Pathophysiologic and electrophysiologic mechanisms of myofascial trigger points

Myofascial Trigger Points: Pathophysiology and Correlation with Acupuncture Points

A review is made of recent studies on myofascial trigger points (MTrP) and their mechanism is discussed. Clinical and basic science studies have shown that there are multiple MTrP loci in a MTrP region. A MTrP locus contains a sensory component (sensitive locus) and a motor component (active locus). A sensitive locus is a point from which tenderness or pain, referred pain, and local twitch response can be elicited by mechanical stimulation. Sensitive loci (probably sensitised nociceptors) are widely distributed in the whole muscle, but are concentrated in the endplate zone. An active locus is a site from which spontaneous electrical activity can be recorded. Active loci appear to be dysfunctional endplates since spontaneous electrical activity is essentially the same as the electrical activity reported by neurophysiologists as that recorded from an abnormal endplate. A MTrP is always found in a taut band which is histologically related to contraction knots caused by excessive release of acetylcholine in abnormal endplates. Both referred pain and local twitch response are mediated through spinal cord mechanisms, as demonstrated in both human and animal studies.

The pathogenesis of MTrPs appears to be related to integration in the spinal cord of response to the disturbance of nerve endings and abnormal contractile mechanism at multiple dysfunctional endplates. There are many similarities between MTrPs and acupuncture points including their location and distribution, pain and referred pain patterns, local twitch responses (de qi), and possible spinal cord mechanism.

Changes in the bioelectric activity of the trapezius muscle following the thermal effect of red light and infrared radiation

BACKGROUND

The therapeutic effects of visible light and infrared is especially often used in physiotherapy.

OBJECTIVE

The purpose of this study was to determine the effect of exposure to radiation on the motor units activity.

METHODS

The study included 29 volunteers of whom the spontaneous and voluntary bioelectric activity of the trapezius muscle was evaluated using surface electromyography (value of average amplitude and frequency), before and immediately after a 15-minute irradiation. Additionally, the range of motion of the cervical spine and trigger points pain sensitivity to the pressure were assessed.

RESULTS

No statistically significant changes in the pain sensitivity threshold and the range of motion after the irradiation was applied. On the other hand, a 15-minute exposure to radiation induced an increase in the value of average amplitude of rest-related as well as exercise-related potentials and an increase in the average value of frequency of the right side biopotentials at rest and of both sides for active elevation.

CONCLUSIONS

Infrared radiation and visible red light have a stimulating effect on the muscle ability to develop active contraction. It is proposed that the observed changes are associated with the thermal effect of radiation as well as with the so-called extra-visual effects.

Experimental myofascial trigger point creation in rodents

Myofascial pain syndrome is one of the most common forms of muscle pain. In this syndrome, pain is originated by the so-called trigger points, which consists of a set of palpable contraction knots in the muscle. It has been proposed that a high, spontaneous neurotransmission may be involved in the generation of these contraction knots. To confirm this hypothesis, we exposed mouse muscles to an anticholinesterasic agent to increase the neurotransmision in the synaptic cleft in two different conditions, in vivo and ex vivo experiments. Using intracellular recordings, a sharp increase in the spontaneous neurotransmission in the levator auris longus muscle and a lower increase in the diaphragm muscle could be seen. Likewise, electromyography recordings reveal an elevated endplate noise in gastrocnemius muscle of treated animals. These changes are associated with structural changes such as abundant neuromuscular contracted zones observed by rhodaminated α-bungarotoxin and the presence of abundant glycosaminoglycans around the contraction knots, as shown by Alcian PAS staining. In a second set of experiments, we aimed at demonstrating that the increases in the neurotransmission reproduced most of the clinical signs associated to a trigger point. We exposed rats to the anticholinesterase agent neostigmine, and 30 min afterward we observed the presence of palpable taut bands, the echocardiographic presence of contraction knots, and local twitch responses upon needle stimulation. In summary, we demonstrated that increased neurotransmission induced trigger points in both rats and mice, as evidenced by glycosaminoglycans around the contraction zones as a novel hallmark of this pathology. NEW & NOTEWORTHY In rodents, when neostigmine was injected subcutaneously, the neuromuscular neurotransmission increased, and several changes can be observed: an elevated endplate noise compared with normal endplate noise, as evidenced by electromyographyc recording; many muscular fibers with contraction knots (narrower sarcomeres and locally thickened muscle fiber) surrounded by infiltration of connective tissue like glycosaminoglycans molecules; and palpable taut bands and local twitch responses upon needle stimulation. Several of these signs are also observed in humans with muscle pain.

Challenging the Cinderella Hypothesis: A New Model for the Role of the Motor Unit Recruitment Pattern in the Pathogenesis of Myofascial Pain Syndrome in Postural Muscles

BACKGROUND

The energy crisis hypothesis, which is a widely accepted model for the pathogenesis of myofascial pain, has been corroborated by experimental observations. However, the nature of the insult leading to the energy crisis remains elusive. A commonly cited model for this insult is the Cinderella hypothesis, suggesting that hierarchical recruitment of motor units leads to a disproportional load on small units, thus driving them towards an energy crisis. New findings cast doubt on this model, showing that in postural muscles motor units are recruited in rotation, rather than in a hierarchical order, precluding the formation of the so-called Cinderella units.

OBJECTIVE

To explore the influence of common myofascial predisposing factors such as muscle load and muscle strength on the relaxation time of postural muscle motor units, assuming they are recruited in rotation.

METHODS

A stochastic model of a postural skeletal muscle was developed which integrates the energy crisis model and motor unit rotation patterns observed in postural muscles. Postulating that adequate relaxation time is essential for the energetic replenishment of motor units, we explored the influence of different parameters on the relaxation time of individual motor units under varying conditions of muscle loads and muscle strengths.

RESULTS

The motor unit relaxation/contraction time ratio decreases with elevated muscle loads and with decreased total muscle strength.

CONCLUSIONS

In a model of a postural muscle, in which motor units are recruited in rotation, common predisposing factors of myofascial pain, such as increased muscle load and decreased muscle force, lead to shortened motor unit relaxation periods.

Is dry needling effective for low back pain?: A systematic review and PRISMA-compliant meta-analysis

BACKGROUND

To evaluate the efficacy and safety of dry needling (DN) for treating low back pain (LBP).

METHODS

Nine databases were searched from inception to October 2017. Eligible randomized controlled trials (RCTs) involving DN for treating LBP were retrieved. Two reviewers independently screened the articles, extracted data, and evaluated the risk of bias among the included studies using the risk of bias assessment tool by Cochrane Collaboration.

RESULTS

Sixteen RCTs were included and the risk of bias assessment of them was "high" or "unclear" for most domains. Meta-analysis results suggested that DN was more effective than acupuncture in alleviating pain intensity and functional disability at postintervention, while its efficacy on pain and disability at follow-up was only equal to acupuncture. Besides, DN was superior to sham needling for alleviating pain intensity at postintervention/follow-up and functional disability at postintervention. Additionally, qualitative review revealed that DN combined with acupuncture had more significant effect on alleviating pain intensity at postintervention and achieved higher response rate than DN alone. However, compared with other treatments (laser, physical therapy, other combined treatments, etc.), it remained uncertain whether the efficacy of DN was superior or equal because the results of included studies were mixed.

