Pathophysiologic and electrophysiologic mechanisms of myofascial trigger points

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Therapeutic Effects of Dry Needling on Lateral Epicondylitis: An Updated Systematic Review and Meta-analysis

OBJECTIVE

To investigate the therapeutic effects of dry needling on lateral epicondylitis and identify a relatively more effective needling technique.

DATA SOURCES

English databases (Pubmed, Web of Science, Scopus, EBSCO, ScienceDirect, Taylor & Francis, ProQuest, Cochrane, Ovid, and Embase) and Chinese databases (China National Knowledge Infrastructure, Wanfang, and VIP) were searched.

STUDY SELECTION

This study included randomized controlled trials for comparing the effectiveness of dry needling with other treatment methods for lateral epicondylitis. The primary outcome measures were pain intensity and elbow disability, while the secondary outcome measures included grip strength and upper limb function.

DATA EXTRACTION

Data extraction was performed by 2 researchers who used the Cochrane risk of bias analysis tool and the Physiotherapy Evidence Database checklist to assess the risk of bias and methodological quality of the included studies. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to assess the quality of evidence.

DATA SYNTHESIS

A total of 17 studies that involved 979 subjects were included in this research. Dry needling exhibited a significant advantage in improving pain intensity among patients with lateral epicondylitis within 1 week after treatment (mean difference [MD]=-0.95, 95% confidence interval [CI], -1.88 to -0.02). Within 1 week and in the follow-ups that exceeded 1 week, dry needling also demonstrated better improvement in elbow disability (<1 week: standardized mean difference [SMD]=-1.37, 95% CI, -1.88 to -0.86; ≥1 week: SMD=-1.32, 95% CI, -2.23 to -0.4) and grip strength (<1 week: SMD=0.27, 95% CI, 0.01 to 0.53; ≥1 week: SMD=0.45, 95% CI, 0.02 to 0.88). Trigger point dry needling with local twitch response exhibited more significant improvement in pain intensity within 1 week (MD=-1.09, 95% CI, -1.75 to -0.44).

CONCLUSIONS

Dry needling demonstrates good therapeutic effects on pain intensity (within 1 week), function, and grip strength among patients with lateral epicondylitis. Local twitch response is necessary in treatment that targets trigger points.

Effect of Mirror Therapy on Post-Needling Pain Following Deep Dry Needling of Myofascial Trigger Point in Lateral Elbow Pain: Prospective Controlled Pilot Trial

Background: This prospective randomized, controlled pilot trial to explore the immediate effect of adding Mirror Visual Feedback Therapy on pain sensitivity and motor performance among subjects suffering from post-needling pain diagnosed as Lateral Elbow Pain. Methods: A total of 49 participants (23 female, 26 male) were enrolled and randomly allocated to either the experimental group, which received Deep Dry Needling in the m. Brachioradialis, Ischemic Compression, Cold Spray, Stretching, and Mirror Visual Feedback Therapy (n = 25), or a control group without Mirror Visual Feedback Therapy (n = 24). Pre- and post-treatment evaluations included assessments of post-needling pain intensity, pressure pain threshold, two-point discrimination threshold, and maximum hand grip strength. Results: Intergroup analysis revealed a statistically significant reduction in post-needling pain intensity favoring the experimental group (U = 188.00, p = 0.034). Additionally, intragroup analysis showed significant improvements in post-needling pain intensity (MD = 0.400, SEM = 0.271, W = 137.00, p = 0.047) and pressure pain threshold (MD = 0.148 Kg/cm2, SEM = 0.038, W = 262.00, p < 0.001) within the experimental group following the intervention. Conclusions: These findings suggest a potential benefit of integrating Mirror Visual Feedback Therapy into treatment protocols for individuals with Lateral Elbow Pain experiencing post-needling discomfort. Further research is necessary to fully elucidate the clinical implications of these findings.

Anatomical Bases of the Temporal Muscle Trigger Points

Method

Temporal muscles of 14 adult cadavers were studied. The muscle bellies were divided into six areas, three superior (1.2 and 3) and three inferior areas (4, 5, and 6) lower, according to a Cartesian plane to analyze and describe the entry points of the branches of the deep temporal nerves into the muscle. The branching distribution was analyzed using Poisson log-linear tests with Bonferroni post hoc tests for comparison between groups (sextants) (p < 0.05).

Results

Deep temporal nerve entry points were found in the temporal muscle in all areas. Most of the branches were observed in areas 2 and 5, which coincide with the muscle fibers responsible for mandible elevation and related to the previously described MTPs. Fewer branches were found in areas 1 and 6, where contraction produces mandible retraction.

Conclusion

There is an anatomical correlation between the branching pattern of the deep temporal nerve and temporal muscle trigger points. Adequate knowledge of the innervation of the temporal muscle may help elucidate the pathophysiology of myofascial syndromes and provide a rational basis for interventional or conservative approaches and help surgeons avoid iatrogenic lesions to the deep temporal nerve lesion.

Assessment of the Performance of Ultrasonography for Detecting Myofascial Trigger Points

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

Effects of Self-Myofascial Release on Athletes' Physical Performance: A Systematic Review

Therapists and strength and conditioning specialists use self-myofascial release (SMR) as an intervention tool through foam rollers or massage rollers for soft tissue massage, with the purpose of improving mobility in the muscular fascia. Moreover, the use of SMR by professional and amateur athletes during warm-ups, cool downs, and workouts can have significant effects on their physical performance attributes, such as range of motion (ROM) and strength. The purpose of this study was to analyse the literature pertaining to these types of interventions and their effects found in different physical performance attributes for athletes. A systematic search was carried out using the following databases: PUBMED, ISI Web of Science, ScienceDirect, and Cochrane, including articles up to September 2023. A total of 25 articles with 517 athletes were studied in depth. SMR seems to have acute positive effects on flexibility and range of motion, without affecting muscle performance during maximal strength and power actions, but favouring recovery perception and decreasing delayed-onset muscle soreness. Some positive effects on agility and very short-range high-speed actions were identified, as well. In conclusion, although there is little evidence of its method of application due to the heterogeneity in that regard, according to our findings, SMR could be used as an intervention to improve athletes' perceptual recovery parameters, in addition to flexibility and range of motion, without negatively affecting muscle performance.

Treatment of postsurgical gastroparesis syndrome with Fu's subcutaneous needling: A case report

Postsurgical gastroparesis syndrome is a syndrome of significantly delayed gastric emptying in the absence of mechanical obstruction after surgery. We presented a case of 69-year-old male patient who suffered from progressive nausea, vomiting and stomach fullness, with a bloating abdomen ten days after laparoscopic radical gastrectomy for gastric cancer. Conventional treatments such as gastrointestinal decompression, gastric acid suppression therapy and intravenous nutritional support were administrated, but there were no obvious improvements in nausea, vomiting, abdominal distension of this patient. Fu's subcutaneous needling was performed once a day for three days, for a total of three treatments. After three days of Fu's subcutaneous needling intervention, he was free of symptoms of nausea, vomiting and stomach fullness. His gastric drainage volume reduced from 1000 ml per day to 10 ml per day. Upper gastrointestinal angiography showed normal peristalsis of remnant stomach. In this case report, Fu's subcutaneous needling showed a potential role of gastrointestinal motility enhancement and gastric drainage volume decrement, which provided a safe and convenient method in palliative care of postsurgical gastroparesis syndrome.

