The impact of latent trigger points on regional muscle function

Effects of Trigger Point Dry Needling on Strength Measurements and Activation Levels of the Gluteus Medius: A Quasi-Experimental Randomized Control Study

Background

Latent trigger points have been identified as a source of impaired muscle function giving rise to a reduction in force production and alterations in muscle activation patterns and movement efficiency. There is limited investigation into the effectiveness of a treatment in reducing these clinical manifestations.

Purpose

To investigate whether the application of trigger point dry needling (TDN) to latent trigger points within the gluteus medius musculature affected strength measurements and muscle activation levels immediately following intervention.

Design

Quasi experimental, single group, pretest-posttest, randomized control study.

Methods

A control and an intervention side were randomly assigned for each participant (N = 39). Hand held dynamometer (HHD) force measurements and raw surface electromyography (sEMG) amplitude readings were recorded during maximal volitional isometric contractions of the gluteus medius in two separate positions before and after application of TDN. Comparison of within and between group data were conducted.

Results

A statistically significant interaction between time (pre-TDN to post-TDN) and groups (intervention side and control side), p < 0.001 was found for HHD measurements in both positions. Post hoc analysis revealed a statistically significant difference (p < 0.001) for all comparisons in the side lying neutral (SL0) position, while statistically significant differences (p < 0.001) were found for pre and post-TDN measurements within intervention side as well as between the intervention and control side for post-TDN measurements in the side lying internal rotation (SLIR) position. For sEMG amplitude measurements, statistically significant differences were found only in the SL0 position for within group comparisons on the intervention side (p = 0.009) and for between group comparisons for post-TDN measurements (p = 0.002).

Conclusion

Application of TDN to latent trigger points within the gluteus medius can significantly increase gluteus muscle force production immediately following intervention while reducing the level of muscle activation required during contraction.

Level of Evidence

Level 2.

Comparison of dry needling and ischaemic compression techniques on pain and function in patients with patellofemoral pain syndrome: a randomised clinical trial

BACKGROUND

To compare the effectiveness of ischaemic compression (IC) applied directly to the knee versus dry needling (DN) with respect to pain, functional status and sensitivity to mechanical stimulation of vastus medialis obliquus (VMO) myofascial trigger points (MTrPs) in patients with patellofemoral pain syndrome (PFPS).

METHODS

A total of 54 patients with unilateral PFPS aged 20-30 years were selected randomly from patients referred to physical therapy clinics of Babol University of Medical Sciences in Iran. Twenty-seven patients were allocated to either IC or DN groups. Three sessions of treatment were applied over 1 week with follow-up at 1 week, 1 month and 3 months. Primary outcome measures comprised the Kujala questionnaire score for functional status, numerical pain rating scale (NPRS) for pain intensity and pressure pain threshold (PPT) for sensitivity to mechanical stimulation; these were measured and recorded before treatment and 1 week, 1 month and 3 months after the last treatment session.

RESULTS

There were no statistically significant differences in the between-group comparisons of any variables at the various follow-up points. Both groups (n = 27 participants each) had significant improvements (p < 0.05) in pain, functional status and PPT values at follow-up.

CONCLUSIONS

There were no differences in markers of pain, function or pressure sensitivity over a 3-month follow-up period between patients with PFPS treated with DN and IC. Temporal improvements in both groups suggested that the two techniques may be similarly effective for the treatment of PFPS.

Gluteus medius muscle function in people with and without low back pain: a systematic review

INTRODUCTION

Globally, low back pain (LBP) is one of the greatest causes of disability. In people with LBP, dysfunction of muscles such as the gluteus medius have been demonstrated to increase spinal loading and reduce spinal stability. Differences in gluteus medius function have been reported in those with LBP compared to those without, although this has only been reported in individual studies. The aim of this systematic review was to determine if adults with a history, or current LBP, demonstrate differences in measures of gluteus medius function when compared to adults without LBP.

METHODS

MEDLINE, EMBASE, AMED, PsycINFO, PubMED, Pro Quest Database, CINAHL and SPORTDiscus were searched from inception until December 2018 for published journal articles and conference abstracts. No language restrictions were applied. Only case-control studies with participants 18 years and over were included. Participants could have had any type and duration of LBP. Studies could have assessed gluteus medius function with any quantifiable clinical assessment or measurement tool, with the participant non-weight bearing or weight bearing, and during static or dynamic activity. Quality appraisal and data extraction were independently performed by two authors.