CONCLUSIONS

Compared with acupuncture and sham needling, DN is more effective for alleviating pain and disability at postintervention in LBP, while its effectiveness on pain and disability at follow-up was equal to acupuncture. Besides, it remains uncertain whether the efficacy of DN is superior to other treatments. Nevertheless, considering the overall "high" or "unclear" risk of bias of studies, all current evidence is not robust to draw a firm conclusion regarding the efficacy and safety of DN for LBP. Future RCTs with rigorous methodologies are required to confirm our findings.

DETAILS OF ETHICS APPROVAL

No ethical approval was required for this systematic review and meta-analysis.

Effectiveness of Ultrasound Therapy on Myofascial Pain Syndrome of the Upper Trapezius: Randomized, Single-Blind, Placebo-Controlled Study

Objectives

This study aims to evaluate the effectiveness of conventional ultrasound (US) therapy in the treatment of myofascial pain syndrome.

Patients and methods

Fifty-four patients (23 males, 31 females; mean age 29.8±5.2 years; range, 22 to 46 years) with myofascial pain syndrome were included in this prospective, randomized, single-blind, placebo-controlled study. Patients were randomized into two groups by computerized method as US group (n=27) and placebo group (n=27). Ten sessions of US were applied to the US group and 10 sessions of placebo US were applied to the placebo group. Treatment effectiveness was evaluated with Visual Analog Scale (VAS), algometer, palpable muscle spasm degree (PMSD), and Beck Depression Inventory (BDI) before and after treatment.

Results

Pain values after treatment in both groups decreased significantly (p<0.05) compared to before treatment. In the US group, the decrease in VAS and palpable muscle degree before and after treatment was significantly higher (p<0.05) than in the placebo group. In the US group, the decrease in PMSD after treatment was significantly higher than the placebo group (p<0.05). The amount of decrease in BDI score before and after treatment in the US group did not differ significantly from the placebo group (p>0.05).

Conclusion

Our findings show that conventional US therapy is effective in the treatment of myofascial pain syndrome.

Relationship between Alexithymia and latent trigger points in the upper Trapezius

Background

Latent trigger points (LTrPs) can be activated by future events, leading to pain. Few studies have reported LTrP risk factors. It has been suggested that alexithymia is associated with myofascial pain and diminished awareness of physical sensation. This study was designed to evaluate the relation between alexithymia and LTrPs found the upper trapezius of healthy individuals.

Methods

The correlation between LTrPs and alexithymia, and between LTrPs and depression was analyzed in 160 healthy participants (80 male, mean age: 40.5 years [20 to 66 years]). Each participant was evaluated for potential LTrPs by careful manual examination and completed the Toronto Alexithymia Scale-20 (TAS-20) and the Beck Depression Inventory (BDI) to assess potential alexithymia and depressive symptoms, respectively.

Results

LTrPs were observed in the upper trapezius of 76 participants (47.5%). TAS-20 scores were significantly higher in subjects with LTrPs than without LTrPs (p < 0.001); in contrast, there was no significant BDI score difference between these groups (p = 0.451). The LTrP risk for alexithymia was 2.74 (95% confidence interval [95% CI]: 2.10–3.58). There was no correlation between the TAS-20 and BDI scores (correlation coefficient: −0.04). Significant risk factors associated with LTrPs included the TAS-20 score (odds ratio [OR]: 1.11, 95% CI: 1.07–1.15) and age (OR: 1.05, 95% CI: 1.01–1.09).

Conclusions

Alexithymia was associated with LTrPs in the upper trapezius of healthy individuals, suggesting that it may serve as a useful predictive factor.

Trial registration

UMIN000027468. Registered 23 May 2017(retrospectively registered).

Histopathological nature of myofascial trigger points at different stages of recovery from injury in a rat model

Objective

To investigate the histopathological nature of myofascial trigger points (MTrPs) or spots (MTrSs) at different stages of recovery from injury in a rat model.

Methods

Forty Sprague–Dawley rats were randomly divided into two groups: a control group (CG) and experimental group (EG). The CG was further randomly subdivided into CG1 and CG2 subgroups. The CG2 was used for palpating the taut band and CG1 as a blank. EG was subdivided into three groups according to recovery times: 4 weeks (4W), 8 weeks (8W) and 12 weeks (12W); these groups consisted of eight rats each. All CG rats received no intervention, whereas the intervention in EG rats was by a blunt strike to the vastus medialis and eccentric exercise for 8 weeks. The taut bands with spontaneous electrical activity were then detected in the muscle to guide a muscle biopsy. The histopathological findings were investigated under optical and electron microscopes in all groups.

Results

Under optical microscopy, the differently augmented sizes of round fibres (contracture knots) with deep staining in the transverse section and fusiform shapes in a longitudinal view were clearly seen in CG2 and EGs with a large diameter; the number of contracture knots was significantly more in EGs than in CGs. Under an electron microscope, the mitochondria in EGs significantly decreased with abnormal structures. The sarcomeres were significantly shortened in the 8W and 12W EGs.

Conclusion

An injury can cause activation of MTrSs in a muscle and an activated level of MTrPs depending on the number of contracture knots in muscle with impaired energy production.

Instrument-assisted soft tissue mobilization increases myofascial trigger point pain threshold

BACKGROUND

A myofascial trigger point (MTrP) has been defined as a hyperirritable, palpable nodule in a skeletal muscle. The signs and symptoms of a MTrP include muscle pain, weakness, and dysfunction. MTrPs are common problems associated with soft tissue pathology. Having an intervention to decrease MTrP pain can be clinically valuable.

PURPOSE

To determine if a series of six instrument-assisted soft tissue mobilization (IASTM) treatments rendered over three weeks would influence the pressure pain threshold (PPT) of a myofascial trigger point (MTrP).

METHODS

Randomized, control trial of healthy individuals (n = 29) with MTrPs in the upper trapezius muscle. The intervention was six IASTM treatments rendered over three weeks. Each treatment included 1 min of sweeping with the GT-1/HG-2 (handle bar), 1 min of swivel with the knob of the GT-1/HG-2 directly over the MTrP, 2 min of fanning with the GT-4/HG-8 (convex single bevel), and concluded with 1 min of sweeping with GT-1/HG-2. The outcome measure used a dolorimeter to compare PPT before and after three weeks in both the treatment and control groups.

RESULTS

Paired t-test for PPT pre-test and post-test of the control and treatment groups were p = 0.42159 and p = 0.00003, respectively. A one-way ANOVA of the control and IASTM groups revealed a statistically significant difference (p < 0.0001). The power calculation was greater than 0.99.

CONCLUSIONS

A 5-min intervention using three IASTM techniques can effectively increase the PPT of a MTrP in six treatments over a three-week period of time.

Characteristics of Myofascial Pain Syndrome of the Infraspinatus Muscle

OBJECTIVE

To report the characteristics of myofascial trigger points (MTrPs) in the infraspinatus muscle and evaluate the therapeutic effect of trigger-point injections.

