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Myofascial Pain Syndromes

Trigger Points

Literature Reviews David G. SimonsJan Dommerholt

In 1977, Melzack and colleaguesconcludedthat there was a 71 percent correlation be-tween myofascial trigger points [TrPs] andacupuncture points. Myofascial trigger pointsand acupuncture points were thought to besimilar. Three recent papers re-examine the

relationship between acupuncture points andTrPs and help to clarify which acupuncturepoints do, and which do not, correspond toTrPs and why. Birch completed the most aca-demic study on the subject and concluded thatat best, only 18 percent-19 percent of acu-puncture points examined in the 1977 studycould possibly correlate with TrPs. Accordingto Birch, acupuncture points and TrPs do notshow any meaningful correlation. At the sametime, Birch suggested that there may a rele-vant correlation between the so-called a shi

points and TrPs, an opinion shared by Hong,Ardette and Blinder.Several clinical studies and case studies are

included in this review. Unfortunately, not allresearchers define TrPs well and some con-fuse fibromyalgia tender points with TrPs. Astudy by Edwards and Knowles supports theuse of superficial dry needling in the treatmentof TrPs. Perhaps superficial dry needling shouldbe referred to as cutaneous dry needling toclearly distinguish it from deep dry needlingintended to penetrate a TrP.

A very important contribution to the litera-ture on TrPs comes from the National Insti-tutes of Health, where Shah and colleagueshave developed a new microanalytical tech-nique that makes it possible to assess the chem-ical milieu at TrP locations. This kind of re-

search could eventually expand the integratedTrP hypothesis and provide new insights inthe basic pathophysiology of TrPs. At thispoint, they have not yet published any full-length research articles detailing their intrigu-ing findings.

Each article review indicates whether it isprepared by Simons [DGS] or Dommerholt[JD].

CLINICAL STUDIES

Musculoskeletal Dysfunction in Men withChronic Pelvic Pain Syndrome Type III: ACase-Control Study: D.C. Hetrick, M.A. Ciol,I. Rothman, J.A. Turner, M. Frest, R.E.Berger. J Urology 170:828-831, 2003.

Summary

Sixty-two men with chronic pelvic pain syn-drome [CPPS] type III and 89 healthy menwere examined by a physical therapist experi-enced with patients with pelvic floor pain and

DavidG. Simons, MD, is ClinicalProfessor [voluntary], Departmentof Rehabilitation Medicine,Emory Univer-

sity, Atlanta, GA.JanDommerholt, PT,MPS, isDirector of Rehabilitation Services,Pain & Rehabilitation Medicine,Bethesda, MD.Address correspondence to: David G. Simons, MD, 3176 Monticello Street, Covington, GA 30014-3535

[E-mail: [email protected]].

Journal of Musculoskeletal Pain, Vol. 12(2) 2004http://www.haworthpress.com/web/JMP

2004 by The Haworth Press, Inc. All rights reserved.Digital Object Identifier: 10.1300/J094v12n02_06 45
http://www.haworthpress.com/web/JMPhttp://www.haworthpress.com/web/JMP


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dysfunction. The examination included sev-eral tests for posture, muscle strength, rangeofmotion and flexibility, and palpation of thepsoas, groin and pelvic muscle attachmentsfor tension and pain. Voluntary muscle con-

tractions were assessed manually for symme-try, substitution, resting tone, muscle spasms,and subject perceived sensation. Initially thephysical therapist was not blinded to subjectpatient or control status; however, as the studyprogressed, she reportedly was blinded. Sixty-nine percent of the pain patients and 70 per-cent of the controls were seen unblinded. Theresearchers found significant differences inmuscle tenderness, tension, and abnormalitiesin pelvic muscle function between patientsand controls. They concluded that musculardysfunction appears to be common in patients

with CPPS type III.

Comments

Although the article refers to previous stud-ies and reports of muscle dysfunction and myo-fascial trigger points [TrPs] associated withpelvic pain dysfunction, the researchers didnot report that they considered TrPs in the pal-pation of muscles. For a thorough review ofTrPs in the pelvic region, see chapter six of thesecond volume of the Trigger Point Manual(1). Several studies have suggested that pelvicpain dysfunction may indeed be significantlydue to TrPs (2,3). Instead, the examiner at-tempted to manually asses muscle tone andspasms without defining these concepts andwithout adequate descriptions of the methodsused. Determining the degree of muscle toneby manual palpation is not all that reliable.Simons and Mense reported that total muscletension is most accurately measured as stiff-ness (4). Measurable sources of muscle ten-sion include viscoelastic tone, physiologicalcontracture, voluntary contraction, and mus-

cle spasm. Voluntary contractions and musclespasms require motor action potentials to gen-erate tension. It is not clear from the paper howthe palpations were executed. Unfortunately,the examiner was only blinded for part of thestudy. Future studies that would include theassessment of TrPs, blinded examiners withestablished interrater reliabilities, and standard-ized evaluation methods may provide more

detailed information about the nature of thenoted muscle dysfunctions. Note: the classifi-cation of CPPS type III is based on a proposalof the 1995 National Institute of Health Work-shop on Chronic Prostatitis. Chronic pelvic

pain syndrome categories I and II are similarto acute and chronic bacterial prostatitis, cate-gory represents inflammatory [III A] and non-inflammatory [III B] CPPS without demon-strable infection, and category IV indicatesnonsymptomatic histological prostatitis [JD].

