Endplate potentials are common to midfiber myofacial trigger points

OBJECTIVES: To compare the prevalence of motor endplate potentials (noise and spikes) in active central myofascial trigger points, endplate zones, and taut bands of skeletal muscle to assess the specificity of endplate potentials to myofascial trigger points. DESIGN: This nonrandomized, unblinded needle examination of myofascial trigger points compares the prevalence of three forms of endplate potentials at one test site and two control sites in 11 muscles of 10 subjects. The endplate zone was independently determined electrically. Active central myofascial trigger points were identified by spot tenderness in a palpable taut band of muscle, a local twitch response to snapping palpation, and the subject's recognition of pain elicited by pressure on the tender spot. RESULTS: Endplate noise without spikes occurred in all 11 muscles at trigger-point sites, in four muscles at endplate zone sites outside of trigger points (P = 0.024), and did not occur in taut band sites outside of an endplate zone (P = 0.000034). CONCLUSIONS: Endplate noise was significantly more prevalent in myofascial trigger points than in sites that were outside of a trigger point but still within the endplate zone. Endplate noise seems to be characteristic of, but is not restricted to, the region of a myofascial trigger point.     

Remote Influences of Acupuncture on the Pain Intensity and the Amplitude Changes of Endplate Noise in the Myofascial Trigger Point of the Upper Trapezius Muscle

Chou L-W, Hsieh Y-L, Kao M-J, Hong C-Z. Remote influences of acupuncture on the pain intensity and the amplitude changes of endplate noise in the myofascial trigger point of the upper trapezius muscle.

Objective

To investigate the remote effect of acupuncture on the pain intensity and the endplate noise (EPN) recorded from a myofascial trigger point (MTrP) of the upper trapezius muscle.

Design

Randomized controlled trial.

Setting

University hospital.

Participants

Patients (N=20) with active MTrPs in upper trapezius muscles and no experience in acupuncture therapy.

Interventions

Patients were divided into 2 groups. Those in the control group received sham acupuncture, and those in the acupuncture group received modified acupuncture therapy with needle insertion into multiple loci to elicit local twitch responses. The acupuncture points of Wai-guan and Qu-chi were treated.

Main Outcome Measures

Subjective pain intensity (numerical pain rating scale) and mean EPN amplitude in the MTrP of the upper trapezius muscle.

Results

The pain intensity in the MTrP was significantly reduced after remote acupuncture (from 7.4±0.8 to 3.3±1.1; P<.001), but not after sham acupuncture (from 7.4±0.8 to 7.1±0.9; P>.05). The mean EPN amplitude was significantly lower than the pretreatment level after acupuncture treatment (from 21.3±9.5μV to 9.5±3.5μV; P<.01), but not after sham acupuncture treatment (from 19.6±7.6μV to 19.3±7.8μV; P>.05). The change in the pain intensity was significantly correlated with the change of EPN amplitude (r = 0.685).

Conclusions

Both subjective changes in the pain intensity and objective changes of the EPN amplitude in the MTrP region of the upper trapezius muscle were found during and after acupuncture treatment at the remote ipsilateral acupuncture points. This study may further clarify the physiological basis of the remote effectiveness of acupuncture therapy for pain control.     

Detecting local twitch responses of myofascial trigger points in the lower-back muscles using ultrasonography

Rha D-w, Shin JC, Kim Y-K, Jung JH, Kim YU, Lee SC. Detecting local twitch responses of myofascial trigger points in the lower-back muscles using ultrasonography.

Objective

To evaluate the role of ultrasonography for detecting local twitch responses (LTRs) of myofascial trigger points (MTrPs) in deeply located lower-back muscles.

Design

Case-control study. Active MTrP was diagnosed in all patients based on the criteria proposed by Travell and Simons in their upper-trapezius or lower-back muscles. One investigator administered trigger point injections while observing LTRs on ultrasonography. The other investigator observed LTRs visually during the procedure.

Setting

University rehabilitation hospital.

Participants

Patients (n=41; mean age, 51.8±11.8y) with MTrPs in the upper-trapezius muscles and patients (n=62; mean age, 56.8±11.9y) with MTrPs in the erector spinae or quadratus lumborum were recruited from April 29 to October 31, 2010.

Interventions

Ultrasound-guided trigger point injection.

