Pathophysiologic and electrophysiologic mechanisms of myofascial trigger points

Evidence for the use of dry needling and physiotherapy in the management of cervicogenic or tension-type headache: A systematic review

Background:

There is good evidence in the literature supporting physiotherapy in the management of some forms of headache. Dry needling of myofascial trigger points is becoming an increasingly common approach despite a paucity of research evidence supporting its use. The purpose of this review was to determine the evidence supporting the use of dry needling in addition to conventional physiotherapy in the management of tension-type and cervicogenic headache.

Methods:

Ten databases were searched for evidence of the effect of dry needling on the severity and frequency of tension and cervicogenic headache based ICHD classifications.

Results:

Three relevant studies were identified and all three showed statistically significant improvements following dry needling, but no significant differences between groups. Only one study reported on headache frequency or intensity, reporting a 45 mm improvement in VAS score following the addition of dry needling to conventional physiotherapy. Two studies showed significant improvements with dry needling over 4–5 weeks of treatment. No adverse events were reported.

Conclusions:

The literature suggests that while there is insufficient evidence to strongly advocate for the use of dry needling, it may be a useful addition to conventional physiotherapy in headache management. Further research with a stronger methodological design is required.

Influence of instrument assisted soft tissue treatment techniques on myofascial trigger points

OBJECTIVE

The purpose of this study was to examine the influence of instrument assisted soft tissue techniques (IASTT) on myofascial trigger points (MTrP).

DESIGN

Randomized, controlled study with the researcher assessing the MTrP sensitivity blinded to the treatment rendered.

PARTICIPANTS

Phase 1 = 27; Phase 2 = 22.

INTERVENTION

MTrPs were identified in the upper back. In phase 1, two MTrPs (right & left) were identified. One was treated with IASTT, the other was a control. In phase 2, one MTrP was identified in a treatment and a control group. In each phase, the treatment groups received six treatments of IASTT.

OUTCOME MEASURES

Sensitivity threshold of the MTrP was assessed with a dolorimeter.

RESULTS

There was a significant improvement in both groups over time but there was no difference between the treatment and control groups.

CONCLUSIONS

The use of a pressure dolorimeter may have served as a form of ischemic compression treatment. This assessment tool may have been a mitigating factor in the over-shadowing any potential influence of the IASTT on the MTrP. Thus, another assessment tool needs to be identified for MTrP assessment. Until that technique is identified, the effect of IASTT on MTrPs in inconclusive.

Clinical implication of latent myofascial trigger point

Myofascial trigger points (MTrPs) are hyperirritable points located within a taut band of skeletal muscle or fascia, which cause referred pain, local tenderness and autonomic changes when compressed. There are fundamental differences between the effects produced by the two basic types of MTrPs (active and latent). Active trigger points (ATrPs) usually produce referred pain and tenderness. In contrast, latent trigger points (LTrPs) are foci of hyperirritability in a taut band of muscle, which are clinically associated with a local twitch response, tenderness and/or referred pain upon manual examination. LTrPs may be found in many pain-free skeletal muscles and may be "activated" and converted to ATrPs by continuous detrimental stimuli. ATrPs can be inactivated by different treatment strategies; however, they never fully disappear but rather convert to the latent form. Therefore, the diagnosis and treatment of LTrPs is important. This review highlights the clinical implication of LTrPs.

Lumbar facet injection for the treatment of chronic piriformis myofascial pain syndrome: 52 case studies

BACKGROUND AND AIMS

The aim of this study was to demonstrate the effectiveness of lumbar facet joint injection for piriformis myofascial pain syndrome.

METHODS

Fifty-two patients with chronic myofascial pain in the piriformis muscle each received a lumbar facet injection into the ipsilateral L5-S1 facet joint region, using the multiple insertion technique. Subjective pain intensity, trunk extension range, and lumbar facet signs were measured before, immediately after, and 2 weeks after injection. Thirty-six patients received follow-up for 6 months.

RESULTS

Immediately after the injection, 27 patients (51.9%) had complete pain subsidence, 19 patients (36.5%) had pain reduction to a tolerable level, and only 6 patients (11.5%) had no pain relief to a tolerable level. Mean pain intensity was reduced from 7.4±0.9 to 1.6±2.1 after injection (P<0.01). This effectiveness lasted for 2 weeks in 49 patients (94.2%), and lasted for approximately 6 months in 35 (97.2%) of 36 patients. The mean range of motion increased from 13.4±6.8 degrees to 22.1±6.0 degrees immediately after injection, and further increased 2 weeks and 6 months later. Immediately after injection, 45 patients (86.5%) had no facet sign. In addition, 90.4% and 94.4% of patients had no facet sign after 2 weeks and after 6 months, respectively.

CONCLUSIONS

It is important to identify the possible cause of piriformis myofascial pain syndrome. If this pain is related to lumbar facet lesions, lumbar facet joint injection can immediately suppress piriformis myofascial pain symptoms. This effectiveness may last for at least 6 months in most patients. This study further supports the importance of eliminating the underlying etiological lesion for complete and effective relief of myofascial pain syndrome.

Targeting myofascial taut bands by ultrasound

Myofascial pain syndrome (MPS) is a frequent diagnosis in chronic pain and is characterized by tender, taut bands known as trigger points. The trigger points are painful areas in skeletal muscle that are associated with a palpable nodule within a taut band of muscle fibers. Despite the prevalence of myofascial pain syndrome, diagnosis is based on clinical criteria alone. A growing body of evidence that suggests that taut bands are readily visualized under ultrasound-guided exam, especially when results are correlated with elastography, multidimensional imaging, and physical exam findings such as local twitch response. The actual image characteristic in B mode appears to be controversial. Ultrasonography provides an objective modality to assist with diagnosis and treatment of trigger points in the future.

