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

Unalan H, Majlesi J, Aydin FY, Palamar D. Comparison of high-power pain threshold ultrasound therapy with local ?njection 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.     

Effects of Deep Cervical Flexor Training on Pressure Pain Thresholds Over Myofascial Trigger Points in Patients With Chronic Neck Pain

Objective

The purpose of this study was to assess the effects of a low-load training program for the deep cervical flexors (DCFs) on pain, disability, and pressure pain threshold (PPT) over cervical myofascial trigger points (MTrPs) in patients with chronic neck pain.

Methods

Thirty patients with chronic idiopathic neck pain participated in a 6-week program of specific training for the DCF, which consisted of active craniocervical flexion performed twice per day (10-20 minutes) for the duration of the trial. Perceived pain and disability (Neck Disability Index, 0-50) and PPT over MTrPs of the upper trapezius, levator scapulae, and splenius capitis muscles were measured at the beginning and end of the training period.

Results

After completion of training, there was a significant reduction in Neck Disability Index values (before, 18.2 ± 12.1; after, 13.5 ± 10.6; P < .01). However, no significant changes in PPT were observed over the MTrPs.

Conclusion

Patients performing DCF training for 6 weeks demonstrated reductions in pain and disability but did not show changes in pressure pain sensitivity over MTrPs in the splenius capitis, levator scapulae, or upper trapezius muscles.     

Attenuated Skin Blood Flow Response to Nociceptive Stimulation of Latent Myofascial Trigger Points

Zhang Y, Ge H-Y, Yue S-W, Kimura Y, Arendt-Nielsen L. Attenuated skin blood flow response to nociceptive stimulation of latent myofascial trigger points.

Objectives

To investigate the effect of painful stimulation of latent myofascial trigger points (MTrPs) on skin blood flow and to evaluate the relative sensitivity of laser Doppler flowmetry (LDF) and thermography in the measurement of skin blood flow.

Design

Painful stimulation was obtained by a bolus injection of glutamate (0.1mL, 0.5M) into a latent MTrP located in the right or left brachioradialis muscles. A bolus of glutamate injection into a non-MTrP served as control. Pain intensity (visual analog scale [VAS]) was assessed after glutamate injection. Pressure pain threshold (PPT) was recorded bilaterally in the brachioradialis muscle before and after glutamate-induced pain. Skin blood flow and surface skin temperature were measured bilaterally in the forearms before, during, and after glutamate-induced pain with LDF and thermography.

Setting

A biomedical research facility.

Participants

Fifteen healthy volunteer subjects.

Interventions

Not applicable.

Main Outcome Measures

VAS, PPT, skin blood flow, and surface skin temperature.

Results

Glutamate injection into latent MTrPs induced higher pain intensity (F=7.16; P<.05) and lower PPT (F=11.41, P<.005) than into non-MTrPs. Glutamate injection into non-MTrPs increased skin blood flow bilaterally in the forearms, but skin blood flow after glutamate injection into latent MTrPs was significantly less increased at the local injection area or decreased at distant areas compared with non-MTrPs (all P<.05). Skin temperature was not affected after glutamate injection into either latent MTrPs or non-MTrPs (all P>.05).

Conclusions

The present study demonstrated an attenuated skin blood flow response after painful stimulation of latent MTrPs compared with non-MTrPs, suggesting increased sympathetic vasoconstriction activity at latent MTrPs. Additionally, LDF was more sensitive than thermography in the detection of the changes in skin blood flow after intramuscular nociceptive stimulation.     

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.     

A comparison between different modes of real-time sonoelastography in visualizing myofascial trigger points in low back muscles

Objective: Currently, there is a lack of objective means to quantify myofascial trigger points (MTrPs) and their core features. Our research compares (1) MTrPs and surrounding myofascial tissue using two-dimensional grayscale ultrasound (2DGSUS) and vibration sonoelastography (VSE); (2) the accuracy of both modes in visualizing MTrPs; (3) ‘active’ and ‘latent’ MTrPs, using VSE; and (4) the accuracy of both modes in visualizing deep and superficially located MTrPs.