Superficial Dry Needling and Active Stretch-ing in the Treatment of Myofascial PainARandomized Controlled Trial: J. Edwardsand N. Knowles. Acupunct Med 21:80-86,2003.

Summary

Forty patients out of a total of sixty-six withmusculoskeletalpain referred to physical ther-apy met the inclusion criteria and were in-cluded in this randomizedprospective study ofsuperficial dry needling combined with activestretching. Inclusion criteria were age 18 andover, presence of active myofascial triggerpoint [TrP], identified by spot tenderness in ataut band, subject recognition of elicited painon palpation andpainful limitation of full range

of motion, no other treatment during the trial,and ability to comply with the trial. The pres-ence of a local twitch response and pain in anexpected distribution were not considered es-sential for inclusion, but were used to confirmthe diagnosis of myofascial pain syndrome[MPS] consistent with the criteria defined bySimons, Travell, and Simons (5). Fourteenpatients were assigned to a group receivingsuperficial dry needling using acupunctureneedles with a needle penetration depth of ap-proximately 4 mm combinedwith active stretch-

ing exercises; 13 subjects received stretchingexercises alone and another 13 subjects wereno-treatment controls. A physical therapisttrained in the identification of TrPs examinedall subjects to determine whether they hadclinically relevant TrPs. A total of six TrPs ineach subject were recorded. Subjects in the in-tervention groups received three weeks of in-tervention followed by three weeks of home

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exercises only. Outcomes were assessed withthe Short Form McGill Pain Questionnaireand pressure pain thresholds of the primaryTrP. Most measurements were conducted bytwo blinded and trained observers. When the

observers were not available, the primary in-vestigator conducted the measurements for atotal of 24 percent of the outcome measure-ments. Interestingly, there were no statisti-cally significant differences between the threegroups after three weeks. However, after an-other three weeks, the group receivingsuperfi-cial dry needling and active stretching scoredsignificantly better on the SFMPQ comparedto the no-intervention group and significantlybetter in the pressure thresholds compared tothe active stretching only group. The authorssuggested that stretching alone might have ad-

verse effects on TrP sensitivity. They also em-phasized that significant numbers of patientswith musculoskeletal pain appear to suffer fromTrPs.

Comments

The introduction to this article suggests thatthe authors are very familiar with the currentthinking about MPS and TrPs. The diagnosticcriteria were appropriate and clearly identi-fied. They emphasized that patients with mul-tiple clinically relevant TrPs are verycommonin clinical practice. Sixty-one percent of thepatients referred to physical therapywith mus-culoskeletal pain by general practitioners suf-fered from MPS. Successful treatment may re-quire multiple treatment sessions. The studyprotocol reflected their insights and consid-ered the effects of superficial dry needlingover a three week period. Superficial dry nee-dling has been promoted by Baldry, but thereare only few clinical outcome studies (6).

Superficial dry needling combined with anactive stretching program was superior to

stretching alone and to no-intervention. Al-though the researchers used the pressure thresh-old of the primary TrP in their outcomes, theydid not indicate how they determined whichTrP was the so-called primary TrP. Simons,Travell, and Simons defined a primary TrP asa central TrP that was apparently activateddirectly by acute or chronic overload, or repet-itive overuse of the muscle in which it occurs

and was not activated as a result of trigger-point activity in another muscle (5). In clini-cal practice, it is not always easy to determinewhich TrPs qualify as primary.

Regrettably not all outcome measures were

blinded, which may have introduced some bias.Yet, the study supports that superficial dryneedling over TrPs is an effective treatmentmodality. Other well-designed studies are neededthat compare the efficacy of superficial dryneedling to deep dry needling and to manualtherapy techniques such as contract-relax tech-niques or TrP pressure release.

The authors suggested that physical thera-pists and general practitioners practicing acu-puncture are well placed to use dry needlingtechniques in their respective practices. In sev-eral countries physical therapists are now au-thorized to usedryneedlingtechniques, includ-ing the United Kingdom, Switzerland, SouthAfrica, and Spain among others. In the UnitedStates, state boards of physical therapy in Mary-land, Virginia, New Hampshire, and New Mex-ico have already ruled that dry needling fallswithin the scope of physical therapy practicein those states [JD].

A Preliminary Comparison of the Efficacyand Tolerability of Botulinum Toxin Sero-types A and B inthe Treatment ofMyofascialPain Syndrome: A Retrospective, Open-La-bel Chart Review: A.M. Lang. Clin Ther25(8):2268-2278, 2003.