Effectiveness of dry needling for upper-quarter myofascial pain: a systematic review and meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

BACKGROUND

Myofascial pain syndrome (MPS) is associated with hyperalgesic zones in muscle called myofascial trigger points. When palpated, active myofascial trigger points cause local or referred symptoms, including pain. Dry needling involves inserting an acupuncture-like needle into a myofascial trigger point, with the goal of reducing pain and restoring range of motion.

OBJECTIVE

To explore the evidence regarding the effectiveness of dry needling to reduce pain in patients with MPS of the upper quarter.

METHODS

An electronic literature search was performed using the key word dry needling. Articles identified with the search were screened for the following inclusion criteria: human subjects, randomized controlled trial (RCT), dry needling intervention group, and MPS involving the upper quarter. The RCTs that met these criteria were assessed and scored for internal validity using the MacDermid Quality Checklist. Four separate meta-analyses were performed: (1) dry needling compared to sham or control immediately after treatment, (2) dry needling compared to sham or control at 4 weeks, (3) dry needling compared to other treatments immediately after treatment, and (4) dry needling compared to other treatments at 4 weeks.

RESULTS

The initial search yielded 246 articles. Twelve RCTs were ultimately selected. The methodological quality scores ranged from 23 to 40 points, with a mean of 34 points (scale range, 0-48; best possible score, 48). The findings of 3 studies that compared dry needling to sham or placebo treatment provided evidence that dry needling can immediately decrease pain in patients with upper-quarter MPS, with an overall effect favoring dry needling. The findings of 2 studies that compared dry needling to sham or placebo treatment provided evidence that dry needling can decrease pain after 4 weeks in patients with upper-quarter MPS, although a wide confidence interval for the overall effect limits the impact of the effect. Findings of studies that compared dry needling to other treatments were highly heterogeneous, most likely due to variance in the comparison treatments. There was evidence from 2 studies that lidocaine injection may be more effective in reducing pain than dry needling at 4 weeks.

CONCLUSION

Based on the best current available evidence (grade A), we recommend dry needling, compared to sham or placebo, for decreasing pain immediately after treatment and at 4 weeks in patients with upper-quarter MPS. Due to the small number of high-quality RCTs published to date, additional well-designed studies are needed to support this recommendation.

LEVEL OF EVIDENCE

Therapy, level 1a-.

Myofascial low back pain

Low back pain is a common condition that is encountered by both primary care physicians as well as various specialists, which include: orthopedic surgeons, physical medicine and rehabilitation specialists, neurologists, rheumatologists, and pain management specialists. Associated muscular pain is very common and often a reactive response from nociception from other structures. Myofascial pain may arise, which is characterized by the presence of myofascial trigger points (MTrPs) that are located in fascia, tendons, and/or muscle. This article reviews the current evidence regarding the pathophysiology, assessment, and recommended treatment options for myofascial low back pain.

The relationship between cortical excitability and pain catastrophizing in myofascial pain

Pain catastrophizing regularly occurs in chronic pain patients. It has been suggested that pain catastrophizing is a stable, person-based construct. These findings highlight the importance of investigating catastrophizing in conceptualizing specific approaches for pain management. One important area of investigation is the mechanism underlying pain catastrophizing. Therefore, this study explored the relationship between a neurophysiological marker of cortical excitability, as assessed by transcranial magnetic stimulation, and catastrophizing, as assessed by the Brazilian Portuguese Pain Catastrophizing Scale, in patients with chronic myofascial pain syndrome. The Pain Catastrophizing Scale is a robust questionnaire used to examine rumination, magnification and helplessness that are associated with the experience of pain. We include 24 women with myofascial pain syndrome. The Brazilian Portuguese Pain Catastrophizing Scale and cortical excitability were assessed. Functional and behavioral aspects of pain were evaluated with a version of the Profile of Chronic Pain scale and by multiple pain measurements (eg, pain intensity, pressure pain threshold, and other quantitative sensory measurements). Intracortical facilitation was found to be significantly associated with pain catastrophizing (β = .63, P = .001). Our results did not suggest that these findings were influenced by other factors, such as age or medication use. Furthermore, short intracortical inhibition showed a significant association with pressure pain threshold (β = .44, P = .04). This study elaborates on previous findings indicating a relationship between cortical excitability and catastrophizing. The present findings suggest that glutamatergic activity may be associated with mechanisms underlying pain catastrophizing; thus, the results highlight the need to further investigate the neurophysiological mechanisms associated with pain and catastrophizing.

PERSPECTIVE

This study highlights the relationship between cortical excitability and catastrophizing. Cortical measures may illuminate how catastrophizing responses may be related to neurophysiological mechanisms associated with chronic pain.

Myofascial trigger points and innervation zone locations in upper trapezius muscles

Background

Myofascial trigger points (MTrPs) are hyperirritable spots located in taut bands of muscle fibres. Electrophysiological studies indicate that abnormal electrical activity is detectable near MTrPs. This phenomenon has been described as endplate noise and it has been purported to be associated MTrP pathophysiology. Thus, it is suggested that MTrPs will be overlap the innervation zone (IZ). The purpose of this work was to describe the location of MTrPs and the IZ in the right upper trapezius.

Methods

We screened 71 individuals and eventually enrolled 24 subjects with neck pain and active MTrPs and 24 neck pain-free subjects with latent MTrPs. Surface electromyography (sEMG) signals were detected using an electrode matrix during isometric contraction of the upper trapezius. A physiotherapist subsequently examined the subject’s trapezius to confirm the presence of MTrPs and establish their location. IZ locations were identified by visual analysis of sEMG signals. IZ and MTrPs locations were described using an anatomical coordinate system (ACS), with the skin area covered by the matrix divided into four quadrants.

Results

No significant difference was observed between active and latent MTrPs locations (P = 0.6). Forty-five MTrPs were in the third quadrant of the ACS, and 3 were included in second quadrant. IZs were located approximately midway between the seventh cervical vertebrae and the acromial angle in a limited area in the second and third quadrants. The mean distance between MTrP and IZ was 10.4 ± 5.8 mm.