METHODS

Medical records of 297 patients (221 women; age, 53.9±11.3 years) with MTrPs in the infraspinatus muscle were reviewed retrospectively. Because there were 83 patients with MTrPs in both infraspinatus muscles, the characteristics of total 380 infraspinatus muscles with MTrPs (214 one side, 83 both sides) were investigated. Specific characteristics collected included chief complaint area, referred pain pattern, the number of local twitch responses, and distribution of MTrPs in the muscle. For statistical analysis, the paired t-test was used to compare a visual analogue scale (VAS) before and 2 weeks after the first injection.

RESULTS

The most common chief complaint area of MTrPs in the infraspinatus muscle was the scapular area. The most common pattern of referred pain was the anterolateral aspect of the arm (above the elbow). Active MTrPs were multiple rather than single in the infraspinatus muscle. MTrPs were frequently in the center of the muscle. Trigger-point injection of the infraspinatus muscle significantly decreased the pain intensity. Mean VAS score decreased significantly after the first injection compared to the baseline (7.11 vs. 3.74; p<0.001).

CONCLUSION

Characteristics of MTrPs and the therapeutic effects of trigger-point injections of the infraspinatus muscle were assessed. These findings could provide clinicians with useful information in diagnosing and treating myofascial pain syndrome of the infraspinatus muscle.

The immediate effects of manual stretching and cervicothoracic junction manipulation on cervical range of motion and upper trapezius pressure pain thresholds

INTRODUCTION

Myofascial pain is a common impairment treated with various manual interventions including spinal thrust manipulation and stretching; however, the comparative efficacy of each intervention is uncertain. Therefore, the purpose of this investigation was to evaluate thrust manipulation targeting the cervicothoracic junction compared to a manual stretch of the upper trapezius muscle on cervical range of motion and upper trapezius pressure pain thresholds (PPTs).

METHODS

Healthy participants with no significant history of neck pain were randomized into a thrust manipulation group, a stretching group, or a control group. Within group differences were evaluated via a dependent t-test, and group by time interactions were evaluated by a two-way repeated measures ANOVA.

RESULTS

One hundred and two participants were recruited to participate. Baseline demographics revealed no significant differences between groups. Significant group by time interactions were found for changes in PPTs for both the right and left upper trapezius. Also, significant differences were found for changes in cervical extension, as well as right and left cervical side bending favoring the treatment groups.

DISCUSSION

This study demonstrates the potential independent effectiveness of spinal thrust manipulation or stretching for reducing PPTs at the upper trapezius. Future research should further evaluate the limitation of PPTs as a measure of muscle sensitivity as well as factors that may contribute to variability in the measurements among individuals seeking care.

Trigeminal Neuralgia, Glossopharyngeal Neuralgia, and Myofascial Pain Dysfunction Syndrome: An Update

Neuropathic pain is a common phenomenon that affects millions of people worldwide. Maxillofacial structures consist of various tissues that receive frequent stimulation during food digestion. The unique functions (masticatory process and facial expression) of the maxillofacial structure require the exquisite organization of both the peripheral and central nervous systems. Neuralgia is painful paroxysmal disorder of the head-neck region characterized by some commonly shared features such as the unilateral pain, transience and recurrence of attacks, and superficial and shock-like pain at a trigger point. These types of pain can be experienced after nerve injury or as a part of diseases that affect peripheral and central nerve function, or they can be psychological. Since the trigeminal and glossopharyngeal nerves innervate the oral structure, trigeminal and glossopharyngeal neuralgia are the most common syndromes following myofascial pain dysfunction syndrome. Nevertheless, misdiagnoses are common. The aim of this review is to discuss the currently available diagnostic procedures and treatment options for trigeminal neuralgia, glossopharyngeal neuralgia, and myofascial pain dysfunction syndrome.

Overactive pelvic floor muscles (OPFM): improving diagnostic accuracy with clinical examination and functional studies

Background

To identify the functional correlation of overactive pelvic floor muscles (OPFM) with cystoscopic and fluoroscopic urodynamic studies (FUDS), including urethral pressure measurements.

Methods

Patients refractory to conservative therapy including bladder retraining, medications and pelvic muscle exercises for a variety of gamut of storage and voiding disorders were evaluated. Prospective data for 201 patients across both genders who underwent flexible cystoscopy and urodynamics for lower urinary tract symptoms (LUTS) refractory to conservative management between 01 Jan 2014 and 01 Jan 2016 was collected. Factors studied included history of LUTS, voiding patterns, physical examination, cystoscopic findings and functional studies, with maximum urethral closing pressure (MUCP).

Results

A total of 201 were patients recruited. The 85 were diagnosed with OPFM based on clinical presentation and presence of pelvic floor tenderness on examination. Significant differences were noted on functional studies with FUDS and urethral pressure measurement. Subjects with pelvic floor tenderness were found to have a higher (MUCP) at 93.1 cm H2O compared to 80.6 cm H2O (P=0.015).

Conclusions

There are distinct characteristics of OPFM on clinical examination and functional studies, in particular MUCP. In patients refractory to conservative treatments, specific urodynamics tests are useful in sub-categorising patients. When OPFM is diagnosed, the impact on patient management is significant, and targeted intervention with pelvic floor physiotherapy is central in the multimodal approach of this complex condition.

Comparison of effectiveness of Transcutaneous Electrical Nerve Stimulation and Kinesio Taping added to exercises in patients with myofascial pain syndrome

BACKGROUND

Although there are several studies of Transcutaneous Electrical Nerve Stimulation (TENS) and exercise in myofascial pain syndrome, there are no studies comparing the effectiveness of Kinesio Taping (KT) and TENS in myofascial pain syndrome patients.

OBJECTIVE

To compare the early and late effects of TENS and KT on pain, disability and range of motion in myofascial pain syndrome patients.

METHODS

Sixty-nine patients were divided into three groups randomly as TENS+Exercise, KT+Exercise and exercise groups. Visual Analogue Scale (VAS), pain threshold, Neck Disability Index and cervical contralateral lateral flexion were employed in the evaluation of the patients performed before treatment, after treatment and 3rd month after treatment.

RESULTS

The VAS, pain threshold, Neck Disability Index and contralateral lateral flexion values were improved in all groups both in after treatment and 3rd month after treatment (p< 0.01). In the comparison of after treatment vs. before treatment evaluations, VAS score was decreased in KT group compared to the TENS and control group (p= 0.001), in the TENS group compared to control group (p= 0.011). In the comparison of 3rd month and before treatment evaluations, VAS score was decreased in the TENS group compared to control group (p= 0.001) and in the KT group compared to the control group (p= 0.001). There was no significant difference between TENS and KT groups. All other parameters did not differ between the groups.

CONCLUSIONS

TENS and KT added exercises can decrease pain severity and increase pain threshold, function and cervical range of motion in myofascial pain syndrome patients. Addition of TENS or KT to the exercise therapy resulted in more significant improvement compared to exercise therapy alone with a more pronounced improvement in KT group compared to the TENS group in the early period. Because KT was found to be more effective in decreasing the pain and had the advantage of being used in every 3 days, it seems to be beneficial in acute painful periods in myofascial pain syndrome patients.