Summary

Dr. Lang conducted a retrospective open-label chart review of 91 patients who had re-ceived either botulinum toxin type A or type Bas part of their treatment regimen for myo-fascial pain syndrome. Fifty-six patients re-ceived botulinum toxin type A and 35 patients

received type B. Myofascial pain syndromewas diagnosed if active myofascial triggerpoints [TrP] and referred pain were identified.Other etiologies, pregnant or lactatingwomen,minors, and patients with neuromuscular junc-tion disease or infection were excluded. Thechoice between botulinum toxin type A and Bwas solely based on insurance approval orpreauthorization. No effort was made to ran-

Literature Reviews 47


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domize subjects. Patients received more thanone injection with some patients receiving in-jections during more than one treatment ses-sion. Patients returned for reassessment onemonth following the procedure or when pain

returned.The primary outcome measure was the re-

duction in Visual Analog Scores with second-ary measures including duration of treatmenteffect and subjective improvements. Most pa-tients received injections in multiple muscles.Both groups experienced significant relief ofpain. However, the Botulinum type A grouphad significantly greater reductions in painthan the type B group. Few patients in eithergroup reported adverse effects. Dr. Lang con-cluded that the two available Botulinum sero-types should not be used interchangeably, asthe treatment effects do appear to differ.

Comments

Dr. Lang acknowledged the limitations ofopen-label retrospective chart reviews. Not onlywas she the only observer, the patients werenot blinded and they were not randomly as-signed to either treatment group. Yet, this kindof research is valuable. Prospective doubleblind randomized control studies are nowneeded to see whether the findings of this

study can be repeated. The choice of whichbotulinum serotype to use for which patient orconditionmayhave important implications forclinical practice [JD].

The Effects of Infrared Laser and MedicalTreatments on Pain and Serotonin Degra-dation Products in Patients with MyofascialPain Syndrome. A Controlled Trial: Y.Ceylan, S. Hizmetli, Y. Silig. Rheumatol IntNov. 20, 2003 [Epub ahead of print. Thepublisherdid not yet assign pagenumbers].

Summary

The authors stated that forty-six subjects di-agnosedwith myofascialpain syndrome[MPS]using criteria of the American College ofRheumatology were randomly assigned to atreatment group [N = 23] or a placebo group[N = 23] in this study of the effects of infrared

[IR] laser therapy on myofascial trigger points[TrP]. Patients with systemic disorders or pa-tients using any medications were excluded.Subjects in the treatment group received IR la-ser and subjects in the placebo group received

sham laser. A Gymna 200 laser with a wave-length of 904 nm was used for three minutesfor each TrP at a frequency of 4 kHz. All pa-tients received medical treatmentconsistingof500 mg naproxene sodium twice a day and400 mg phenbrobomat three times a day. Allpatients were given a diet free of banana, pine-apple, walnut, tomato, and eggplant. On thefifth day, the study protocol was started. Painwas evaluated using a visual analog scale foreach TrP following digital palpation until thenail bed of the first finger whitened. The samephysician applied the pressure in all subjects.Twenty-four hour urinary excretions of 5-hy-droxy indole acetic acid [5-HIAA], serotonin[5-HT] 5-hydroxy tryptophan [5-HTP] werecollected on day five and on day nine. Sevensubjects were excluded from the final dataanalysis leaving 19 and 20 subjects in the treat-ment and placebo group, respectively. Post-treatment decreases in the Visual Analog Scalescores and increases in 5-HIAA, 5-HT, and5HTP excretions were all significantly greaterin the treatment group compared to the controlgroup. The authors concluded that IR laser

treatment of TrPs was significantly more ef-fective than placebo treatment.

Comments

This study demonstrates that the use of IRlaser is beneficial in the treatment of TrPs, as-suming that the authors actually treated TrPs.They stated that the patients were diagnosedwith MPS accordingto theAmerican Collegeof Rheumatology criteria. This is problematicsince the American College of Rheumatologynever developed criteria for MPS. It appears

that rather than treating TrPs, the authors ap-plied IR laser to fibromyalgia tender points.While it is likely that in some patients withfibromyalgia, fibromyalgia tender points mayin fact represent TrPs, it is not clear from thisstudy which points the authors treated (7).Measuring urine excretions of 5-HIAA [a met-abolic metabolite], 5-HT, and 5-HTP [a sero-tonin precursor] is an outcome method thathas



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not been applied previously to research onTrPs. It appears that the physician applyingthe pressure over TrPs was not blinded to theresearch. Also, using manual palpation is notareliable method to assess pressure thresholds.

In future studies, the authors should considerusing standardized algometry with blinded eval-uators [JD].

Investigation of the Effect of GaAs LaserTherapy on Cervical Myofascial Pain Syn-drome: L. Altan, U. Bingl, M. Ayka, M.Yurtkuran. Rheumtol IntDec. 12,2003 [Epubahead of print. The publisher did not yet as-sign page numbers].