Conclusions

According to the acquired results, we conclude that IZ and MTrPs are located in well-defined areas in upper trapezius muscle. Moreover, MTrPs in upper trapezius are proximally located to the IZ but not overlapped.

The neurophysiological effects of dry needling in patients with upper trapezius myofascial trigger points: study protocol of a controlled clinical trial

INTRODUCTION

Dry needling (DN) is an effective method for the treatment of myofascial trigger points (MTrPs). There is no report on the neurophysiological effects of DN in patients with MTrPs. The aim of the present study will be to assess the immediate neurophysiological efficacy of deep DN in patients with upper trapezius MTrPs.

METHODS AND ANALYSIS

A prospective, controlled clinical trial was designed to include patients with upper trapezius MTrPs and volunteered healthy participants to receive one session of DN. The primary outcome measures are neuromuscular junction response and sympathetic skin response. The secondary outcomes are pain intensity and pressure pain threshold. Data will be collected at baseline and immediately after intervention.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Research Council, School of Rehabilitation and the Ethics Committee of Tehran University of Medical Sciences. The results of the study will be disseminated in a peer-reviewed journal and presented at international congresses.

Botulinum toxin for the treatment of myofascial pain syndromes involving the neck and back: a review from a clinical perspective

Introduction. Botulinum toxin inhibits acetylcholine (ACh) release and probably blocks some nociceptive neurotransmitters. It has been suggested that the development of myofascial trigger points (MTrP) is related to an excess release of ACh to increase the number of sensitized nociceptors. Although the use of botulinum toxin to treat myofascial pain syndrome (MPS) has been investigated in many clinical trials, the results are contradictory. The objective of this paper is to identify sources of variability that could explain these differences in the results. Material and Methods. We performed a content analysis of the clinical trials and systematic reviews of MPS. Results and Discussion. Sources of differences in studies were found in the diagnostic and selection criteria, the muscles injected, the injection technique, the number of trigger points injected, the dosage of botulinum toxin used, treatments for control group, outcome measures, and duration of followup. The contradictory results regarding the efficacy of botulinum toxin A in MPS associated with neck and back pain do not allow this treatment to be recommended or rejected. There is evidence that botulinum toxin could be useful in specific myofascial regions such as piriformis syndrome. It could also be useful in patients with refractory MPS that has not responded to other myofascial injection therapies.

Myoelectrical activity and muscle morphology in a rat model of myofascial trigger points induced by blunt trauma to the vastus medialis

OBJECTIVES

To explore myoelectrical activity and muscle morphology of myofascial trigger points (MTrPs) in an injury model of rats.

METHODS

A total of 24 male SD rats were randomly divided into a control group (group A) and model group (group B). A blunt striking injury and eccentric exercise were applied to the vastus medialis (VM) of rats in group B for 8 weeks. Later, the palpable taut band (TB), local twitch response, myoelectrical activities and morphology in the two groups were examined.

RESULTS

An average of 2.5 (30/12) palpable TBs were detected in the VM in group B compared with none in group A. The MTrPs had two types of abnormal potential. Their amplitudes were significantly higher than those in the control group (p<0.01) but their durations showed no significant differences. A series of reflex contractions appeared in groups A and B in response to external stimulation to the ear. Their amplitude and duration in group B were significantly lower than those in group A. A series of lower fibrillation potentials repeatedly occurred in model MTrPs in group B. The morphology of MTrPs showed abnormal muscle fibres with large round or ellipse shapes in cross-section and enlarged tapering shapes in longitudinal section.

CONCLUSIONS

Active MTrPs can be provoked by repeated blunt injury. Active MTrPs are a group of muscle fibres with abnormal shapes and abnormal myoelectrical potentials. External stimulation provokes low-voltage responses in MTrPs, which is different from the response of normal muscle fibres.

Probable mechanisms of needling therapies for myofascial pain control

Myofascial pain syndrome (MPS) has been defined as a regional pain syndrome characterized by muscle pain caused by myofascial trigger points (MTrPs) clinically. MTrP is defined as the hyperirritable spot in a palpable taut band of skeletal muscle fibers. Appropriate treatment to MTrPs can effectively relieve the clinical pain of MPS. Needling therapies, such as MTrP injection, dry needling, or acupuncture (AcP) can effectively eliminate pain immediately. AcP is probably the first reported technique in treating MPS patients with dry needling based on the Traditional Chinese Medicine (TCM) theory. The possible mechanism of AcP analgesia were studied and published in recent decades. The analgesic effect of AcP is hypothesized to be related to immune, hormonal, and nervous systems. Compared to slow-acting hormonal system, nervous system acts in a faster manner. Given these complexities, AcP analgesia cannot be explained by any single mechanism. There are several principles for selection of acupoints based on the TCM principles: “Ah-Shi” point, proximal or remote acupoints on the meridian, and extra-meridian acupoints. Correlations between acupoints and MTrPs are discussed. Some clinical and animal studies of remote AcP for MTrPs and the possible mechanisms of remote effectiveness are reviewed and discussed.

Remote subcutaneous needling to suppress the irritability of myofascial trigger spots: an experimental study in rabbits

Objective. To obtain electrophysiological effects of Fu's subcutaneous needling (FSN) on needling distance by assessment of endplate noise (EPN) recorded from the myofascial trigger spots (MTrSs) in rabbit skeletal muscle. Method. Eighteen New Zealand rabbits weighing 2.5–3.0 kg were randomly divided into two groups as follows: proximal needling (PN) group and distal needling (DN) group. The needling procedure followed the instructions described by the inventor of FSN, including needling insertion and swaying movement. The amplitudes of EPN on the MTrS region of BF muscle were recorded as an index of MTrS irritability. Random sampling of EPN tracings were taken for further analyses before, during, and after FSN treatment. Results. In PN and DN groups, the trends of EPN amplitude alterations were similar at conditions before, during, and after FSN treatment. The degree of reduction in the EPN amplitude in PN group was significantly higher than that in DN group. There were no significant changes in EPN amplitudes in the MTrS of contralateral BF without FSN intervention either in DN or PN group. Conclusion. The irritability of proximal MTrSs could be modulated after ipsilateral FSNs. The placement of FSN may affect the effectiveness of suppression of irritability of MTrSs.