Self-Massage Techniques for the Management of Pain and Mobility With Application to Resistance Training: A Brief Review

ABSTRACT

MacLennan, M, Ramirez-Campillo, R, and Byrne, PJ. Self-massage techniques for the management of pain and mobility with application to resistance training: a brief review. J Strength Cond Res 37(11): 2314-2323, 2023-Fascial restrictions that occur in response to myofascial trigger points (MTrP), exercise-induced muscle damage (EIMD), and delayed onset of muscle soreness (DOMS) cause soft tissue to lose extensibility, which contributes to abnormal muscle mechanics, reduced muscle length, and decrements in joint range of motion (ROM) and actively contributes to musculoskeletal pain. Resistance training and in particular, weightlifting movements have unique mobility requirements imperative for movement efficacy and safety with ROM restrictions resulting in ineffective volume and intensity tolerance and dampened force output and power, which may lead to a failed lift or injury. Self-massage (SM) provides an expedient method to promote movement efficiency and reduce injury risk by improving ROM, muscular function, and reducing pain and allows athletes to continue to train at their desired frequency with minimal disruption from MTrPs-associated adverse effects. Thus, the aim of this review was to determine the efficacy of various self-massage tools in managing pain and mobility and to explore the potential benefits of SM on resistance training performance. Many SM devices are available for athletes to manage ROM restrictions and pain, including differing densities of foam rollers, roller massagers, tennis balls, and vibrating devices. To attenuate adverse training effects, a 10-to-20-minute bout consisting of 2-minute bouts of SM on the affected area may be beneficial. When selecting a SM device, athletes should note that foam rollers appear to be more effective than roller massagers, with vibrating foam rollers eliciting an increased reduction to pain perception, and tennis balls and soft massage balls were shown to be efficacious in targeting smaller affected areas.

Effectiveness of Dry Needling and Ischaemic Trigger Point Compression of the Levator Scapulae in Patients with Chronic Neck Pain: A Short-Term Randomized Clinical Trial

BACKGROUND

Chronic neck pain (CNP) may be associated with latent myofascial trigger points (MTrPs) in the levator scapulae (LS), which can be treated with ischemic compression (IC) and dry needling (DN). Variables and elastography changes are evaluated to compare the short-term efficacy of two treatments with DN.

METHODS

A randomized clinical trial is conducted with 80 participants in two groups: the DN group (n = 40) and IC group (n = 40). The duration is 12 weeks, and mechanical heterogeneity index, pressure pain threshold (PPT), and pain intensity are measured at baseline, immediately after, 48 h after, and one week after treatment.

RESULTS

Statistically significant changes were immediately observed between the two groups: PPT decreased in the DN group (p = 0.05), while it increased in the IC group. At 48 h and one week after treatment, these values increased in the DN group and remained higher than in the IC group. The heterogeneity index improved in both groups but more significantly in the DN group than in the IC group.

CONCLUSIONS

In subjects with CNP who had latent plus hyperalgesic MTrPs in the LS muscle, DN outperformed IC in PPT, pain intensity, and mechanical heterogeneity index at 48 h and one week after initiating therapy.

Stress increases the spontaneous release of ACh and may be involved in the generation and maintenance of myofascial trigger points in mouse

An increase in spontaneous neurotransmission may be related to myofascial pain. Sympathetic neurons innervate most of the neuromuscular junction sand are involved in the modulation of synaptic transmission. Therefore, a direct action of stress on acetylcholine release is expected. For this reason, this study aims to evaluate the relationship between stress and spontaneous neurotransmission. Five acute stressors (immobilization, forced swimming, food and water deprivation, social isolation and ultrasound) were tested in 6 weeks adult Swiss male mice. Subsequently, these types of stress were combined to generate a model of chronic stress. The study of ACh release was evaluated before and after the application of stress by intracellular recording of spontaneous neurotransmission (mEPPs). In each one of the stressors, an increase in the frequency of mEPPs was obtained immediately after treatment, which remained elevated for 5 days and thereafter returned to control values after a week. With chronic stress, a much higher increase in the frequency of mEPPs was obtained and it was maintained for 15 days. In summary, stress, both in its acute and chronic forms, increased spontaneous neurotransmission significantly. There is a possibility that chronic stress is related with the genesis or maintenance of myofascial pain.

Bibliometric and Visual Analysis in the Field of Dry Needling for Myofascial Pain Syndrome from 2000 to 2022

Background

Evidence has shown that dry needling (DN) is effective for myofascial pain syndrome (MPS). However, bibliometrics has rarely been used to analyze the literature related to DN for MPS. The purpose of this study is to provide a systematic overview of global frontiers and research hotspots of DN in the treatment of MPS from 2000 to 2022.

Methods

A search was conducted on Web of Science Core Collection (WoS CC) for literature on DN for MPS from 2000 to 2022. Based on the basic information provided by WoS CC, CiteSpace software was used to conduct bibliometric analysis of the countries, institutions, categories, journals, authors, references and keywords involved in this topic.

Results

A total of 458 papers were obtained, with the number of publications increasing over time. Journal of Bodywork and Movement Therapies (31) was the most productive journal based on the number of publications, while Arch Phys Med Rehab (329) was the most co-cited journal. The most productive countries and institutions were USA (112) and Universidad Rey Juan Carlos (39), respectively. Fernandez-de-las-penas, Cesar has the highest number of publications (24) and Simons DG, who was an author with the highest number of citations (250). The article published by Gattie et al (co-citations: 65), and Mejuto-Vazquez et al (centrality: 0.36) were the most representative and symbolic. Based on the co-cited literature and keywords, myofascial trigger point, research methods, and acupuncture were the hot research topics and trends in the field.

Conclusion

The current status and trends in clinical research of DN for MPS are revealed according to the results of this bibliometric study, which may facilitate researchers to identify hot topics and new directions for future research.

Sensory and emotional responses to deep pressure stimulation at myofascial trigger points: a pilot study

Objective

Although manual pressure, such as that used during a massage, is often associated with pain, it can simultaneously be perceived as pleasant when applied to certain body areas. We hypothesized that stimulation of myofascial trigger points (TPs) leads to simultaneous pain and pleasure. TPs are hyperirritable points located in the taut band of the skeletal muscle.

Method

In this study, we measured the muscle tone, muscle stiffness, and pressure pain threshold of TPs and control points in the left brachioradialis muscle of 48 healthy participants. We also applied deep compression to the two points and collected subjective data on pain, pleasantness, unpleasantness, and relief.

Result

Greater muscle stiffness was observed in the TPs versus control points (t = 6.55, p < 0.001), and the pain threshold was significantly lower in the TPs (t = -6.21, p < 0.001). Unpleasantness ratings after deep compression were significantly lower in the TPs compared with control points (t = -2.68, p < 0.05). Participants experienced greater relief at the TPs compared with control points (t = 2.01, p < 0.05), although the perceived pain did not differ between the two types of points.

Conclusion

We compared the properties of TPs and control points, and found that deep compression at TPs was associated with higher muscle tone and stiffness, lower unpleasantness ratings, and higher relief ratings compared with the control points. These findings suggest that, at least for some TPs, pain and pleasantness are simultaneously elicited by deep pressure stimulation.

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).

