title: An in vivo microanalytical technique for measuring the local biochemical milieu of human skeletal muscle. Incidence of Myofascial Pain Syndrome in Breast Cancer Surgery: A Prospective Study Dry needle stimulation of myofascial trigger points evokes segmental anti-nociceptive effects. Active myofascial trigger points might be more frequent in patients with cervical radiculopathy. Proximal myofascial dysfunction in complex regional pain syndrome: a retrospective prevalence study. The nuts and bolts of PROSPERO: an international prospective register of systematic reviews Prevalence of myofascial trigger points in the hip in patellofemoral pain. Bilateral Activation of Motor Unit Potentials with Unilateral Needle Stimulation of Active Myofascial Trigger Points Stimulation of myofascial trigger points with ultrasound induces segmental antinociceptive effects: A randomized controlled study High prevalence of shoulder girdle muscles with myofascial trigger points in patients with shoulder pain
abstract: Myofascial pain associated with myofascial trigger points ( MTrPs ) is a common cause of nonarticular musculoskeletal pain . Although the presence of MTrPs can be determined by soft tissue palpation , little is known about the mechanisms and biochemical milieu associated with persistent muscle pain . A microanalytical system was developed to measure the in vivo biochemical milieu of muscle in near real time at the subnanogram level of concentration . The system includes a microdialysis needle capable of continuously collecting extremely small sample s ( approximately 0.5 microl ) of physiological saline after exposure to the internal tissue milieu across a 105-microm-thick semi-permeable membrane . This membrane is positioned 200 microm from the tip of the needle and permits solutes of < 75 kDa to diffuse across it . Three subjects were selected from each of three groups ( total 9 subjects ) : normal ( no neck pain , no MTrP ) ; latent ( no neck pain , MTrP present ) ; active ( neck pain , MTrP present ) . The microdialysis needle was inserted in a st and ardized location in the upper trapezius muscle . Due to the extremely small sample size collected by the microdialysis system , an established microanalytical laboratory , employing immunoaffinity capillary electrophoresis and capillary electrochromatography , performed analysis of selected analytes . Concentrations of protons , bradykinin , calcitonin gene-related peptide , substance P , tumor necrosis factor-alpha , interleukin-1beta , serotonin , and norepinephrine were found to be significantly higher in the active group than either of the other two groups ( P < 0.01 ) . pH was significantly lower in the active group than the other two groups ( P < 0.03 ) . In conclusion , the described microanalytical technique enables continuous sampling of extremely small quantities of substances directly from soft tissue , with minimal system perturbation and without harmful effects on subjects . The measured levels of analytes can be used to distinguish clinical ly distinct groups Background Pain  after breast cancer therapy  is a recognized complication found to have an adverse impact on patient 's quality of life , increasing psychosocial distress . In recent years , case reports about myofascial pain syndrome are emerging in thoracic surgery as a cause of postsurgery pain . Myofascial pain syndrome is a regional pain syndrome characterized by myofascial trigger points in palpable taut b and s of skeletal muscle that refers pain a distance , and that can cause distant motor and autonomic effects . Objective The objective of this study was to assess the incidence of myofascial pain syndrome prospect ively 12 months after breast cancer surgery . Methods Each participant was assessed preoperatively , postoperatively between day 3 and day 5 , and at 1 , 3 , 6 , and 12 months after surgery . A physical therapist , expert in the diagnosis of myofascial pain syndrome , performed follow-up assessment s.  Pain descriptions by the patients and pain pattern drawings in body forms guided the physical examination . The patients were not given any information concerning myofascial pain or other muscle pain syndromes . Results One year follow-up was completed by 116 women . Of these , 52 women developed myofascial pain syndrome ( 44.8 % , 95 % confidence interval : 35.6 , 54.3 ) . Conclusion Myofascial pain syndrome is a common source of pain in women undergoing breast cancer surgery that includes axillary lymph node dissection at least during the first year after surgery . Myofascial pain syndrome is one potential cause of chronic pain in breast cancer survivors who have undergone this kind of surgery OBJECTIVE To test the hypothesis that dry needle stimulation of a myofascial trigger point ( sensitive locus ) evokes segmental anti-nociceptive effects . DESIGN Double-blind r and omized controlled trial . SUBJECTS Forty subjects ( 21 males , 19 females ) . METHODS Test subjects received intramuscular dry needle puncture to a right supraspinatus trigger point ( C4,5 ) ; controls received sham intramuscular dry needle puncture .  