A critical evaluation of the trigger point phenomenon

Shear Wave Elastography for Measuring the Stiffness of Latent Trigger Points and Surrounding Areas in the Infraspinatus Muscle: Intra- and Interexaminer Reliability Analysis

OBJECTIVES

To explore the intra- and interexaminer reliability of shear wave elastograhy (SWE), (an objective alternative to highly subjective procedures with poor inter-rater reliability such as manual palpation) in measuring the stiffness of latent myofascial trigger points (MTrPs) and healthy surrounding areas in the infraspinatus muscle, pressure pain threshold (PPT), interexaminer reliability, and mean differences in SWE and PPTs between MTrPs and control points.

DESIGN

Longitudinal observational study: Intra- and interexaminer reliability study.

SETTING

A university laboratory.

PARTICIPANTS

Forty participants (N=40) with latent MTrPs within the infraspinatus muscle.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

One experienced examiner identified and classified latent MTrPs and selected an asymptomatic control point within the infraspinatus muscle. Later, 2 blinded examiners assessed once the PPTs (blinded to the scores) and acquired 2 SWE images of each location. Reliability estimates were calculated for assessing PPT interexaminer reliability and SWE intra- and interexaminer reliability. PPT and SWE scores were compared by location (MTrP and control) and gender (male/female).

RESULTS

PPTs were significantly lower in MTrPs than control points in males (P=.003) and females (P=.006), and lower in females than males (MTrP P<.001; control point P=.001). Good interexaminer reliability was found for PPTs (intraclass correlation coefficient [ICC]>0.84) and SWE (ICC>0.82). Intraexaminer reliability for SWE was excellent (ICC>0.95) in both the novice and experienced examiners.

CONCLUSIONS

This study demonstrated excellent SWE intraexaminer reliability (ICCs>0.9) and good interexaminer reliability (ICCs>0.82). Although PPT scores indicated significant differences in hyperirritability between latent MTrPs and control points, SWE measurements revealed no significant differences in muscle stiffness.

Anatomical landmarks and procedure technique of Levator Scapulae Plane Block (LeSP block): Case report: Ultrasound-guided block of the superficial, deep and distal planes of the levator scapulae muscle for treatment of shoulder girdle myofascial pain

Neck pain is a prevalent issue associated with musculoskeletal disorders. This study describes the interfascial Levator Scapulae Plane Block (LeSP Block) technique, using ultrasound guidance for local anesthetic administration to treat chronic neck pain. Two patients, 1 77-year-old female and 1 50-year-old female, underwent the LeSP Block. Immediate postprocedure pain relief was achieved in both, with 1 patient experiencing complete pain remission (VAS = 0) and the other showing significant improvement (VAS = 2) after 30 days. The LeSP Block demonstrated effectiveness and ease of use, suggesting its inclusion in pain management strategies for shoulder girdle and scapular pain. Further anatomical studies aimed at improving the anatomical description of the accessory spinal nerve are recommended to refine the technique.

Critical Appraisal of Clinical Trials Evaluating Physical Therapy Treatments for Temporomandibular Disorders: A Scoping Review

BACKGROUND

Physical therapy seems the most promising treatment for temporomandibular disorders (TMD), although their effectiveness is controversial in general, due to high heterogeneity regarding study designs, applied treatments and outcomes measures.

OBJECTIVES

The aim of this scoping review is to analyse the methodological characteristics of clinical trials evaluating physical therapy treatments in subjects with TMD.

METHODS

A systematic search was conducted in Medline/PubMed, SPORTDiscus, Scopus, Web of Science, SciELO, Cochrane, ScienceDirect and EMBASE databases on 31 October 2023. Clinical trials evaluating physical therapy interventions in patients older than 18 years with TMD, published in English or Spanish languages. Data regarding content reporting of study designs, sample characteristics, interventions and outcome measures was extracted. Descriptive summary statistics were reported.

RESULTS

The search retrieved 15 322 records, and 136 were included. There were 107 randomised clinical trials, 5 non-randomised controlled trials and 24 non-controlled trials. Most studies had moderate to high risk of bias, small sample sizes (median, 44 subjects) and short follow-up periods (1-3 months). The most common diagnostic criteria used was the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) (48.9%). The most reported experimental interventions were manual therapy (40.4%), exercise (30.2%) and electrotherapy modalities (27.2%), and the most common outcome measure domains were pain (83.8%), range of movement (61.8%), disability (45.6%) and mechanosensitivity (29.4%). There was poor content reporting of experimental interventions.

CONCLUSIONS

Current literature of clinical trials of physical therapy interventions for TMD has moderate to high risk of bias, poor content reporting, small sample size and short-term follow-ups which limit internal and external validity, as well as applicability into clinical practice.

Holistic Approaches in Endometriosis - as an Effective Method of Supporting Traditional Treatment: A Systematic Search and Narrative Review

Endometriosis is one of the gynecological diseases where women suffer from pain, quality of life decreased. The aim of this review was to describe the most common non-medical methods used in the treatment of symptoms associated with endometriosis and to determine their effectiveness. The review was performed in PubMed, Embase and Web of Science databases. Randomized controlled trials, case studies, observational studies, retrospective studies, prospective studies, pilot studies, trails, publications in English or Polish were searched based on the Participant-Intervention-Comparator-Outcomes-Study design (PICOS) format. The criteria used to select studies were: women with endometriosis, no cancer, included any physiotherapeutic or non-medical intervention. 3706 articles were found, however only 26 met the inclusion criteria and were included in the review. Quality of the studies was assessed by Risk of Bias 2 tool and ROBINS-1 tool. The most holistic approach used in the treatment of symptoms of endometriosis include physical therapy, manual therapy, electrophysical agents acupuncture, diet and psychological interventions. Most research has focused on relieving pain and increasing quality of life. Non-medical methods showed reduction of symptoms of endometriosis. Physical activity, manual therapy, electrophysical agents, acupuncture, diet and cognitive behavioral therapy showed no negative side effects and reduced pain, what improved the quality of life and reduced the perceived stress.