Summary

Fifty-three patients were randomly assignedto a treatment group [N = 23] or a control group[N = 25] in this study of the effect of GaAs la-ser on myofascial trigger points [TrP]. Inclu-sion criteria were 1. localized pain and tautbands in the neck for at least three months;2. bilateral and significantly more tendernessin the three cervical trigger points [midpoint ofthe upper border of the trapezius muscle, ori-gin of the supraspinatus muscle, and insertionof the suboccipital muscle] compared to a con-trol point [a non-tender point over the deltoid

muscle]; 3. existence of no other criterion forfibromyalgia syndrome [FMS] diagnosis; 4. nohistory of finding of cervical arthrosis, discalhernia, cervical vertebral fracture, radiculo-pathy, or myelopathy; 5. no pathological find-ing in blood count, urinalysis, sedimentation,or cervical x-ray. Subjects in the treatmentgroup received an infrared 27 GaAs diode la-ser treatment for 10 days during a period oftwo weeks with a wavelength of 904 nm and afrequency of 1000 Hz. Subjects in the controlgroup received sham treatments. Treatmentwas directed toward the three points described

in the inclusion criteria and a point in a tautband in the trapezius muscle. Baseline andoutcome measurements were performed justbefore, immediately after [two weeks], and 12weeks following the treatment by a blindedevaluator. Outcome measures included a visualanalog scale, a numerical ratingscale, algometryover the various points, and goniometry forcervical lateral range of motion. Five subjects

were excluded, as they were not available forfollow up assessments. The authors concludedthat there were significant advantages of GaAslaser over placebo in the treatment of cervicalmyofascial pain syndrome.

Comments

This studyappeared promising at firstglance.The outcome measures were reasonably ob-jective and were assessed by a blinded evalua-tor. However, the authors confuse the litera-ture on TrPs with the literature on FMS. Thetreated points were FMS tender points and notTrPs, making it impossible to draw any mean-ingful conclusions about the efficacy of GaAslaser therapy on TrPs [JD].

Back Extensor Muscle Fatigability in ChronicLow Back Pain Patients and Controls: Re-lationship Between Electromyogram PowerSpectrum Changes and Body Mass Index:M. Psuke, E. Johanson, M. Proosa, J.Ereline, H. Gapeyeva. J Back MusculoskeRehab 16:17-24, 2002.

Although there was no recognition of theexistence of myofascial trigger points in thiswell-designed research study, it is of interestto these reviewers because of the congruence

between their findings in subjects with lowback pain and the effects of TrPs on musclefunction. They found that the muscles of theirpatients exhibited significantly shorter endur-ance times, increased rate of decrement of themean power frequency with exercise, and re-duced isometric endurance time. Also, reducedisometric endurance time was correlated withincreased body mass index [DGS].

CASE REPORTS

Myofascial Pain from Pectoralis MajorFollowing Trans-Axillary Surgery: M.Cummings. Acupunct Med 21(3):105-107,2003.

Summary

A 28-year-old female presented to an acu-puncture teaching clinic with complaints of



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pain in the left arm and chest. Eighteen monthsearlier, the patient had a trans-axillary resec-tion of the left first rib because of a left axillaryvein thrombosis. Two months after the sur-gery the patient required a venoplasty. Ini-

tially, the patient described left-sided chestpain at a drain site, which eventually devel-oped into a permanent heavy aching with sharpand burning exacerbations involving not onlythe chest, but also the medial aspect of the leftarm, forearm, and hand. The patient experi-enced a pinching sensation in the pectoralismajor and a pulling in the fourth web spaceof her left hand. Her medic intercostobrachialnerve, rotator cuff atrophy, Raynauds phe-nomenon, and possible scarring around theC8/T1 nerve root.

Approximately seven months after the on-

set of the permanent pain, the patient con-sulted the acupuncture clinic. A myofascialtrigger point [TrP] was observed in the leftpectoralis major muscle at the drain site. TheTrP was treated with two gentle and brief nee-dle insertions of 10 seconds each. The patientwas instructed to stretch the muscle at home.Two weeks later, she reported that the pare-sthesia in the arm had resolved with improve-ment of the pinching feeling. The pullingin the hand had increased. Two additional nee-dle insertions in the pectoralis TrP using a dryneedling technique completely resolved thesymptoms within two hours following the sec-ond treatment.

Comments

Trigger points are commonly seen aftertrauma, irrespective of the nature of the trau-matic insult. Cummings described an interest-ing case of myofascial pain syndrome at adrain site following a surgical procedure. Sev-eral aspects of this case report are relevant asthey illustrate broader issues. Myofascial pain

syndrome was not considered in the differen-tial diagnosis by the patients medical consul-tants. The symptoms caused by TrPs mim-icked other pathologies, which indeed had tobe considered. However, by excluding myo-fascial pain syndrome as a possible option, thepatient was deprived from effective manage-ment and suffered needlessly for many months.The author had considered that the pulling

sensation in the hand could be due toa satelliteTrP. It is rarely possible to distinguish a satel-lite TrP from a primary or key TrP by exami-nation alone. As Simons, Travell, and Simonsdescribed, the relation usually is confirmed by

simultaneous inactivation of the satellite,when the key TrP is inactivated (5). The reportillustrates that in some chronic cases, a singleTrP can be responsible for a multitude of symp-toms. The author did report examining othermuscles of the functional muscle unit, but didnot find any other clinically relevant TrPs. Theauthor did not indicate whether the patient re-mained symptom-free several weeks or monthsafter the treatments [JD].