RESULTS

The 24 included articles involved 1088 participants with LBP and 998 without LBP. The gluteus medius muscle in participants with LBP tended to demonstrate reduced strength and more trigger points compared to the gluteus medius muscle of those without LBP. The level of activity, fatigability, time to activate, time to peak activation, cross sectional area, and muscle thickness showed unclear results. Meta-analysis was not performed due to the heterogeneity of included studies.

CONCLUSION

Clinically, the findings from this systematic review should be considered when assessing and managing patients with LBP. Future studies that clearly define the type and duration of LBP, and prospectively assess gluteus medius muscle function in those with and without LBP are needed.

TRIAL REGISTRATION

PROSPERO ( CRD42017076773 ).

The prevalence of myofascial trigger points in hip and thigh areas in anterior knee pain patients

BACKGROUND

Anterior knee pain (AKP) is a widespread problem among young athletes and soldiers. There are many theories on the etiology of AKP but there is little reference to myofascial trigger points (MTrPs) as a possible contributor.

AIM

To evaluate the association between AKP and prevalence of active and latent MTrPs in the hip and thigh muscles in soldiers.

METHODS

A cross-sectional study was conducted in the Beer-Sheva military outpatient physical therapy clinic. Subjects were 42 men and 23 women referred for physical therapy, 33 with a diagnosis of AKP (cases) and 32 with upper limb complaints (without AKP, controls). All subjects underwent physical evaluation by an examiner blinded to their identity and medical condition. The following muscles were assessed bilaterally for active or latent MTrPs: rectus femoris (proximal), vastus medialis (middle and distal), vastus lateralis (middle and distal) and gluteus medius (anterior, posterior and distal).

RESULTS

In six out of eight areas, the cases had a higher prevalence of total active and latent MTrPs than the controls. When summarizing MTrPs by muscle, cases had significantly more MTrPs than controls in each muscle. The largest difference was found in vastus medialis and vastus lateralis; nearly half of the cases had MTrPs in these muscles.

CONCLUSIONS

Subjects with AKP have a greater prevalence of MTrPs in their hip and thigh muscles than controls, indicating an association between MTrPs and AKP. Further research is necessary to determine whether MTrPs are the cause or the consequence of AKP.

Responsiveness of Myofascial Trigger Points to Single and Multiple Trigger Point Release Massages: A Randomized, Placebo Controlled Trial

OBJECTIVE

This study aimed to assess the effects of single and multiple massage treatments on pressure-pain threshold (PPT) at myofascial trigger points (MTrPs) in people with myofascial pain syndrome expressed as tension-type headache.

DESIGN

Individuals (n = 62) with episodic or chronic tension-type headache were randomized to receive 12 twice-weekly 45-min massage or sham ultrasound sessions or wait-list control. Massage focused on trigger point release (ischemic compression) of MTrPs in the bilateral upper trapezius and suboccipital muscles. PPT was measured at MTrPs with a pressure algometer pre and post the first and final (12th) treatments.

RESULTS

PPT increased across the study timeframe in all four muscle sites tested for massage, but not sham ultrasound or wait-list groups (P < 0.0001 for suboccipital; P < 0.004 for upper trapezius). Post hoc analysis within the massage group showed (1) an initial, immediate increase in PPT (all P values < 0.05), (2) a cumulative and sustained increase in PPT over baseline (all P values < 0.05), and (3) an additional immediate increase in PPT at the final (12th) massage treatment (all P values < 0.05, except upper trapezius left, P = 0.17).

CONCLUSIONS

Single and multiple massage applications increase PPT at MTrPs. The pain threshold of MTrPs have a great capacity to increase; even after multiple massage treatments additional gain in PPT was observed.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Understand the contribution of myofascial trigger points to myofascial pain; (2) Describe an effective treatment for decreasing tenderness of a myofascial trigger point; and (3) Discuss the relative values of single vs. multiple massage sessions on increasing pressure-pain thresholds at myofascial trigger points.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Comparison of ischemic compression and lumbopelvic manipulation as trigger point therapy for patellofemoral pain syndrome in young adults: A double-blind randomized clinical trial

OBJECTIVE

To compare the effectiveness of ischemic compression (IC) directly to the vastus medialis obliquus (VMO) versus lumbopelvic manipulation (LPM) in improving pain, functional status and sensitivity to mechanical stimulation of the VMO trigger point in patients with patellofemoral pain syndrome (PFPS).