Main Outcome Measures

LTR detection rate according to the depth of MTrPs; subjective pain intensity using a visual analog scale before and immediately after the trigger point injection.

Results

In upper-trapezius muscles, all LTRs were detected by means of both ultrasonographic and visual inspection. In the lower-back muscles, many LTRs were detected only on ultrasonography during the trigger point injection. For deep muscles, ultrasound helped identify LTRs that were not detected by using visual assessment. Pain was alleviated more significantly in the group with LTRs during trigger point injections compared with the group without LTRs.

Conclusions

These findings suggest that ultrasonography was useful for detecting LTRs of MTrPs, especially for LTRs in the deep muscles. Ultrasound guidance may improve the therapeutic efficacy of trigger point injection for treating MTrPs in the deep muscles.     

A distinct pattern of myofascial findings in patients after whiplash injury

Ettlin T, Schuster C, Stoffel R, Brüderlin A, Kischka U. A distinct pattern of myofascial findings in patients after whiplash injury.

Objective

To identify objective clinical examinations for the diagnosis of whiplash syndrome, whereby we focused on trigger points.

Design

A cross-sectional study with 1 measurement point.

Setting

A quiet treatment room in a rehabilitation center.

Participants

Patients (n=124) and healthy subjects (n=24) participated in this study. Among the patient group were patients with whiplash-associated disorders (n=47), fibromyalgia (n=21), nontraumatic chronic cervical syndrome (n=17), and endogenous depression (n=15).

Interventions

Not applicable.

Main Outcome Measure

Each patient and control subject had a manual examination for trigger points of the semispinalis capitis, trapezius pars descendens, levator scapulae, scalenus medius, sternocleidomastoideus, and masseter muscles bilaterally.

Results

Forty (85.1%) of the patients with whiplash had positive trigger points in the semispinalis capitis muscle. The patients with whiplash had a significantly higher prevalence of positive trigger points in the semispinalis capitis muscle than any of the control groups (P<.05). For the other examined muscles, the prevalence of trigger points in the patients with whiplash did not differ significantly from the patients with fibromyalgia or nontraumatic chronic cervical syndrome. It did differ from the patients with endogenous depression and the healthy controls.

Conclusions

Patients with whiplash showed a distinct pattern of trigger point distribution that differed significantly from other patient groups and healthy subjects. The semispinalis capitis muscle was more frequently affected by trigger points in patients with whiplash, whereas other neck and shoulder muscles and the masseter muscle did not differentiate between patients with whiplash and patients with nontraumatic chronic cervical syndrome or fibromyalgia.     

Effect of botulinum toxin on endplate noise in myofascial trigger spots of rabbit skeletal muscle

OBJECTIVE: To assess the effect of botulinum toxin type A (BTX-A) on the endplate noise prevalence in rabbit myofascial trigger spots to confirm the role of excessive acetylcholine release on the pathogenesis of myofascial trigger points and to develop an objective indicator of the effectiveness of BTX-A in the treatment of myofascial trigger points. DESIGN: Eighteen adult New Zealand rabbits were divided into three groups that received a single bolus of BTX-A over a myofascial trigger spot region on one side of the biceps femoris muscle. Another 10 rabbits received multiple-point injections in a myofascial trigger spot where endplate noises were found. A control study was performed on the other side of the biceps femoris muscle. The endplate noise prevalence in a myofascial trigger spot region was assessed. RESULTS: It was found that injection of BTX-A reduced the prevalence of endplate noise. No significant differences between a single bolus injection and multiple-point injections were noted, although there was some evidence that multiple-point injections might maintain the endplate noise decreasing effect much longer than a single injection. CONCLUSIONS: This study demonstrated the suppressive effect of BTX-A on endplate noise prevalence in a myofascial trigger spot region. The prevalence of endplate noise in the myofascial trigger point region may be a useful objective indicator for evaluating the therapeutic effectiveness of BTX-A injection to treat myofascial trigger points.     

Reliability of different methodologies of infrared image analysis of myofascial trigger points in the upper trapezius muscle

BACKGROUND:

Infrared thermography is recognized as a viable method for evaluation of subjects with myofascial pain.

OBJECTIVE:

The aim of the present study was to assess the intra- and inter-rater reliability of infrared image analysis of myofascial trigger points in the upper trapezius muscle.