Toothache of Nonodontogenic Origin: A

Case Report: P. Mascia, B.R. Brown, S.Friedman. J Endod 29(9):608-610, 2003.

Summary

A 25-year-old female presented to a post-graduate endodontics university clinic withcomplaints of spontaneous pain on the left sideof her face that began several hours earlier andradiated to her ear and temporal region. Tak-ing 650 mg of acetaminophen had providedno relief. Tooth #18 exhibited symptoms ofpericementitis, but anesthetizing the tooth hadno effect on her symptoms and no other dentalsource of the pain could be identified. Since nodental source of the pain could be found thepatient was examined for a myofascial triggerpoint [TrP] cause. An TrP was located in theleft masseter muscle that when compressed re-ferred pain to the mouth, effectively duplicat-ing the patients chief complain. Injecting itwith Carbocaine without epinephrine and afan-like pattern of dry needling produced im-mediate pain relief that had continued at the 12months follow-up examination.

Comments

This is another example of referred painfrom a masticatory muscle that was confus-ingly similar to pain that can originating in theteeth. The authors are to be congratulated onconsidering TrPs in the differential diagnosis.The prompt elimination of the TrP source of



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the pain was easily accomplished just a fewhours after onset and before substantial centralnervous system plasticity changes convertedthe acute episode into a chronic pain conditionthat is much harder and more expensive to

treat. Although the authors did not mention atrial of manual therapy techniques before turn-ing to injection, in acute cases like this, theyare usually also promptly effective [DGS].

Myofascial Pain Response to Topical Lido-caine Patch Therapy: Case Report: A.S.Dalpiaz, T.A. Dodds. J Pain Palliat CarePharmacoth 16(1):99-104, 2002.

Summary

A 39-year-old female with chronic myo-fascial pain syndrome, fibromyalgia, and sys-temic lupus erythematosus participated in anopen clinical trial assessing the efficacy oftopically applied lidocaine 5 percent patchesas an alternative to trigger point injections. Thepain evaluation for the purpose of this reportwas limited to myofascial pain. After 28 daysof lidocaine therapy averaging three patchesper day over active myofascial trigger points[TrP], the patient reported a decrease of herworst pain from a 9 to a 5 on a visual analogscale from 0 to 10 and a decrease of her aver-

age pain from a 7 to a 2. The patients func-tional capacity increased as measured by suchactivities as vacuuming her home and garden-ing. She reduced her medication intake con-siderably. The authors commented that othersubjects in the study did not always reportsuch dramatic improvements.

Comments

Relying on a subjects score on a visual ana-log scale is not the most reliable method to de-

termine the efficacy of a therapeutic interven-tion on TrP pain, particularly when the subjecthas at least two other painful medical condi-tions. Studies of clinical efficacy should in-cludeother moreobjective measurements, suchas algometry over TrPs. While lidocaine patchesmay be useful in the treatment of TrPs, thiscase study has too many confounding aspectsto reliably come to that conclusion. The au-

thors correctly acknowledge that a conclusionabout the potential usefulness of the lidocainefive percent patch in myofascial pain mustawait completion of this open-label trial andsubsequent controlled trials [JD].

REVIEWS

Myofascial Trigger Points: Pathophysiologyand Correlation with Acupuncture Points:C.-Z.Hong.AcupunctMed 18(1):41-47,2000.

Summary

Hong summarized the clinical features ofmyofascial trigger points [TrPs], and exten-sivelydescribed the research reports including

animal studies that clearly describe a crediblepathophysiology of TrPs. He reached two con-clusions on the relationship between acupunc-ture points and TrPs. First, the Ah-Shi points[Oh Yes! Points] of acupuncture correspondto TrPs and that the mechanism for pain reliefby needling TrPs may be similar to relief byacupuncture of Ah-Shi points. Second, he be-lieves that the de-chi response is a sensationproduced by the acupuncture needle that iscomparable to the local twitch response andthat in both cases, the best therapeutic resultsare related to eliciting these responses. Hongemphasizes the strong relation of these pointsto central nervous system function.

Comments

Hong is a leader inclinical and basic TrP re-search and a native of Taiwan who was ini-tially trained in acupuncture. He is particularlywell qualified to address this issue and is inagreement with Birch and with Audette andBlinder whose opinions were also reviewed inthis issue. We agree that the original Melzack

article relating acupuncture points and TrPs ishighly flawed in a number of ways, not theleast of which was the way that the location ofTrPs was determined. There are many morelocations for TrPs in muscles. We also agreethat one class of acupuncture points correlatehighly with TrPs. A number of clinicians haveobserved noteworthy better responses of TrPsto treatment that incorporates both acupunc-



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ture and TrP principles. This is an approachthat deserves serious research investigation[DGS].

Trigger Point-Acupuncture Point Correla-tions Revisited: S. Birch. J Altern Compli-ment Med 9(1):91-103, 2003.

