Identification Of Myofascial Trigger Points Research Articles

New application of multimodal ultrasound imaging for identification of myofascial trigger points in the trapezius muscle.

The study aimed to quantify the characteristics of trapezius myofascial trigger points (MTrPs) using shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS) and explore the application value of the new ultrasound techniques in identifying MTrPs. Forty patients participated in this study. MTrPs in the trapezius muscle were determined by palpation, and SWE and CEUS were used to quantify the focal and adjacent areas. The elastic modulus values and CEUS parameters between the focal area of MTrPs and adjacent areas were evaluated and compared. Pathological biopsy was performed according to the above two methods, and the pathological tissues were observed by Masson staining, immunohistochemistry and electron microscope. The elastic modulus values were significantly higher for the focal area of MTrPs compared to those for adjacent areas (P<0.05). There were statistically significant differences in MTrP parameters, including peak intensity, mean transit time, and area between the focal and adjacent areas (P<0.05). Masson staining showed that there were inflammatory cell infiltration dominated by lymphocytes in the vascular wall. Electron microscopy showed a large number of fibroblast proliferation, lamellar collagen proliferation and lysosomal deposition; immunohistochemical results: the expression of CD3+, CD4+, CD8+, CD68+, mhc-1+, dys+, CD8 was more than that of CD20 (F=4.385, P=0.036). Combined use of SWE and CEUS provides a new detection approach for quantitative identification of MTrPs in the trapezius muscle, which has high application value and is a method worthy of wider use in clinical practice.

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

BackgroundMyofascial 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.MethodsEthical 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.DiscussionThis 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 registrationNational Institutes of Health ClinicalTrials.gov NCT03944889. Registered on May 07, 2019

The effect of dry needling in basketball players analyzed using thermographic cameras

Abstract Background Approximately 30% of patients attend primary care consultations for pain, in which the presence of myofascial pain syndrome (MPS) has been confirmed, provoked by myofascial trigger points (MTrPs). Unfortunately, the treatment of this syndrome is resistant to medication and entails an erroneous diagnosis. Novel methods such as sonoelastography and elastography using magnetic resonance, have recently enabled non-invasive images of trigger points. However, both are costly and difficult to access. Therefore, the identification of MTrPs is still based on the palpable diagnosis criteria defined by Travell and Simons. Interestingly, MPS has been defined as nociceptive pain, however, currently the sympathetic nervous system (SNS) is considered increasingly important for the widespread pain related to MPS and this is indicated with greater frequency. The use of the infrared camera is accepted as an objective method for the diagnosis of patients with pain, especially if activity of the SNS is involved. Thermography has high reliability for muscle exam. Hyperthermic images appear when inflammatory reactions are present, increasing the blood flow due to a greater cell activation. In contrast, hypothermic activation is found when there is compression or degenerative processes. Dry needling (DN) is considered to be a safe and effective method for reducing pain and improving muscle function, provoking a local contraction response in the muscle of myofascial trigger points. Aims The main aim of this study was to evaluate the physiological changes that take place in the medial gastrocnemius (MG) with DN treatment using thermography. Material and Methods In total, 20 basketball players participated in this study, aged between 21 and 39 years old. Initially, before performing DN, pre-intervention images were taken. Subsequently, DN was performed on the MG with the maximum of local twitch responses, evaluating both MG of both legs. Images were taken immediately after DN, and at 15 and at 30 minutes. For this study, a thermographic camera was used (FLIR TUR E60) and the images were analyzed using FLIR TOOLS software. For the DN technique, needles were used measuring 0.30 × 40. The variables studied were the maximum temperature (Tmax), minimum temperature (Tmin) and mean temperature (Tavg), in degrees Celsius. Results A decreased temperature exists (T°) both for Tmax, Tmin and Tavg before and after the DN intervention. We observed a significant difference (p = 0.035) between Tmin pre-intervention and immediately after the intervention in the left leg. The other significant difference found was between Tmin pre-intervention on the left leg and after 30 minutes (p = 0.009). We found significant differences between Tmin pre and immediately post intervention on the left leg (p = 0.021), Tmin pre and after 15 minutes on the left leg (p = 0.007) and pre intervention and after 30 minutes on the left leg (p = 0.002). Other significant differences on the right leg were Tmin pre-intervention and immediately after (p = 0.019), and after 15 minutes (p = 0.008). Conclusions Dry needling may be a good method for reducing inflammation of the trigger point for its ability to decrease temperature, and therefore may allow us to decrease the maximum, minimum and average temperature of the muscle belly.