Dry needling at myofascial trigger spots of rabbit skeletal muscles modulates the biochemicals associated with pain, inflammation, and hypoxia

Background and Purpose. Dry needling is an effective therapy for the treatment of pain associated with myofascial trigger point (MTrP). However, the biochemical effects of dry needling that are associated with pain, inflammation, and hypoxia are unclear. This study investigated the activities of β-endorphin, substance P, TNF-α, COX-2, HIF-1α, iNOS, and VEGF after different dosages of dry needling at the myofascial trigger spots (MTrSs) of a skeletal muscle in rabbit. Materials and Methods. Dry needling was performed either with one dosage (1D) or five dosages (5D) into the biceps femoris with MTrSs in New Zealand rabbits. Biceps femoris, serum, and dorsal root ganglion (DRG) were sampled immediately and 5 d after dry needling for β-endorphin, substance P, TNF-α, COX-2, HIF-1α, iNOS, and VEGF immunoassays. Results. The 1D treatment enhanced the β-endorphin levels in the biceps femoris and serum and reduced substance P in the biceps femoris and DRG. The 5D treatment reversed these effects and was accompanied by increase of TNF-α, COX-2, HIF-1α, iNOS, and VEGF production in the biceps femoris. Moreover, the higher levels of these biochemicals were still maintained 5 d after treatment. Conclusion. Dry needling at the MTrSs modulates various biochemicals associated with pain, inflammation, and hypoxia in a dose-dependent manner.

Usefulness of a myofascial trigger point injection for groin pain in patients with chronic prostatitis/chronic pelvic pain syndrome: a pilot study

OBJECTIVE

To investigate the therapeutic effectiveness of trigger point injection into the muscles around the groin in patients with clinically diagnosed chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS).

DESIGN

Prospective, unicenter trial.

SETTING

University rehabilitation hospital.

PARTICIPANTS

Patients (N=21) with clinically diagnosed CP/CPPS who are suspected of having myofascial pain syndrome.

INTERVENTION

Ultrasound-guided trigger point injection.

MAIN OUTCOME MEASURES

Visual analog scale (VAS), National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) score, and injection-associated complications.

RESULTS

Ultrasound (US)-guided trigger point injection of the iliopsoas, hip adductor, and lower abdominal muscles resulted in excellent outcomes. The mean values of the NIH-CPSI score decreased significantly from 20.2 pretreatment to 12.5 after the first treatment (P<.05). The mean values of VAS decreased significantly from 6.3 pretreatment to 2.9 after the first treatment (P<.05).

CONCLUSIONS

In patients with CP/CPPS, US-guided trigger point injections of the iliopsoas, hip adductor, and abdominal muscles are safe and effective for both diagnosis and treatment when the cause of groin pain is suspected to originate from muscles. In particular, the iliopsoas muscle was affected in all patients in this study.

Therapeutic effects of lidocaine patch on myofascial pain syndrome of the upper trapezius: a randomized, double-blind, placebo-controlled study

OBJECTIVE

The aim of this study was to compare topical 5% lidocaine patch with placebo patch in the treatment of myofascial pain syndrome of the upper trapezius.

DESIGN

In this prospective, randomized, double-blind, placebo-controlled study, 60 participants were randomly assigned, placing 31 subjects in the 5% lidocaine patch group and 29 subjects in the placebo patch group. We used the Verbal Rating Scale (VRS), the Pressure Pain Threshold, the ranges of motion of the neck, and the Neck Disability Index to evaluate the subjective pain intensity, objective pain intensity, ranges of motion, and disability of the neck, respectively. Outcome measures were performed before (day 0) the treatment course, 12 hrs after removal of the final patch on the seventh day (day 7), and 1 wk (day 14) and 3 wks (day 28) after the completion of treatment course.

RESULTS

The characteristics of the participants did not differ at baseline. Pain intensity assessed by the VRS decreased at day 7 in both the lidocaine patch and placebo patch groups. There was no significant difference between the two groups in the VRS, the Pressure Pain Threshold, the ranges of motion, and the Neck Disability Index. At day 14, the experimental group continued to improve in the VRS (1.06), but the pain of the placebo group aggravated (VRS, 1.5). The difference is significant (P = 0.03). In addition, the Neck Disability Index in the lidocaine patch group decreased significantly as compared to that in the placebo group. The pain-relieving effect of the lidocaine patch attenuated, and it was not significantly different between the two groups at day 28 in the VRS and the Neck Disability Index. Neither the Pressure Pain Threshold nor the ranges of motion were significantly different through the periods of this study.

CONCLUSIONS

The application of the 5% lidocaine patch is probably superior to the placebo patch in relieving pain and in reducing associated neck disability for a period of longer than 1 wk for treating patients with myofascial pain syndrome of the upper trapezius.

Percutaneous soft tissue release for treating chronic recurrent myofascial pain associated with lateral epicondylitis: 6 case studies

Objective. The purpose of this pilot study is to investigate the effectiveness of the percutaneous soft tissue release for the treatment of recurrent myofascial pain in the forearm due to recurrent lateral epicondylitis. Methods. Six patients with chronic recurrent pain in the forearm with myofascial trigger points (MTrPs) due to chronic lateral epicondylitis were treated with percutaneous soft tissue release of Lin's technique. Pain intensity (measured with a numerical pain rating scale), pressure pain threshold (measured with a pressure algometer), and grasping strength (measured with a hand dynamometer) were assessed before, immediately after, and 3 months and 12 months after the treatment. Results. For every individual case, the pain intensity was significantly reduced (P < 0.01) and the pressure pain threshold and the grasping strength were significantly increased (P < 0.01) immediately after the treatment. This significant effectiveness lasts for at least one year. Conclusions. It is suggested that percutaneous soft tissue release can be used for treating chronic recurrent lateral epicondylitis to avoid recurrence, if other treatment, such as oral anti-inflammatory medicine, physical therapy, or local steroid injection, cannot control the recurrent pain.