Decreased Spontaneous Electrical Activity and Acetylcholine at Myofascial Trigger Spots after Dry Needling Treatment: A Pilot Study

OBJECTIVE

The aims of this study are to investigate the changes in spontaneous electrical activities (SEAs) and in acetylcholine (ACh), acetylcholine receptor (AChR), and acetylcholine esterase (AChE) levels after dry needling at myofascial trigger spots in model rats.

MATERIALS AND METHODS

Forty-eight male Sprague-Dawley rats were divided into four groups. Thirty-six rats were assigned to three model groups, which underwent MTrSs modeling intervention. Twelve rats were assigned to the blank control (BC) group. After model construction, the 36 model rats were randomly subdivided into three groups according to treatment: MTrSs model control (MC) and two dry needling groups. One dry needling group received puncturing at MTrSs (DN-M), whereas the other underwent puncturing at non-MTrSs (DN-nM). Dry needling treatment will last for two weeks, once a week. SEAs and ACh, AChR, and AChE levels were measured after one-week rest of dry needling treatment.

RESULTS

The amplitudes and frequencies of endplate noise (EPN) and endplate spike (EPS) significantly decreased after dry needling treatment in the DN-M group. Moreover, ACh and AChR levels significantly decreased, whereas AChE significantly increased after dry needling treatment in the DN-M group.

CONCLUSION

Dry needling at the exact MTrSs is more effective than dry needling at non-MTrSs.

Compression at Myofascial Trigger Point on Chronic Neck Pain Provides Pain Relief through the Prefrontal Cortex and Autonomic Nervous System: A Pilot Study

Compression at myofascial trigger points (MTrPs), known as “ischemic compression,” has been reported to provide immediate relief of musculoskeletal pain and reduce the sympathetic activity that exacerbates chronic pain. We conducted a pilot study to investigate the possible involvement of the prefrontal cortex in pain relief obtained by MTrP compression in the present study, and analyzed the relationships among prefrontal hemodynamic activity, activity of the autonomic nervous system, and subjective pain in patients with chronic neck pain, with and without MTrP compression. Twenty-one female subjects with chronic neck pain were randomly assigned to two groups: MTrP compression (n = 11) or Non-MTrP compression (n = 10). Compression for 30 s was conducted 4 times. During the experiment, prefrontal hemodynamic activity [changes in Oxy-hemoglobin (Hb), Deoxy-Hb, and Total-Hb concentrations] and autonomic activity based on heart rate variability (HRV) were monitored by using near infrared spectroscopy (NIRS) and electrocardiography (ECG), respectively. The results indicated that MTrP compression significantly reduced subjective pain compared with Non-MTrP compression. The spectral frequency-domain analyses of HRV indicated that a low frequency (LF) component of HRV was decreased, and a high frequency (HF) component of HRV was increased during MTrP compression, while LF/HF ratio was decreased during MTrP compression. In addition, prefrontal hemodynamic activity was significantly decreased during MTrP compression compared with Non-MTrP compression. Furthermore, changes in autonomic activity were significantly correlated with changes in subjective pain and prefrontal hemodynamic activity. Along with previous studies indicating a role for sympathetic activity in the exacerbation of chronic pain, the present results suggest that MTrP compression in the neck region alters the activity of the autonomic nervous system via the prefrontal cortex to reduce subjective pain.

The local twitch response during trigger point dry needling: Is it necessary for successful outcomes?

BACKGROUND

Myofascial trigger point (MTrP) injection and trigger point dry needling (TrPDN) are widely accepted therapies for myofascial pain syndrome (MPS). Empirical evidence suggests eliciting a local twitch response (LTR) during needling is essential.

OBJECTIVE

This is the first review exploring the available literature, regardless of study design, on the neurophysiological effects and clinical significance of the LTR as it relates to reductions in pain and disability secondary to MTrP needling.

METHODS

PubMed, MEDLINE, Science Direct and Google Scholar were searched up until October 2016 using terms related to trigger point needling and the LTR.

RESULTS

and Discussion: Several studies show that eliciting a LTR does not correlate with changes in pain and disability, and multiple systematic reviews have failed to conclude whether the LTR is relevant to the outcome of TrPDN. Post needling soreness is consistently reported in studies using repeated in and out needling to elicit LTRs and increases in proportion to the number of needle insertions. In contrast, needle winding without LTRs to MTrPs and connective tissue is well supported in the literature, as it is linked to anti-nociception and factors related to tissue repair and remodeling. Additionally, the positive biochemical changes in the MTrP after needling may simply be a wash out effect related to local vasodilation. While the LTR during TrPDN appears unnecessary for managing myofascial pain and unrelated to many of the positive effects of TrPDN, further investigation is required.

The Possible Role of Meditation in Myofascial Pain Syndrome: A New Hypothesis

BACKGROUND OF HYPOTHESIS

Myofascial pain syndrome (MPS) is the most common musculoskeletal pain disorder of the head and neck area. In the past, several theories were put forth to explain its origin and nature, but none proved complete. Myofascial pain responds to changing psychological states and stress, anxiety, lack of sleep, anger, depression and chronic pain are direct contributional factors. Myofascial pain syndrome may be considered as a psychosomatic disorder. There are numerous accepted palliative approaches, but of all, relaxation techniques stand out and initiate healing at the base level. In this article, the connection between mental factors, MPS and meditation are highlighted. Recent literature has shed light on the fundamental role of free radicals in the emergence of myofascial pain. The accumulating free radicals disrupt mitochondrial integrity and function, leading to sustenance and progression of MPS. Meditation on the other hand was shown to reduce free radical load and can result in clinical improvement. 'Mindfulness' is the working principle behind the effect of all meditations, and I emphasize that it can serve as a potential tool to reverse the neuro-architectural, neurobiological and cellular changes that occur in MPS.

CONCLUSIONS

The findings described in this paper were drawn from studies on myofascial pain, fibromyalgia, similar chronic pain models and most importantly from self experience (experimentation). Till date, no hypothesis is available connecting MPS and meditation. Mechanisms linking MPS and meditation were identified, and this paper can ignite novel research in this direction.

Protocol: Testing the Relevance of Acupuncture Theory in the Treatment of Myofascial Pain in the Upper Trapezius Muscle

A protocol for a prospective single-blind parallel four-arm randomized placebo-controlled trial with repeated measures was designed to test the effects of various acupuncture methods compared with sham. Eighty self-selected participants with myofascial pain in the upper trapezius muscle were randomized into four groups. Group 1 received acupuncture to a myofascial trigger point (MTrP) in the upper trapezius. Group 2 received acupuncture to the MTrP in addition to relevant distal points. Group 3 received acupuncture to the relevant distal points only. Group 4 received a sham treatment to both the MTrP and distal points using a deactivated acupuncture laser device. Treatment was applied four times within 2 weeks with outcomes measured throughout the trial and at 2 weeks and 4 weeks posttreatment. Outcome measurements were a 100-mm visual analog pain scale, SF-36, pressure pain threshold, Neck Disability Index, the Upper Extremity Functional Index, lateral flexion in the neck, McGill Pain Questionnaire, Massachusetts General Hospital Acupuncture Sensation Scale, Working Alliance Inventory (short form), and the Credibility Expectance Questionnaire. Two-way analysis of variance (ANOVA) with repeated measures were used to assess the differences between groups.