Summary

In 1977, Melzack and colleagues publisheda literature-based review examining the possi-ble correspondence of acupuncture points andmyofascial trigger points [TrP] for the treat-ment of pain (8). They reported that all of the56 examined TrPs were within 3 cm of an acu-puncture point. Forty of these TrPs [71 per-

cent] were reported to have the same pain in-dications as the corresponding acupuncturepoints. Melzack andcolleaguesconcluded thatthere was a 71 percent correlation and thatTrPs and acupuncture points represent thesame phenomenon. As Birch summarized,this study had a profound impact particularlyon the further development of the theoreticalfoundations of acupuncture, but also on thetreatment of TrPs (6). Melzacks study pro-vided evidence for many researchers and cli-nicians that acupuncture had an establishedphysiologic basis and that acupuncture prac-

tice could be based on the reported correla-tions with TrPs.

Birch concluded that the 1977 study wasbased on several poorly conceived aspectsand questionable assumptions, including thenotion that all acupuncture points must exhibitpressure pain; that the 40 correlated acupunc-ture points are normally used in the treatmentof pain conditions and are among the morecommonly used acupuncture points; and thatonly the local pain indications of acupuncturepoints are sufficient to establish a correlation.

Birch conducted an extensive study of the cur-rent literature on acupuncture practice, someof which was either not available or includedin the mid-1970s review.

Birch found that only approximately 18 per-cent-19 percent of acupuncture points exam-ined in the 1977 study could possibly correlatewith TrPs. According to Birch, acupuncturepoints and TrPs do not show any meaningful

correlation. At the same time, Birch suggestedthat there may a relevant correlation betweenthe so-called Ah-Shi points and TrPs. He ex-plained that in the acupuncture literature, theAh-Shi points belong to one of three major

classes of acupuncture points. There are 361primary acupuncture points referred to as chan-nel points. There are hundreds of secondaryclass acupuncture points, known as extra ornon-channel points. The third class of acu-puncture points is referred to as a shi points.By definition, a shi points must have pressurepain. They are used primarily for pain andspasm conditions. Melzack and colleagues didnot consider the Ah-Shi points in their study,but focused exclusively on the channel pointsand extra points.

Comments

Birchs argument that the primary acupunc-ture points and TrPs do not have any meaning-ful correlation is a radical turn from the con-clusions drawn by Melzack and colleagues 26years ago. Yet, the rational he has developedto reject the previous conclusions is quite con-vincing. Birch is a world-renowned acupunc-turist and author of several books and articleson acupuncture (9-11). In his writings as inthis study he displays an in-depth understand-ing of acupuncture and the different classesand applications of acupuncture points. Birchhas incorporated more recent findings fromthe acupuncture literature into the current studydesign. We agree with Birch, that the Ah-Shiacupuncture points may indeed be TrPs. Anacupuncturist identifying a shi points may notbe familiar with the literature on TrPs and thusnot identify them as such.

Oneadditional difficulty with the 1977 studyis that TrPs were assumed to be in rather fixedanatomical locations making comparisons withacupuncture point maps of primary acupunc-

ture points feasible. Although the trigger pointmaps suggest that there may be certain fixedlocations, clinicians and researchers should beaware that TrPs can occur in various locationswithin a muscle. Melzack and colleagues useda somewhat arbitrary 3 cm criterion and foundthat all examined TrPs corresponded to anacupuncture point. But to quote Birch: it isprobable that there is some overlap in the loca-



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tion of acupuncture points and trigger points,but it is unlikely to be more than chance, andsuch similarity of location does not imply acorrelation. Classical acupuncture points andTrPs mayafter all not necessarily represent the

same phenomena [JD].

The Pathogenesis of Muscle Pain: S. Mense.Current Pain and Headache Reports 7(6):419-425, 2003.

Summary

In this review article, Dr. Mense providedan overview of several peripheral and centralmechanisms of muscle pain. He focused onthe neurobiology of muscle nociceptors, in-

cluding the various receptor molecules, theirneuropeptide content, andespecially thesensi-tization of peripheral nociceptors leading totenderness and hyperalgesia. Animal researchhas shown that different types of nociceptorsare present in muscle, including a nociceptorthat is sensitive to ischemic contractions. Inanother section of the article, Mense reviewedmuch of his and other researchers findings onmechanisms of muscle pain at the spinal level,including expansion of receptive fields, hyper-excitability, and central sensitization, whichcan account for referred pain from myofascialtrigger points [TrP]. Due to neuroplasticity,the functional reorganization of the spinal dor-sal horn may outlast the initiating peripherallesion. In addition, inhibitory interneurons maybecome dysfunctional causing nociceptive neu-rons to be chronically disinhibited and hyper-active. In Menses words this tells us to abol-ish the muscle pain as early and effectively aspossible to preventcentral nervous alterations.If a patient already has developed alterations,treatment will be difficult and long-lasting be-cause alterations need time to disappear.