Effects of platelet-rich plasma injection on electrical activity and biomechanics of the erector spinae muscles in lumbar myofascial pain syndrome

Low back pain (LBP) is a highly prevalent disease. Among the various causes of LBP, one of the most frequent is myofascial pain syndrome (MPS) which affects the spinal stabilizer muscles. The aims of this study were to compare the differences in muscular electrical activity and biomechanical properties between the painful and non-painful sides in patients with unilateral MPS and to verify the feasibility of surface electromyography (sEMG) and MyotonPRO for assisting in MPS assessment. Forty patients with unilateral lumbar MPS were recruited via the Department of Rehabilitation Medicine Center of West China Hospital Sichuan University from October 2022 to October 2023. The electrical properties of the bilateral erector spinae muscles were characterized by sEMG signals during a trunk extension task. The following four time-domain features of sEMG were extracted: root mean square (RMS), mean absolute value (MAV), integrated EMG (iEMG), and waveform length (WL). And two frequency domain features were extracted: the median frequency (MDF) and mean power frequency (MPF). The mechanical properties of the muscles were assessed by MyotonPRO at rest. The following biomechanical parameters were acquired: oscillation frequency [Hz], dynamic stiffness [N/m], logarithmic decrement, relaxation time [ms], and Creep. The visual analog scale (VAS) was used to evaluate the pain severity, and the Oswestry Disability Index (ODI) was used to evaluate the severity of disability and disruption to lifestyle activities caused by LBP pain. The outcome measures were obtained prior to the Platelet-rich plasma (PRP) treatment and repeated two weeks after treatment. (1) Prior to the PRP treatment, all sEMG time-domain features on the painful side were significantly higher than those on the non-painful side (RMS, p < 0.001; MAV, p < 0.001; iEMG, p < 0.001; WL, p = 0.001). However, there was no significant difference in the sEMG frequency-domain features (MPF, p = 0.478; MDF, p = 0.758). On the mechanical side, there were significant differences in oscillation frequency (p = 0.041) and logarithmic decrement (p = 0.022) between the painful side and non-painful side, but no significant differences in dynamic stiffness, relaxation time, and creep (both p > 0.05). (2) Two weeks after the PRP treatment, statistically significant decreases were observed in both post-treatment VAS (p < 0.001) and ODI scales (p < 0.001), indicating the PRP treatment clinically significantly reduced the level of. MPS. This change coincided with all sEMG time-domain features, in which the values at the painful side decreased significantly (RMS, p = 0.001; MAV, p = 0.001; iEMG, p = 0.001; WL, p = 0.001). However, no significant difference in the sEMG frequency-domain features (MPF, p = 0.620; MDF, p = 0.850) was found. On the mechanical side, only logarithmic decrement on the painful side increased significantly (p < 0.001). Our combined MyotonPRO and sEMG results indicated that MPS likely leads to increased muscle tone and decreased muscle elasticity, manifested by abnormal time-domain features of sEMG and biomechanical properties. The changes in these objective measurements were agreed with the changes in subjective outcome measures of pain and function currently assessed in the patients with MPS. A single PRP treatment may alleviate muscle dysfunction caused by MPS. These preliminary results demonstrated the potential feasibility of using sEMG and MyotonPRO as tools for assessing the neuromuscular function of MPS.

Additional Effect of Interfascial Hydrodissection With Dextrose on Shoulder and Neck Function in Patients With Myofascial Pain Syndrome: A Randomized Control Trial

OBJECTIVE

The aim of the study is to evaluate whether the application of an interfascial injection with dextrose water could result in reduced pain and improved shoulder function and range of motion.

DESIGN

This is a double-blind randomized controlled trial. Thirty-five patients with chronic shoulder pain were randomly assigned to receive either an interfascial injection of 10 mL of 10% dextrose water guided by ultrasound or a sham injection of 0.5 mL of 10% dextrose water into the subcutaneous layer. All patients received education on a home program of self-massage and self-stretching. Shoulder pain, shoulder range of motion, and neck and shoulder function were measured before injection and at 4 and 12 wks after injection.

RESULTS

Both groups showed significant improvements in visual analog scale scores at 12-wk follow-up. The interfascial injection group exhibited a significant pain reduction compared with the sham group at the 12-wks follow-up. No between-group differences were observed in shoulder range of motion, pain threshold, and neck and shoulder function.

CONCLUSIONS

Interfascial injection is effective in decreasing pain in patients with myofascial pain syndrome.

Assessment of Lumbar Muscles Activation in Patients with Unilateral Myofascial Pain Syndrome Based on High-density Surface Electromyography: A Preliminary Study

Myofascial pain syndrome (MPS) is a chronic musculoskeletal pain characterized by myofascial trigger points (MTrPs), which are related to dysfunctional motor endplate. However, the changes in neuromuscular functions incurred by the MTrPs are still not well understood. High-density surface electromyography (HD-sEMG) provides a non-invasive method to identify motor endplates and quantify the muscle activity distribution. This study aimed to analyze the differences in lumbar muscle activity distribution between patients with MPS and healthy individuals during an isometric trunk extension task and to compare the location between the centroid of the low-energy region calculated from the HD-sEMG topography and the MTrPs identified by palpation. We observed that the centroid of the low-energy region and the location of the MTrPs identified by palpation are very close to each other. Furthermore, we found that, as the fatiguing task progressed, the muscle activity distribution changed more significantly in healthy participants, compared to MPS patients. These results demonstrated the potential feasibility of using HD-sEMG as a tool for assessing the neuromuscular function of MPS.

Association between myofascial trigger point therapy and conditioned pain modulation

INTRODUCTION

Myofascial trigger point therapy (MTrP) is a widely used therapeutic approach, although the underlying mechanisms remain unclear. Mechanisms discussed include peripheral involvement of muscles as well as central pain modulating processes such as the conditioned pain modulation (CPM). The aim of this study was to investigate whether the analgesic response of MTrP and the analgesic response of CPM correlate in asymptomatic participants in order to identify shared underlying mechanisms of MTrP and CPM.

METHOD

Both, CPM and MTrP protocols consisted of heat-based test stimuli (heat pain thresholds before and after the intervention) and pressure-based (conditioning) stimuli. Asymptomatic participants (n = 94) were randomly assigned to receive either mild, intense or no pressure stimuli (between-group design) to both the fingernail and the MTrP of the infraspinatus muscle (within-group design). Pressure stimuli at both locations (fingernail, MTrP) were applied with a pressure algometer for 120 s and continuously adjusted to maintain a constant pain intensity of mild or intense pain. All thermal stimuli were applied on the lower leg with a thermal stimulator.

RESULTS

A significant correlation was shown between the analgesic effect of CPM and MTrP therapy for mild (r = 0.53, p = 0.002) and intensive stimuli (r = 0.73, p < 0.001). 17.3% of the variance of the MTrP effect were explained by CPM after mild stimulation, and 47.1% after intense stimulation. Pain-related characteristics did not explain the variance within the analgesic response using a regression analysis.

CONCLUSIONS

Between the analgesic responses following MTrP and CPM paradigms, a moderate to strong correlation was observed, suggesting shared underlying mechanisms.