Selenium and Zinc Status in Chronic Myofascial Pain: Serum and Erythrocyte Concentrations and Food Intake

INTRODUCTION

Nutritional disorders have been reported to be important causal factors that can intensify or cause a painful response in individuals with chronic musculoskeletal pain.

AIM

To assess the habitual intake of and the serum and erythrocyte levels of selenium and zinc in patients with chronic myofascial pain.

MATERIALS AND METHODS

A case-control study of 31 patients with chronic myofascial pain (group I) and 31 subjects without pain (group II). Dietary record in five days for assessing food intake were used. The serum and erythrocyte concentrations of selenium and zinc were analyzed using an atomic absorption spectrophotometry. Pain intensity was assessed using a visual analog scale.

RESULTS

The group of patients with chronic myofascial pain, compared with the control group, showed a lower erythrocyte concentration of selenium (79.46 ± 19.79 μg/L vs. 90.80 ± 23.12 μg/L; p = 0.041) and zinc (30.56 ± 7.74 μgZn/gHb vs. 38.48 ± 14.86 μgZn/gHb, respectively; p = 0.004). In this study, a compromised food intake of zinc was observed in the majority of the subjects in both groups. The selenium intake was considered to be safe in 80% of the subjects in both groups; however, the likelihood of inadequate intake of this mineral was twice as high in group I (49.5% vs. 24.4%, respectively). In the logistic regression analysis, the erythrocyte concentration of zinc was associated with the presence of pain. In each additional 1 mg of Zn2+ per gram of hemoglobin, a reduction of 12.5% was observed in the risk of the individual having chronic myofascial pain (B = -0.133; adjusted OR = 0.875, 95% CI = 0.803 to 0.954, Wald = 9.187, standard error = 0.044, p = 0.002). Physical inactivity and obesity were noted more commonly in group I compared with the control group.

CONCLUSION

In this study, patients with chronic myofascial pain showed lower intracellular stores of zinc and selenium and inadequate food intake of these nutrients.

Immediate and short-term effects of the combination of dry needling and percutaneous TENS on post-needling soreness in patients with chronic myofascial neck pain

Background

Dry needling (DN) and percutaneous electrical nerve stimulation (PENS) are widely used techniques in the treatment of myofascial pain.

Objective

To investigate the immediate and short-term effects of the combination of DN and PENS compared to DN alone on the upper trapezius muscle.

Method

This is a 72-hour follow-up single-blinded randomized controlled trial. Sixty-two volunteer patients with chronic myofascial neck pain with active Myofascial Trigger Points (MTrPs) in the upper trapezius muscle were recruited. Randomization was performed, and 31 patients received DN treatment (DN group) and 31 received DN and PENS (DN+PENS group). The primary outcomes were neck disability index (NDI) and visual analog scale for pain for both post-needling soreness (PNS) and neck pain intensity (NPI). Pressure pain threshold (PPT) and cervical range of motion (CROM) were the secondary outcomes.

Results

We detected between-group differences in NPI and PNS in favor of the DN+PENS group immediately after treatment. No between-group differences in NDI were observed.

Conclusion

PENS application after dry needling treatment is more effective than dry needling alone for decreasing soreness in the short term and improving neck pain intensity immediately in patients with myofascial chronic neck pain.

Laryngeal myofascial pain syndrome as a new diagnostic entity of dysphonia

OBJECTIVE

To consider the feasibility of diagnosing intrinsic laryngeal muscle myofascial pain syndrome (MPS) in dysphonic patients who demonstrated immediate symptom and stroboscopic finding improvement after laryngeal electromyography (LEMG) without further treatment.

METHODS

A chart review of patients who showed subtle vocal fold movement abnormalities on a stroboscopic examination and underwent ultrasonography (US)-guided LEMG was performed. Patients with vocal fold paralysis, mucosal lesions, spasmodic dysphonia, and vocal tremor on stroboscopic examination were excluded. Among them, patients with normal EMG findings were included in this study. The patients who reported voice symptom improvement after LEMG without further treatment were placed in laryngeal MPS (LMPS) group and the other patients were placed in non-laryngeal MPS (non-MPS) group. Predisposing factors, voice symptom, symptom-duration, and stroboscopic findings of these patients were reviewed.

RESULTS

Among the 16 patients, LEMG findings were normal, five (31%) were included in the LMPS group and the other 11 patients (69%) were included in the non-MPS group. All LMPS group patients had a history of voice abuse and reported odynophonia. The Korean Voice Handicap Index-10 score decreased significantly after US-guided LEMG without additional treatment in the LMPS group. The stroboscopic findings revealed that vocal fold hypomobility was the most common finding in the LMPS group, and two patients showed a muscle tension dysphonia pattern. The LMPS groups showed improvement of vocal fold mobility on 1-week stroboscopic evaluation.

CONCLUSION

LMPS is a potential diagnosis for patients with vocal fold hypomobility finding on stroboscopic findings but with normal EMG results. Diagnosis of LMPS could be considered in patients who showed symptom and vocal fold movement improvement after LEMG.

Effect of exams period on prevalence of Myofascial Trigger points and head posture in undergraduate students: Repeated measurements study

BACKGROUND

Myofascial Trigger points (MTrPs) may be caused or aggravated by many factors, such as mental stress associated with exams and impaired posture.

AIM

To compare the prevalence and sensitivity of MTrPs, and forward head position (FHP) during exam period vs. mid-semester among physical therapy students.

METHODS

39 physical therapy students were palpated for MTrPs in neck and shoulder muscles and were photographed laterally for FHP measurement during the academic semester and during the academic examination period.

RESULTS

The subjects showed higher prevalence of active MTrPs in the right Trapezius and Levator Scapula muscles, and higher prevalence of latent MTrPs in the left Sternocleidomastoideus and Levator Scapula muscles during exams, as well as a higher rate of tenderness in suboccipital musculature.

CONCLUSIONS

Physical therapy students show greater prevalence of MTrPs during exams. The authors recommend implementing preventative programs towards the examination period.

Injections for chronic pain

Although interventional procedures should be used cautiously in the setting of chronic pain, there is a role for a variety of injections to facilitate a patient's overall rehabilitation program. There are many resources available, including a prior issue of Physical Medicine and Rehabilitation Clinics of North America, which discuss the more conventional spinal injections. The focus of this article is on lesser-known injection options for treating chronic pain. The authors separately discuss trigger point injections, regenerative injections (prolotherapy), and injections using botulin toxins.

Effectiveness of trigger point dry needling for multiple body regions: a systematic review

BACKGROUND

Trigger point dry needling (TDN) is commonly used to treat musculoskeletal pain related to myofascial trigger points (MTrPs). To date, no systematic review of high-quality randomised controlled trials (RCTs) investigating TDN to multiple body regions exists.

PURPOSE

The aim of this review is to determine the effectiveness of TDN based on high-quality RCTs for all body regions.

METHODS

To ensure thorough reporting, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed as the methodological basis for this systematic review. PubMed, Physiotherapy Evidence Database (PEDro), Cinahl, Cochrane and reference lists were searched for the years 2000-2014 and the terms 'TDN', 'dry needling NOT trigger point', 'functional dry needling' and 'intramuscular manual therapy'.