Identification of Myofascial Trigger Points in Breast Cancer Survivors with Upper Limb Pain: Interrater Reliability.

Despite the increasing awareness of the contribution of myofascial dysfunctions to upper limb pain in breast cancer survivors, reliability of the identification of myofascial trigger points (MTPs) in this population has not yet been investigated. Therefore, the aim of the present study was to investigate the interrater reliability of the identification of MTPs by palpation at the upper limb region in breast cancer survivors with upper limb pain. Interrater reliability study. University Hospitals Leuven, Belgium. Thirty breast cancer survivors with pain at the upper limb region. Nine muscles (upper trapezius, levator scapulae, infraspinatus, supraspinatus, teres major and minor, subscapularis, pectoralis major, and scalene muscles) at the operated side were examined. The weighted kappa (WK) coefficient and Absolute Agreement with 95% confidence intervals were calculated. Moderate agreement was found for all examined upper limb muscles (WK = 0.41-0.60), except for the trapezius muscle, for which the agreement was almost perfect (WK = 0.83), and the supraspinatus muscle (WK = 0.23), for which the agreement was only fair. For most muscles, moderate interrater reliability for the identification of MTPs by palpation in breast cancer survivors with upper limb pain was found. Therefore, we concluded that the identification of MTPs by palpation may add to the diagnosis of the myofascial pain syndrome in breast cancer survivors.

Interrater Agreement of Manual Palpation for Identification of Myofascial Trigger Points: A Systematic Review and Meta-Analysis.

To achieve a statistical estimate of the agreement of manual palpation for identification of myofascial trigger points (MTrPs) and secondarily to investigate potential factors impacting the agreement of this technique. We searched MEDLINE(R) and Embase for studies examining the reproducibility of manual palpation for the identification of MTrPs from the year 2007 to present. In addition, we utilized studies identified by 2 comprehensive systematic reviews that covered the period before 2007. The included studies were original peer-reviewed research articles and included Cohen κ measures or data with which to calculate Cohen κ. Studies were excluded if they lacked a measure of variability or information required to calculate variability. Studies that examined palpation through body cavities were also excluded. Of the 18 potentially relevant articles only 6 met inclusion criteria including 363 patients. Modified QUADAS tool was used to assess study validity. Subgroup comparisons were made utilizing Q and Z tests. An estimate of κ=0.452 (95% confidence interval, 0.364-0.540) was obtained for interrater agreement of manual palpation of MTrPs. Localized tenderness (κ=0.676) and pain recognition (κ=0.575) were the most reliable criteria. Only 1 study met inclusion criteria for intrarater agreement and therefore no meta-analysis was performed. Use of manual palpation for identification of MTrPs is unreliable, and future investigation should focus on integration with more reliable techniques.

Role of myofascial trigger points in post-amputation pain

Post-amputation pain is a multifactorial issue and thus necessitates multiple treatment strategies. Myofascial trigger points-related pain remains under diagnosed and hence not addressed. This study investigates causation and management. To identify the presence and role of myofascial trigger points in post amputation pain. Post-amputation pain clinic review and recruitment. Twenty one identified patients in the post-amputation pain clinic with myofascial trigger points were recruited, of which 13 were transtibial and eight transfemoral and all had phantom limb pain and stump pain. The trigger points were identified and injected with long-acting local anaesthetic on a weekly basis and patients were followed up on an ongoing basis. There was significant resolution of pain on the Visual Analogue Scale in the majority of these patients within five weeks, though some of the transtibial cohort needed further eight injections on a weekly basis for resolution of the pain. Identification of myofascial trigger points in amputation stumps and their role in post-amputation pain, followed by appropriate intervention is an important facet of management of this complex chronic pain. Clinical relevance Myofascial trigger points in amputation stumps can lead to ongoing chronic post-amputation pain and our results indicate that identification and intervention of these trigger points does lead to notable resolution of this pain.