Interventional pathway in the management of refractory post cholecystectomy pain (PCP) syndrome: a 6-year prospective audit in 60 patients

OBJECTIVES

Post cholecystectomy pain syndrome can affect over a third of patients undergoing laparoscopic cholecystectomy. Acute exacerbations can result in recurrent emergency admission with excessive healthcare utilization. Standard surgical management appears to focus on visceral aetiology. Abdominal myofascial pain syndrome is a poorly recognised somatic pathology that can cause refractory pain in this cohort. It develops as a result of trigger points in the abdominal musculature. The report describes the pathophysiology and a novel interventional pathway in the management of post cholecystectomy pain secondary to abdominal myofascial pain syndrome.

METHODS

The prospective longitudinal audit was performed at a tertiary pain medicine clinic in a university teaching hospital. Over a six-year period, adult patients with refractory abdominal pain following laparoscopic cholecystectomy were included in a structured interventional management pathway. The pathway included two interventions. Intervention I was a combination of abdominal plane blocks and epigastric port site trigger injection with steroids. Patients who failed to report durable relief (>50% pain relief at 12 weeks) were offered pulsed radiofrequency treatment to the abdominal planes (Intervention II). Outcomes included patient satisfaction, change in opioid consumption and impact on emergency visits.

RESULTS

Sixty patients who failed to respond to standard management were offered the pathway. Four patients refused due to needle phobia. Fifty-six patients received Intervention I. Failure rate was 14% (8/56). Forty-eight patients (48/56, 86%) reported significant benefit at 12 weeks while 38 patients reported durable relief at 24 weeks (38/56, 68%). Nine patients received Intervention II and all (100%) reported durable relief. Emergency admissions and opioid consumption were reduced.

CONCLUSIONS

Abdominal myofascial pain syndrome is a poorly recognised cause of post cholecystectomy pain. The novel interventional management pathway could be an effective solution in patients who fail to benefit from standard management.

Nerve entry points - The anatomy beneath trigger points

INTRODUCTION

Myofascial trigger points (MTrPs) have been the subject of considerable scientific research for almost forty years. In their seminal paper, Travell and Simons described a model based on the presence of highly irritable, palpable nodules within taut bands of muscle. Since then, a significant number of studies have increased our understanding of the phenomenon, which has, in turn, resulted in refutation of the original model. Alternative models have explained certain properties of MTrP but fail to provide an explanation of their spatial distribution. The aim of this paper was to propose a hypothesis connecting MTrPs and distinct points along the course of the nerve called nerve entry points (NEPs). A literature review was performed in order to identify studies to support hypothesis development.

METHODS

Literature search of digital databases.

RESULTS

A total of 4631 abstracts were screened; 72 were selected for further review. Four articles made a direct connection between MTrPs and NEPs. Another fifteen articles provided high-quality data regarding the distribution of NEPs, thus strengthening the hypothesis.

CONCLUSIONS

There is sufficient evidence to hypothesise that NEPs are the anatomical basis for MTrPs. This presented hypothesis addresses one of the crucial issues in diagnosing trigger points, which is the lack of repeatable and reliable diagnostic criteria. By connecting subjective phenomenon of trigger points with objective anatomy, this paper provides a novel and practical foundation for identifying and treating pain conditions associated with MTrPs.

A New Unified Theory of Trigger Point Formation: Failure of Pre- and Post-Synaptic Feedback Control Mechanisms

The origin of the myofascial trigger point (TrP), an anomalous locus in muscle, has never been well-described. A new trigger point hypothesis (the new hypothesis) presented here addresses this lack. The new hypothesis is based on the concept that existing myoprotective feedback mechanisms that respond to muscle overactivity, low levels of adenosine triphosphate, (ATP) or a low pH, fail to protect muscle in certain circumstances, such as intense muscle activity, resulting in an abnormal accumulation of intracellular Ca²⁺, persistent actin-myosin cross bridging, and then activation of the nociceptive system, resulting in the formation of a trigger point. The relevant protective feedback mechanisms include pre- and postsynaptic sympathetic nervous system modulation, modulators of acetylcholine release at the neuromuscular junction, and mutations/variants or post-translational functional alterations in either of two ion channelopathies, the ryanodine receptor and the potassium-ATP ion channel, both of which exist in multiple mutation states that up- or downregulate ion channel function. The concepts that are central to the origin of at least some TrPs are the failure of protective feedback mechanisms and/or of certain ion channelopathies that are new concepts in relation to myofascial trigger points.

Response to Mechanical Properties and Physiological Challenges of Fascia: Diagnosis and Rehabilitative Therapeutic Intervention for Myofascial System Disorders

Damage to the fascia can cause significant performance deficits in high-performance sports and recreational exercise and may contribute to the development of musculoskeletal disorders and persistent potential pain. The fascia is widely distributed from head to toe, encompassing muscles, bones, blood vessels, nerves, and internal organs and comprising various layers of different depths, indicating the complexity of its pathogenesis. It is a connective tissue composed of irregularly arranged collagen fibers, distinctly different from the regularly arranged collagen fibers found in tendons, ligaments, or periosteum, and mechanical changes in the fascia (stiffness or tension) can produce changes in its connective tissue that can cause pain. While these mechanical changes induce inflammation associated with mechanical loading, they are also affected by biochemical influences such as aging, sex hormones, and obesity. Therefore, this paper will review the current state of knowledge on the molecular level response to the mechanical properties of the fascia and its response to other physiological challenges, including mechanical changes, innervation, injury, and aging; imaging techniques available to study the fascial system; and therapeutic interventions targeting fascial tissue in sports medicine. This article aims to summarize contemporary views.

The Utility of Myotonometry in Musculoskeletal Rehabilitation and Human Performance Programming

Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and a higher incidence of injury. This indicates optimal stiffness levels may promote athletic performance, whereas too much or too little may lead to an increased risk of injury. Authors of numerous studies suggested that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improve athletic performance, mitigate injury risk, guide therapeutic interventions, and optimize return-to-activity decision-making. Thus, the purpose of our narrative review was to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.

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.