Global hotspots and trends in Myofascial Pain Syndrome research from 1956 to 2022: A bibliometric analysis

Myofascial Pain Syndrome (MPS) is a prevalent disease, and the related literature research has been increasing in recent years. However, there is a lack of scientific and comprehensive bibliometric analyses in the MPS research field. This study aimed to summarize and visualize the literature distribution laws, research hotspots and development trends in MPS based on bibliometric methods. Relevant literature on MPS research from 1956 to 2022 was retrieved from the Web of Science Core Collection database. Quantitative and visual analyses of the collected literature were performed using Microsoft Office 2021, Bibliometrics, VOSviewer, and CiteSpace. A total of 1099 papers were included, and the number of papers in this research field is generally upward. The USA has the most publications (270), and Univ Sao Paulo is the institution with the most publications (31). Hong CZ and Calvo-Lobo C have the same number of publications and are the authors with the most publications (20), and Simons DG is the author with the most co-citations (1078). Journal of Musculoskeletal Pain is the journal with the most publications (61), and Pain is the journal with the most co-cited papers (2598) and the highest impact factor (7.926). Lidocaine injection versus dry needling to myofascial trigger point. The importance of the local twitch response is the reference with the highest number of co-citations (136). The top 5 keywords in this period are myofascial pain syndrome (571), trigger points (218), pain (97), myofascial pain (92), and myofascial trigger point (80). The keywords of recent bursts are dry needling (2016-2022), efficacy (2020-2022), validity (2020-2022), temporomandibular joint disorder (2020-2022), and orofacial pain (2020-2022). This study summarizes and visualizes the evolution, research hotspots, and future trends of the global MPS domain from 1956 to 2022. It is helpful for scholars to understand the general situation of MPS research quickly and provide a reference for clinical decision-making and future research directions.

Preliminary Study: Short-term Beneficial Effects of Thai Tok Sen Massage on Pain, Pressure Pain Threshold, and Upper Trapezius Muscle Thickness Among People with Shoulder Pain

Background

Shoulder muscle pain and spasm is the most common problem in people after prolonged working, similar to that resulting from office syndrome. Various medicinal treatments with analgesic drugs, hot packs, therapeutic ultrasound, or deep friction techniques can be clinically applied. Alternatively, traditional Thai massage (TM) with deep compression gentle technique also can help to release that problem. In addition, an traditional Thai treatment with Tok Sen (TS) massage has been generally performed in the Northern part of Thailand without any scientific evidence support. Thus, the aim of this preliminary study was to reveal the scientific value of Tok Sen massage on shoulder muscle pain and upper trapezius muscle thickness among people with shoulder pain.

Materials & Methods

Twenty participants (6 males and 14 females) who suffered from shoulder pain were randomized into TS (n =10, aged 34.2 ± 7.34 yrs) or TM (n=10, aged 32.8 ± 7.24 yrs). Each group received two times 5-10 minutes of treatment, one week apart. At the baseline and after completing two times of each intervention, pain score, pain pressure threshold (PPT), and specific trapezius muscle thickness were evaluated.

Results

Before both TM and TS interventions, pain score, PPT, and muscle thickness were not statistically different between groups. After two times of intervention, pain scores significantly reduced in TM (3.1 ± 0.56; p = .02, 2.3 ± 0.48; p < .001), as same as in TS (2.3 ± 0.67; p = .01, 1.3 ± 0.45; p < .001) when compared to baseline. This was the same as the results of PPT in TM (4.02 ± 0.34; p = .012, 4.55 ± 0.42; p = .001) and TS (5.67 ± 0.56; p = .001, 6.8 ± 0.72; p < .001). However, the trapezius muscle thickness reduced significantly after two interventions by TS (10.42 ± 1.04; p = 0.002 & 9.73 ± 0.94 mm, p < .001), but did not change in TM (p > .05). Moreover, when compared between intereventions at the first and second periods, TS showed a significant difference in pain score (p = .01 & p <.001), muscle thickness (p = .008 & p = .001) as well as PPT (p < .001 & p < .001) when compared to TM.

Conclusion

Tok Sen massage improves upper trapezius thickness from muscle spasms and reduces pain perception and increases the pressure threshold pain among participants who suffer from shoulder pain similar to that of office syndrome.

Myofascial Pelvic Pain: Best Orientation and Clinical Practice. Position of the European Association of Urology Guidelines Panel on Chronic Pelvic Pain

CONTEXT

Despite the high prevalence of a myofascial pain component in chronic pelvic pain (CPP) syndromes, awareness and management of this component are lacking among health care providers.

OBJECTIVE

To summarize the current state of the art for the management of myofascial pain in chronic primary pelvic pain syndromes (CPPPS) according to scientific research and input from experts from the European Association of Urology (EAU) guidelines panel on CPP.

EVIDENCE ACQUISITION

A narrative review was undertaken using three sources: (1) information in the EAU guidelines on CPP; (2) information retrieved from the literature on research published in the past 3 yr on myofascial pelvic pain; and (3) expert opinion from panel members.

EVIDENCE SYNTHESIS

Studies confirm a high prevalence of a myofascial pain component in CPPPS. Examination of the pelvic floor muscles should follow published recommendations to standardize findings and disseminate the procedure. Treatment of pelvic floor muscle dysfunction and pain in the context of CPP was found to contribute to CPP control and is feasible via different physiotherapy techniques. A multidisciplinary approach is the most effective.

CONCLUSIONS

Despite its high prevalence, the myofascial component of CPP has been underevaluated and undertreated to date. Myofascial pain must be assessed in all patients with CPPPS. Treatment of the myofascial pain component is relevant for global treatment success. Further studies are imperative to reinforce and better define the role of each physiotherapy technique in CPPPS.

PATIENT SUMMARY

Pain and inflammation of the body's muscle and soft tissues (myofascial pain) frequently occurs in pelvic pain syndromes. Its presence must be evaluated to optimize management for each patient. If diagnosed, myofascial pain should be treated.

Dry needling for the treatment of acute myofascial pain syndrome in general practitioners' clinics: a cohort study

BACKGROUND

Musculoskeletal pain is one of the leading complaints in the ambulatory setting. There are many ways to treat it, including pharmacologic and non-pharmacologic approaches. Dry needling (DN) is an option that is easy to learn, cheap and has a good safety profile. The aim of this study was to assess the association between DN performed by GPs for acute myofascial pain syndrome (MPS) and pain relief and to evaluate factors associated with treatment success.

METHODS

In this prospective cohort study, two GPs performed DN in their clinics. Patients were asked to rank their pain using the Short-Form McGill Pain Questionnaire (SF-MPQ) before, 10-min and 1-week after the procedure. The SF-MPQ index consists of 3 parts; visual analog scale (VAS), pain rating index (PRI) and present pain intensity (PPI). Logistic regressions were performed to assess the variables associated with short- and medium- term success.

RESULTS

Fifty two patients were recruited from September 2019 until August 2020. VAS was 6.0 ± 2.3 (before), 4.1 ± 2.5 (10-min after) and 2.6 ± 2.71 (1-week after), P < 0.05. PRI was 17 ± 9.1 (before), 10.8 ± 8.5 (10-min after) and 5.1 ± 6.5 (1-week after), P < 0.05. PPI was 2.6 ± 1.0 (before), 1.7 ± 1.0 (10-min after) and 1.1 ± 1.2 (1-week after), P < 0.05. Short-term success was associated with the physician who performed the procedure (OR 10.08, 95% CI 1.15,88.4) and with the use of a single needle (vs. multiple needles inserted) (OR 4.55, 95% CI 1.03,20.11). Medium-term success was associated with being a native born (non-immigrant), OR 8.59, 95% CI 1.11,66.28 and with high level of initial pain, OR 11.22, 95% CI 1.82,69.27.