Pain pressure threshold ( PPT ) readings were recorded from right infraspinatus ( C5,6 ) and right gluteus medius ( L4,5S1 ) trigger points at 0 ( pre-needling baseline ) , 1 , 3 , 5 , 10 and 15 min post-needling and normalized to baseline values . The supraspinatus and infraspinatus trigger points are neurologically linked at C5 ; the supraspinatus and gluteus medius are segmentally unrelated . The difference between the infraspinatus and gluteus medius PPT values ( PPTseg ) represents a direct measure of the segmental anti-nociceptive effects acting at the infraspinatus trigger point . RESULTS Significant increases in PPTseg were observed in test subjects at 3 ( p = 0.002 ) and 5 ( p = 0.015 ) min post-needling , compared with controls . CONCLUSION One intervention of dry needle stimulation to a single trigger point ( sensitive locus ) evokes short-term segmental anti-nociceptive effects . These results suggest that trigger point ( sensitive locus ) stimulation may evoke anti-nociceptive effects by modulating segmental mechanisms , which may be an important consideration in the management of myofascial pain BACKGROUND Myofascial trigger points ( MTrPs ) are commonly observed in the neck , parascapular region , and upper back muscles of patients with cervical pathology . AIM To assess the frequency of latent and active myofascial trigger point ( aMTrP ) in the neck and upper back muscles in patients with cervical radiculopathy and healthy subjects . DESIGN Controlled clinical trials . SETTING Out patients and controls . POPULATION Two hundred and forty four patients and 122 controls METHODS The patients clinical ly diagnosed as cervical radiculopathy with positive Spurling 's test and confirmed by MRI , were enrolled in this study . All subjects were examined for active and latent MTrP. In patients with cervical radiculopathy , an aMTrP was distinguished from a latent one when the referred pain elicited by exploration of the MTrP is recognized as familiar . RESULTS The patients comprised of 128 female ( 52.5 % ) and 116 male ( 47.5 % ) patients . Mean age was 44.58(20 - 65 years ) . In 125 ( 51.2 % ) of patients with cervical radiculopathy were found an aMTrP at least one muscle from upper trapezius , multifidus , splenius capitis , levator scapulae , rhomboid major , minor and deep paraspinal muscles . Number and distribution of MTrPs in patients with 244 cervical radiculopathy and in healthy controls .  aMTrPs were detected most common in levator scapula ( 16.3 % ) , splenius capitis ( 14.7 % ) , rhomboid minor ( 14.3 % ) , upper part of trapezius ( 13.5 % ) , rhomboid major ( 10.2 % ) and multifidus ( 8.6 % ) muscles . Patients with cervical radiculopathy showed latent MTrP in levator scapula ( 27 % ) , splenius capitis ( 16.8 % ) , rhomboid minor ( 24.6 % ) , upper part of trapezius ( 33.2 % ) , rhomboid major ( 9 % ) and multifidus ( 8.2 % ) muscles . There was significant difference in terms of distribution of active and latent MTrPs in patients with cervical radiculopathy ( P=0.019 ) . Number of latent MTrPs in upper trapezius muscles in patients with cervical radiculopathy was more than the expected distribution . None of the subjects of control group had aMTrP. However , healthy controls showed latent MTrP in levator scapula ( 33.6 % ) , splenius capitis ( 16.4 % ) , rhomboid minor ( 21.3 % ) , upper part of trapezius ( 40.2 % ) , rhomboid major ( 6.5 % ) and multifidus ( 17.2 % ) muscles . There was no significant difference in terms of distribution of latent MTrPs between cervical radiculopathy and control groups ( P=0.249 ) . The frequency of aMTrP was found to be significantly higher in CDH with median localization as compared to posterolateral herniations ( P=0.041 ) . After conservative treatment for two weeks , number of patients with active MTrP in cervical radiculopathy were decreased about 50 % . CONCLUSION Cervical root compression would be considered as the starting or maintaining factor of aMTrP. CLINICAL REHABILITATION IMPACT The treatment of cervical radiculopathy might be facilitated the improving in aMTrPs located in aforementioned muscles OBJECTIVE To assess the prevalence of clinical ly evident myofascial dysfunction ( MD ) and its relationship to motor neglect ( MN ) in Complex Regional Pain Syndrome ( CRPS ) . DESIGN Retrospective chart review . PATIENTS Forty-one consecutively evaluated CRPS patients . OUTCOME MEASURES ( a ) Prevalence of trigger points in the proximal musculature of the CRPS limb . ( b ) Prevalence of MN in a subset ( n = 34 ) . RESULTS MD was detected in 61 % of CRPS patients . It was more prevalent in the upper limb ( 70 % ) than in the lower limb ( 47 % ) . MN was more common in those who also had MD . CONCLUSION MD is common in CRPS patients , especially in the upper limb and in those patients with MN . Prospect i ve trials are needed to confirm these intriguing findings , which may have important