A Potential Objective Sign of Central Sensitization: Referred Pain Elicited by Manual Gluteus Minimus Muscle Exploration is Coincident with Pathological Autonomic Response Provoked by Noxious Stimulation

Referred pain/sensation provoked by trigger points suits the nociplastic pain criteria. There is a debate over whether trigger points are related to a peripheral phenomenon or central sensitization (CS) processes. Referred pain is considered a possible sign of CS, which occurs probably mainly due to the abnormal activity of the immune and autonomic nervous systems. To confirm abnormal autonomic reactivity within the referred pain zone of active trigger points, a new diagnostic tool, the Skorupska Protocol® (the SP test®), was applied. The test uses noxious stimulation (10 minutes of dry needling under infrared camera control) as a diagnostic tool to confirm abnormal autonomic nervous system activity. A response to the SP test® of healthy subjects with referred pain sensations provoked by latent trigger points (LTrPs) stimulation was not explored before. The study aims at examining if LTrPs can develop an autonomic response. Methods. Two groups of healthy subjects, (i) gluteus minimus LTrPs with referred pain (n = 20) and (ii) control (n = 27), were examined using the SP test®. Results. Abnormal autonomic activity within the referred pain zone was confirmed for all analyzed LTrPs subjects. 70% of control subjects had no feature of vasodilatation and others presented minor vasomotor fluctuations. The size of vasomotor reactivity within the referred pain zone was LTrPs 11.1 + 10.96% vs. control 0.8 + 0.6% (p < 0.05). Conclusions. Noxious stimulation of latent TrPs induces abnormal autonomic nervous system activity within the referred pain zone. The observed phenomenon supports the concept of central nervous system involvement in the referred pain patomechanizm.

Suboccipital Muscles, Forward Head Posture, and Cervicogenic Dizziness

Dizziness or vertigo can be caused by dysfunction of the vestibular or non-vestibular systems. The diagnosis, treatment, and mechanism of dizziness or vertigo caused by vestibular dysfunction have been described in detail. However, dizziness by the non-vestibular system, especially cervicogenic dizziness, is not well known. This paper explained the cervicogenic dizziness caused by abnormal sensory input with references to several studies. Among head and neck muscles, suboccipital muscles act as stabilizers and controllers of the head. Structural and functional changes of the suboccipital muscles can induce dizziness. Especially, myodural bridges and activation of trigger point stimulated by abnormal head posture may be associated with cervicogenic dizziness.

Dry Needling Alone or in Combination with Exercise Therapy versus Other Interventions for Reducing Pain and Disability in Subacromial Pain Syndrome: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis examined the effects of dry needling alone or in combination with exercise therapy for reducing pain and disability in people with subacromial pain syndrome. Systematic searches of randomized clinical trials (RCTs) were performed in five different databases. A meta-analysis was carried out with the data obtained, and the risk of bias and quality of the studies was assessed using the Cochrane ROB 2.0 and GRADE tools. Finally, five RCTs (n = 315) were included in the meta-analysis and qualitative analysis. Our results determine that dry needling alone or combined with exercise therapy showed improvements in pain in the short-term (5RCTs: SMD: -0.27; [-0.49, -0.05]; low-quality) and mid-term (4RCTs: SMD: -0.27; [-0.51, -0.04]; low-quality) compared to a range of interventions. However, no differences were shown for disability at short-term (3 RCTs: SMD: -0.97; [-2.04, 0.11]; very-low quality) and mid-term (3 RCTs: SMD: -0.85; [-1.74, 0.04]; very-low quality). Dry needling alone or in combination with exercise therapy may result in a slight reduction in pain in the short-term and mid-term. However, the evidence about the effect of this therapy on disability in the short- or mid-term is very uncertain compared to the range of interventions analyzed in this systematic review (Registration: INPLASY202260112).

Clarifying "chronic primary musculoskeletal pain"? The waters remain murky

Commentary on: Fitzcharles M-A, Cohen SP, Clauw DJ, Littlejohn G, Usui C, Häuser W. Chronic primary musculoskeletal pain: a new concept of non-structural regional pain. PAIN Reports 2022;7:e1024. See also: Treede R-D. Chronic musculoskeletal pain: traps and pitfalls in classification and management of a major global disease burden. PAIN Reports 2022;7:e1023.

Scoping review and interpretation of myofascial pain/fibromyalgia syndrome: An attempt to assemble a medical puzzle

BACKGROUND

Myofascial Pain Syndrome (MPS) is a common, overlooked, and underdiagnosed condition and has significant burden. MPS is often dismissed by clinicians while patients remain in pain for years. MPS can evolve into fibromyalgia, however, effective treatments for both are lacking due to absence of a clear mechanism. Many studies focus on central sensitization. Therefore, the purpose of this scoping review is to systematically search cross-disciplinary empirical studies of MPS, focusing on mechanical aspects, and suggest an organic mechanism explaining how it might evolve into fibromyalgia. Hopefully, it will advance our understanding of this disease.

METHODS

Systematically searched multiple phrases in MEDLINE, EMBASE, COCHRANE, PEDro, and medRxiv, majority with no time limit. Inclusion/exclusion based on title and abstract, then full text inspection. Additional literature added on relevant side topics. Review follows PRISMA-ScR guidelines. PROSPERO yet to adapt registration for scoping reviews.

FINDINGS

799 records included. Fascia can adapt to various states by reversibly changing biomechanical and physical properties. Trigger points, tension, and pain are a hallmark of MPS. Myofibroblasts play a role in sustained myofascial tension. Tension can propagate in fascia, possibly supporting a tensegrity framework. Movement and mechanical interventions treat and prevent MPS, while living sedentarily predisposes to MPS and recurrence.

CONCLUSIONS

MPS can be seen as a pathological state of imbalance in a natural process; manifesting from the inherent properties of the fascia, triggered by a disrupted biomechanical interplay. MPS might evolve into fibromyalgia through deranged myofibroblasts in connective tissue ("fascial armoring"). Movement is an underemployed requisite in modern lifestyle. Lifestyle is linked to pain and suffering. The mechanism of needling is suggested to be more mechanical than currently thought. A "global percutaneous needle fasciotomy" that respects tensegrity principles may treat MPS/fibromyalgia more effectively. "Functional-somatic syndromes" can be seen as one entity (myofibroblast-generated-tensegrity-tension), sharing a common rheuma-psycho-neurological mechanism.

Local myalgia compared to myofascial pain with referral according to the DC/TMD: Axis I and II results

BACKGROUND

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) categorized TMD muscle disorders into 3 subgroups: local myalgia, myofascial pain with spreading and myofascial pain with referral. However, the rationale for such division into subgroups and the pathogenesis and prognosis of muscle-related TMD are still poorly understood. The aim of this study was to explore the differences between local myalgia and myofascial pain with referral by means of a biopsychosocial model based on the DC/TMD.

METHODS

This retrospective study included all consecutive TMD patients who were diagnosed according to the DC/TMD in our institution between 2015 and 2018. The Axis I and II findings of patients diagnosed with local myalgia were compared to those of patients with myofascial pain with referral. A p value < 0.05 was considered statistically significant.