CONCLUSION

Our study demonstrated improvement in acute pain 10-min and 1-week after DN performed by a GP, in all parts of the SF-MPQ. Therefore, we believe DN is a good therapeutic option for GPs to aid patients suffering from MPS.

Therapeutic ultrasound versus injection of local anesthetic in the treatment of women with chronic pelvic pain secondary to abdominal myofascial syndrome: a randomized clinical trial

Background

Chronic pelvic pain (CPP) is defined as recurrent or continuous pain in the lower abdomen or pelvis, either non-menstrual or noncyclical, lasting for at least 6 months. There is strong evidence that up to 85% of patients with CPP have serious dysfunctions of the musculoskeletal system, including abdominal myofascial pain syndrome (AMPS). AMPS is characterized by intense and deep abdominal pain, originating from hyperirritable trigger points, usually located within a musculoskeletal band or its lining fascia. In the literature, there are few studies that address AMPS.

Objectives

To evaluate and compare the efficacy of therapeutic ultrasound (TUS) and injection of local anesthetic (IA) to improve pain in women with abdominal myofascial syndrome secondary to CPP.

Study design

Randomized controlled clinical trial.

Setting

Tertiary University Hospital.

Materials and methods

A randomized clinical trial was conducted, patients were allocated to two types of treatment: group TUS (n = 18), and group IA (n = 20). The instruments used for evaluation and reassessment were the Visual Analog Scale, Numerical Categorical Scale, McGill Pain Questionnaire, and SF-36 quality of life assessment questionnaire. They were evaluated before starting treatment, 1 week after the end of treatment, and at 1, 3, and 6 months.

Results

TUS and IA were effective in reducing clinical pain and improving quality of life through the variables analyzed among study participants. There was no significant difference between groups.

Limitations: absence of blinding; exclusion of women with comorbidities and other causes of CPP, the absence of a placebo group, the difference between the number of sessions used for each technique, and the COVID-19.

Conclusion

Treatment with TUS and IA were effective in reducing clinical pain and improving quality of life in women with AMPS secondary to CPP.

Trail registration

We declare that this clinical trial has been registered under the number [(ReBEC) no. RBR-39czsv] on 07/18/2018 in the Brazilian Registry of Clinical Trials.

Effects of Trigger Point Dry Needling on Strength Measurements and Activation Levels of the Gluteus Medius: A Quasi-Experimental Randomized Control Study

Background

Latent trigger points have been identified as a source of impaired muscle function giving rise to a reduction in force production and alterations in muscle activation patterns and movement efficiency. There is limited investigation into the effectiveness of a treatment in reducing these clinical manifestations.

Purpose

To investigate whether the application of trigger point dry needling (TDN) to latent trigger points within the gluteus medius musculature affected strength measurements and muscle activation levels immediately following intervention.

Design

Quasi experimental, single group, pretest-posttest, randomized control study.

Methods

A control and an intervention side were randomly assigned for each participant (N = 39). Hand held dynamometer (HHD) force measurements and raw surface electromyography (sEMG) amplitude readings were recorded during maximal volitional isometric contractions of the gluteus medius in two separate positions before and after application of TDN. Comparison of within and between group data were conducted.

Results

A statistically significant interaction between time (pre-TDN to post-TDN) and groups (intervention side and control side), p < 0.001 was found for HHD measurements in both positions. Post hoc analysis revealed a statistically significant difference (p < 0.001) for all comparisons in the side lying neutral (SL0) position, while statistically significant differences (p < 0.001) were found for pre and post-TDN measurements within intervention side as well as between the intervention and control side for post-TDN measurements in the side lying internal rotation (SLIR) position. For sEMG amplitude measurements, statistically significant differences were found only in the SL0 position for within group comparisons on the intervention side (p = 0.009) and for between group comparisons for post-TDN measurements (p = 0.002).

Conclusion

Application of TDN to latent trigger points within the gluteus medius can significantly increase gluteus muscle force production immediately following intervention while reducing the level of muscle activation required during contraction.

Level of Evidence

Level 2.

Comparative Effectiveness of Manual Therapy Interventions on Pain and Pressure Pain Threshold in Patients With Myofascial Trigger Points: A Network Meta-analysis

OBJECTIVES

Myofascial trigger points (MTPs) are one of the most important causes of musculoskeletal pain. Evidence has suggested a positive effect of manual therapy in the treatment of MTPs. However, a comprehensive review comparing the effect of different manual therapy techniques are lacking. Thus, we conducted a network meta-analysis of randomized controlled trials to determine the type of manual therapy technique that has the greatest positive influence in patients with MTPs.

MATERIALS AND METHODS

PubMed, Web of Science, Cochrane Library, and Scopus databases were searched to identify direct and indirect evidence comparing the effectiveness of different types of manual therapy interventions on pain intensity and pressure pain threshold (PPT) in patients with MTPs. Risk of bias was assessed using the Cochrane RoB2 tool. A pairwise meta-analysis for direct and indirect comparisons between intervention and control/nonintervention groups was carried out.

RESULTS

A total of 37 studies were eligible for analysis. Combined interventions had the highest effect size for pain (-1.40; 95% CI, -2.34, -0.47), and the highest probability to be the best intervention and the highest Surface Under the Cumulative Ranking (64.7% and 87.9%, respectively). Afferent reduction techniques, understood as the interventions aimed to restore muscle spindles helping to dictate sarcomere length and tone in MTPs, had the highest effect size for PPT (0.93; 95% CI, 0.47, 1.39), and the highest probability to be the best intervention and the highest Surface Under the Cumulative Ranking (34.7% and 71.2%, respectively). The results were consistent in sensitivity analyses, with minimal inconsistencies between direct and indirect results.

DISCUSSION

Manual therapy interventions should be considered an effective strategy for pain and PPT in patients with MTPs. The results suggest that among the different manual therapy modalities, combined and afferent reduction techniques are the most effective for pain and PPT, respectively.

Effectiveness of Dry Needling and Ischemic Trigger Point Compression in the Gluteus Medius in Patients with Non-Specific Low Back Pain: A Randomized Short-Term Clinical Trial

BACKGROUND

The presence of latent myofascial trigger points (MTrPs) in the gluteus medius is one of the possible causes of non-specific low back pain. Dry needling (DN) and ischemic compression (IC) techniques may be useful for the treatment of these MTrPs.

METHODS

For this study, 80 participants were randomly divided into two groups: the dry needling group, who received a single session of DN to the gluteus medius muscle plus hyperalgesia (n = 40), and the IC group, who received a single session of IC to the gluteus medius muscle plus hyperalgesia (n = 40). Pain intensity, the pressure pain threshold (PPT), range of motion (ROM), and quality of life were assessed at baseline, immediately after treatment, after 48 h, and one week after treatment.

RESULTS

Statistically significant differences were shown between the two groups immediately after the intervention, showing a decrease in PPT (p < 0.05) in the DN group and an increase in PPT in the IC group. These values increased more and were better maintained at 48 h and after one week of treatment in the DN group than in the IC group. Quality of life improved in both groups, with greater improvement in the DN group than in the IC group.

CONCLUSIONS

IC could be more advisable than DN with respect to UDP and pain intensity in the most hyperalgesic latent MTrPs of the gluteus medius muscle in subjects with non-specific low back pain, immediately after treatment. DN may be more effective than IC in terms of PPT, pain intensity, and quality of life in treating latent plus hyperalgesic gluteus medius muscle MTrPs in subjects with non-specific low back pain after 48 h and after one week of treatment.

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.