Topographical mapping and mechanical pain sensitivity of myofascial trigger points in the infraspinatus muscle

Objectives To screen for the presence of latent and active myofascial trigger points (MTrPs) in patients with unilateral shoulder and arm pain and perform topographical mapping of mechanical pain sensitivity bilaterally in the infraspinatus muscles. Methods Nineteen patients with unilateral musculoskeletal shoulder pain participated in the study. The area overlying the infraspinatus on each side was divided into 10 adjacent sub-areas of 1 cm 2, corresponding to the area of a pressure algometer probe. Pressure pain threshold (PPT) was measured in each sub-area bilaterally in the infraspinatus muscles. Following PPT measurement, an acupuncture needle was inserted into each sub-area five times in different directions in order to induce local twitch response and/or referred pain. Results A significantly lower PPT level in the infraspinatus muscle was detected on the painful side compared with the non-painful side ( P = 0.001). PPT at midfiber region of the infraspinatus muscles was lower than that at other muscle parts ( P < 0.05). Multiple, but not single, active MTrPs were found in the infraspinatus muscle on the painful side and there were also multiple latent MTrPs bilaterally in the infraspinatus muscles. PPT at active MTrPs was much lower than the latent MTrPs and again lower than the non-MTrPs. Conclusions There exists bilateral mechanical hyperalgesia in patients with unilateral shoulder pain. Further, the association of multiple active MTrPs with unilateral shoulder pain and the heterogeneity of mechanical pain sensitivity distribution suggest a crucial role of peripheral sensitization in chronic myofascial pain conditions. Additionally, the locations of MTrPs identified with dry needling correspond well to PPT topographical mapping, suggesting that dry needling and PPT topographical mapping are sensitive techniques in the identification of MTrPs.

New Views of Myofascial Trigger Points: Etiology and Diagnosis

Simons DG. New views of myofascial trigger points: etiology and diagnosis.Two studies appearing in Archives, one by Shah and colleagues and another one by Chen and colleagues, present groundbreaking findings that can reduce some of the controversy surrounding myofascial trigger points (MTPs). Both author groups recognize the ubiquity of this disease and the importance to patients of health care professionals becoming better acquainted with the cause and identification of MTPs. The integrated hypothesis is the most credible and most complete proposed etiology of MTPs. However, the feedback loop suggested in this hypothesis has a few weak links, and studies by Shah and colleagues in particular supply a solid link for one of them. The feedback loop connects the hypothesized energy crisis with the milieu changes responsible for noxious stimulation of local nociceptors that causes the local and referred pain of MTPs. Shah’s reports quantify the presence of not just 1 noxious stimulant but 11 of them with outstanding concentrations of immune system histochemicals. The results also strongly place a solid histochemical base under the important clinical distinction between active and latent MTPs. The study by Chen on the use of magnetic resonance elastography (MRE) imaging of the taut band of an MTP in an upper trapezius muscle may open a whole new chapter in the centuries-old search for a convincing demonstration of the cause of MTP symptoms. MRE is a modification of existing magnetic resonance imaging equipment, and it images stress produced by adjacent tissues with different degrees of tension. This report seems to present an MRE image of the taut band that shows the chevron signature of the increased tension of the taut band compared with surrounding tissues.

The Evaluation of Electrodermal Properties in the Identification of Myofascial Trigger Points

Shultz SP, Driban JB, Swanik CB. The evaluation of electrodermal properties in the identification of myofascial trigger points. Objectives To determine whether skin resistance measurements can objectively identify the location of myofascial trigger points (MTPs) and to differentiate between 3 states. Design Static group comparison. Setting Climate-controlled laboratory. Participants Forty-nine participants (age, 20.5±2.6y) were assigned to 1 of 3 groups based on clinical examination result: absent (n=21), latent (n=16), or active (n=12) MTP. Interventions Not applicable. Main Outcome Measure Skin resistance (in kilo-ohms). Results The 16 data points were divided into 3 categories for analysis: MTP site, surrounding tissue proximal to the MTP (first ring), and area furthest from the MTP (second ring). There was a significant increase in skin resistance between the MTP (403.64±124.73kΩ), first ring (419.66±123.04kΩ), and second ring (454.61±163.19kΩ) ( P<.01). The measurements did not differ significantly between the 3 MTP states. Conclusions The changes in skin resistance between the MTP and the surrounding tissue support the inclusion of this technique to help identify MTPs. The similarity between MTP states warrants investigation into the physiologic differences at specific anatomic locations.