PARTICIPANTS

40 patients with unilateral PFPS aged 20-30 years were selected randomly among patients with unilateral PFPS referred to physical therapy clinics of Shiraz University of Medical Sciences in Shiraz, Iran, between March 2014 and July 2014. 30 young adults participated. Participants were blinded to treatment allocation, and 15 patients were allocated to either IC or LPM.

INTERVENTIONS

Patients in both groups were treated in three sessions per week. IC consisted of three sets of continuous pressure applied for on the myofascial trigger point (MTrP) of VMO. LPM consisted of supine rotational glide manipulation of the ipsilateral lumbopelvic region of the involved knee.

MAIN OUTCOME MEASURES

Numeric pain rating scale (VAS) for pain intensity, Kujala questionnaire for functional status, and pressure pain threshold (PPT) for sensitivity to mechanical stimulation. All three were recorded before treatment, 1 week, 1 month and 3 months after the last session.

RESULTS

Both groups showed significant improvement (p < 0.05, 95% confidence interval) in pain, functional status and PPT values. However, the IC group showed greater improvements, and outcome measures remained significantly better than in the LPM group during post-intervention follow-up.

CONCLUSIONS

Both groups showed improvements throughout the study and follow-up period. However, the IC showed better short-term and long-term effectiveness than LPM for treating PFPS.

Differential activation of scapular muscles, during arm elevation, with and without trigger points

BACKGROUND

Latent Myofascial Trigger Points (LMTrPs) are defined as certain pain-free hyperirritable spots in a muscle taut band which lead to muscle activation pattern alternation in both loaded and unloaded conditions during scaption. The current study aimed to investigate the onset of upward scapular rotator muscle activations during rapid arm elevation in three planes of movement in patients with upper trapezius LMTrPs compared to healthy control participants.

METHOD

Three planes of scapular movement were evaluated. The onset of Deltoid (DEL) was considered as the starting point in marking the onset of Upper Trapezius (UT) and Serratus Anterior (SA) muscle activations.

RESULTS

There were significant differences in the relative muscle latencies between the LMTrPs and the control group. Those with LMTrPs showed a delayed and inconsistent activity of UT during all three planes of elevation (p < 0.05) and the same pattern happened for SA during flexion (p < 0.05).

CONCLUSIONS

Both hosted and synergistic muscles experience delay in muscle activation and alterations in their recruitment pattern during rapid arm elevation in all planes of movement. These changes may serve as adaptive motor control strategies due to the presence of LMTrPs in UT muscles.

Effect of cervical mobilization and ischemic compression therapy on contralateral cervical side flexion and pressure pain threshold in latent upper trapezius trigger points

Studies have shown a clinical relationship between trigger points and joint impairments. However the cause-and effect relationship between muscle and joint dysfunctions in trigger points could not be established. The purpose of this study was to investigate effects of mobilization and ischemic compression therapy on cervical range of motion and pressure pain sensitivity in participants with latent trigger point in the upper trapezius muscle. Ninety asymptomatic participants with upper trapezius latent trigger point were randomized in to 3 groups: mobilization, ischemic compression and a control. The outcomes were measured over a 2 week period. Repeated measures ANOVA showed statistically and clinically significant pre to post improvement in both the interventional groups compared to control (p < 0.05). However the effect sizes between the intervention groups were small (<0.3) revealing minimal clinical detectable difference.

Dry needling for the management of thoracic spine pain

Thoracic spine pain is as disabling as neck and low back pain without receiving the same level of attention in the scientific literature. Among the different structures that can refer pain to the thoracic spine, muscles often play a relevant role. Trigger points (TrPs) from neck, shoulder and spinal muscles can induce pain in the region of the thoracic spine. There is a lack of evidence reporting the presence of TrPs in the region of the thoracic spine, but clinical evidence suggests that TrPs can be a potential source of thoracic spine pain. The current paper discusses the role of TrPs in the thoracic spine and dry needling (DN) for the management of TrPs in the thoracic multifidi and longissimus thoracis. This paper also includes a brief discussion of the application of DN in other tissues such as tendons, ligaments and scars.

Association between muscle trigger points, ongoing pain, function, and sleep quality in elderly women with bilateral painful knee osteoarthritis

OBJECTIVE

The objectives of this study were to investigate if referred pain elicited by active trigger points (TrPs) reproduced the symptoms in individuals with painful knee osteoarthritis (OA) and to determine the relationship between the presence of active TrPs, intensity of ongoing pain, function, quality of life, and sleep quality in individuals with painful knee OA.