Methods: Fifty participants with more than two MTrPs in their quadratus lumborum, longissimus thoracis, piriformis, and gluteus medius muscles were assigned to an active MTrP (low back pain) group or a latent (currently pain free) MTrP group. MTrP identification was based on their essential criteria. An electronic algometer measured repeatedly the tenderness of MTrPs with reference to pressure pain threshold values. A handheld vibrator was applied over MTrPs, while VSE and 2DGSUS readings were taken using an EUB-7500 ultrasound scanner.

Results: There was a significant difference between MTrP strain and that of the immediately surrounding myofascial tissue, as measured using VSE (P?=?0·001). VSE visualized all superficial and deep MTrPs with an accuracy of 100% (for both groups); the blinded results obtained using 2DGSUS achieved 33% and 35% accuracy, respectively. There was no significant difference found between the tissue strain ratios of active and latent MTrPs (P?=?0·929).

Discussion: Sonoelastography can visualize superficial and deep MTrPs, and differentiate them from surrounding myofascial structure through tissue stiffness and echogenicity. VSE was more accurate than 2DGSUS in visualizing and imaging MTrPs.     

The prevalence of latent myofascial trigger points and diagnostic criteria of the triceps surae and upper trapezius: a cross sectional study

Objectives

To determine the prevalence of latent myofascial trigger points (MTrPs), specific diagnostic criteria and the association between gender and MTrP prevalence in the triceps surae and upper trapezius.

Design

Cross-sectional study.

Setting

University, Faculty of Health and Life Sciences.

Participants

Two hundred and twenty healthy volunteers (132 females and 88 males; mean age 29.7 (SD 11.0).

Interventions

Not applicable.

Main outcome measures

Prevalence of latent MTrPs in the triceps surae and comparative upper trapezius; specific diagnostic criteria and pressure pain threshold (PPT).

Results

Latent MTrPs were prevalent in all triceps surae (range: 13 to 30%), left upper trapezius (23%) and right upper trapezius (20%). No MTrPs (0%) identified in the middle fibres of deltoid. For each specific diagnostic criterion, taut bands were most prevalent in the right gastrocnemius medial head (81%); tender spot in left gastrocnemius medial head (52%) and nodules in the right upper trapezius (35%). Local twitch response (0.5%), the least frequent diagnostic criterion was only found in the left gastocnemius medial head. A significant increase in latent MTrP prevalence for females compared to males in five of the six triceps surae MTrP sites, with no significant association for gender and latent MTrP prevalence in the left or right upper trapezius.

Conclusions

This study established the prevalence of latent MTrPs, specific diagnostic criteria and baseline normative data in the triceps surae. The middle fibres of deltoid were identified as a potential MTrP control site for future clinical research in the upper limb.     

Effects of burst-type transcutaneous electrical nerve stimulation on cervical range of motion and latent myofascial trigger point pain sensitivity

Rodríguez-Fernández AL, Garrido-Santofimia V, Güeita-Rodríguez J, Fernández-de-las-Peñas C. Effects of burst-type transcutaneous electrical nerve stimulation on cervical range of motion and latent myofascial trigger point pain sensitivity.

Objective

To assess the effects of a burst application of transcutaneous electrical nerve stimulation (TENS) on cervical range of motion and pressure point sensitivity of latent myofascial trigger points (MTrPs).

Design

A single-session, single-blind randomized trial.

Setting

General community rehabilitation clinic.

Participants

Individuals (N=76; 45 men, 31 women) aged 18 to 41 years (mean ± SD, 23±4y) with latent MTrPs in 1 upper trapezius muscle.

Interventions

Subjects were randomly divided into 2 groups: a TENS group that received a burst-type TENS (pulse width, 200μs; frequency, 100Hz; burst frequency, 2Hz) stimulation over the upper trapezius for 10 minutes, and a placebo group that received a sham-TENS application over the upper trapezius also for 10 minutes.

Main Outcome Measures

Referred pressure pain threshold (RPPT) over the MTrP and cervical range of motion in rotation were assessed before, and 1 and 5 minutes after the intervention by an assessor blinded to subjects' treatment.

Results

The analysis of covariance revealed a significant group × time interaction (P<.001) for RPPT: the TENS group exhibited a greater increase compared with the control group; however, between-group differences were small at 1 minute (0.3kg/cm²; 95% confidence interval [CI], 0.1–0.4) and at 5 minutes (0.6kg/cm²; 95% CI, 0.3–0.8) after treatment. A significant group × time interaction (P=.01) was also found for cervical rotation in favor of the TENS group. Between-group differences were also small at 1 minute (2.0°; 95% CI, 1.0–2.8) and at 5 minutes (2.7°; 95% CI, 1.7–3.8) after treatment.