INCLUSION CRITERIA

RCTs with PEDro scores 6-10 investigating TDN.

EXCLUSION CRITERIA

duplicates, non-human participants, non-English language, exclusive focus on acupuncture or medicinal injections. Three investigators searched databases, applied criteria, read and assigned PEDro scores to every RCT. Nineteen studies met the criteria. As compared to either baseline or control groups, significant differences were found for pain (14 studies), range of motion (ROM) (five studies) and at least one item on function and quality of life measures (six studies).

LIMITATIONS

This review was limited by inclusion criteria, timeframe, language and databases searched.

CONCLUSION

The majority of high-quality studies included in this review show measured benefit from TDN for MTrPs in multiple body areas, suggesting broad applicability of TDN treatment for multiple muscle groups. Further high-quality research is warranted to standardise TDN methods to determine clinical applicability.

Percutaneous Fascia Release for Treating Chronic Recurrent Gluteal Myofascial Pain—A Pilot Study of a New Technique

Objective

To investigate the therapeutic effectiveness of percutaneous fascia release to treat chronic recurrent gluteal myofascial pain related to recurrent tendonitis or bursitis at the attachment sites.

Methods

Five patients (three males, two females; aged 48.6 ± 8.9 years) with myofascial trigger points in the gluteus medius muscle were treated. Outcome measures, including pain intensity, pressure pain threshold, and the relative strength of hip abduction, were assessed before, immediately after, and six months after the treatment. The data measured before and after treatment (different times) on visual analog scale, pressure pain threshold, and relative hip abduction strength were analyzed by Wilcoxon signed-rank test and paired t-test, respectively, for the comparisons between time points.

Results

Reduction in pain intensity and increase in the pressure pain threshold and the relative hip abduction strength were found in all five patients after treatment when compared with those of before treatment ( P < 0.05). Moreover, all of these improvements existed for at least six months ( P > 0.05).

Conclusions

Percutaneous fascia release of gluteal muscle insertion sites can be used to treat chronic gluteal pain related to subtrochanteric bursitis to avoid recurrence, if other treatment cannot control the recurrence, although this was demonstrated only on a small sample size without control and blind assessment in the pilot study.

Effectiveness of Soft Tissue Massage for Nonspecific Shoulder Pain: Randomized Controlled Trial

BACKGROUND

Soft tissue massage and exercise are commonly used to treat episodes of shoulder pain.

OBJECTIVE

The study objective was to compare the effects of soft tissue massage and exercise with those of exercise alone on pain, disability, and range of motion in people with nonspecific shoulder pain.

DESIGN

This was a randomized controlled trial.

SETTING

The study was conducted in public hospital physical therapy clinics in Sydney, New South Wales, Australia.

PARTICIPANTS

The study participants were 80 people with an average age of 62.6 years (SD=12.2) who were referred to physical therapists for treatment of nonspecific shoulder pain.

INTERVENTION

Participants were randomly assigned to either a group that received soft tissue massage around the shoulder and exercises (n=40) or a group that received exercise only (n=40) for 4 weeks.

MEASUREMENTS

The primary outcome was improvement in pain, as measured on a 100-mm visual analog scale, 1 week after the cessation of treatment. Secondary outcomes were disability and active flexion, abduction, and hand-behind-back range of motion. Measurements were obtained at baseline, 1 week after the cessation of treatment, and 12 weeks after the cessation of treatment.

RESULTS

The between-group difference in pain scores from the baseline to 12 weeks after the cessation of treatment demonstrated a small significant difference in favor of the group receiving exercise only (mean difference=14.7 mm). There were no significant differences between groups in any other variable.

LIMITATIONS

It was not possible to mask therapists or participants to group allocation. Diagnostic tests were not used on participants to determine specific shoulder pathology.

CONCLUSIONS

The addition of soft tissue massage to an exercise program for the shoulder conferred no additional benefit for improving pain, disability, or range of motion in people with nonspecific shoulder pain.

The Effect of Monochromatic Infrared Photo Energy on the Irritability of Myofascial Trigger Spot of Rabbit Skeletal Muscle

Objective. To determine whether the vasodilatation effect of monochromatic infrared photo energy (MIRE) had the potential for the treatment of myofascial trigger spot (MTrS) in rabbits. Design. A randomized-controlled animal study. Subjects. Twelve adult New Zealand rabbits. Methods. For each rabbit, a MTrS (equivalent to a myofascial trigger point in humans) in one side of the biceps femoris muscle was randomly selected for MIRE treatment (experimental side), while another MTrS in the other side (control side) received a sham treatment. The intervention consisted of a daily 40 minutes treatment, three times per week for 2 weeks. The prevalence of endplate noise (EPN) loci in the MTrS was assessed before, immediately after, and one week after the completion of the 2-week treatment. Results. MIRE could suppress the prevalence of EPN in the MTrS. The degree of reduction in EPN prevalence in the MTrS between the experimental side and the control side was significantly different immediately after MIRE treatment, but not significantly different one week after MIRE treatment. Conclusion. Our study suggests that MIRE may be a useful therapeutic option for the management of the myofascial trigger point in humans.

Myofascial Trigger Points Then and Now: A Historical and Scientific Perspective

The intent of this article is to discuss the evolving role of the myofascial trigger point (MTrP) in myofascial pain syndrome (MPS) from both a historical and scientific perspective. MTrPs are hard, discrete, palpable nodules in a taut band of skeletal muscle that may be spontaneously painful (i.e., active) or painful only on compression (i.e., latent). MPS is a term used to describe a pain condition that can be acute or, more commonly, chronic and involves the muscle and its surrounding connective tissue (e.g. fascia). According to Travell and Simons, MTrPs are central to the syndrome-but are they necessary? Although the clinical study of muscle pain and MTrPs has proliferated over the past two centuries, the scientific literature often seems disjointed and confusing. Unfortunately, much of the terminology, theories, concepts, and diagnostic criteria are inconsistent, incomplete, or controversial. To address these deficiencies, investigators have recently applied clinical, imaging (of skeletal muscle and brain), and biochemical analyses to systematically and objectively study the MTrP and its role in MPS. Data suggest that the soft tissue milieu around the MTrP, neurogenic inflammation, sensitization, and limbic system dysfunction may all play a role in the initiation, amplification, and perpetuation of MPS. The authors chronicle the advances that have led to the current understanding of MTrP pathophysiology and its relationship to MPS, and review the contributions of clinicians and researchers who have influenced and expanded our contemporary level of clinical knowledge and practice.