METHODS

Eighteen women with bilateral painful knee OA, aged 79 to 90 years, and 18 matched controls participated. Muscle TrPs were bilaterally explored in several muscles of the lower extremity. Trigger points were considered active if the elicited referred pain reproduced knee symptoms, and TrPs were considered latent if the elicited pain did not reproduce symptoms. Pain was collected with a numerical pain rate scale (0-10), function was assessed with Western Ontario and McMaster Universities, quality of life was assessed with the Medical Outcomes Study Short Form 36 questionnaire, and sleep quality was determined with the Pittsburgh Sleep Quality Index.

RESULTS

Women with knee OA exhibited a greater number of active TrPs (mean, 1 ± 1; P < .001) but similar number of latent TrPs (mean, 4 ± 2) than healthy women (mean, 4 ± 3; P = .613). A greater number of active TrPs were associated with higher intensity of ongoing pain (r = 0.605; P = .007). Higher intensity of ongoing knee pain was associated with lower physical function (P < .05).

CONCLUSIONS

The referred pain elicited by active TrPs in the lower extremity muscles contributed to pain symptoms in painful knee OA. A higher number of active TrPs was associated with higher intensity of ongoing knee pain.

Short- and medium-term effects of manual therapy on cervical active range of motion and pressure pain sensitivity in latent myofascial pain of the upper trapezius muscle: a randomized controlled trial

OBJECTIVE

The purpose of this study was to investigate effects of different manual techniques on cervical ranges of motion and pressure pain sensitivity in subjects with latent trigger point of the upper trapezius muscle.

METHODS

One hundred seventeen volunteers, with a unilateral latent trigger point on upper trapezius due to computer work, were randomly divided into 5 groups: ischemic compression (IC) group (n=24); passive stretching group (n=23); muscle energy technique group (n=23); and 2 control groups, wait-and-see group (n=25) and placebo group (n=22). Cervical spine range of movement was measured using a cervical range of motion instrument as well as pressure pain sensitivity by means of an algometer and a visual analog scale. Outcomes were assessed pretreatment, immediately, and 24 hours after the intervention and 1 week later by a blind researcher. A 4×5 mixed repeated-measures analysis of variance was used to examine the effects of the intervention and Cohen d coefficient was used.

RESULTS

A group-by-time interaction was detected in all variables (P<.01), except contralateral rotation. The immediate effect sizes of the contralateral flexion, ipsilateral rotation, and pressure pain threshold were large for 3 experimental groups. Nevertheless, after 24 hours and 1 week, only IC group maintained the effect size.

CONCLUSIONS

Manual techniques on upper trapezius with latent trigger point seemed to improve the cervical range of motion and the pressure pain sensitivity. These effects persist after 1 week in the IC group.

Myofascial trigger points, pain, disability, and sleep quality in individuals with mechanical neck pain

OBJECTIVE

The purpose of this study was to investigate the presence of active myofascial trigger points (MTrPs) in a greater number of muscles than previous studies and the relation between the presence of MTrPs, the intensity of pain, disability, and sleep quality in mechanical neck pain.

METHODS

Fifteen patients with mechanical neck pain (80% women) and 12 comparable controls participated. Myofascial trigger points were bilaterally explored in the upper trapezius, splenius capitis, semispinalis capitis, sternocleidomastoid, levator scapulae, and scalene muscles in a blinded design. Myofascial trigger points were considered active if the subject recognized the elicited referred pain as a familiar symptom. Myofascial trigger points were considered latent if the elicited referred pain was not recognized as a symptom. Pain was collected with a numerical pain rate scale (0-10); disability was assessed with Neck Disability Index; and sleep quality, with the Pittsburgh Sleep Quality Index.

RESULTS

Patients exhibited a greater disability and worse sleep quality than controls (P < .001). The Pittsburgh Sleep Quality Index score was associated with the worst intensity of pain (r = 0.589; P = .021) and disability (r = 0.552; P = .033). Patients showed a greater (P = .002) number of active MTrPs (mean, 2 ± 2) and similar number (P = .505) of latent MTrPs (1.6 ± 1.4) than controls (latent MTrPs, 1.3 ± 1.4). No significant association between the number of latent or active MTrPs and pain, disability, or sleep quality was found.

