPS) affecting muscles of mastication, traditional trigger point therapy treatment regimens can prove inconvenient, due to the short duration of pain relief after each injection and expense of repeated visits which are often not covered by insurance. We present a case of a patient treated using an alternative technique that could develop into an additional modality for treating MPS patients who are refractory to conservative treatment. This technique involves identifying and marking the patient's trigger points and surgically cauterizing each location using a Bovie electrosurgical unit. While traditional trigger point injection therapy for myofascial pain syndrome is a well-described technique with acceptable pain relief expected for a period of 8-12 weeks, this technique provided up to 24 months of adequate pain relief in a patient. While further studies are indicated before widespread adoption can be recommended, this patient's response suggests that this technique may be useful in offering longer-term pain relief compared with trigger point injection therapy.

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.

Effects of Distinct Force Magnitude of Spinal Manipulative Therapy on Blood Biomarkers of Inflammation: A Proof of Principle Study in Healthy Young Adults

OBJECTIVES

The purpose of this preliminary study was to determine the influence of thoracic spinal manipulation therapy (SMT) of different force magnitudes on blood biomarkers of inflammation in healthy adults.

METHODS

Nineteen healthy young adults (10 female, age: 25.6 ± 1.2 years) were randomized into the following 3 groups: (1) control (preload only), (2) single thoracic SMT with a total peak force of 400N, and (3) single thoracic SMT with a total peak force of 800N. SMT was performed by an experienced chiropractor, and a force-plate embedded treatment table (Force Sensing Table Technology) was used to determine the SMT force magnitudes applied. Blood samples were collected at pre intervention (baseline), immediately post intervention, and 20 minutes post intervention. A laboratory panel of 14 different inflammatory biomarkers (pro, anti, dual role, chemokine, and growth factor) was assessed by multiplex array. Change scores from baseline of each biomarker was used for statistical analysis. Two-way repeated-measures analysis of variance was used to investigate the interaction and main effects of intervention and time on cytokines, followed by Tukey's multiple comparison test (P ≤ .05).

RESULTS

A between-group (800N vs 400N) difference was observed on interferon-gamma, interleukin (IL)-5, and IL-6, while a within-group difference (800N: immediately vs 20 minutes post-intervention) was observed on IL-6 only.

CONCLUSION

In this study, we measured short-term changes in plasma cytokines in healthy young adults and found that select plasma pro-inflammatory and dual-role cytokines were elevated by higher compared to lower SMT force. Our findings aid to advance our understanding of the potential relationship between SMT force magnitude and blood cytokines and provide a healthy baseline group with which to compare similar studies in clinical populations in the future.

Repetitive Transcranial Magnetic Stimulation of the Primary Motor Cortex beyond Motor Rehabilitation: A Review of the Current Evidence

Transcranial magnetic stimulation (TMS) has emerged as a novel technique to stimulate the human brain through the scalp. Over the years, identifying the optimal brain region and stimulation parameters has been a subject of debate in the literature on therapeutic uses of repetitive TMS (rTMS). Nevertheless, the primary motor cortex (M1) has been a conventional target for rTMS to treat motor symptoms, such as hemiplegia and spasticity, as it controls the voluntary movement of the body. However, with an expanding knowledge base of the M1 cortical and subcortical connections, M1-rTMS has shown a therapeutic efficacy that goes beyond the conventional motor rehabilitation to involve pain, headache, fatigue, dysphagia, speech and voice impairments, sleep disorders, cognitive dysfunction, disorders of consciousness, anxiety, depression, and bladder dysfunction. In this review, we summarize the latest evidence on using M1-rTMS to treat non-motor symptoms of diverse etiologies and discuss the potential mechanistic rationale behind the management of each of these symptoms.

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.

Pressing Intervention Promotes the Skeletal Muscle Repair of Traumatic Myofascial Trigger Points in Rats

Objective

To observe the effect of pressing intervention on the skeletal muscle repair of myofascial trigger points (MTrPs) in rats and explore the mechanism of pressing intervention on the deactivation of trigger points.

Methods

Thirty SPF rats were randomly divided into blank group, model group and press group, with 10 rats in each group. The MTrPs models were established by blunt striking plus eccentric exercise, and then evaluated. The press group was given a pressing intervention with a self-made device for 14 days, and the rats in the other two groups were fed normally. Soft tissue tension (STT) D_0.2 and pressure pain threshold (PPT) were measured before and after intervention. The skeletal muscle tissue at MTrPs was extracted and assessed by hematoxylin–eosin (HE) and Masson staining. The expression of collagen I, collagen III, α- smooth muscle actin (α-SMA), myosin heavy chain (MHC) and fibronectin (FN) were detected by Western Blotting. Enzyme linked immunosorbent assay (ELISA) was used to evaluate the expression of substance P (SP), 5-hydroxytryptamine (5-HT), cyclooxygenase 2 (COX-2) and prostaglandin E2 (PGE2).

Results

(1) Compared with the blank group, the PPT and D_0.2 reduced (P < 0.05) in the model group; while compared with the model group, the PPT and D_0.2 increased (P < 0.05) in the press group. (2) Compared with the blank group, the model group showed obvious spontaneous potentials with higher amplitude and frequency, which were also much higher than those of the press group (P < 0.05). (3) The HE and Masson staining results showed evident fibrosis in the muscle tissue of the model group, with a larger area of collagen fibers relative to that of the press group (P < 0.05). (4) The amount of collagen I, collagen III, FN, α- SMA, SP, 5-HT, COX-2 and PGE2 increased and the content of MHC decreased (P < 0.05) in the model group, as compared to the blank group; while all the substances (P < 0.05), instead of MHC which increased (P < 0.05), in the press group were decreased as compared to the model group.

Conclusion

Pressing intervention on the MTrPs in rats can alleviate chronic inflammation, inhibit fibrosis, promote skeletal muscle repair and relieve pain.