RESULTS

A total of 255 patients (61 men and 194 women, mean age 37.8 ± 15.34 years) were enrolled into the study, 114 in the local myalgia group and 83 in the myofascial pain with referral group. The levels of depression and nonspecific physical symptoms, headache attributed to TMD (HAattrTMD), and characteristic pain intensity (CPI) were significantly higher in the latter group. The significant differences for depression and nonspecific physical symptoms persisted after excluding patients diagnosed with HAattrTMD, however, the levels of significance were lower (p = 0.006 compared to p = 0.033 for depression total score, and p = 0.001 compared to p = 0.046 for nonspecific physical symptoms total score). CPI levels, extent of disability, and pain duration were similar for both groups when excluding for HAattrTMD.

CONCLUSION

The current study findings highlight the importance of differentiating between subgroups of myalgia according to the DC/TMD. The diagnosis of myofascial pain with referral may point to a significant Axis II component.

Amplified Vasodilatation within the Referred Pain Zone of Trigger Points Is Characteristic of Gluteal Syndrome-A Type of Nociplastic Pain Mimicking Sciatica

Gluteal syndrome (GS) mimicking sciatica is a new disease that has been recently recognized and included in the International Classification of Diseases, 11th Revision. The present study examines nociplastic pain involvement in GS and sciatica patients using a new Skorupska protocol (SP) test that provokes amplified vasodilatation in the area of expected muscle-referred pain. A positive test is confirmed if there is (i) a development of autonomic referred pain (AURP) and (ii) an increase in the delta of average temperature (Δ₸°) > 0.3 °C at the end of the stimulation and during the observation SP phases. Chronic GS (n = 20) and sciatica (n = 30) patients were examined. The SP test confirmed muscle-referred pain for (i) all GS patients with 90.6% positive thermograms (Δ₸° 0.6 ± 0.8 °C; maximum AURP 8.9 ± 13.6% (both p < 0.05)) and (ii) those sciatica (n = 8) patients who reported pain sensation during the test with 20.6% positive thermograms (Δ₸° 0.7 ± 0.7 °C; maximum AURP 15.1 ± 17.8% (both p < 0.05)). The remaining sciatica (n = 22) patients did not report pain during the test and presented a Δ₸° decrease and the AURP size below 1%. Conclusion: Amplified vasodilatation suggesting nociplastic pain involvement was confirmed for all GS and sciatica patients who reported painful sensations in the zone typical for gluteus minimus referred pain during the test.

The Area of Pressure-Induced Referred Pain Is Dependent on the Intensity of the Suprathreshold Stimulus: An Explorative Study

OBJECTIVE

To investigate the pain referral area (number of pixels) and extent (vector length) as elicited from increasing intensities of pressure-induced pain at the shoulder.

DESIGN

Cross-sectional design.

SETTING

Clinical laboratory setting.

PARTICIPANTS

Twenty-two healthy men and women participated in two experimental sessions.

METHODS

Delayed onset of muscle soreness (DOMS) was induced in the dominant shoulder and assessed 24 hours later. Participants rated the level of DOMS on a 6-point Likert scale. Four different intensities (pressure pain threshold [PPT]+20%, PPT+30%, PPT+40%, and PPT+50%) were applied to the infraspinatus in a randomized, balanced fashion for 60 seconds from low to high intensity or vice versa. The resulting location, area, and extent of referred pain as drawn by the participants on a digital body chart were extracted and expressed in pixels. The extent of pain was defined as the vector length extending from the ipsilateral earlobe to the most distal location of the pain.

RESULTS

The referred pain area from PPT+20% was smaller than PPT+30%, PPT+40%, and PPT+50%. The extent of referred pain did not differ between the pressure pain intensities.

CONCLUSIONS

Pressure intensity at PPT+30%, but no more, produces the greatest referred pain area as compared with the traditional pressure intensity of PPT+20%. Thus, the intensity of PPT+30% may be ideal for exploring the mechanisms of referred pain. The extent of the pain represents an independent expression of the intensity of the provoking stimulus and may be more closely related to the location of the stimulus.

Interventional treatment for myofascial pelvic floor pain in women: systematic review with meta-analysis

INTRODUCTION AND HYPOTHESIS

Female myofascial pain (MFP) of the pelvic floor muscles (PFM) is a subtype of chronic pelvic pain associated with urinary, anorectal, and sexual symptoms, such as dyspareunia. Treatment remains poorly discussed, and we hypothesized that different treatments could improve outcomes versus placebo or no treatment.

METHODS

A systematic review (CRD 42020201419) was performed in June 2020 using the following databases: PubMed, Cochrane Library, Web of Science, Embase, Scopus, BVSalud, Clinicaltrials.gov , and PEDro, including randomized clinical trials related to MPF of PFM. Primary outcome was pain after treatment, and secondary outcomes were quality of life and sexual function. Risk of bias and quality of evidence (GRADE criteria) were evaluated. Meta-analysis for continuous variables was performed (mean difference between baseline and treatment and post-treatment mean between groups).

RESULTS

Five studies were included (n = 218). Final mean VAS score (GRADE: very low) after 4 weeks of treatment (p = 0.14) and the mean difference from baseline and 4 weeks (p = 0.66) between groups were not different between the intervention and control groups. Quality of life according to the SF-12 questionnaire (GRADE: very low) followed the same pattern. However, sexual function (GRADE: low) according to the total FSFI score (MD = -5.07 [-8.31, -1.84], p < 0.01, i² = 0%) and the arousal, orgasm, and pain domains improved in the intervention groups when the mean difference from baseline and 4 weeks was compared with controls.

CONCLUSION

Pain and quality of life after 4 weeks of heterogeneous intervention differed between the intervention and control groups in sexual function: FSFI in studies improved in almost all domains. VAS (in three studies) and SF-12 (in two studies) failed to demonstrate differences.

Invasive and Non-Invasive Electrical Neuromodulation in Trigeminal Nerve Neuralgia: A Systematic Review and Meta-Analysis

BACKGROUND

Trigeminal neuralgia is a chronic disease characterized by intense facial pain that is caused by trigeminal nerve affectation. It usually affects adults from 50 years of age, and is more frequent in women. Additionally, it presents serious psychological effects that often lead to depression, which is why it is considered highly disabling. The therapeutic approach is based on the modification of nerve activity through electrical, surgical or chemical stimulation in specific regions of the nervous system.

OBJECTIVE

To perform a meta-analysis of the scientific literature related to invasive and non-invasive electrical neuromodulation of trigeminal neuralgia, in order to assess their effects over pain and adverse effects.

METHODS

A literature search was conducted in 4 databases, followed by a manual search of articles on invasive or non-invasive electrical neuromodulation to control the pain of trigeminal neuralgia, including the last 15 years.