implication s regarding CRPS pathophysiology and treatment Background Following publication of the PRISMA statement , the UK Centre for Review s and Dissemination ( CRD ) at the University of York in Engl and began to develop an international prospect i ve register of systematic review s with health-related outcomes . The objectives were to reduce unplanned duplication of review s and provide transparency in the review process , with the aim of minimizing reporting bias . Methods An international advisory group was formed and a consultation undertaken to establish the key items necessary for inclusion in the register and to gather views on various aspects of functionality . This article describes the development of the register , now called PROSPERO , and the process of registration . Results PROSPERO offers free registration and free public access to a unique prospect i ve register of systematic review s across all areas of health from all around the world . The dedicated web-based interface is electronically search able and available to all prospect i ve registrants . At the moment , inclusion in PROSPERO is restricted to systematic review s of the effects of interventions and strategies to prevent , diagnose , treat , and monitor health conditions , for which there is a health-related outcome .Ideally , registration should take place before the research ers have started formal screening against inclusion criteria but review s are eligible as long as they have not progressed beyond the point of completing data extraction .The required data set captures the key attributes of review design as well as the administrative details necessary for registration .Su bmi tted registration forms are checked against the scope for inclusion in PROSPERO and for clarity of content before being made publicly available on the register , rejected , or returned to the applicant for clarification . The public records include an audit trail of major changes to planned methods , details of when the review has been completed , and links to result ing publications when provided by the authors . Conclusions There has been international support and an enthusiastic response to the principle of prospect i ve registration of protocol s for systematic review s and to the development of PROSPERO .In October 2011 , PROSPERO contained 200 records of systematic review s being undertaken in 26 countries around the world on a diverse range of interventions OBJECTIVES To determine the prevalence of myofascial trigger points ( MTrPs ) in the gluteus medius ( GMe ) and quadratus lumborum ( QL ) for subjects with patellofemoral pain ( PFP ) , and to examine the relationship between MTrPs and force production of the GMe after treatment . DESIGN R and omized controlled trial . SETTING A physical therapy clinic . PARTICIPANTS Subjects ( N=52 ; mean age ± SD , 30±12y ; mean height ± SD , 172±10 cm ; mean mass ± SD , 69±14 kg ) volunteered and were divided into 2 groups : a PFP group ( n=26 ) consisting of subjects with PFP , and a control group ( n=26 ) with no history of PFP .  INTERVENTIONS Patients with PFP received trigger point pressure release therapy ( TPPRT ) . MAIN OUTCOME MEASURES Hip abduction isometric strength and the presence of MTrPs . RESULTS Prevalence of bilateral GMe and QL MTrPs for the PFP group was significantly higher compared with controls ( P=.001 ) . Subjects in the PFP group displayed significantly less hip abduction strength compared with the control group ( P=.007 ) . However , TPPRT did not result in increased force production . CONCLUSIONS Subjects with PFP have a higher prevalence of MTrPs in bilateral GMe and QL muscles . They demonstrate less hip abduction strength compared with controls , but the TPPRT did not result in an increase in hip abduction strength Audette JF , Wang F , Smith H : Bilateral activation of motor unit potentialswith  unilateral needle stimulation of active myofascial trigger points . Am J Phys Med Rehabil 2004;83:368–374 . 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 prospect ively . 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 b and s 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 Abstract Musculoskeletal pain affects a significant proportion of the general population . The myofascial trigger point is recognized as a key factor in the pathophysiology of musculoskeletal pain . Ultrasound is commonly employed in the treatment and management of soft tissue pain and , in this study , we set out to investigate the segmental antinociceptive effect of ultrasound .  Subjects ( n = 50 ) with identifiable myofascial trigger points in the supraspinatus , infraspinatus and gluteus medius muscles were selected from an outpatient rehabilitation clinic and r and omly assigned to test or control groups . Test subjects received a therapeutic dose of ultrasound to the right supraspinatus trigger point while control groups received a sham ( null ) exposure .  