Myelinated Afferents Are Involved in Pathology of the Spontaneous Electrical Activity and Mechanical Hyperalgesia of Myofascial Trigger Spots in Rats

Myofascial trigger points (MTrPs) are common causes for chronic pain. Myelinated afferents were considered to be related with muscular pain, and our clinical researches indicated they might participate in the pathology of MTrPs. Here, we applied myofascial trigger spots (MTrSs, equal to MTrPs in human) of rats to further investigate role of myelinated afferents. Modified pyridine-silver staining revealed more nerve endings at MTrSs than non-MTrSs (P < 0.01), and immunohistochemistry with Neurofilament 200 indicated more myelinated afferents existed in MTrSs (P < 0.01). Spontaneous electrical activity (SEA) recordings at MTrSs showed that specific block of myelinated afferents in sciatic nerve with tetrodotoxin (TTX) led to significantly decreased SEA (P < 0.05). Behavioral assessment showed that mechanical pain thresholds (MPTs) of MTrSs were lower than those of non-MTrSs (P < 0.01). Block of myelinated afferents by intramuscular TTX injection increased MPTs of MTrSs significantly (P < 0.01), while MPTs of non-MTrSs first decreased (P < 0.05) and then increased (P > 0.05). 30 min after the injection, MPTs at MTrSs were significantly lower than those of non-MTrSs (P < 0.01). Therefore, we concluded that proliferated myelinated afferents existed at MTrSs, which were closely related to pathology of SEA and mechanical hyperalgesia of MTrSs.

Dry needling for management of pain in the upper quarter and craniofacial region

Dry needling is a therapeutic intervention that has been growing in popularity. It is primarily used with patients that have pain of myofascial origin. This review provides background about dry needling, myofascial pain, and craniofacial pain. We summarize the evidence regarding the effectiveness of dry needling. For patients with upper quarter myofascial pain, a 2013 systematic review and meta-analysis of 12 randomized controlled studies reported that dry needling is effective in reducing pain (especially immediately after treatment) in patients with upper quarter pain. There have been fewer studies of patients with craniofacial pain and myofascial pain in other regions, but most of these studies report findings to suggest the dry needling may be helpful in reducing pain and improving other pain related variables such as the pain pressure threshold. More rigorous randomized controlled trials are clearly needed to more fully elucidate the effectiveness of dry needling.

Ischemic Compression After Dry Needling of a Latent Myofascial Trigger Point Reduces Postneedling Soreness Intensity and Duration

OBJECTIVE

To investigate the effect of ischemic compression (IC) versus placebo and control on reducing postneedling soreness of 1 latent myofascial trigger point and on improving cervical range of motion (CROM) in asymptomatic subjects.

DESIGN

A randomized, double-blind, placebo-controlled trial with 72-hour follow-up.

SETTING

A university community.

PARTICIPANTS

Asymptomatic volunteers (N = 90: 40 men and 50 women) aged 18 to 39 years (mean ± standard deviation [SD]: 22 ± 3 years).

INTERVENTION

All subjects received a dry needling application over the upper trapezius muscle. Participants were then randomly divided into 3 groups: a treatment group who received IC over the needled trapezius muscle, a placebo group who received sham IC, and a control group who did not receive any treatment after needling.

MAIN OUTCOME MEASURES

Visual analog scale (VAS; during needling, at posttreatment and 6, 12, 24, 48, and 72 hours) and CROM (at preneedling, postneedling, and 24 and 72 hours).

RESULTS

Subjects in the IC group showed significantly lower postneedling soreness than the placebo and the control group subjects immediately after treatment (mean ± standard deviation [SD]: IC, 20.1 ± 4.8; placebo, 36.7 ± 4.8; control, 34.8 ± 3.6) and at 48 hours (mean ± SD: IC, 0.6 ± 1; placebo, 4.8 ± 1; control, 3.8 ± 0.7). In addition, subjects in the dry needling+IC group showed significantly lower postneedling soreness duration (P = .026). All subjects significantly improved CROM in contralateral lateroflexion and both homolateral and contralateral rotations, but only the improvements found in the IC group reached the minimal detectable change.

CONCLUSIONS

IC can potentially be added immediately after dry needling of myofascial trigger point in the upper trapezius muscle because it has the effect of reducing postneedling soreness intensity and duration. The combination of dry needling and IC seems to improve CROM in homolateral and contralateral cervical rotation movements.

The failed back surgery syndrome: pitfalls surrounding evaluation and treatment

This article describes the costs and risk factors for failed back surgery syndrome and reviews the diagnosis and treatment strategies commonly used to address this syndrome. The purpose of this review is to describe some of the treatment pitfalls associated with these approaches from a physiatric perspective.

Ultrasound-guided myofascial trigger point injection into brachialis muscle for rotator cuff disease patients with upper arm pain: a pilot study

OBJECTIVE

To assess the efficacy of trigger point injection into brachialis muscle for rotator cuff disease patients with upper arm pain.

METHODS

A prospective, randomized, and single-blinded clinical pilot trial was performed at university rehabilitation hospital. Twenty-one patients clinically diagnosed with rotator cuff disease suspected of having brachialis myofascial pain syndrome (MPS) were randomly allocated into two groups. Effect of ultrasound (US)-guided trigger point injection (n=11) and oral non-steroidal anti-inflammatory drug (NSAID) (n=10) was compared by visual analog scale (VAS).

RESULTS

US-guided trigger point injection of brachialis muscle resulted in excellent outcome compared to the oral NSAID group. Mean VAS scores decreased significantly after 2 weeks of treatment compared to the baseline in both groups (7.3 vs. 4.5 in the injection group and 7.4 vs. 5.9 in the oral group). The decrease of the VAS score caused by injection (ДVAS=-2.8) was significantly larger than caused by oral NSAID (ДVAS=-1.5) (p<0.05).

CONCLUSION

In patients with rotator cuff disease, US-guided trigger point injection of the brachialis muscle is safe and effective for both diagnosis and treatment when the cause of pain is suspected to be originated from the muscle.

The effects of the CORE programme on pain at rest, movement-induced and secondary pain, active range of motion, and proprioception in female office workers with chronic low back pain: a randomized controlled trial

OBJECTIVE

To investigate the effects of the CORE programme on pain at rest, movement-induced pain, secondary pain, active range of motion, and proprioception deficits in female office workers with chronic low back pain.

DESIGN

Randomized controlled trial.

SETTING

Rehabilitation clinics.

SUBJECTS

A total of 53 participants with chronic low back pain were randomized into the CORE group and the control group.

INTERVENTION

CORE group participants underwent the 30-minute CORE programme, five times per week, for eight weeks, with additional use of hot-packs and transcutaneous electrical nerve stimulation, while the control group used only hot-packs and transcutaneous electrical nerve stimulation.

MAIN MEASURES

Participants were evaluated pretest, posttest, and two months after the intervention period to measure resting and movement-induced pain, pressure pain as secondary pain, active range of pain-free motion, and trunk proprioception.

RESULTS

Pain intensity at rest (35.6 ±5.9 mm) and during movement (39.4 ±9.1 mm) was significantly decreased in the CORE group following intervention compared with the control group. There were significant improvements in pressure pain thresholds (quadratus lumborum: 2.2 ±0.7 kg/cm(2); sacroiliac joint: 2.0 ±0.7 kg/cm(2)), active range of motion (flexion: 30.8 ±14.3°; extension: 6.6 ±2.5°), and proprioception (20° flexion: 4.3 ±2.4°; 10° extension: 3.1 ±2.0°) in the CORE group following intervention (all p < 0.05). These improvements were maintained at the two-month follow-up. The control group did not show significant improvements in any measured parameter.

CONCLUSION

The CORE programme is an effective intervention for reducing pain at rest and movement-induced pain, and for improving the active range of motion and trunk proprioception in female office workers with chronic low back pain.