Comments

Mense has published an excellent up-to-date review article on muscle pain that in manycases can apply to TrPs. Although Mensewarned that applying animal research data tohuman conditions is at best speculative, he didindicate that several pain syndromes might in-

volve peripheral muscle nociceptors. Nocicep-tors sensitive to ischemic contractures are likelyinvolved in patients with tension type head-aches, myofascial pain syndrome or fibromy-algia. Persistent pain referred from TrPs is

likely due to neuroplastic changes and centralsensitization that are likely to persist longafterthe initiating event has been resolved. Clini-cally, it is important to prevent the onset ofcentral nervous system alterations. Evaluatingacute and subacute patients for the presence ofTrPs is critical. By treating TrPs early on, pa-tients may be spared from becoming chronicpain patients, even though not all patients withmuscle lesions become chronic pain patients.If a patient has developed chronic pain, the re-covery is much slower, as the central nervoussystem alterations can take much time to re-verse and disappear [JD].

Evaluation of Treatments for MyofascialPain Syndrome and Fibromyalgia: N.J.Rudin. Current Pain and Headache Reports7(6) 433-442, 2003.

Summary

This review article described both myofas-cial pain syndrome [MPS] and fibromyalgia.One of the objectives of the article was to as-

sist clinicians in designing individualized treat-ments in the context of pathophysiology, clini-cal evidence, and experimental support. Aftera brief general introduction, Dr. Rudin reviewedboth clinical syndromes, detailing some epi-demiologic data, diagnostic criteria, pathophys-iology, and a review of several treatment op-tions. According to Dr. Rudin, there are threemajor constructs to explain the pathophysi-ology of MPS. The first construct was de-scribed as a result of tissue injury secondary torepetitive muscleoverload or direct muscle in-

jury, and the subsequent release of kinins andinflammatory mediators. This would lead tosensitization of peripheral nociceptors and theformation of painful local muscle contractionand the development of myofascial triggerpoints [TrPs]. The second construct brieflymentioned Hubbards hypothesis that TrPs aredue to muscle spindle dysfunction. Along thesame lines, Rudin mentioned that another



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theory posits excessive activity of acetylcho-line at the motor endplate. Rudin suggestedthat the most promising construct consideredTrPs as a referred pain phenomenon. He brieflymentioned a few neuroplastic changes at the

spinal dorsal horn, including expansion of re-ceptive fields, but did not explain how TrPswould fit into this construct. The final part ofthe section on MPS described several treat-ment options, including muscle stretch, exer-cise, TrP injection, massage, pharmacologicinterventions, modalities, acupuncture, psychol-ogy, and multidisciplinary team treatments.

Comments

There are several issues with the section on

MPS in this article. Although Rudin suggestedthat there are three different constructs to ex-plain MPS, heactuallymentioned four constructs[overload, muscle spindle, motor endplate, andreferred pain]. None of the constructs were ex-plained very well. Rudins presentation sug-gests that these constructs would be mutuallyexclusive, which they are not. Muscle over-load can result in the formation of TrPs, whichin turn can initiate both peripheral and centralsensitization processes, including an expan-sion of receptive fields. The role of the musclespindle is clearly not a primary factor (5,

pp. 78-81). Dr. Rudin supported the overloadconstruct with three references that have littleto do with MPS or TrPs. One reference dis-cusses excitation of cutaneous nociceptors; thesecond reference is a chapter about the role ofthe sympathetic nervous system in pain, whilethe third reference discusses the importance ofneuropeptides in complex regional pain syn-drome. Rudin ignored the important motor ef-fects of TrPs, including the local twitch re-sponse.

The review of available treatment options

highlights that there is a lack of good clinicalstudies. Several references in the treatmentsection are nonspecific for TrPs. For example,Rudin quoted multiple dental studies, that donot include TrPs, but are based on DworkinandLeReschescriteria for temporomandibulardisorders, that are not designed to identifyTrPs reliably (12). In summary, this review ar-ticle contains many inaccuracies and inade-

quacies; as a result it tends to confuse ratherthan clarify the issue [JD].

Myofascial Pain Syndrome: P. Reilich andD. Pongratz. In: Botulinum Toxin in Pain-ful Diseases: W.H. Jost (ed). Basel, Karger,14:23-41, 2003.

Summary

This review begins with a clear descriptionof myofascial pain caused by trigger points[TrP] and tabulates 15 clinical differences be-tween TrPs and fibromyalgia. It describes theintegrated hypothesis as the basis of TrPs andincludes illustrations of histopathological sub-stantiation and spontaneous electrical activity

characteristic of TrPs. Well established man-ual and needling methods of treatment of TrPsare reviewed before an extensive review of theuse of Botulinum toxin. The authors illustratetheir technique and conclude that botulinumtoxin is effective, but more studies are neededto determine when and how best to use it.

Comments

The authors present an up-to-date under-standing of the integrated hypothesis and ofthe clinical characteristics of TrPs. They pres-

ent a knowledgeable perspective to the injec-tion technique and expected results, but makeno mention of the relative effectiveness of al-ternative TrP treatment approaches such asdry needling or manual therapy [DGS].

A Search for the Pathophysiology of the Non-specific Occupational Overuse Syndromein Musicians: J.W. White, M.G. Hays, G.G.Jamieson, I. Pilowsky. HandClin 19:331-341,2003.