Conclusions

A 10-minute application of burst-type TENS increases in a small but statistically significant manner the RPPT over upper trapezius latent MTrPs and the ipsilateral cervical range of motion.     

Interrater Reliability of Palpation of Myofascial Trigger Points in Three Shoulder Muscles

This observational study included both asymptomatic subjects (n=8) and patients with unilateral or bilateral shoulder pain (n=32). Patient diagnoses provided by the referring medical physicians included subacromial impingement, rotator cuff disease, tendonitis, tendinopathy, and chronic subdeltoid-subacromial bursitis. Three raters bilaterally palpated the infraspinatus, the anterior deltoid, and the biceps brachii muscles for clinical characteristics of a total of 12 myofascial trigger points (MTrPs) as described by Simons et al. The raters were blinded to whether the shoulder of the subject was painful. In this study, the most reliable features of trigger points were the referred pain sensation and the jump sign. Percentage of pair-wise agreement (PA) was ≥ 70% (range 63–93%) in all but 3 instances for the referred pain sensation. For the jump sign, PA was ≥ 70% (range 67–77%) in 21 instances. Finding a nodule in a taut band (PA = 45–90%) and eliciting a local twitch response (PA = 33–100%) were shown to be least reliable. The best agreement about the presence or absence of MTrPs was found for the infraspinatus muscle (PA = 69–80%). This study provides preliminary evidence that MTrP palpation is a reliable and, therefore, potentially useful diagnostic tool in the diagnosis of myofascial pain in patients with non-traumatic shoulder pain.Key Words: Myofascial Pain Syndrome, Myofascial Trigger Points, Interrater Reliability, Palpation, Shoulder PainShoulder complaints are very common in modern industrial countries. Recent reviews^1–4 have indicated a one-year prevalence ranging from 4.7 to 46.7%. These reviews have also reported a lifetime prevalence between 6.7 and 66.7%. This wide variation in reported prevalence can be explained by the different definitions used for shoulder complaints and by differences in the age and other characteristics of the various study populations. Because making a specific structure-based diagnosis for patients with shoulder complaints is considered difficult due to the lack of reliable tests for shoulder examination, recent guidelines developed by the Dutch Society of General Practitioners have recommended instead using the term “shoulder complaints” as a working diagnosis⁵. Shoulder complaints have been defined in a similarly non-specific manner as signs and symptoms of pain in the deltoid and upper arm region, and stiffness and restricted movements of the shoulder, often accompanied by limitations in daily activities⁶.Despite the absence of reliable diagnostic tests to implicate these structures, the currently prevailing assumption is that in non-traumatic shoulder complaints, mostly the anatomical structures in the subacromial space are involved, i.e., the subacromial bursa, the rotator cuff tendons, and the tendon of the long head of the biceps muscle^7–9. However, this assumption does not take into account that muscle tissue itself can also give rise to pain in the shoulder region¹⁰. In our clinical experience, myofascial trigger points (MTrPs) may lead to myofascial pain in the shoulder and upper arm region and contribute to the burden of shoulder complaints.The term myofascial pain was first introduced by Travell¹⁰, who described it as “the complex of sensory, motor, and autonomic symptoms caused by myofascial trigger points.” An MTrP is a hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band. In addition, the spot is painful on compression and may produce characteristic referred pain, referred tenderness, motor dysfunction, and autonomic phenomena. Two different types of MTrPs have been described: active and latent. Active trigger points are associated with spontaneous complaints of pain. In contrast, latent trigger points do not cause spontaneous pain, but pain may be elicited with manual pressure or with needling of the trigger point. Despite not being spontaneously painful, latent MTrPs have been hypothesized to restrict range of motion¹¹ and to alter motor recruitment patterns¹².As noted above, referred pain is a key characteristic of myofascial pain. Referred pain is felt remote from the site of origin¹³. The area of referred pain may be discontinuous from the site of local pain or it can be segmentally related to the lesion, both of which may pose a serious problem for the correct diagnosis and subsequent appropriate treatment of muscle-related pain. The theoretical model for this phenomenon of referred pain was first proposed by Ruch¹⁴ and later modified by Mense^13–15 and Hoheisel¹⁴. Referred pain patterns originating in muscles have been documented using injection of hypertonic saline, electrical stimulation, or pressure on the most sensitive spot in the muscle^17–21. In the clinical setting, palpation is the only method capable of diagnosing myofascial pain. Therefore, reliable MTrP palpation is the necessary prerequisite for considering myofascial pain as a valid diagnosis²². Published interrater studies have reported poor to good reliability for MTrP palpation^23–29. However, only one study has included a muscle that could produce shoulder pain: Gerwin et al²⁷ reported a percent agreement (PA) of 83% for tenderness in the infraspinatus muscle (κ=0.48), 83% (κ=0.40) for the taut band, 59% (κ=0.17) for the local twitch response, and 89% (κ=0.84) for the referred pain.In light of this near absence of data, of the societal impact of shoulder complaints as noted above, and of the potential role of myofascial pain syndrome with regard to shoulder pain, the aim of this study was to determine the interrater reliability of MTrP palpation in three human shoulder muscles deemed by us to be clinically relevant, i.e., the infraspinatus, the anterior deltoid, and the biceps brachii muscles.     