The effect of interactive neurostimulation therapy on myofascial trigger points associated with mechanical neck pain: a preliminary randomized, sham-controlled trial

OBJECTIVES

This trial was conducted to assess the effectiveness of interactive neurostimulation (INS) therapy on the treatment of pain associated with myofascial trigger points (MTPs) in adults with mechanical neck pain.

DESIGN

This was a preliminary, randomized, sham-controlled trial.

SETTING

The trial was conducted in a tertiary-care institution.

SUBJECTS

The participants were 23 adults with pain and MTPs in the neck or shoulder lasting>2 weeks.

INTERVENTIONS

INS (active or sham) was delivered for 10 minutes in a single session over the MTP area in each patient.

OUTCOME MEASURES

Immediately following the intervention, subjects were tested for pressure pain thresholds (PPTs) and 10-cm visual analogue scale score (VAS) for pain intensity. At the 5 day follow-up, two additional tests were performed: the neck disability index (NDI) and the patient specific functional scale (PSFS) for function.

RESULTS

Improvements in function (PSFS) were observed in the treatment group, which were of clinical significance in selected subjects. These effects were statistically greater than those obtained in the sham group but were overall not at a level of clinical significance in this small population. Improvements in pain intensity (VAS) and neck disability (NDI) were observed in both the treatment and sham groups, indicating that INS had no greater benefit using these measures. There was no change in PPTs following either the active or sham treatment.

CONCLUSIONS

INS is a new and emerging therapy, which may be efficacious for managing musculoskeletal conditions, such as myofascial pain syndrome. This study demonstrated improvements in function in individuals with MTPs following INS therapy, which may be of clinical significance in certain patients with neck or shoulder pain. Further large-scale clinical trials are required to confirm this effect and to determine if INS also reduces pain and neck disability.

Endometriosis and abdominal myofascial pain in adults and adolescents

Endometriosis and myofascial pain are common disorders with significant impact on quality of life. Increasingly, these conditions are being recognized as highly interconnected through processes that have been described for more than a century. This review is directed to this interconnection through a description of the relationships of endometriosis to proposed mechanisms of pain and chronic pain physiology; the clinical assessment of myofascial representations of this pain; and an approach to the management of these interconnected disorders.

The relationship between latent trigger points and depression levels in healthy subjects

Our purpose was to study the relationship between latent trigger points (LTrP) and levels of depression in healthy subjects. A total of 76 healthy subjects consisting of 40 men and 36 women (mean age, 25.4 ± 4.8 years; age range, 19-42 years) from the School of Physical Therapy and Rehabilitation and the Orthopaedics and Traumatology Department of Istanbul University Medical Faculty were selected for the study. Latent trigger points on the scapular muscles of each subject were evaluated. The upper and middle trapezius, supraspinatus, serratus anterior, and rhomboideus muscles were examined respectively, by palpation with the thumb, to determine whether there was pain. The first group consisted of 30 subjects (20 men and 10 women; mean age, 24.2 ± 5.02 years) who had previously been diagnosed as negative after an LTrP examination (control group), while the second group consisted of 28 subjects (12 men and 16 women; mean age, 23.6 ± 2.24 years) who had been diagnosed with at least five LTrPs. The third group consisted of 18 subjects (8 men and 10 women; mean age, 26. 9 ± 7.23 years) who had been diagnosed with more than five LTrPs. All groups were assessed, using the Beck Depression Inventory (BDI). The mean BDI value was found to be 8.0 ± 4.2 in the first group, 10.3 ± 3.4 in the second, and 28.5 ± 4.8 in the third. A significant difference was found between the mean BDI values of the first and second groups and also between the first and third groups. The mean BDI values of the second and third groups were also found to be statistically significant (p = 0.042). We observed a close relationship between the presence of LTrPs and depression levels in healthy people.

Mechanical pain sensitivity of deep tissues in children--possible development of myofascial trigger points in children

BACKGROUND

It is still unclear when latent myofascial trigger points (MTrPs) develop during early life. This study is designed to investigate the mechanical pain sensitivity of deep tissues in children in order to see the possible timing of the development of latent MTrPs and attachment trigger points (A-TrPs) in school children.

METHODS

Five hundreds and five healthy school children (age 4- 11 years) were investigated. A pressure algometer was used to measure the pressure pain threshold (PPT) at three different sites in the brachioradialis muscle: the lateral epicondyle at elbow (site A, assumed to be the A-TrP site), the mid-point of the muscle belly (site B, assumed to be the MTrP site), and the muscle-tendon junction as a control site (site C).

RESULTS

The results showed that, for all children in this study, the mean PPT values was significantly lower (p < 0.05) at the assumed A-TrP site (site A) than at the other two sites, and was significantly lower (p < 0.05) at the assumed MTrP site (site B) than at the control site (site C). These findings are consistent if the data is analyzed for different genders, different dominant sides, and different activity levels.

CONCLUSIONS

It is concluded that a child had increased sensitivity at the tendon attachment site and the muscle belly (endplate zone) after age of 4 years. Therefore, it is likely that a child may develop an A-Trp and a latent MTrP at the brachioradialis muscle after the age of 4 years. The changes in sensitivity, or the development for these trigger points, may not be related to the activity level of children aged 7-11 years. Further investigation is still required to identify the exact timing of the initial occurrence of a-Trps and latent MTrPs.