METHOD:

A reliability study was conducted with 24 volunteers of both genders (23 females) between 18 and 30 years of age (22.12±2.54), all having cervical pain and presence of active myofascial trigger point in the upper trapezius muscle. Two trained examiners performed analysis of point, line, and area of the infrared images at two different periods with a 1-week interval. The intra-class correlation coefficient (ICC_2,1) was used to assess the intra- and inter-rater reliability.

RESULTS:

With regard to the intra-rater reliability, ICC values were between 0.591 and 0.993, with temperatures between 0.13 and 1.57 °C for values of standard error of measurement (SEM) and between 0.36 and 4.35 °C for the minimal detectable change (MDC). For the inter-rater reliability, ICC ranged from 0.615 to 0.918, with temperatures between 0.43 and 1.22 °C for the SEM and between 1.19 and 3.38 °C for the MDC.

CONCLUSION:

The methods of infrared image analyses of myofascial trigger points in the upper trapezius muscle employed in the present study are suitable for clinical and research practices.     

Trigger points and myofascial pain: toward understanding how they affect headaches

Myofascial pain, referred from hyperalgesic trigger points located in skeletal muscle and its associated fascia, is a common cause of persistent regional pain. Clinical and experimental literature on manifestations, pathophysiology, and management of pain from myofascial trigger points is reviewed with priority given to how pain referred from trigger points generates, triggers, and maintains headaches—especially chronic and recurrent ones. Because treating myofascial problems may be the only way to offer complete relief from certain types of headache, clinicians must learn to diagnose and manage trigger points in neck, shoulder, and head muscles.     

Novel Applications of Ultrasound Technology to Visualize and Characterize Myofascial Trigger Points and Surrounding Soft Tissue

Sikdar S, Shah JP, Gebreab T, Yen R-H, Gilliams E, Danoff J, Gerber LH. Novel applications of ultrasound technology to visualize and characterize myofascial trigger points and surrounding soft tissue.

Objective

To apply ultrasound (US) imaging techniques to better describe the characteristics of myofascial trigger points (MTrPs) and the immediately adjacent soft tissue.

Design

Four sites in each patient were labeled based on physical examination as active myofascial trigger points (A-MTrPs; spontaneously painful), latent myofascial trigger points (L-MTrPs; nonpainful), or normal myofascial tissue. US examination was performed on each subject by a team blinded to the physical findings. A 12∼5MHz US transducer was used. Vibration sonoelastography (VSE) was performed by color Doppler variance imaging while simultaneously inducing vibrations (∼92Hz) with a handheld massage vibrator. Each site was assigned a tissue imaging score as follows: 0, uniform echogenicity and stiffness; 1, focal hypoechoic region with stiff nodule; 2, multiple hypoechoic regions with stiff nodules. Blood flow in the neighborhood of MTrPs was assessed using Doppler imaging. Each site was assigned a blood flow waveform score as follows: 0, normal arterial flow in muscle; 1, elevated diastolic flow; 2, high-resistance flow waveform with retrograde diastolic flow.

Setting

Biomedical research center.

Participants

Subjects (N=9) meeting Travell and Simons' criteria for MTrPs in a taut band in the upper trapezius.

Interventions

Not applicable.

Main Outcome Measures

MTrPs were evaluated by (1) physical examination, (2) pressure algometry, and (3) three types of US imaging including gray-scale (2-dimensional [2D] US), VSE, and Doppler.

Results

MTrPs appeared as focal, hypoechoic regions on 2D US, indicating local changes in tissue echogenicity, and as focal regions of reduced vibration amplitude on VSE, indicating a localized, stiff nodule. MTrPs were elliptical, with a size of .16±.11cm². There were no significant differences in size between A-MTrPs and L-MTrPs. Sites containing MTrPs were more likely to have a higher tissue imaging score compared with normal myofascial tissue (P<.002). Small arteries (or enlarged arterioles) near A-MTrPs showed retrograde flow in diastole, indicating a highly resistive vascular bed. A-MTrP sites were more likely to have a higher blood flow score compared with L-MTrPs (P<.021).

Conclusions

Preliminary findings show that, under the conditions of this investigation, US imaging techniques can be used to distinguish myofascial tissue containing MTrPs from normal myofascial tissue (lacking trigger points). US enables visualization and some characterization of MTrPs and adjacent soft tissue.     