LA PUNCIÓN SECA AUMENTA EL RENDIMIENTO DE SALTO EN JUGADORES ÉLITE DE VÓLEY PLAYA

El objetivo del presente estudio es evaluar si la aplicación de la punción seca en los puntos gatillo miofasciales latentes se asocia con cambios en el rendimiento de salto. Seis jugadores internacionales de vóley playa sub-21 recibieron tratamiento en el vasto lateral y medial. Se midió la altura de salto SJ y CMJ en cuatro sesiones: antes y después de la intervención (efecto agudo), 48 h y 7 días tras la intervención (efectos a largo plazo). Los jugadores mostraron una pequeña disminución post-intervención seguida de un aumento no significativo a las 48 h. Sin embargo, ambos tipos de salto dieron lugar a un aumento con efecto moderado muy probable tras una semana: 4,13 cm (+10,8%) y 3,54 cm (+8,9%) para SJ y CMJ, respectivamente. A pesar de este aumento significativo, la disminución del rendimiento post-test desalienta su uso inmediatamente antes de una competición.

Effects on Neuromuscular Function After Ischemic Compression in Latent Trigger Points in the Gastrocnemius Muscles: A Randomized Within-Participant Clinical Trial

OBJECTIVE

The purpose of this study was to evaluate changes in neuromuscular function, pain perception, and basic physical properties in latent myofascial trigger points (TrPs) after a single treatment session of ischemic compression in the gastrocnemius muscle.

METHODS

A randomized within-participant clinical trial with a blinded assessor was conducted. Twenty-nine asymptomatic volunteers with latent gastrocnemius-muscle TrPs were bilaterally explored. Each extremity was randomly assigned to the control group (no treatment) or the experimental group (90 seconds of ischemic compression over each TrP). Neuromuscular function of the gastrocnemius muscle was assessed using a MyotonPro. Muscle flexibility was analyzed using the lunge test and the passive ankle range of motion. The strength was determined with a handheld dynamometer (MicroFET2). Pain perception was analyzed with a 0-to-10 numerical pain rating scale and determination of pressure pain thresholds over each latent TrP.

RESULTS

The results revealed a reduction of 15.8% in pain perception and an increment of pressure tolerance of 9.9% without pain in the treatment group. Changes in muscle flexibility (active and passive) and most parameters for neuromuscular response (rigidity, elasticity, and relaxation) were also observed, but they were not significantly different between groups. The clinical effect sizes were moderate for pain perception (d = 0.69), pressure pain threshold (d = 0.78), muscle tone (d = 0.51), and elasticity (d = 0.54) in favor of the treated extremity. Small clinical effect sizes were observed for muscle physical outcomes.

CONCLUSION

The present study shows that the use of a single session of ischemic compression for latent gastrocnemius-muscle TrPs improved some sensory outcomes. The effects on ankle range of motion and neuromuscular responses were inconclusive.

Assessing the efficacy and safety of Juan Bi Tang for dialysis-related myofascial pain in the fistula arm: Study protocol for a randomized cross-over trial

Background

Dialysis-related myofascial pain in hemodialysis (HD) patients is an important issue that is associated with many other psychosomatic problems. Effective interventions are required to alleviate pain in this group. Chinese herbal medicine (CHM) may be a potential therapeutic treatment for reducing pain. The aim of this study is to evaluate the effects of a classic CHM formula intervention on pain intensity, daily function, quality of life (QOL), and safety in patients receiving HD in a dialysis center within the context of southern Taiwan.

Methods

This will be a randomized, open label, cross-over trial with two parallel groups in a pre- and post-test study. Forty patients reporting myofascial pain related to the arteriovenous (AV) fistula in the arm during regular HD sessions will be recruited. Participants will receive 4 weeks of treatment with Juan Bi Tang (JBT) and 4 weeks of no treatment in a random order, separated by a washout period of 2 weeks. Treatment doses (3 g JBT) will be consumed thrice daily. The primary outcome measure will be the Kidney Disease Quality of Life 36-Item Short-Form Survey. Secondary outcomes will include the Fugl-Meyer Assessment-arm, Visual Analogue Scale (VAS) of pain, and grip strength. Outcomes will be collected before and after each intervention, for a total of four times per participant. The safety evaluation will focus on adverse events (AEs).

Discussion

This study will be the first to use CHM to treat patients receiving HD with dialysis-related myofascial pain in their fistula arm and to perform a complete assessment of the treatment, including records of QOL, arm function and muscle power, severity of pain, and safety. The results of the study will provide convincing evidence on the use of JBT as an adjuvant treatment for dialysis-related myofascial pain.

Trial registration

Clinicaltrials.gov registry (NCT04417101) registered 30 May 2020.

Immediate Effect of Dry Needling on the Viscoelastic Properties of a Trigger Point on the Infraspinatus Muscle Measured with MyotonPRO

Purpose: This article investigates the immediate effects of a dry needling (DN) puncture on the viscoelastic properties (tone, stiffness, elasticity) of a trigger point (TP) in the infraspinatus muscle in non-traumatic chronic shoulder pain. Method: Forty-eight individuals with non-traumatic chronic shoulder pain were recruited. The presence of a TP in the infraspinatus muscle was confirmed by a standardized palpatory exam. The viscoelastic properties were measured with a MyotonPRO device at baseline (T1), immediately after DN (T2), and 30 minutes later (T3). A DN puncture was applied to the TP to obtain a local twitch response while performing the technique. Results: Analyses of variance showed significant decreases in tone ( p < 0.001) and stiffness ( p = 0.003) across time after the DN technique. Post hoc tests revealed a significant reduction in tone and stiffness from T1 to T2 ( p ≤ 0.004) and no significant changes from T2 to T3 ( p ≥ 0.10). At T3, only stiffness remained significantly lower compared to T1 ( p = 0.013). Conclusions: This study brings new insights on the immediate mechanical effect of DN on tone and stiffness of TPs. Whether these effects are associated with symptom improvement and long-term effects still needs to be verified.

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.

Exploring the Underlying Mechanisms of Action of Dry Needling: What Is the Immediate Effect on Muscle Electrophysiology? An Experimental Randomized Controlled Trial

OBJECTIVE

Dry needling is a commonly used treatment technique for myofascial pain syndromes, such as trapezius myalgia. Despite the shown positive clinical effects on pain, the underlying mechanisms of action, such as the effect on muscle electrophysiology, remain unclear. The aim of this study was to investigate the effect of dry needling, compared with sham needling, in the upper trapezius muscle on surface electromyography activity and the relation with pain in office workers with trapezius myalgia.

DESIGN

For this experimental randomized controlled trial, 43 office workers with work-related trapezius myalgia were included. Surface electromyography activity was measured before and after a pain-provoking computer task and immediately after, 15, and 30 mins after treatment with dry or sham needling. Pain scores were evaluated at the same time points as well as 1, 2, and 7 days after treatment.

RESULTS

No significant differences in surface electromyography activity between dry needling and sham needling were found. Significant positive low to moderate Spearman correlations were found between surface electromyography activity and pain levels after dry needling treatment.

CONCLUSIONS

This study shows no immediate effects of dry needling on the electrophysiology of the upper trapezius muscle, compared with sham needling.