Remote therapeutic effectiveness of acupuncture in treating myofascial trigger point of the upper trapezius muscle

OBJECTIVE

This study aimed to investigate the remote effect of acupuncture (AcP) on the pain intensity and the irritability of the myofascial trigger point in the upper trapezius muscle.

DESIGN

Forty-five patients were equally divided into three groups: patients in the placebo control group received sham AcP, those in the simple needling group were treated using simple needling, and those in the modified AcP received AcP with the rapid "screwed in and out" into multiple sites to elicit local twitch responses. The acupoints of Wai-guan and Qu-chi were treated. The outcome assessments included changes in subjective pain intensity, pressure pain threshold, range of motion, and mean amplitude of endplate noise in the myofascial trigger point region.

RESULTS

Immediately after acupuncture, all measured parameters improved significantly in the simple needling and modified AcP groups, but not in the placebo control group. There were significantly larger changes in all parameters in the modified AcP group than that in the simple needling group.

CONCLUSIONS

The myofascial trigger point irritability could be suppressed after a remote acupuncture treatment. It appears that needling to the remote AcP points with multiple needle insertions of modified AcP technique is a better technique than simple needling insertion of simple needling technique in terms of the decrease in pain intensity and prevalence of endplate noise and the increase in pressure pain threshold in the needling sites (represented either AcP points and or myofascial trigger points). We have further confirmed that the reduction in endplate noise showed good correlation with a decreased in pain.

The effects of pressure release, phonophoresis of hydrocortisone, and ultrasound on upper trapezius latent myofascial trigger point

OBJECTIVE

To compare the effects of pressure release (PR), phonophoresis of hydrocortisone (PhH) 1%, and ultrasonic therapy (UT) in patients with an upper trapezius latent myofascial trigger point (MTP).

DESIGN

Repeated-measure design.

SETTING

A pain control medical clinic.

PARTICIPANTS

Subjects (N=60; mean±SD age, 21.78±1.76y) with a diagnosis of upper trapezius MTP participated in this study. Subjects were randomly divided into 4 groups: PR, PhH, UT, and control (15 in each group). All patients had a latent MTP in the upper trapezius muscle.

INTERVENTIONS

PR, PhH, UT.

MAIN OUTCOME MEASURES

Subjective pain intensity, pain pressure threshold (PPT), and active cervical lateral flexion range of motion were assessed in 6 sessions.

RESULTS

All 3 treatment groups showed decreases in pain and PPT and an increase in cervical lateral flexion range of motion (P<.001) compared with the control group. Both PhH and PR techniques showed more significant therapeutic effects than UT (P<.001).

CONCLUSIONS

Our results indicate that all 3 treatments used in this study were effective for treating MTP. According to this study, PhH is suggested as a new method effective for the treatment of MTP.

A new look at trigger point injections

Trigger point injections are commonly practised pain interventional techniques. However, there is still lack of objective diagnostic criteria for trigger points. The mechanisms of action of trigger point injection remain obscure and its efficacy remains heterogeneous. The advent of ultrasound technology in the noninvasive real-time imaging of soft tissues sheds new light on visualization of trigger points, explaining the effect of trigger point injection by blockade of peripheral nerves, and minimizing the complications of blind injection.

Electrophysiologic evidence of spinal accessory neuropathy in patients with cervical myofascial pain syndrome

OBJECTIVE

To evaluate whether or not spinal accessory neuropathy exists in patients with cervical myofascial pain syndrome (MFPS).

DESIGN

Prospective study.

SETTING

A neurophysiologic laboratory in a university hospital.

PARTICIPANTS

Patients with cervical MFPS (n=25) and healthy controls (n=20).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We performed nerve conduction studies (NCSs) in bilateral spinal accessory nerves, and electromyography and stimulated single-fiber electromyography in the trapezius muscles of all patients and controls. Parameters including nerve conduction velocities (NCVs), amplitudes and areas of compound muscle action potentials (CMAPs), and mean consecutive differences (MCDs) in single-fiber electromyography were measured, analyzed, and compared with the disease durations of the patients.

RESULTS

Spinal accessory NCSs showed normative NCVs but with prominently reduced CMAP amplitude in the patients with cervical MFPS, which is recognized as an axonal neuropathy of the spinal accessory nerves. Electromyography showed prominent evidence of denervation and reinnervation patterns in 48% of the MFPS patients. The abnormal MCDs in single-fiber electromyography indicated a synaptic delay of motor endplates in the motor units, and may signify evolving instability of neuromuscular transmission in the spinal accessory nerves innervating trapezius muscles of the patients.

CONCLUSIONS

This study demonstrates electrophysiologic evidence of neuroaxonal degeneration and neuromuscular transmission disorder in a significant proportion of patients with cervical MFPS. We suggest that spinal accessory neuropathy may be associated with cervical MFPS.

Changes in Clinical Parameters in Patients with Tension-type Headache Following Massage Therapy: A Pilot Study

Complementary and alternative medicine approaches to treatment for tension-type headache are increasingly popular among patients, but evidence supporting its efficacy is limited. The objective of this study was to assess short term changes on primary and secondary headache pain measures in patients with tension-type headache (TTH) receiving a structured massage therapy program with a focus on myofascial trigger point therapy. Participants were enrolled in an open label trial using a baseline control with four 3-week phases: baseline, massage (two 3-week phases) and follow-up. Twice weekly, 45-minute massage sessions commenced following the baseline phase. A daily headache diary was maintained throughout the study in which participants recorded headache incidence, intensity, and duration. The Headache Disability Index was administered upon study entry and at 3-week intervals thereafter. 18 subjects were enrolled with 16 completing all headache diary, evaluation, and massage assignments. Study participants reported a median of 7.5 years with TTH. Headache frequency decreased from 4.7+/-0.7 episodes per week during baseline to 3.7+/-0.9 during treatment period 2 (P<0.001); reduction was also noted during the follow-up phase (3.2+/-1.0). Secondary measures of headache also decreased across the study phases with headache intensity decreasing by 30% (P<0.01) and headache duration from 4.0+/-1.3 to 2.8+/-0.5 hours (P<0.05). A corresponding improvement in Headache Disability Index was found with massage (P<0.001). This pilot study provides preliminary evidence for reduction in headache pain and disability with massage therapy that targets myofascial trigger points, suggesting the need for more rigorously controlled studies.