Are "cervicogenic" headaches due to myofascial pain and cervical spine dysfunction?

The purpose of this investigation was to evaluate whether the pain of cervicogenic headache could be due to referred symptoms from myofascial trigger points. The presence or absence of cervical spine dysfunction was also of interest. Eleven patients with cervicogenic headaches were systematically examined for myofascial trigger points and cervical spine dysfunction. All patients had at least three myofascial trigger points on the symptomatic side. In eight of these patients, trigger point palpation clearly reproduced their headache. There were 70 myofascial trigger points (35 "very tender", 35 "tender") and 17 non-myofascial tender points on the symptomatic side, compared to 22 myofascial trigger points (one "very tender", 21 "tender") and 19 non-myofascial tender points on the asymptomatic side. These differences were statistically significant [chi-square (2df) = 22.04, p less than 0.0001]. All patients had some evidence of cervical dysfunction. Ten patients (91%) had specific segmental dysfunction of occiput on atlas and/or atlas on axis. Five patients were entered into a non-invasive, interdisciplinary pain management program designed to treat cervical spine dysfunction and myofascial pain. Treated patients reported a significant decrease in the frequency and intensity of their headaches during a median two-year follow-up. It is concluded that myofascial trigger points may be an important pain producing mechanism in cervicogenic headache and that segmental cervical dysfunction is a common feature in such patients. Conservative, non-surgical treatment appears to be effective in reducing the frequency and intensity of cervicogenic headache. These data suggest that surgical approaches should be reserved only for those patients who fail conservative therapy.     

激痛点缺血性压迫治疗颈肩肌筋膜疼痛综合征疗效观察

目的:观察激痛点缺血性压迫法治疗颈肩肌筋膜疼痛综合征的疗效。方法:选择颈肩肌筋疼痛膜综合征患者20例,按照随机数字表法分为对照组和治疗组,每组10例。对照组仅接受健康宣教;治疗组在对照组基础上实施激痛点缺血性压迫疗法。首先通过Booster Pro3筋膜枪渐次提高振动频率的方法松解斜方肌上束,提高痛阈,达到放松并激活上斜方肌的目的,随后使用缺血性压迫激痛点的方法进行干预,治疗1次/d,连续治疗2周。分别在治疗前、后,采用肌力与脊柱活动度测量仪测量颈部关节活动度与肌力,采用疼痛视觉模拟评分法(VAS)评价颈肩部的疼痛程度,采用颈椎功能障碍指数(NDI)评价颈部功能障碍水平。结果:与治疗前比较,治疗第1次结束即刻治疗组左右侧肌力明显增加,治疗后2周治疗组颈部关节活动度(前屈方向)、左右侧肌力明显增加,左屈、右屈、右旋方向上的VAS评分与NDI评分明显降低,差异有统计学意义(P<0.05);与对照组比较,治疗后2周治疗组颈部关节活动度(前屈方向)、左右侧肌力更高,左屈、右屈、右旋方向上的VAS评分与NDI评分更低,差异有统计学意义(P<0.05)。结论:激痛点缺血性压迫疗法治疗颈肩肌筋膜疼痛综合征,可以有效提高MPS患者颈部关节活动度、左右侧肌力,缓解颈部肌肉僵硬不适和疼痛,改善颈椎功能障碍状态,值得临床推广应用。     

Dry needling in chronic abdominal wall pain of uncertain origin

Background

Abdominal wall pain is considered as pain that arises from the abdominal muscles rather than the underlying viscera or the spine. It is frequently overlooked and is often misdiagnosed, as these patients continue to suffer with pain. Many such patients would have even been subjected to a psychiatric evaluation in view of the absence of any ostensible clinical cause for the pain. In this study, we describe the role of myofascial trigger points in the abdominal wall pain that could be a cause of chronic pain and present our findings of pain relief by dry needling technique.