Needling therapy for myofascial pain: recommended technique with multiple rapid needle insertion

Myofascial trigger point (MTrP) is a major cause of muscle pain, characterized with a hyperirritable spot due to accumulation of sensitized nociceptors in skeletal muscle fibers. Many needling therapy techniques for MTrP inactivation exist. Based on prior human and animal studies, multiple insertions can almost completely eliminate the MTrP pain forthwith. It is an attempt to stimulate many sensitive loci (nociceptors) in the MTrP region to induce sharp pain, referred pain or local twitch response. Suggested mechanisms of needling analgesia include effects related to immune, hormonal or nervous system. Compared to slow-acting biochemical effects involving immune or hormonal system, neurological effects can act faster to provide immediate and complete pain relief. Most likely mechanism of multiple needle insertion therapy for MTrP inactivation is to encounter sensitive nociceptors with the high-pressure stimulation of a sharp needle tip to activate a descending pain inhibitory system. This technique is strongly recommended for myofasical pain therapy in order to resume patient's normal life rapidly, thus saving medical and social resources.

Dry needling: a literature review with implications for clinical practice guidelines

BACKGROUND

Wet needling uses hollow-bore needles to deliver corticosteroids, anesthetics, sclerosants, botulinum toxins, or other agents. In contrast, dry needling requires the insertion of thin monofilament needles, as used in the practice of acupuncture, without the use of injectate into muscles, ligaments, tendons, subcutaneous fascia, and scar tissue. Dry needles may also be inserted in the vicinity of peripheral nerves and/or neurovascular bundles in order to manage a variety of neuromusculoskeletal pain syndromes. Nevertheless, some position statements by several US State Boards of Physical Therapy have narrowly defined dry needling as an 'intramuscular' procedure involving the isolated treatment of 'myofascial trigger points' (MTrPs).

OBJECTIVES

To operationalize an appropriate definition for dry needling based on the existing literature and to further investigate the optimal frequency, duration, and intensity of dry needling for both spinal and extremity neuromusculoskeletal conditions.

MAJOR FINDINGS

According to recent findings in the literature, the needle tip touches, taps, or pricks tiny nerve endings or neural tissue (i.e. 'sensitive loci' or 'nociceptors') when it is inserted into a MTrP. To date, there is a paucity of high-quality evidence to underpin the use of direct dry needling into MTrPs for the purpose of short and long-term pain and disability reduction in patients with musculoskeletal pain syndromes. Furthermore, there is a lack of robust evidence validating the clinical diagnostic criteria for trigger point identification or diagnosis. High-quality studies have also demonstrated that manual examination for the identification and localization of a trigger point is neither valid nor reliable between-examiners.

CONCLUSIONS

Several studies have demonstrated immediate or short-term improvements in pain and/or disability by targeting trigger points (TrPs) using in-and-out techniques such as 'pistoning' or 'sparrow pecking'; however, to date, no high-quality, long-term trials supporting in-and-out needling techniques at exclusively muscular TrPs exist, and the practice should therefore be questioned. The insertion of dry needles into asymptomatic body areas proximal and/or distal to the primary source of pain is supported by the myofascial pain syndrome literature. Physical therapists should not ignore the findings of the Western or biomedical 'acupuncture' literature that have used the very same 'dry needles' to treat patients with a variety of neuromusculoskeletal conditions in numerous, large scale randomized controlled trials. Although the optimal frequency, duration, and intensity of dry needling has yet to be determined for many neuromusculoskeletal conditions, the vast majority of dry needling randomized controlled trials have manually stimulated the needles and left them in situ for between 10 and 30 minute durations. Position statements and clinical practice guidelines for dry needling should be based on the best available literature, not a single paradigm or school of thought; therefore, physical therapy associations and state boards of physical therapy should consider broadening the definition of dry needling to encompass the stimulation of neural, muscular, and connective tissues, not just 'TrPs'.

Additional effects of transcranial direct-current stimulation and trigger-point injection for treatment of myofascial pain syndrome: a pilot study with randomized, single-blinded trial

BACKGROUND

Chronic pain caused by myofascial pain syndrome (MPS) results in generalized and debilitating conditions. Trigger-point injection (TPI) is the mainstay of MPS management to reduce acute and localized pain. Other adjunctive intervention to modulate the central pain pathway might be helpful if they are combined with TPI. Transcranial direct-current stimulation (tDCS), which is a form of neurostimulation, has been reported to be safe and effective in treating chronic pain by changing cortical excitability.

OBJECTIVES

To determine whether there is an additional effect of tDCS and TPI to reduce pain in patients with MPS.

PATIENTS

Twenty-one patients with newly diagnosed MPS of shoulder girdle muscles.

INTERVENTIONS

Patients were randomly assigned into 1 of 3 groups (2 active and 1 sham stimulation groups) and received TPI. Immediately after TPI, tDCS (2 mA for 20 minutes on 5 consecutive days) was administered. For the active stimulation groups, tDCS was applied over 2 different locations (primary motor cortex and dorsolateral prefrontal cortex [DLPFC]).

OUTCOME MEASURES

Visual analogue scale (VAS), Pain Threshold Test, and short form of the McGill Pain Questionnaire were measured before and immediately after stimulation for 5 consecutive days.

RESULTS

The mean VAS values were decreased in all three groups after 5 days. There was a significant change between before and after stimulation only in the DLPFC group. The significant change in the mean VAS value was shown from after the second stimulation session (p=0.031), and this remained significant until the last stimulation session (p=0.027).

CONCLUSION

This study suggests that tDCS over DLPFC may have additional effects with TPI to reduce pain in patients with MPS. tDCS over DLPFC can be used to reverse central pain pathway by modulating cortical plasticity.

Application of ultrasound-guided trigger point injection for myofascial trigger points in the subscapularis and pectoralis muscles to post-mastectomy patients: a pilot study

PURPOSE

To investigate the therapeutic effectiveness of ultrasound (US)-guided trigger point injection for myofascial trigger points (MTrPs) in the internal rotator muscles of the shoulder in post-mastectomy patients.

MATERIALS AND METHODS

This pilot study was a non-controlled, prospective, clinical trial. Nineteen post-mastectomy patients with a diagnosis of at least one active MTrP in the subscapularis and/or pectoralis muscles were included. We performed trigger point injections into the subscapularis muscle deep behind the scapula as well as the pectoralis muscle for diagnostic and therapeutic purpose by the newly developed US-guided method.

RESULTS

Visual analogue scale and range of motion of the shoulder for external rotation and of abduction showed significant improvement immediately after the first injection and 3 months after the last injection compared with baseline (p<0.05 for both). Duration from onset to surgery and duration of myofascial pain syndrome in the good responder group were significantly shorter than in the bad responder group (p<0.05). Patients did not report any complications related to the procedure or serious adverse events attributable to the treatment.

CONCLUSION

In post-mastectomy patients with shoulder pain, US-guided trigger point injections of the subscapularis and/or pectoralis muscles are effective for both diagnosis and treatment when the cause of shoulder pain is suspected to originate from active MTrPs in these muscles, particularly, the subscapularis.