RESULTS

Regarding non-invasive methods, clinical trials did not present enough results in order to perform a meta-analysis. Regarding invasive methods, clinical trials meta-analysis showed no statistical differences between different treatment methods. In all cases, improvements in patients' pain were reported, although results regarding adverse effects were variable.

CONCLUSION

In the treatment of trigeminal neuralgia, the continuous radiofrequency provides better short and medium-term results, but pulsed radiofrequency shows less adverse effects after treatment, and has better results in the long-term.

The Case for Comorbid Myofascial Pain-A Qualitative Review

Myofascial pain syndrome is widely considered to be among the most prevalent pain conditions, both in the community and in specialized pain clinics. While myofascial pain often arises in otherwise healthy individuals, evidence is mounting that its prevalence may be even higher in individuals with various comorbidities. Comorbid myofascial pain has been observed in a wide variety of medical conditions, including malignant tumors, osteoarthritis, neurological conditions, and mental health conditions. Here, we review the evidence of comorbid myofascial pain and discuss the diagnostic and therapeutic implications of its recognition.

Myofascial pain syndrome and trigger points: evaluation and treatment in patients with musculoskeletal pain

PURPOSE OF REVIEW

Myofascial pain syndrome is a chronic pain condition characterized by the presence of myofascial trigger point, a hyperirritable painful spot involving a limited number of muscle fibers. The literature suggest that myofascial trigger points should be considered peripheral pain generators and this critical review will summarize recent findings concerning the clinical evaluation and the treatment of myofascial trigger points.

RECENT FINDINGS

The clinical features of myofascial trigger points and their contribution to the patient pain and disability have been detailed in several recent studies, which support the clinical relevance of the condition. Recent studies reported that manual palpation to identify MTrPs has good reliability, although some limitations are intrinsic to the diagnostic criteria. During the last decade, a plethora of treatments have been proposed and positive effects on pain and function demonstrated.

SUMMARY

The myofascial trigger point phenomenon has good face validity and is clinically relevant. Clinicians are encouraged to consider the contribution of myofascial trigger points to the patient's pain and disability through a careful medical history and a specific manual examination. Patients with myofascial trigger points will benefit from a multimodal treatment plan including dry needling and manual therapy techniques. Internal and external validity of research within the field must be improved.

The relationship between citations, downloads and alternative metrics in rheumatology publications: a bibliometric study

OBJECTIVE

Scientific journals and authors are frequently judged on 'impact'. Commonly used traditional metrics are the Impact Factor and H-index. However, both take several years to formulate and have many limitations. Recently, Altmetric-a metric that measures impact in a non-traditional way-has gained popularity. This project aims to describe the relationships between subject matter, citations, downloads and Altmetric within rheumatology.

METHODS

Data from publications in Rheumatology were used. Articles published from 2010 to 2015 were reviewed. Data were analysed using Stata 14.2 (StataCorp, College Station, TX, USA). Correlation between citations, downloads and Altmetric were quantified using linear regression, comparing across disease topics. Relationship between downloads and months since publications were described using negative binomial regression, clustering on individual articles.

RESULTS

A total of 1460 Basic Science and Clinical Science articles were identified, with the number of citations, downloads and Altmetric scores. There were no correlations between disease topic and downloads (R2 = 0.016, P = 0.03), citations (R2 = 0.011, P = 0.29) or Altmetric (R2 = 0.025, P = 0.02). A statistically significant positive association was seen between the number of citations and downloads (R2 = 0.29, P < 0.001). No correlations were seen between Altmetric and downloads (R2 = 0.028, P < 0.001) or citations (R2 = 0.004, P = 0.445).

CONCLUSION

Disease area did not correlate with any of the metrics compared. Correlations were apparent with clear links between downloads and citations. Altmetric identified different articles as high impact compared with citation or download metrics. In conclusion: tweeting about your research does not appear to influence citations.

Interprofessional Collaboration in Dentistry: Role of physiotherapists to improve care and outcomes for chronic pain conditions and sleep disorders

Physiotherapists can manage chronic pain patients by using technical interventions such as mobility, strengthening, manual therapy, or flexibility in a specific and functional manner, being a key component of a multidisciplinary team. Dentists are involved in the management of different chronic pain conditions such as temporomandibular disorders and sleep disorders such as obstructive sleep apnea. However, they are frequently unaware of the benefits of collaborating with physical therapists. In this review, the collaboration of physical therapists and dentists will be explored when managing orofacial pain, headaches, and sleep disorders. The physical therapist is important in the management of these disorders and also in the screening of risk factors.

State of the art: What have the pain sciences brought to physiotherapy?

Background

Pain is the most common reason for patients to seek help from a health care professional. In the past few decades, research has yielded gains in the Pain Sciences - multiple fields of scientific research that, when integrated, help to clarify what causes and influences human pain.

Objectives

In this article, we discuss the key areas in which the Pain Sciences have shifted the physiotherapy profession.

Method

A narrative review of the Pain Sciences literature was conducted. The review analyses how the Pain Sciences have influenced physiotherapy in several categories: assessment; clinical reasoning; treatment; research rigor and building the profile of the profession.

Results

Scientific research on pain has largely converged in support of three ‘game-changing’ concepts that have shifted the physiotherapy profession’s understanding and treatment of pain: (1) pain is not a signal originating from bodily tissues, (2) pain is not an accurate measure of tissue damage and (3) the plasticity of the nervous system means the nervous system itself is a viable target of treatment. These three concepts have influenced physiotherapy assessment and treatment approaches, and research design to consider pain mechanisms using patient-centred models.

Conclusion

The Pain Sciences have shifted physiotherapists’ assessment and treatment approaches and shifted the status of the physiotherapy profession. Ultimately the Pain Sciences have embedded interdisciplinary teams and expanded physiotherapy practice.

Clinical implications

We believe that the pain sciences should be embedded in undergraduate and postgraduate education and training of physiotherapists (including the three key concepts regarding pain) to benefit physiotherapists and their patients.

The effect of the twin block compared with trigger point injections in patients with masticatory myofascial pain: a pilot study

OBJECTIVE

The twin block, a novel nerve block that blocks the deep temporal and masseteric branches of the trigeminal nerve, has been shown to be effective in the short-term management of masticatory myofascial pain. However, little is known about its effectiveness in long-term management. The objective of this study was to assess the efficacy of the twin block in comparison with trigger point injections for the treatment of masticatory myofascial pain.

STUDY DESIGN

Forty-eight patients age 18 to 89 years were randomly assigned to the twin block group (n = 23) or the trigger point injection group (n = 25). The final analysis was based on a total number of 40 patients.