Hypoalgesic and Motor Effects of Neural Mobilisation versus Soft-Tissue Interventions in Experimental Craniofacial Hyperalgesia: A Single-Blinded Randomised Controlled Trial

Objective: The present trial aimed to compare the effects of the mobilisation of the nervous system (NS) to those of a soft-tissue intervention in subjects exposed to an experimentally induced hyperalgesia of the masticatory muscles. Methods: The study was a single-blinded randomised controlled trial. A total of 49 participants (mean ± SD age: 41 ± 11 years; 61% female) with latent myofascial trigger points (LMTrPs) in the craniofacial region were randomly assigned to one of three groups: neural mobilisation (NM), soft-tissues techniques and stretching (STT-S), and control group (CG). An initial assessment (baseline) was performed before the provocation chewing masticatory test. The pre-treatment measurements were registered 24 h later. Next, the randomised intervention was applied, and afterwards, post-treatment data were obtained. Outcome measures included pain-free maximum mouth opening (MMO), pressure pain thresholds (PPTs) in the trigeminal and cervical region, and trigeminal and cervical two-point discrimination (TPD). Results: ANOVA revealed significant differences for the time × group interaction for pain-free MMO and PPTs. The results showed an improvement in the MMO and the PPTs for NM and STT-S groups but not for the CG. There were no differences between the NM and STT-S groups. However, the effect sizes were large for the NM and medium for the STT-S. No differences were found for TDP between groups nor over time. Conclusions: The results show that with NM and STT-S techniques, we could influence motor and sensory variables in asymptomatic subjects with LMTrPs after a masticatory provocation test. Both techniques increased MMO and PPTs in the short term. These beneficial effects lead us to consider the importance of including these methods in clinical practice.

Ultra-Low Frequency Transcutaneous Electrical Nerve Stimulation on Pain Modulation in a Rat Model with Myogenous Temporomandibular Dysfunction

Masticatory myofascial pain (MMP) is one of the most common causes of chronic orofacial pain in patients with temporomandibular disorders. To explore the antinociceptive effects of ultra-low frequency transcutaneous electrical nerve stimulation (ULF-TENS) on alterations of pain-related biochemicals, electrophysiology and jaw-opening movement in an animal model with MMP, a total of 40 rats were randomly and equally assigned to four groups; i.e., animals with MMP receiving either ULF-TENS or sham treatment, as well as those with sham-MMP receiving either ULF-TENS or sham treatment. MMP was induced by electrically stimulated repetitive tetanic contraction of masticatory muscle for 14 days. ULF-TENS was then performed at myofascial trigger points of masticatory muscles for seven days. Measurable outcomes included maximum jaw-opening distance, prevalence of endplate noise (EPN), and immunohistochemistry for substance P (SP) and μ-opiate receptors (MOR) in parabrachial nucleus and c-Fos in rostral ventromedial medulla. There were significant improvements in maximum jaw-opening distance and EPN prevalence after ULF-TENS in animals with MMP. ULF-TENS also significantly reduced SP overexpression, increased MOR expression in parabrachial nucleus, and increased c-Fos expression in rostral ventromedial medulla. ULF-TENS may represent a novel and applicable therapeutic approach for improvement of orofacial pain induced by MMP.

Combined Effects of Extracorporeal Shockwave Therapy and Integrated Neuromuscular Inhibition on Myofascial Trigger Points of Upper Trapezius: A Randomized Controlled Trial

Objective

To investigate the combined effect of extracorporeal shockwave therapy (ESWT) and integrated neuromuscular inhibition (INI) on myofascial trigger points in the upper trapezius.

Methods

Sixty subjects aged 18–24 years old with active myofascial trigger points in the upper trapezius were studied. Participants were assigned randomly to either group A who received ESWT one session/week, group B who received INI three sessions/week, or group C who received ESWT in addition to INI. All groups completed 4 weeks of intervention. The following main outcome measures were evaluated at baseline and after 4 weeks of intervention: pain intensity, functional disability, pressure pain threshold (PPT), sympathetic skin response (SSR), and neuromuscular junction response (NMJR).

Results

Within-group analysis revealed a significant decline in visual analog scale (VAS), Arabic neck disability index (ANDI), and NMJR and incline in PPT and SSR latency post-intervention (p<0.001). Multiple comparison analysis showed a substantial difference between the groups, while the major changes favored group C (p<0.05).

Conclusion

Combined treatment with ESWT and INI for treating myofascial trigger points in the upper trapezius is more effective than using only one of the two approaches in terms of clinical, functional, and neurophysiological aspects.

Immediate decrease of muscle biomechanical stiffness following dry needling in asymptomatic participants

BACKGROUND

Biomechanical muscle stiffness has been linked to musculoskeletal disorders. Assessing changes in muscle stiffness following DN may help elucidate a physiologic mechanism of DN. This study characterizes the effects of dry needling (DN) to the infraspinatus, erector spinae, and gastrocnemius muscles on biomechanical muscle stiffness.

METHOD

60 healthy participants were randomized into infraspinatus, erector spinae, or gastrocnemius groups. One session of DN was applied to the muscle in standardized location. Stiffness was assessed using a MyotonPRO at baseline, immediately post DN, and 24 h later. The presence of a localized twitch response (LTR) during DN was used to subgroup participants.

RESULTS

A statistically significant decrease in stiffness was observed in the gastrocnemius, the LTR gastrocnemius, and the LTR erector spinae group immediately following DN treatment. However, stiffness increased after 24 h. No significant change was found in the infraspinatus group.

CONCLUSIONS

DN may cause an immediate, yet transitory change in local muscle stiffness. It is unknown whether these effects are present in a symptomatic population or related to improvements in clinical outcomes. Future studies are necessary to determine if a decrease in biomechanical stiffness is related to improvement in symptomatic individuals.

Expert consensus on the diagnosis and treatment of myofascial pain syndrome

Myofascial pain syndrome (MPS) is characterized by myofascial trigger points and fascial constrictions. At present, domestic and foreign scholars have not reached a consensus on the etiology and pathogenesis of MPS. Due to the lack of specific laboratory indicators and imaging evidence, there is no unified diagnostic criteria for MPS, making it easy to confuse with other diseases. The Chinese Association for the Study of Pain organized domestic experts to formulate this Chinese Pain Specialist Consensus on the diagnosis and treatment of MPS. This article reviews relevant domestic and foreign literature on the definition, epidemiology, pathogenesis, clinical manifestation, diagnostic criteria and treatments of MPS. The consensus is intended to normalize the diagnosis and treatment of MPS and be used by first-line doctors, including pain physicians to manage patients with MPS.

Experimentally induced spine osteoarthritis in rats leads to neurogenic inflammation within neurosegmentally linked myotomes

Naturally occurring spine osteoarthritis is clinically associated with the manifestation of chronic inflammatory muscle (myofascial) disease. The purpose of this study was to investigate the causal association between experimentally induced spine osteoarthritis and neurogenic inflammatory responses within neurosegmentally linked myotomes. Wistar Kyoto rats were randomly assigned to spine facet compression surgery (L4-L6) or sham surgery. Animals exposed to facet compression surgery demonstrated radiographic signs of facet-osteoarthritis (L4-L6 spinal levels) and sensory changes (allodynia, thermal hyperalgesia) at 7, 14 and 21 days post-intervention, consistent with the induction of central sensitization; no radiologic or sensory changes were observed after sham surgery. Increased levels of proinflammatory biomarkers including substance P (SP), calcitonin gene related peptide (CGRP), protease-activated receptor-2 (PAR2) and calcium/calmodulin dependent protein kinase II (CaMKII) were observed post-surgery within neurosegmentally-linked rectus femoris (L2-L5) muscle when compared to the non-segmentally linked biceps brachii (C4-C7) muscle; no differences were observed between muscles in the sham surgery group. These findings offer novel insight into the potential role of spine osteoarthritis and neurogenic inflammatory mechanisms in the pathophysiology of chronic inflammatory muscle (myofascial) disease.