Comparison of 3 Needle Sizes for Trigger Point Injection in Myofascial Pain Syndrome of Upper- and Middle-Trapezius Muscle: A Randomized Controlled Trial

Yoon S-H, Rah UW, Sheen SS, Cho KH. Comparison of 3 needle sizes for trigger point injection in myofascial pain syndrome of upper- and middle-trapezius muscle: a randomized controlled trial.

Objectives

To investigate (1) the relation between needle diameter and treatment efficacy of myofascial pain syndrome and (2) the relation between needle diameter and pain intensity during injection.

Design

Randomized controlled trial.

Setting

University-affiliated tertiary-care hospital.

Participants

Volunteers (N=77) with myofascial pain syndrome affecting upper- and middle-trapezius muscles with at least 3 months' duration of pain.

Intervention

Participants were randomly assigned to receive trigger point injections on 1 side of the trapezius with a 21-, 23-, or 25-gauge needle. After a 1-time injection, participants were followed up for 14 days. Participants and the assessor were blinded for group assignment.

Main Outcome Measures

Treatment efficacy was measured with the visual analog scale (VAS; at pretreatment, and posttreatment on days 1, 4, 7, 14) for neck and upper-back pain, the Neck Disability Index (NDI; at pretreatment, and posttreatment on days 7, 14), and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36, at pretreatment and posttreatment on days 7, 14) for health-related quality of life. Pain intensity during injection was evaluated immediately after injection with VAS.

Results

VAS scores for posttreatment on days 4, 7, and 14 decreased significantly compared with pretreatment scores in all groups; NDI scores on days 7 and 14 decreased significantly compared with pretreatment scores in all groups; SF-36 scores on days 7 and 14 decreased significantly compared with pretreatment scores in the 21- and 23-gauge needle groups; and SF-36 score on day 14 showed significant difference between the 21- and 25-gauge needle groups. For pain intensity during injection, VAS scores indicated no significant difference between the 3 groups.

Conclusions

No difference between the needle types was observed in terms of VAS or NDI, or in terms of pain intensity felt by patients during injection. In terms of SF-36 scores, injections with 21- or 23-gauge needles were found to be more effective. However, a well-controlled investigation is needed to explore the effect of needle thickness on health-related quality of life.     

Short-term effects of kinesio taping on trigger points in upper trapezius and gastrocnemius muscles

Background

Kinesio taping is a possible therapeutic modality for myofascial pain, nevertheless, very scarce research has been performed on this subject.

Einfluss der CMD auf die mechanische Schmerzschwelle außerhalb der Kopf-Gesichts-Region

Background and objective

There is currently no evidence of changes in pressure sensitivity of myofascial trigger points (MTrPs) in extra-trigeminal regions in patients with craniomandibular dysfunction (CMD). The purpose of this study was to evaluate whether pressure sensitivity of MTrPs in patients with CMD increases in trigeminal and extra-trigeminal regions compared to a healthy control group. Furthermore, the extent to which MTrPs can be used as diagnostic markers for hyperalgesia in patients with CMD was investigated.