RESULTS

Mean numerical pain intensity at baseline was 6.54 ± 1.90 for the trigger point injection group and 6.47 ± 2.23 for the twin block group. At the 6th month visit, it was 1.85 ± 1.85 for the trigger point injection group and 1.85 ± 1.94 for the twin block group. There were no statistically significant differences in pain intensity between the 2 groups at baseline (P = .64) and at the 6th month follow-up (P = .45).

CONCLUSIONS

The twin block is effective in the long-term management of masticatory myofascial pain compared with trigger point injections.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03870191.

An Anatomical Basis for the Myofascial Trigger Points of the Abductor Hallucis Muscle

Myofascial pain syndrome is characterized by pain and a limited range of joint motion caused by muscle contracture related to motor-end-plate dysfunction and the presence of myofascial trigger points (MTrPs). It is the most frequent cause of musculoskeletal pain, with a worldwide prevalence varying between 13.7% and 47%. Of the patients with myofascial pain syndrome, approximately 17% have pain in the medial hindfoot area. The abductor hallucis muscle is located in the medial, posterior region of the foot and is related to painful plantar syndromes. The objective of this study was to describe the distribution of the medial plantar nerve and their anatomical relationship with MTrPs found in the literature. Thirty abductor hallucis muscles were dissected from 15 human cadavers (8 males and 7 females). The muscles were measured, and the distribution data of the medial plantar nerve branches in each quadrant were recorded. For statistical analysis, we used generalized estimation equations with a Poisson distribution and a log logarithm function followed by Bonferroni multiple comparisons of the means. The data are expressed as the mean ± standard deviation. The level of significance was adjusted to 5% (p < 0.05). A high concentration of nerve branches was observed in the first quadrant (Q1) of the abductor hallucis muscle, which is the same area in which the MTrPs are described. The topography of the entry points of the branches of the medial plantar nerve to the abductor hallucis muscle correlates with the topography of the muscular trigger points. The anatomical structure of the MTrPs may be useful for a better understanding of the pathophysiology of myofascial disorders and provide a basis for surgical and clinical treatments.

Myofascial trigger points alter the modular control during the execution of a reaching task: a pilot study

Myofascial trigger points (TP) constitute a conundrum in research and clinical practice as their etiopathogenesis is debated. Several studies investigating one or few muscles have shown that both active and latent TP causes an increased muscle activity, however the influence of TP on modular motor control during a reaching task is still unclear. Electromyographic signals, recorded from the muscles of the shoulder girdle and upper arm during a reaching task, were decomposed with Non-Negative Matrix Factorization algorithm. The extracted matrices of motor modules and activation signals were used to label the muscles condition as dominant or non-dominant. The presence of latent and active TP was detected in each muscle with manual examination. Despite a similar muscle activity was observed, we found that muscles with active TP had increased weighting coefficients when labeled in the dominant condition. No influences were found when muscles were in the non-dominant condition. These findings suggest that TP altered the motor control without co-contraction patterns. As a preliminary evidence, the present results suggest that the increased weighting coefficients in presence of TPs are associated with an alteration of the modular motor control without affecting the dimensionality of motor modules for each individual and reciprocal inhibition.

Inter and Intra Operator Reliability of Motor and Palpation Evaluation in Fascial Manipulation in individuals with coxarthrosis

OBJECTIVE

An inter and intra rater reliability (INTERR and INTRAR) study was designed.

METHODS

71 subjects, with primary hip coxarthrosis, were included and randomly divided in a study group (SG= 36) and a control group (CG= 35) to assess the efficacy of the Fascial Manipulation® (FM®) method. The primary objective was the assessment of INTERR and INTRAR about movement verification (MV) and palpation verification (PV) of FM® performed by two physiotherapists (PtA and PtB). The secondary objective was evaluate the efficacy of FM® through MV, PV and pain score. Pain was assessed using the Numeric Rating Scale (NRS). SG received three weekly sessions of FM® byPtA. PtB re-evaluated all the subjects at the end of the study.

RESULTS

Results of the INTERR analysis showed for SG: MV (ICC= 0.92, k= 72.7%); PV (ICC= 0.91, k= 75.7%). For CG : MV (ICC= 0.95, k= 84.2%); PV (ICC= 0.90, k= 75%). Results of the INTRAR analysis for SG reported: MV (ICC= 0.82, k= 74,8%); PV (ICC= 0.60, k= 46.8%); for CG: MV (ICC= 0.93, k= 78.7%); PV (ICC= 0.84, k= 53.3%). Statistical significance were reported in NRS (p = 0.001), MV (p = 0.0003) and PV (p < 0.0001) with better results for SG using "Intention To Treat" method.

DISCUSSION

This study demonstrates that FM® assessment procedures have a high reliability even if applied by practitioners with basic experience. Furthermore FM® treatment can improve pain and ROM in individuals with primary coxarthrosis.

Placebo trials without mechanisms: How far can they go?

In this paper, I suggest that placebo effects, as we know them today, should be understood as experimental phenomena, low-level regularities whose causal structure is grasped through particular experimental designs with little theoretical guidance. Focusing on placebo interventions with needles for pain reduction -one of the few placebo regularities that seems to arise in meta-analytical studies- I discuss the extent to which it is possible to decompose the different factors at play through more fine-grained randomized clinical trials. My sceptical argument is twofold. On the one hand, I argue that experiments alone are not enough to standardize interventions, and that it is necessary to include theories. On the other hand, I argue that the social interactions that seem to be part of placebo effects are difficult, if not impossible, to blind. Therefore, the measurement biases arising from the participants' reactivity to the experimental setup cannot be controlled for. Further decomposition of placebo effects requires a theoretical account of the existing experimental regularities that may guide further tests.

Pathophysiology and Management of Abdominal Myofascial Pain Syndrome (AMPS): A Three-Year Prospective Audit of a Management Pathway in 120 Patients

Background

Chronic abdominal wall pain arising from the myofascial structures is termed abdominal myofascial pain syndrome and is an important cause of refractory abdominal pain that utilizes significant health care costs. The current literature is vague on its management.

Design

The author presents a prospective audit of a structured management pathway and discusses the pathophysiology of abdominal myofascial pain syndrome. The objective was to identify an effective and durable treatment for the individual patient and evaluate patient satisfaction with the management pathway.

Methods

Over a three-year period, 120 patients diagnosed with abdominal myofascial pain syndrome were included in a structured management pathway and were prospectively audited at a tertiary care university hospital.