Quantitative response of healthy muscle following the induction of capsaicin: an exploratory randomized controlled trial

Background

Myofascial pain syndrome (MPS) is a prevalent chronic pain disorder primarily characterized by myofascial trigger points (MTrPs). There is limited knowledge on the pathophysiology and mechanisms underlying MTrP and its development. Research has previously demonstrated the identification of MTrPs using ultrasound and vibration sonoelastography, although there is some contradictory evidence regarding if MTrPs present as hyper or hypoechoic regions. Electromyography (EMG) investigations of MTrP have demonstrated that MTrPs are usually located proximal to innervation zones where the peak surface EMG signals are obtained from. Central sensitization has been proposed as the primary mechanism underlying MTrP development. Central sensitization is associated with hyperexcitability of neuronal responses to normal or noxious stimuli. There is a need for a study that measures ultrasound image textural changes and motor unit activity responses in the muscle following sensitization. The purpose of this study is to determine whether sensitizing healthy muscle using capsaicin induces a regional change in image texture variables within the specific and surrounding muscles, as well as the motor unit frequency and amplitude changes that accompany them. This is an exploratory trial that aims to provide preliminary evidence on whether central sensitization is a direct cause of taut band and MTrP development.

Methods

Ethical approval was obtained from the University Health Network (UHN) Research Ethics Board. This proposed study is a single centered, factorial, randomized placebo-controlled trial with two independent variables, depth of capsaicin application and dose of capsaicin, for a total of six treatment arms and three control treatment groups.

Discussion

This will be the first study that assesses the B-mode ultrasound image texture of induced sensitized muscles and will provide more evidence on muscle motor unit activity and regional changes of central sensitization. Findings from this study may support one of few hypotheses proposed delineating the involvement of central sensitization in the development of trigger points.

Trial registration

National Institutes of Health ClinicalTrials.gov NCT03944889. Registered on May 07, 2019

Anatomical Study of the Innervation of the Masseter Muscle and Its Correlation with Myofascial Trigger Points

Background and Purpose

Myofascial pain syndrome (MPS) is widely prevalent in the general population; some reports estimate its prevalence ranges from 9 to 85%. Among the different locations where MPS may arise, pain related to the masseter muscle is referred as masticatory myofascial pain. MPS is characterized by myofascial trigger points (MTPs), which represent tender anatomical areas of a muscle where painful symptoms are elicited whenever stimulated. Previous publications have found MTPs to coincide with neuromuscular junctions at the motor end plate, at the innervation zone (IZ). Our study aimed to describe the innervation of the masseter muscle and relate it to clinically described myofascial trigger points (MTPs).

Materials and Methods

We mapped the nerve fiber distribution into the masseter muscles from 16 cadavers by anatomical dissection. We divided the muscle into six regions, three superior (I–III) and three inferior (IV–VI), and classified the nerve’s branches distribution according to these predetermined areas. Statistical analyses was made by Poisson distribution and logarithm link function followed by Bonferroni multiple comparisons (P<0.05).

Results

All six areas received branches from the masseteric nerve. Areas I and II (upper posterior and upper intermediate, respectively) had a significant higher number of nerve entries as compared to the remaining areas.

Conclusion

The penetration areas of the masseteric nerve have been established and MTPs are found in the innervation zones, clinicians should focus initially on the regions of the penetration points, for diagnostics and therapeutic measures, such as injections, dry needling and soft tissue interventions. Anatomical study of nerve supply to the masseter muscle can provide useful additional knowledge to further understanding masticatory myofascial pain and to direct therapeutic interventions and diagnostic studies of temporomandibular junction dysfunction.

Pragmatic Randomized Controlled Pilot Trial on Trigger Point Injections With 1% Lidocaine Versus Conventional Approaches for Myofascial Pain in the Emergency Department

BACKGROUND

Myofascial neck and back pain is an increasingly common chief symptom in the emergency department. Currently, there are no widely accepted conventional therapies, and there is little evidence on the efficacy of interventions such as trigger point injections (TPIs).

OBJECTIVE

This study evaluates whether TPIs with 1% lidocaine can improve myofascial back and neck pain compared with conventional therapies. Secondary outcomes include changes in length of stay and number of opioid prescriptions on discharge.

METHODS

This single-center, prospective, randomized, pragmatic trial was carried out in patients clinically determined to have myofascial back or neck pain. Patients were randomized into the experimental arm (TPI with 1% lidocaine) or the control arm (standard conventional approach). Numeric Rating Scores (NRS) for pain and additional surveys were obtained prior to and 20 min after the intervention.

RESULTS

The NRS for pain was lower in the TPI group compared with the control group after adjustment for initial pain (median difference -3.01; 95% confidence interval -4.20 to -1.83; p < 0.001). Median length of stay was 2.61 h for the TPI group and 4.63 h for the control group (p < 0.001). More patients in the control group (47.4%) were discharged home with an opioid compared with the TPI group (2.9%) (p < 0.001).

CONCLUSIONS

TPI is an effective method for managing myofascial pain in the emergency department. This study indicates it may improve pain compared with conventional methods, reduce length of stay in the emergency department, and reduce opioid prescriptions on discharge.

Comparison of the effects between lasers applied to myofascial trigger points and to classical acupoints for patients with cervical myofascial pain syndrome

Background

To compare the immediate effectiveness of low-level laser therapy (LLLT) applied to classical acupoints versus trigger points for patients with cervical myofascial pain syndrome (MPS).

Methods

This was a single-blinded, randomized, placebo-controlled trial. This study was performed in a university-affiliated medical center. One hundred participants with cervical myofascial pain syndrome were randomly allocated to four treatment groups, including (1) acupoint therapy (AcuT), (2) acupoint control (AcuC), (3) trigger point therapy (TriT), and (4) trigger point control (TriC) groups. Low-level laser (810-nm) therapy was used in both therapy groups, while the same procedure was performed without laser in the acupoint control groups. The patients were evaluated based on visual analogue scale (VAS) pain score, pressure pain threshold, and cervical range of motion (ROM) before and after the therapy.

Results

Immediate pain relief was observed in the TriT group (p < 0.01). The TriT group showed improved cervical ROM in ipsilateral bending (p < 0.01), while the AcuT group did not.

Conclusions

LLLT applied to trigger points could significantly relieve myofascial pain and was effective in relieving cervical ROM limitations. Considering the risk of pneumothorax, laser therapy at trigger points for patients with cervical MPS may be a choice when acupuncture therapy is unavailable.

Trial registration

ClinicalTrials.gov ID: NCT01516502.

Comparison of radial shockwave and dry needling therapies in the treatment of myofascial pain syndrome

Background/Aims

Myofascial pain syndrome is a frequent problem in the musculoskeletal system. As a method of treatment for myofascial pain syndrome, dry needling therapy is an effective and convenient treatment for patients because they do not need to be treated every day. However, as patients often have post-needle soreness or some patients are afraid of needles, there are limitations to this treatment. The purpose of this study is to compare the effectiveness of radial shockwave therapy with dry needling therapy to treat myofascial pain.

Methods

A total of 42 patients attending the rehabilitation department with at least one myofascial pain trigger point in their upper back muscles, were randomly assigned to receive radial shockwave therapy or dry needling therapy. Treatment was performed once a week for 3 weeks in both groups. Participants' pain pressure threshold, measured using an algometer, and pain levels, measured using a numeric pain scale, were assessed before the designated treatment was applied each week. Each patient also performed upper trapezius, rhomboid and infraspinatus muscle stretches twice a day throughout the study period.