基于筋膜线理论的冲击波治疗肱骨外上髁炎临床研究

目的:以筋膜线理论为依据,本着解剖与功能的整体观,探讨冲击波法治疗肱骨外上髁炎的疗效。方法:将80例肱骨外上髁炎患者随机分为对照组和观察组,每组40例,对照组采用传统的方法(肱骨外上髁局部)进行冲击波治疗,观察组采用肌筋膜经线理论(沿臂表浅线)进行冲击波治疗。每3天1次治疗,共治疗5次。分别于治疗前、治疗后1周、1、3、6个月对2组进行视觉模拟评分(VAS)、上肢功能评分(DASH)及肱骨外上髁压痛阈值(PPT)评价。结果:治疗后1周、1、3、6个月,2组在VAS及DASH评分均较治疗前明显降低(均P0.05),观察组在治疗后各时间点VAS及DASH评分均更低于对照组(均P0.05)。2组在治疗后1周PPT与治疗前无明显变化,在治疗后1、3、6个月PPT明显提高(均P0.05),尤以观察组提高更显著(P0.05)。对照组在治疗后6个月时VAS、DASH评分及PPT较前轻度反弹,而观察组相对稳定。结论:以肌筋膜经线理论为依据,沿臂表浅线进行冲击波治疗的效果优于单纯肱骨外上髁局部治疗。     

Das myofasziale Schmerzsyndrom

Background

Pain and/or functional disorders, such as weakness or movement control disorders, often have a myofascial origin. The pathophysiological substrates of myofascial problems are myofascial trigger points (mTrP) and reactive connective tissue alterations. Typical for myofascial pain is that the site of the origin of pain and the site of pain perception often do not lie in the same place (referred pain). Myofascial disorders can have a primary or a secondary cause and often make a substantial contribution to stimulus summation problems. In the process of clinical reasoning it needs to be investigated what value mTrP and fascial alterations have for the current problem in question (e.g. primary, secondary and contribution to stimulus summation).

Methods

The causal and sustained therapy of myofascial disorders considers the contractile part of muscle (contracture knots) as well as the noncontractile parts (reactive connective tissue alterations). Predisposition and maintaining factors have to be recognized and if possible included in the therapy, depending on the necessity. The trigger point therapy IMTT® (“Interessengemeinschaft für Myofasziale Triggerpunkt-Therapie”) encompasses manual techniques and if necessary dry needling for deactivation of the disruption potential of mTrP, stretching/detonization and functional training/ergonomics.     

Electrophysiological characteristics according to activity level of myofascial trigger points

[Purpose] This study compared the differences in electrophysiological characteristics of normal muscles versus muscles with latent or active myofascial trigger points, and identified the neuromuscular physiological characteristics of muscles with active myofascial trigger points, thereby providing a quantitative evaluation of myofascial pain syndrome and clinical foundational data for its diagnosis. [Subjects] Ninety adults in their 20s participated in this study. Subjects were equally divided into three groups: the active myofascial trigger point group, the latent myofascial trigger point group, and the control group. [Methods] Maximum voluntary isometric contraction (MVIC), endurance, median frequency (MDF), and muscle fatigue index were measured in all subjects. [Results] No significant differences in MVIC or endurance were revealed among the three groups. However, the active trigger point group had significantly different MDF and muscle fatigue index compared with the control group. [Conclusion] Given that muscles with active myofascial trigger points had an increased MDF and suffered muscle fatigue more easily, increased recruitment of motor unit action potential of type II fibers was evident. Therefore, electrophysiological analysis of these myofascial trigger points can be applied to evaluate the effect of physical therapy and provide a quantitative diagnosis of myofascial pain syndrome.Key words: Electromyography, Electrophysiological characteristics, Myofascial trigger point     

Ultrasound Imaging of Embedded Shrapnel Facilitates Diagnosis and Management of Myofascial Pain Syndrome

Trigger points can result from a variety of inciting events including muscle overuse, trauma, mechanical overload, and psychological stress. When the myofascial trigger points occur in cervical musculature, they have been known to cause headaches. Ultrasound imaging is being increasingly used for the diagnosis and interventional management of various painful conditions. A veteran was referred to the pain clinic for management of his severe headache following a gunshot wound to the neck with shrapnel embedded in the neck muscles a few years prior to presentation. He had no other comorbid conditions. Physical examination revealed a taut band in the neck. An ultrasound imaging of the neck over the taut band revealed the deformed shrapnel located within the levator scapulae muscle along with an associated trigger point in the same muscle. Ultrasound guided trigger point injection, followed by physical therapy resolved his symptoms. This is a unique report of embedded shrapnel and coexisting myofascial pain syndrome revealed by ultrasound imaging. The association between shrapnel and myofascial pain syndrome requires further investigation.     