Results

Patient satisfaction with the pathway was high. Trigger point injection with local anesthetic was useful in diagnosis but ineffective in providing durable relief. Trigger point injection with steroids and pulsed radiofrequency treatment of trigger point(s) were effective therapeutic interventions, providing durable relief lasting six months in 32% and 60%, respectively. There was improvement reported in pain intensity scores, quality of life, anxiety, and depression scores following the interventional management of abdominal myofascial pain syndrome.

Conclusions

Abdominal myofascial pain syndrome is often unrecognized, especially in patients with a history of visceral inflammation. The suggested pathway may be an option in its management. Trigger point injection with steroids may have a role in the differential diagnosis of chronic abdominal pain.

A randomized clinical trial comparing non-thrust manipulation with segmental and distal dry needling on pain, disability, and rate of recovery for patients with non-specific low back pain

Objective: The purpose of this study was to examine the within and between-group effects of segmental and distal dry needling (DN) without needle manipulation to a semi-standardized non-thrust manipulation (NTM) targeting the symptomatic spinal level for patients with non-specific low back pain (NSLBP). Methods: Sixty-five patients with NSLBP were randomized to receive either DN (n = 30) or NTM (n = 35) for six sessions over 3 weeks. Outcomes collected included the oswestry disability index (ODI), patient specific functional scale (PSFS), numeric pain rating scale (NPRS), and pain pressure thresholds (PPT). At discharge, patients perceived recovery was assessed. Results: A two-way mixed model ANOVA demonstrated that there was no group*time interaction for PSFS (p = 0.26), ODI (p = 0.57), NPRS (p = 0.69), and PPT (p = 0.51). There was significant within group effects for PSFS (3.1 [2.4, 3.8], p = 0.018), ODI (14.5% [10.0%, 19.0%], p = 0.015), NPRS (2.2 [1.5, 2.8], p = 0.009), but not for PPT (3.3 [0.5, 6.0], p = 0.20). Discussion: The between-group effects were neither clinically nor statistically significant. The within group effects were both significant and exceeded the reported minimum clinically important differences for the outcomes tools except the PPT. DN and NTM produced comparable outcomes in this sample of patients with NSLBP. Level of evidence: 1b.

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.

[An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for the conservative and non-pharmacological management of female pelvic floor dysfunction]

INTRODUCTION

There has been an increasing need for the terminology for the conservative management of female pelvic floor dysfunction to be collated in a clinically-based consensus report.

METHODS

This report combines the input of members and elected nominees of the Standardization and Terminology Committees of two International Organizations, the International Urogynecological Association (IUGA) and the International Continence Society (ICS), assisted at intervals by many external referees. An extensive process of nine rounds of internal and external review was developed to exhaustively examine each definition, with decision-making by collective opinion (consensus). Before opening up for comments on the webpages of ICS and IUGA, five experts from physiotherapy, neurology, urology, urogynecology and nursing were invited to comment on the paper.

RESULTS

A terminology report for the conservative management of female pelvic floor dysfunction, encompassing over 200 separate definitions, has been developed. It is clinically-based with the most common symptoms, signs, assessments, diagnoses and treatments defined. Clarity and user-friendliness have been key aims to make it interpretable by practitioners and trainees in all the different specialty groups involved in female pelvic floor dysfunction. Ongoing review is not only anticipated but will be required to keep the document updated and as widely acceptable as possible.

CONCLUSION

A consensus-based terminology report for the conservative management of female pelvic floor dysfunction has been produced aimed at being a significant aid to clinical practice and a stimulus for research.

Comparison of masseter muscle referred sensations after mechanical and glutamate stimulation: a randomized, double-blind, controlled, cross-over study

Referred sensations (RS) are commonly found in various musculoskeletal pain conditions. Experimental studies have shown that RS can be elicited through glutamate injection and mechanical stimulation. Despite this, differences and similarities between these modalities in RS outcomes remain unclear. The aim of this study was to assess differences between mechanical-induced and glutamate injection-induced RS in the trigeminal region. The present randomized, double-blind, controlled, cross-over study recruited 60 healthy participants who were assessed in 2 different sessions. In both sessions, pressure was applied to the masseter muscle with 4 different forces (0.5, 1, 2, and 4 kg), and glutamate (1 mol/L or 0.25 mol/L) was injected into the same area. Participants rated their perceived masseter sensations and rated and drew any RS they experienced. No difference was found in number of participants reporting RS after glutamate injection compared with mechanical stimulation. More participants reported RS when the stimulus was painful compared with a nonpainful stimulus. Furthermore, it was shown that the more intense the stimulus, the higher the frequency of RS. Finally, RS centre-of-gravity location was similar between the 2 sessions. In summary, RS was elicited in healthy individuals through both modalities, and no differences in frequency of RS were observed in the orofacial region. Hence, RS does not seem to be modality-dependent, and only the painfulness of the stimulus caused an increase in frequency of RS. Finally, RS location for each participant was similar in both sessions possibly indicating a preferred location of referral. These findings may have implications for our understanding of RS in craniofacial pain conditions.

Trigger Point Sensitivity Is a Differentiating Factor between Cervicogenic and Non-Cervicogenic Headaches: A Cross-Sectional, Descriptive Study

Purpose: A common factor in all forms of headache is the presence of myofascial trigger points (TrPs). The aim of this study was to compare the presentation of patients with cervicogenic headaches and patients with non-cervicogenic headaches in the sensitivity of TrPs in their upper trapezius, sternocleidomastoid, temporalis, and posterior cervical muscles. Method: This was a descriptive, cross-sectional study. The following variables were compared between patients with cervicogenic (n=20) and patients with non-cervicogenic (n=20) headaches: sensitivity (pain-pressure threshold) of TrPs in the upper trapezius, sternocleidomastoid, posterior cervical, and temporalis muscles (using a handheld, digital algometer); level of disability (using the Henry Ford Hospital Headache Disability Inventory questionnaire); demographics (age, sex); anthropometrics (BMI); and clinical presentation (duration and intensity of symptoms). The independent Student t-test and χ² test were used to determine the differences between the two groups. Effect sizes (Cohen's d) were calculated when relevant. Results: The two groups were similar in level of disability, demographic and anthropometric data, and clinical presentation. However, TrP sensitivity in the right upper trapezius (p=0.006; Cohen's d=0.96) and the left upper trapezius (p=0.003; Cohen's d=1.06) muscles was higher in the cervicogenic group. Conclusions: Increased sensitivity of TrPs in the upper trapezius muscle may be used as a differentiating factor in the diagnosis of cervicogenic headaches. This finding emphasizes the importance of integrating this muscle into the rehabilitation programs of patients with cervicogenic headache.