Subjects and methods

In this study 34 patients with CMD (15–64 years old) and 30 healthy control subjects (22–65 years old) were included. The pressure pain threshold of MTrPs in trigeminal and extra-trigeminal regions was measured and compared. Additionally, the most suitable diagnostic marker of hyperalgesia in patients with CMD was investigated using ROC curve analysis.

Results

Pressure sensitivity of all MTrPs was significantly increased in the CMD group. Even after correction for multiple testing, most of the effects continued to be significant. The trapezius muscle was the most suitable among all MTrPs for the classification of hyperalgesia in patients with CMD. Assuming a false positive rate of below 5?%, 42?% of patients with CMD were classified as hyperalgetic.

Discussion

The significant differences in pressure sensitivity of MTrPs in trigeminal and extra-trigeminal regions indicate that hyperalgesia is present in patients with CMD. The trapezius muscle might be a marker for diagnosing hyperalgesia. Further studies are required in order to identify gender and age-specific indicators.     

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.     

Bilateral activation of motor unit potentials with unilateral needle stimulation of active myofascial trigger points

OBJECTIVE: The objective of this study was to determine if there are electromyographic differences between active and latent myofascial trigger points (MTrPs) during trigger point needling. DESIGN: A total of 21 subjects were recruited prospectively. The experimental group consisted of 13 subjects who had active myofascial pain in the neck for >6 mos. The age-matched, control group consisted of eight subjects without neck pain but with taut bands in the cervical musculature. The active MTrPs (or latent MTrPs in the control group) were identified in the trapezius or levator scapulae muscles, then needle electrodes were inserted ipsilaterally into the muscle with the MTrPs and into the same muscle on the contralateral side. Electromyographic activity was recorded bilaterally with a dual-channel electromyographic machine, and local twitch responses were obtainedusinganacupuncturedryneedlingtechniqueonlyonthesideoftheactiveMTrPs. RESULTS: We demonstrated that in subjects with active MTrPs, bilateral motor unit activation could be obtained with unilateral needle stimulation of the trigger point. In contrast, in all the subjects with latent MTrPs, only unilateral motor unit activation could be obtained in the muscle on the same side of the needle stimulation. The motor unit potentials seen on the electromyograph were similar in morphology to a fasciculation potential but more complex. CONCLUSION: We demonstrated bilateral or mirror-image electromyographic activity associated with unilateral needle stimulation of active MTrPs. We have found no previous mention of this phenomenon in the literature. Our study supports the concept that the perpetuation of pain and muscle dysfunction in active MTrPs may be related to abnormal central nervous system processing of sensory input at the level of the spinal cord.     

Quantification of Dry Needling and Posture Effects on Myofascial Trigger Points Using Ultrasound Shear-Wave Elastography

Objectives

To determine (1) whether the shear modulus in upper trapezius muscle myofascial trigger points (MTrPs) reduces acutely after dry needling (DN), and (2) whether a change in posture from sitting to prone affects the shear modulus.

Design

Ultrasound images were acquired in B mode with a linear transducer oriented in the transverse plane, followed by performance of shear-wave elastography (SWE) before and after DN and while sitting and prone.

Setting

University.

Participants

Women (N=7; mean age ± SD, 46±17y) with palpable MTrPs were recruited.

Intervention

All participants were dry needled in the prone position using solid filament needles that were inserted and manipulated inside the MTrPs. SWE was performed before and after DN in the sitting and prone positions.

Main Outcome Measure

MTrPs were evaluated by shear modulus using SWE.

Results

Palpable reductions in stiffness were noted after DN and in the prone position. These changes were apparent in the shear modulus map obtained with ultrasound SWE. With significant main effects, the shear modulus reduced from before to after DN (P<.01) and from the sitting to the prone position (P<.05). No significant interaction effect between time and posture was observed.

Conclusions

The shear modulus measured with ultrasound SWE reduced after DN and in the prone position compared with sitting, in agreement with reductions in palpable stiffness. These findings suggest that DN and posture have significant effects on the shear modulus of MTrPs, and that shear modulus measurement with ultrasound SWE may be sensitive enough to detect these effects.     

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.