Baseline pain pressure threshold ( PPT ) readings were recorded at the ipsilateral infraspinatus and gluteus medius trigger‐point sites prior to ultrasound exposure . The infraspinatus point was chosen due to its segmental neurologic link with the supraspinatus point ; the gluteus medius acted as a segmental control point . Following the ultrasound intervention , PPT readings were recorded at 1 , 3 , 5 , 10 and 15 min intervals at both infraspinatus and gluteus medius trigger points ; the difference between infraspinatus and gluteus medius PPT values , PPTseg , represents the segmental influence on the PPT . The ultrasound test group demonstrated statistically significant increases in PPTseg ( decreased infraspinatus sensitivity ) at 1 , 3 and 5 min , when compared with PPTseg in the sham ultrasound group . These results establish that low‐dose ultrasound evokes short‐term segmental antinociceptive effects on trigger points which may have applications in the management of musculoskeletal pain Background Shoulder pain is reported to be highly prevalent and tends to be recurrent or persistent despite medical treatment . The pathophysiological mechanisms of shoulder pain are poorly understood . Furthermore , there is little evidence supporting the effectiveness of current treatment protocol s. Although myofascial trigger points ( MTrPs ) are rarely mentioned in relation to shoulder pain , they may present an alternative underlying mechanism , which would provide new treatment targets through MTrP inactivation . While previous research has demonstrated that trained physiotherapists can reliably identify MTrPs in patients with shoulder pain , the percentage of patients who actually have MTrPs remains unclear . The aim of this observational study was to assess the prevalence of muscles with MTrPs and the association between MTrPs and the severity of pain and functioning in patients with chronic non-traumatic unilateral shoulder pain . Methods An observational study was conducted . Subjects were recruited from patients participating in a controlled trial study ing the effectiveness of physical therapy on patients with unilateral non-traumatic shoulder pain .  Sociodemographic and patient-reported symptom scores , including the Disabilities of the Arm , Shoulder , and H and ( DASH ) Question naire , and Visual Analogue Scales for Pain were compared with other studies . To test for differences in age , gender distribution , and education level between the current study population and the population s from Dutch shoulder studies , the one sample T-test was used . One observer examined all subjects ( n = 72 ) for the presence of MTrPs . Frequency distributions , means , medians , st and ard deviations , and 95 % confidence intervals were calculated for descriptive purpose s. The Spearman 's rank-order correlation ( ρ ) was used to test for association between variables . Results MTrPs were identified in all subjects . The median number of muscles with MTrPs per subject was 6 ( active MTrPs ) and 4 ( latent MTrPs ) . Active MTrPs were most prevalent in the infraspinatus ( 77 % ) and the upper trapezius muscles ( 58 % ) , whereas latent MTrPs were most prevalent in the teres major ( 49 % ) and anterior deltoid muscles ( 38 % ) . The number of muscles with active MTrPs was only moderately correlated with the DASH score . Conclusion The prevalence of muscles containing active and latent MTrPs in a sample of patients with chronic non-traumatic shoulder pain was high
target: Within spinal pain , patients with neck pain were found to have the highest prevalence rates of MTrPs .
  The trapezius descendens , levator scapulae , and suboccipitales muscles were the most prevalent locations for active MTrPs in patients with neck pain .
  Latent MTrPs were present in asymptomatic people , but no significant differences were found in the prevalence rate of latent MTrPs between patients with spinal ( neck ) pain and healthy controls .
  The only study investigating prevalence of MTrPs in different localizations of the same muscle reported no significant differences in prevalence between active and latent MTrPs within the trapezius descendens muscle .
  Studies examining pathophysiological mechanisms underlying MTrPs demonstrated an acidic environment , high concentration of algogenic/inflammatory substances , stiffer muscle tissue , retro grade diastolic blood flows , spontaneous muscle activity at rest , and loss of muscle contractibility in muscles with MTrPs .
  Altered central processing was also found to play a role in the development of MTrPs .
  Myofascial trigger points are a prevalent clinical entity , especially in patients with neck pain .
  Evidence was not found to support or deny the role of MTrPs in other spinal pain .
  Compelling evidence supports local mechanisms underlying MTrPs .
background: OBJECTIVE A systematic review was performed to evaluate the existing evidence related to the prevalence , incidence , localization , and pathophysiology of myofascial trigger points ( MTrPs ) in patients with spinal ( back and neck ) pain .