Results

There was no difference in pain pressure threshold at the three trigger points before treatment with the different modalities commenced. At the end of the study, the radial shockwave therapy group had a significant improvement in trapezius pain pressure threshold, increasing from 11.7 at baseline to 14.8 at the end of study. There was no significant between-group difference in pain level (P=3.4 vs P=2.6) at the end of the study. Both treatments significantly reduced pain levels: from 7.2 to 3.4 in the radial shockwave group (P<0.001) and from 6.8 to 2.6 in the dry needling therapy group (P<0.001).

Conclusions

Dry needling and radial shock wave therapies are effective in reducing myofascial pain syndrome originating in the upper back muscles. Participants' pain pressure threshold increased after 3 weeks of treatment with both therapies. Radial shock therapy can be used as an alternative to dry needling in the treatment of myofascial pain syndrome in patients who have trouble attending daily physical therapy or in whom dry needling therapy is contraindicated.

Ultrasound imaging for sarcopenia, spasticity and painful muscle syndromes

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Intramuscular stimulation as a novel alternative method of pain management after thoracic surgery

Background

The purpose of this study was to determine whether electrical twitch-obtaining intramuscular stimulation (ETOIMS) can be an alternative to intravenous patient-controlled analgesia (IV-PCA) for postoperative pain management in pneumothorax patients undergoing single-port video-assisted thoracoscopic surgery (VATS).

Methods

This preliminary prospective randomized study was conducted between March 2017 and July 2017. A total of 26 patients undergoing single-port VATS were randomly assigned to two groups: the ETOIMS group (n=12), which received intramuscular stimulation prior to chest tube insertion toward the end of procedure, and the IV-PCA group (n=14), which received continuous infusion of fentanyl with a basal rate of 10 µg/mL/h. To measure postoperative pain, visual analogue scale (VAS; range, 0-10) was used as the primary endpoint.

Results

Baseline characteristics were not different between the two groups. According to the linear mixed model, there was statistical difference in the serial VAS score between the two groups (P=0.007). The ETOIMS group showed a significantly lower VAS score compared with the IV-PCA group, especially at postoperatively hour 8, day 1, and day 2.

Conclusions

We showed that ETOIMS may be a safe, effective, and simple alternative for pain management after single-port VATS.

The Parameters of Foam Rolling, Self-Myofascial Release Treatment: A Review of the Literature

Self-myofascial release (SMR) is a well-known and popular therapy. Its growing popularity is based on high effectiveness and availability. However, there is a lack of agreement about which parameters should be used to optimize the effects of the therapy. The purpose of this review is to critically select and assess current literature and ascertain the values of the follow­ing parameters: (1) therapy duration, (2) volume of applied pressure, (3) speed and (4) frequency of roll, (5) type of roller, (6) the number of treatment applications during one session, (7) the duration of intervals between applications that yield the best results in terms of soft tissue.

The authors launched their research in May 2018. The search strategy included the electronic databases EBSCOhost and PubMed. The following inclusion criteria were assessed:

- English language, high quality manuscripts (evaluation in PEDro scale)

- at least one of the groups using the foam roller, tennis ball or the stick to fascial release

- basic parameters of therapy described.A total 55 articles met the inclusion criteria. Patients can usually withstand a maximum tolerable pressure for 30-120 seconds, repeated 1-3 times, separated by 30 seconds of rest. The intensity of a single rolling movement should be moderate, and the movement should last about 3 seconds. Keeping the roller on particularly sensitive areas is recommended to release tension and enhance blood perfusion.Currently, there is no consensus on an optimal FR programme. However, there is a tendency to use SMR tools with a physiol­ogy-based method to enhance therapeutic efficiency.

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

Background

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

Methods

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

Results

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

Conclusions

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

Quantitative proteomics analysis to identify biomarkers of chronic myofascial pain and therapeutic targets of dry needling in a rat model of myofascial trigger points

Background

Proteomics analysis may provide important information regarding the pathogenesis of chronic myofascial pain and the mechanisms underlying the treatment effects of dry needling.

Materials and methods

This study used a rat model of myofascial trigger points (MTrPs) to perform a proteomics analysis. Three biological replicate experiments were used to compare the proteomes of healthy control rats, a rat model of MTrP, MTrP model rats following dry needling of MTrPs, and MTrP model rats following dry needling of non-MTrPs. Tandem mass tag (TMT) labeling technology based on nanoscale liquid chromatography-tandem mass spectrometry was used. Hierarchical clustering, gene ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein–protein interaction network analysis were performed to characterize the proteins. To validate the TMT results, three candidate biomarker proteins were verified using parallel reaction monitoring and Western blot analysis.

Results

A total of 2,635 proteins were identified. GO and KEGG enrichment analyses showed that the glycolysis/gluconeogenesis pathways played dominant roles in the pathogenesis of chronic myofascial pain. The three candidate biomarker proteins were the pyruvate kinase muscle isozyme (encoded by the PKM gene), the muscle isoform of glycogen phosphorylase (encoded by the PYGM gene), and myozenin 2 (encoded by the MYOZ2 gene). The validation results were consistent with the TMT results.

Conclusion

This is the first proteomics study that has investigated the pathogenesis of chronic myofascial pain and the mechanisms underlying the treatment effects of dry needling in an in vivo rat model of MTrPs, which might promote our understanding of the molecular mechanisms underlying chronic myofascial pain.

Effect of Local Anesthetic Versus Botulinum Toxin-A Injections for Myofascial Pain Disorders: A Systematic Review and Meta-Analysis

OBJECTIVE

Myofascial pain is a chronic pain disorder characterized by the presence of painful localized regions of stiff muscle and/or myofascial trigger points. Intramuscular myofascial trigger point injections are considered first-line treatments for myofascial pain. Common injectates include local anesthetics and botulinum toxin-A (BTX-A). The objective of this systematic review was to compare the effectiveness of local anesthetics and BTX-A on pain intensity in patients with myofascial pain.

METHODS

A comprehensive systematic search of 3 databases, EMBASE, CENTRAL, and Medline was conducted. The search was comprised of words to describe "myofascial pain" and "injections." We performed a meta-analysis comparing local anesthetic and BTX-A injections across these follow-up week periods: 0 (immediately following the injection), 1 to 2, 3 to 4, 5 to 6, 7 to 8, 9 to 10, 11 to 12, 16, 18, 24 weeks with local anesthetics and BTX-A as subgroups. We also performed subgroup analyses comparing the effectiveness of local anesthetic injections and BTX-A injections at various muscle locations and comparing the effectives of single versus multiple injection sessions.

RESULTS

In total, 33 studies were included. A qualitative analysis suggested that local anesthetics and BTX-A were inconsistently effective at mitigating pain across all follow-up periods. The meta-analyses revealed that local anesthetic injections were more effective than BTX-A at mitigating pain intensity. Multiple injection sessions of local anesthetics were more beneficial than a single session.

CONCLUSIONS

Additional studies are needed to determine sources of heterogeneity mediating the observed differences in effectiveness of local anesthetic and BTX-A injections among the studies. Additional replicative studies are also needed to delineate the relative efficacy and effectiveness of local anesthetic and BTX-A injection. The quantitative results of this study suggest that patients overall experience more pain relief with local anesthetic injections.