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

Objectives: To screen for the presence of latent and active myofascial trigger points (MTrPs) in patients with unilateral shoulder and arm pain and perform topographical mapping of mechanical pain sensitivity bilaterally in the infraspinatus muscles. Methods: Nineteen patients with unilateral musculoskeletal shoulder pain participated in the study. The area overlying the infraspinatus on each side was divided into 10 adjacent sub‐areas of 1cm², corresponding to the area of a pressure algometer probe. Pressure pain threshold (PPT) was measured in each sub‐area bilaterally in the infraspinatus muscles. Following PPT measurement, an acupuncture needle was inserted into each sub‐area five times in different directions in order to induce local twitch response and/or referred pain. Results: A significantly lower PPT level in the infraspinatus muscle was detected on the painful side compared with the non‐painful side (P=0.001). PPT at midfiber region of the infraspinatus muscles was lower than that at other muscle parts (P<0.05). Multiple, but not single, active MTrPs were found in the infraspinatus muscle on the painful side and there were also multiple latent MTrPs bilaterally in the infraspinatus muscles. PPT at active MTrPs was much lower than the latent MTrPs and again lower than the non‐MTrPs. Conclusions: There exists bilateral mechanical hyperalgesia in patients with unilateral shoulder pain. Further, the association of multiple active MTrPs with unilateral shoulder pain and the heterogeneity of mechanical pain sensitivity distribution suggest a crucial role of peripheral sensitization in chronic myofascial pain conditions. Additionally, the locations of MTrPs identified with dry needling correspond well to PPT topographical mapping, suggesting that dry needling and PPT topographical mapping are sensitive techniques in the identification of MTrPs.     

Manuelle Triggerpunkttherapie bei Schulterschmerzen

Background

Although chronic shoulder pain is highly prevalent and myofascial trigger points (mTrP) are thought to be found in the majority of patients with shoulder complaints, the influence on the pain mechanism remains unclear. There are only very few controlled clinical studies on the effects of manual trigger point compression therapy.

Objective

This randomized controlled trial (RCT) compared the short-term effects of manual trigger point compression therapy (n = 6) with manual sham therapy (n = 6) in patients with unilateral shoulder pain due to myofascial syndrome (MFS).

Material and methods

The measurement data were collected before and after two sessions of therapy. Pressure pain thresholds (PPT) of mTrP and symmetrically located points on the asymptomatic side were measured together with neutral points in order to detect a potential unilateral or generalized hyperalgesia. Additionally, the pain was assessed on a visual analog scale (VAS) at rest and during movement and the neck disability index (NDI) and disabilities of the arm, shoulder and hand (DASH) questionnaires were also completed and evaluated.

Results

Both treatment modalities led to a significant improvement; however, the manual trigger point compression therapy was significantly more effective in comparison to sham therapy, as measured by different parameters.

Conclusion

The significant improvement of PPT values in the interventional group even at sites that were not directly treated, indicates central mechanisms in pain threshold modulation induced by manual compression therapy. The weaker but still measurable effects of sham therapy might be explained by the sham modality being a hands on technique or by sufficient stimulation of the trigger point region during the diagnostics and PPT measurements.

     

Manuelle Triggerpunkttherapie bei Schulterschmerzen

Background

Although chronic shoulder pain is highly prevalent and myofascial trigger points (mTrP) are thought to be found in the majority of patients with shoulder complaints, the influence on the pain mechanism remains unclear. There are only very few controlled clinical studies on the effects of manual trigger point compression therapy.

Objective

This randomized controlled trial (RCT) compared the short-term effects of manual trigger point compression therapy (n = 6) with manual sham therapy (n = 6) in patients with unilateral shoulder pain due to myofascial syndrome (MFS).

Material and methods

The measurement data were collected before and after two sessions of therapy. Pressure pain thresholds (PPT) of mTrP and symmetrically located points on the asymptomatic side were measured together with neutral points in order to detect a potential unilateral or generalized hyperalgesia. Additionally, the pain was assessed on a visual analog scale (VAS) at rest and during movement and the neck disability index (NDI) and disabilities of the arm, shoulder and hand (DASH) questionnaires were also completed and evaluated.

Results

Both treatment modalities led to a significant improvement; however, the manual trigger point compression therapy was significantly more effective in comparison to sham therapy, as measured by different parameters.

Conclusion

The significant improvement of PPT values in the interventional group even at sites that were not directly treated, indicates central mechanisms in pain threshold modulation induced by manual compression therapy. The weaker but still measurable effects of sham therapy might be explained by the sham modality being a hands on technique or by sufficient stimulation of the trigger point region during the diagnostics and PPT measurements.

     

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.