Involvement of NGF in the rat model of persistent muscle pain associated with taut band

Myofascial pain syndrome (MPS) is an important clinical condition characterized by chronic muscle pain and a myofascial trigger point (MTrP) located in a taut band (TB). However, its pathogenic mechanism is still unclear. We developed an animal model relevant to conditions of MPS, and analyzed the mechanism of the muscle pain in this model. We applied eccentric contraction (EC) to a rat's gastrocnemius muscle (GM) for 2 weeks, and examined the mechanical withdrawal thresholds, histological changes, and expressions and contents of nerve growth factor (NGF). The mechanical withdrawal threshold decreased significantly at the next day of first EC and continued up to 9 days after EC. TBs were palpable at 3 to 8 days after initiation of EC. In EC animals, necrotic and regenerating muscle cells were found significantly more than in control animals. In EC animals, NGF expressions in regenerating muscle cells and NGF contents of GM were significantly higher than control animals. Administration of NGF receptor (TrkA) inhibitor K252a showed significant suppression of mechanical hyperalgesia in EC animals. Repeated EC induced persistent mechanical muscle hyperalgesia associated with TB. NGF expressed in regenerating muscle cells may have an important role in persistent mechanical muscle hyperalgesia which might be relevant to pathogenesis of MPS.

PERSPECTIVE

The present study shows that NGF expressed in regenerating muscle cells is involved in persistent muscular mechanical hyperalgesia. NGF-TrkA signaling in primary muscle afferent neurons may be one of the most important and promising targets for MPS.

Comparison of high-power pain threshold ultrasound therapy with local injection in the treatment of active myofascial trigger points of the upper trapezius muscle

OBJECTIVE

To compare the effects of high-power pain threshold ultrasound (HPPTUS) therapy and local anesthetic injection on pain and active cervical lateral bending in patients with active myofascial trigger points (MTrPs) of the upper trapezius muscle.

DESIGN

Randomized single-blinded controlled trial.

SETTING

Physical medicine and rehabilitation department of university hospital.

PARTICIPANTS

Subjects (N=49) who had active MTrPs of the upper trapezius muscle.

INTERVENTIONS

HPPTUS or trigger point injection (TrP).

MAIN OUTCOME MEASURES

Visual analog scale, range of motion (ROM) of the cervical spine, and total length of treatments.

RESULTS

All patients in both groups improved significantly in terms of pain and ROM, but there was no statistically significant difference between groups. Mean numbers of therapy sessions were 1 and 1.5 in the local injection and HPPTUS groups, respectively.

CONCLUSIONS

We failed to show differences between the HPPTUS technique and TrP injection in the treatment of active MTrPs of the upper trapezius muscle. The HPPTUS technique can be used as an effective alternative to TrP injection in the treatment of myofascial pain syndrome.

Spinal cord mechanism involving the remote effects of dry needling on the irritability of myofascial trigger spots in rabbit skeletal muscle

OBJECTIVE

To elucidate the neural mechanisms underlying the remote effects produced by dry needling rabbit skeletal muscle myofascial trigger spots (MTrSs) via analyses of their endplate noise (EPN) recordings.

DESIGN

Experimental animal controlled trial.

SETTING

An animal laboratory of a university.

ANIMALS

Male New Zealand rabbits (N=96) (body weight, 2.5-3.0kg; age, 16-20wk).

INTERVENTION

Animals received no intervention for neural interruption in group I, transection of the tibial nerve in group II, transection of L5 and L6 spinal cord in group III, and transection of the T1 and T2 spinal cord in group IV. Each group was further divided into 4 subgroups: animals received ipsilateral dry needling, contralateral dry needling, ipsilateral sham needling, or contralateral sham needling of gastrocnemius MTrSs.

MAIN OUTCOME MEASURES

EPN amplitudes of biceps femoris (BF) MTrSs.

RESULTS

BF MTrS mean EPN amplitudes significantly increased (P<.05) initially after gastrocnemius verum needling but reduced to a level significantly lower (P<.05) than the preneedling level in groups I and IV with ipsilateral dry needling or contralateral dry needling, and in group II with contralateral dry needling (but not ipsilateral dry needling). No significant EPN amplitude changes were observed in BF MTrS in group III or in the control animals receiving superficial needling (sham).

CONCLUSION

This remote effect of dry needling depends on an intact afferent pathway from the stimulating site to the spinal cord and a normal spinal cord function at the levels corresponding to the innervation of the proximally affected muscle.

Gait characteristics, range of motion, and spasticity changes in response to massage in a person with incomplete spinal cord injury: case report

PURPOSE

Our study set out to measure the effect of a specific routine of massage on gait characteristics, range of motion, and spasticity in a person with incomplete spinal cord injury.

METHODS

This descriptive, pre-post case study, conducted at the outpatient program of a rehabilitation facility, used neuromuscular techniques in massage for a 42-year-old man with incomplete chronic C5 spinal cord injury. The massage was applied to the iliopsoas, triceps surae, and hamstring muscle groups for 3 consecutive days.

MAIN OUTCOME MEASURES

Pre- and post-intervention testing included standard goniometric measurement of joint range of motion in the lower extremities, spasticity evaluation using the modified Ashworth scale, and evaluation of gait characteristics using GAITRite Walkway (CIR Systems, Havertown, PA, USA) pressure mapping for ambulation time, cadence, velocity, stride length, base of support, and single- and double-limb support.