超声引导下针刺触发点治疗足底筋膜炎

目的 观察超声引导下针刺触发点治疗足底筋膜炎的临床效果。方法 选取48例足底筋膜炎患者，并随机分为2组，对单纯组（n=24）采用单纯非负重跖腱膜拉伸训练，联合组（n=24）采用超声引导下针刺触发点结合非负重跖腱膜拉伸训练；分别于治疗前（T₀）及治疗后1个月（T₁）、3个月（T₂）对患者进行"第1步"数字疼痛评分（NPRS）、美国矫形外科足踝协会踝-后足功能评分（AOFAS）以及36条目健康调查量表中生理（PCS）和心理（MCS）评分。结果 治疗前后2组NPRS、AOFAS、PCS和MCS评分总体差异均有统计学意义（P均<0.01），治疗后均较治疗前改善。联合组T₁和T₂的NPRS均低于单纯组（P均<0.01），T₁和T₂的AOFAS、PCS评分均高于单纯组（P均<0.05），而2组间T₁和T₂的MCS评分差异均无统计学意义（P均>0.05）。结论 超声引导下针刺触发点联合拉伸训练和单纯非负重跖腱膜拉伸训练对于足底筋膜炎均有效，前者缓解疼痛和改善足踝功能效果更佳。     

Myofascial trigger points in persistent posttraumatic shoulder pain

Persistent pain and disability after injuries to the shoulder sometimes create a difficult diagnostic and therapeutic problem. In many such cases, myofascial trigger points seem to cause symptoms. Three cases in which pain had persisted for eight to 33 months after injury illustrate the manifestations of posttraumatic myofascial trigger point disorders. Trigger points are located by finding discrete foci of tenderness in muscles. Trigger points may be palpably firmer than surrounding muscle, forming nodules; they may twitch in response to palpation and may refer pain to a specific area when stimulated. Failure to recognize the myofascial source of pain can lead to erroneous diagnoses of articular, neurologic, or emotional disorder. Current pathophysiologic theories about trigger points may explain the persistence and topographic spreading of pain after muscular injuries. Appropriate treatment of myofascial trigger points can relieve chronic pain and disability.     

A Critical Appraisal of the Evidence for Botulinum Toxin Type A in the Treatment for Cervico‐Thoracic Myofascial Pain Syndrome

Myofascial pain syndrome (MPS) is a musculoskeletal condition characterized by regional pain and muscle tenderness associated with the presence of myofascial trigger points (MTrPs). The last decade has seen an exponential increase in the use of botulinum toxin (BTX) to treat MPS. To understand the medical evidence substantiating the role of therapeutic BTX injections and to provide useful information for the medical practitioner, we applied the principles of evidence‐based medicine to the treatment for cervico‐thoracic MPS. A search was conducted through MEDLINE (PubMed, OVID, MDConsult), EMBASE, SCOPUS and the Cochrane database for the period 1966 to 2012 using the following keywords: myofascial pain, muscle pain, botulinum toxin, trigger points, and injections. A total of 7 trials satisfied our inclusion criteria and were evaluated in this review. Although the majority of studies found negative results, our analysis identified Gobel et al.'s as the highest quality study among these prospectively randomized investigations. This was due to appropriate identification of diagnostic criteria, excellent study design and objective endpoints. The 6 other identified studies had significant failings due to deficiencies in 1 or more major criteria. We conclude that higher quality, rigorously standardized studies are needed to more appropriately investigate this promising treatment modality.     

Untersuchung myofaszialer Triggerpunkte ist zuverlässig

Background

The objective of this study is to respond to the demand for a scientific verification of the reliability of various examination techniques used in manual medicine. As a basis for further scientific research, the intertester reliability of the clinical examination of myofascial trigger points (MTrP) in selected trunk and buttock muscles was verified.

Patients and methods

A total of 304 muscles were examined in 38 test subjects by a doctor and a physiotherapist with extensive experience in the field of MTrP following a standardized procedure. The evaluation was made using kappa statistics.

Results

The reliability of the clinical examination of the MTrP ranged from good to excellent, with kappa values up to 0.82.

Conclusion

In view of these results, MTrP can be considered a valuable clinical parameter in the assessment of pain in the locomotor system.