CONCLUSIONS

The referred pain elicited by active MTrPs in the neck and shoulder muscles contributed to symptoms in mechanical neck pain. Patients exhibited higher disability and worse sleep quality than controls. Sleep quality was associated with pain intensity and disability. No association between active MTrPs and the intensity of pain, disability, or sleep quality was found.

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, 200 μs; frequency, 100 Hz; burst frequency, 2 Hz) 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 (0.3 kg/cm²; 95% confidence interval [CI], 0.1-0.4) and at 5 minutes (0.6 kg/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.

Objective sonographic measures for characterizing myofascial trigger points associated with cervical pain

OBJECTIVES

The purpose of this study was to determine whether the physical properties and vascular environment of active myofascial trigger points associated with acute spontaneous cervical pain, asymptomatic latent trigger points, and palpably normal muscle differ in terms of the trigger point area, pulsatility index, and resistivity index, as measured by sonoelastography and Doppler imaging.

METHODS

Sonoelastography was performed with an external 92-Hz vibration in the upper trapezius muscles in patients with acute cervical pain and at least 1 palpable trigger point (n = 44). The area of reduced vibration amplitude was measured as an estimate of the size of the stiff myofascial trigger points. Patients also underwent triplex Doppler imaging of the same region to analyze blood flow waveforms and calculate the pulsatility index of blood flow in vessels at or near the trigger points.

RESULTS

On sonoelastography, active sites (spontaneously painful with palpable myofascial trigger points) had larger trigger points (mean ± SD, 0.57 ± 0.20 cm(2)) compared to latent sites (palpable trigger points painful on palpation; 0.36 ± 0.16 cm(2)) and palpably normal sites (0.17 ± 0.22 cm(2); P < .01). Analysis of receiver operating characteristic curves showed that area measurements could robustly distinguish between active, latent, and normal sites (areas under the curve, 0.9 for active versus latent, 0.8 for active versus normal, and 0.8 for latent versus normal, respectively). Doppler spectral waveform data showed that vessels near active sites had a significantly higher pulsatility index (median, 8.3) compared to normal sites (median, 3.0; P < .05).

CONCLUSIONS

The results presented in this study show that myofascial trigger points may be classified by area using sonoelastography. Furthermore, monitoring the trigger point area and pulsatility index may be useful in evaluating the natural history of myofascial pain syndrome.

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.

Myofascial trigger points: spontaneous electrical activity and its consequences for pain induction and propagation

Active myofascial trigger points are one of the major peripheral pain generators for regional and generalized musculoskeletal pain conditions. Myofascial trigger points are also the targets for acupuncture and/or dry needling therapies. Recent evidence in the understanding of the pathophysiology of myofascial trigger points supports The Integrated Hypothesis for the trigger point formation; however unanswered questions remain. Current evidence shows that spontaneous electrical activity at myofascial trigger point originates from the extrafusal motor endplate. The spontaneous electrical activity represents focal muscle fiber contraction and/or muscle cramp potentials depending on trigger point sensitivity. Local pain and tenderness at myofascial trigger points are largely due to nociceptor sensitization with a lesser contribution from non-nociceptor sensitization. Nociceptor and non-nociceptor sensitization at myofascial trigger points may be part of the process of muscle ischemia associated with sustained focal muscle contraction and/or muscle cramps. Referred pain is dependent on the sensitivity of myofascial trigger points. Active myofascial trigger points may play an important role in the transition from localized pain to generalized pain conditions via the enhanced central sensitization, decreased descending inhibition and dysfunctional motor control strategy.

The immediate effects of atlanto-occipital joint manipulation and suboccipital muscle inhibition technique on active mouth opening and pressure pain sensitivity over latent myofascial trigger points in the masticatory muscles

DESIGN

A randomized controlled trial.

OBJECTIVE

To investigate the immediate effects on pressure pain thresholds over latent trigger points (TrPs) in the masseter and temporalis muscles and active mouth opening following atlanto-occipital joint thrust manipulation or a soft tissue manual intervention targeted to the suboccipital muscles.

BACKGROUND

Previous studies have described hypoalgesic effects of neck manipulative interventions over TrPs in the cervical musculature. There is a lack of studies analyzing these mechanisms over TrPs of muscles innervated by the trigeminal nerve.