RESULTS

AFTER THE THERAPEUTIC INTERVENTION, THE FOLLOWING GAIT CHANGES WERE DEMONSTRATED: increase in velocity and cadence of gait, decrease in ambulation time, increase in stride length, and improvements in the percentages of the swing and stance phases of the gait cycle.

CONCLUSIONS

Specific application of massage therapy influenced gait speed, stride length, and swing and stance phase percentages in one person with incomplete spinal cord injury. Further study is warranted to determine the extent to which massage may affect musculoskeletal and neural impairments that limit gait in people with incomplete spinal cord injury, and the method or routine whose application will yield the most benefit.

Sliding pressure algometer, a development in eliciting pressure pain thresholds at the boundaries of surface markings of abnormally tender regions

The pressure algometer probe tip is usually held stationary and pressure is steadily increased from zero until a pressure pain threshold (PPT) is elicited. In order to explore the extent of surface markings of abnormally tender regions in more detail an improved method is proposed whereby the pressure algometer is not kept still. It is slid over the tissues at a predetermined downward pressure and velocity to produce compressive, tensile and shear stress within underlying tissues. It is moved over surrounding non-tender regions until it reaches the surface overlying an abnormally tender region where a PPT is evoked. The probe is removed immediately and the skin marked. When this is repeated from different directions, the boundary of the surface markings of a tender region will appear in corresponding detail. Provided that this 'sliding pressure algometer' produces sufficiently similar amounts of stress when applied on separate occasions, it can be used to monitor the progress of a condition or the effects of treatment. To reduce cost and increase availability, this pressure algometer may be made of a plastic syringe converted into a gas-tight chamber.

Myofascial low back pain: a review

Myofascial pain syndrome is a common nonarticular local musculoskeletal pain syndrome caused by myofascial trigger points located at muscle, fascia, or tendinous insertions, affecting up to 95% of people with chronic pain disorders. Clinically, myofascial pain syndrome can present as painful restricted range of motion, stiffness, referred pain patterns, and autonomic dysfunction. The underlying cause is often related to muscular imbalances, and following a thorough physical examination the condition should be treated with a comprehensive rehabilitation program. Additional treatment options include pharmacologic, needling with or without anesthetic agents or nerve stimulation, and alternative medicine treatments such as massage or herbal medicines. Repeated trigger point injections should be avoided, and corticosteroids should not be injected into trigger points.

Treatment of myofascial trigger points in patients with chronic shoulder pain: a randomized, controlled trial

BACKGROUND

Shoulder pain is a common musculoskeletal problem that is often chronic or recurrent. Myofascial trigger points (MTrPs) cause shoulder pain and are prevalent in patients with shoulder pain. However, few studies have focused on MTrP therapy. The aim of this study was to assess the effectiveness of multimodal treatment of MTrPs in patients with chronic shoulder pain.

METHODS

A single-assessor, blinded, randomized, controlled trial was conducted. The intervention group received comprehensive treatment once weekly consisting of manual compression of the MTrPs, manual stretching of the muscles and intermittent cold application with stretching. Patients were instructed to perform muscle-stretching and relaxation exercises at home and received ergonomic recommendations and advice to assume and maintain good posture. The control group remained on the waiting list for 3 months. The Disabilities of Arm, Shoulder and Hand (DASH) questionnaire score (primary outcome), Visual Analogue Scale for Pain (VAS-P), Global Perceived Effect (GPE) scale and the number of muscles with MTrPs were assessed at 6 and 12 weeks in the intervention group and compared with those of a control group.

RESULTS

Compared with the control group, the intervention group showed significant improvement (P < 0.05) on the DASH after 12 weeks (mean difference, 7.7; 95% confidence interval (95% CI), 1.2 to 14.2), on the VAS-P1 for current pain (mean difference, 13.8; 95% CI, 2.6 to 25.0), on the VAS-P2 for pain in the past 7 days (mean difference, 10.2; 95% CI, 0.7 to 19.7) and VAS-P3 most severe pain in the past 7 days (mean difference, 13.8; 95% CI, 0.8 to 28.4). After 12 weeks, 55% of the patients in the intervention group reported improvement (from slightly improved to completely recovered) versus 14% in the control group. The mean number of muscles with active MTrPs decreased in the intervention group compared with the control group (mean difference, 2.7; 95% CI, 1.2 to 4.2).

CONCLUSIONS

The results of this study show that 12-week comprehensive treatment of MTrPs in shoulder muscles reduces the number of muscles with active MTrPs and is effective in reducing symptoms and improving shoulder function in patients with chronic shoulder pain.

TRIAL REGISTRATION NUMBER

ISRCTN: ISRCTN75722066.

[Symptomatic approach to musculoskeletal dysfunction and chronic pelvic and perineal pain]

INTRODUCTION

Clinical examination of a patient with chronic pelvic and perineal pain often demonstrates muscle hypertonia or muscle contracture sometimes associated with local tenderness or real muscle trigger points. It is sometimes very difficult to determine whether this muscle pain detected on clinical examination is the cause or a consequence of the pain. The purpose of this article is to review musculoskeletal dysfunction in the context of chronic pelvic and perineal pain.

MATERIAL AND METHODS

Review of the literature devoted to musculoskeletal aspects of pelvic and perineal pain.

RESULTS

Definitions of pelvic floor dysfunction, hyperactive pelvic floor, myofascial pain and muscle trigger points, and the concept of fibromyalgia.

CONCLUSION

Musculoskeletal pain is certainly underestimated in the management of chronic pelvic and perineal pain. The pathophysiology of musculoskeletal pain involves disorders of the lumbar, pelvic and femoral equilibrium, myofascial pain characterized by the presence of trigger points for which the pathophysiology remains controversial: a purely muscle disease, reaction to adjacent inflammatory reactions causing hypersensitization, or simply a sign of central hypersensitization in a context of chronic pain syndrome.