METHODS

One hundred twenty-two volunteers, 31 men and 91 women, between the ages of 18 and 30 years, with latent TrPs in the masseter muscle, were randomly divided into 3 groups: a manipulative group who received an atlanto-occipital joint thrust, a soft tissue group who received an inhibition technique over the suboccipital muscles, and a control group who did not receive an intervention. Pressure pain thresholds over latent TrPs in the masseter and temporalis muscles, and active mouth opening were assessed pretreatment and 2 minutes posttreatment by a blinded assessor. Mixed-model analyses of variance (ANOVA) were used to examine the effects of interventions on each outcome, with group as the between-subjects variable and time as the within-subjects variable. The primary analysis was the group-by-time interaction.

RESULTS

The 2-by-3 mixed-model ANOVA revealed a significant group-by-time interaction for changes in pressure pain thresholds over masseter (P<.01) and temporalis (P = .003) muscle latent TrPs and also for active mouth opening (P<.001) in favor of the manipulative and soft tissue groups. Between-group effect sizes were small.

CONCLUSIONS

The application of an atlanto-occipital thrust manipulation or soft tissue technique targeted to the suboccipital muscles led to an immediate increase in pressure pain thresholds over latent TrPs in the masseter and temporalis muscles and an increase in maximum active mouth opening. Nevertheless, the effects of both interventions were small and future studies are required to elucidate the clinical relevance of these changes.

LEVEL OF EVIDENCE

Therapy, level 1b.J Orthop Sports Phys Ther 2010;40(5):310-317, Epub 12 April 2010. doi:10.2519/jospt.2010.3257.

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 approximately 5MHz US transducer was used. Vibration sonoelastography (VSE) was performed by color Doppler variance imaging while simultaneously inducing vibrations (approximately 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+/-.11 cm(2). 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.

Contributions of myofascial pain in diagnosis and treatment of shoulder pain. A randomized control trial

BACKGROUND

Rotator cuff tendinopathy and subacromial impingement syndrome present complex patomechanical situations, frequent difficulties in clinical diagnosis and lack of effectiveness in treatment. Based on clinical experience, we have therefore considered the existence of another pathological entity as the possible origin of pain and dysfunction. The hypothesis of this study is to relate subacromial impingement syndrome (SIS) with myofascial pain syndrome (MPS), since myofascial trigger points (MTrPs) cause pain, functional limitation, lack of coordination and alterations in quality of movement, even prior to a tendinopathy. MTrPs can coexist with any degenerative subacromial condition. If they are not taken into consideration, they could perpetuate and aggravate the problem, hindering diagnosis and making the applied treatments ineffective.The aims and methods of this study are related with providing evidence of the relationship that may exist between this condition and MPS in the diagnosis and treatment of rotator cuff tendonitis and/or SIS.

METHOD/DESIGN

A descriptive transversal study will be made to find the correlation between the diagnosis of SIS and rotator cuff tendonitis, positive provocation test responses, the existence of active MTrPs and the results obtained with ultrasonography (US) and Magnetic Renonance Imaging (MRI). A randomized double blinded clinical trial will be carried out in experimental conditions: A Protocolized treatment based on active and passive joint repositioning, stabilization exercises, stretching of the periarticular shoulder muscles and postural reeducation. B. The previously described protocolized treatment, with the addition of dry needling applied to active MTrPs with the purpose of isolating the efficacy of dry needling in treatment.

DISCUSSION

This study aims to provide a new vision of shoulder pain, from the perspective of MPS. This syndrome can, by itself, account for shoulder pain and dysfunction, although it can coexist with real conditions involving the tendons.

TRIAL REGISTRATION

ISRCTN Number: 30907460.

Performing arts medicine - instrumentalist musicians: part III - case histories

In parts I and II of this article series, the basic principles of examining musicians in a healthcare setting were reviewed [Dommerholt, J. Performing arts medicine - instrumentalist musicians: part I: general considerations. J. Bodyw. Mov. Ther., in press-a; Dommerholt, J. Performing arts medicine - instrumentalist musicians: part II: the examination. J. Bodyw. Mov. Ther., in press-b]. Part III describes three case reports of musicians with hand pain, interfering with their ability to play their instruments. The musicians consulted with a performing arts physiotherapist. Neither musician had a correct medical diagnosis if at all, when they first contacted the physiotherapist. Each musician required an individualized approach not only to establish the correct diagnosis, but also to develop a specific treatment program. The treatment programs included ergonomic interventions, manual therapy, trigger point therapy, and patient education. All musicians returned to playing their instruments without any residual pain or dysfunction.