Summary

The literature reflects a strong controversyas to whether this condition does or does notdepend on physical pathology. Of 27 articlesaddressing possible pathology of occupationaloveruse syndrome, only one considered fibro-myalgia/myofascial pain. The authors notedthat the pain is caused by activities in music in



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the workplace without recognized evidence ofspecific disease or injury. They propose thatcontinuous or repeated musculoskeletal activ-ity varies the sensitivity of some part of thestructure proportional to the intensity and du-

ration and inversely proportional to the effi-ciency of the activity. The sensitivity can bemodulated by numerous other factors. Thisprocess limits the level of activity when it ex-ceeds the individuals current level of fitness[which can be described as musculoskeletaloverload]. The authors recognize the need forfurther effort to identify the reasons for poorresponse to treatment but ignore myofascialtrigger points as a likely cause of the symp-toms.

Comments

This current article on this important topicdemonstrates the lack of clinical literature re-lated to TrPs and this clinical condition, thesense of frustration with the current situation,and presents the authors suggested solutionthat is compatible with TrPs as the underlyingcause. The one reference to TrPs that was citedwas written by this reviewer 17 years ago andled them to conclude that myofascial pain hasnot received generally accepted explanations.However, acceptable explanations are in the

subsequent literature by numerous authors,evidenced by related reviews by Hong, and byReilich and Pongratz in this issue [DGS].

DifferentialDiagnosis: MyofascialPain Syn-drome (Chapter 8): J. Dommerholt, T.S.Issa. In: FibromyalgiaSyndrome: A Practi-tioners Guide to Treatment, Ed. 2: Chaitow(ed). Edinburgh, 149-177, 2003.

Summary

An initial scholarly critique of the diagnos-tic criteria of the fibromyalgia syndrome [FMS]precedes a thoughtful review of 12 differentialdiagnoses to be considered. Following this isan extensive summary of the myofascial painsyndrome caused by trigger points [TrP]. Thissummary includes a discussion of four thera-peutic approaches, of its pathophysiologybasedon a clear understanding of the integrated hy-

pothesis, and diagnostic considerations. Thelatter summarizes the key features of the pa-tients medical history and the dependence ofconfirmationof the diagnostic impression on askilled physical examination of the muscles.

The article concludes with the characteristicreferred pain patterns of 50 skeletal musclesand suggests that an assessment of FMS ten-der points should be followed by an assess-ment of TrPs that refer pain into the region ofthe FMS tender points.

Comments

This is an unusually clear and knowledge-able review of FMS and TrPs and of theirclose interaction. The review emphasizes theimportance of learning to recognize each con-dition and the importance of looking for themin musculoskeletal pain patients.

There is a major source of confusion. Re-cent literature strongly supports the clinicalimpression that nearly all FMS patients havesome active TrPs,and some patients have manyactive TrPs contributing to their pain. Whenboth conditions are active, it is important torecognize that fact and include both in the pa-tients total management plan [DGS].

The Relationship of Neck Injury and Post-traumatic Headache: R.C. Packard. CurrPain Headache Rep 6(4):301-307, 2002.

Summary

This review of literatureconcerning the causeof headache following whiplash injury identi-fied structuraldamage,myofascial triggerpoints[TrPs], stimulation of the occipital nerve, tis-sue changes with healing, and psychologicalfactors. Conclusions included the statementthat . . . performing a physical examination is

unable to determine the site or the severity ofthe pathology.

Comments

Clearly the author of this literature reviewarticle had some awareness of the TrP litera-ture and is to be commended for his feeling forthe importance of TrPs in whiplash injuries.



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He cited the second edition of volume 1 andcopied several figures [with appropriate rec-ognition of the source with one exception]from the Trigger Point Manual but with errorsin the reference, as is often the case (5). The

authors conclusion concerning physical ex-amination of these patients suggests that hehas not developed sufficient skill in palpatingfor TrPs to find them in these patients, whereasthey were commonly present for a skilled ex-aminer (13,14). The author was at a seriousdisadvantage to present literature documenta-tion for the importance of TrPs, because of theamazing lack of recently published articles onthe role of TrPs in whiplash injuries, sinceTrPs are so common and so important in thiscondition [DGS].

ManagingMyofascial Pain Syndrome; Sort-ing Through the Diagnosis and HoningTreat-ment: J.M. Daniels,T. Ishmael, R.M. Wesley.Physician Sportsmed 31(10):39-45, 2003.

Summary

This article, written by a family practicephysician for sports medicine physicians, re-views the clinical characteristics of myofas-cial pain caused by myofascial trigger points[TrPs], its pathophysiology, and its treatment

by manual techniques and injection. In addi-tion, the authors briefly summarize distinc-tions between the TrPs of myofascial painsyndrome and the tender points of fibromy-algia [FMS]. The authors tabulated11 featuresof both conditions. Eight features, except twowere either more localized in TrPs or, if thefeature involved the whole body, they wereless common in TrPs. Two features, taut bandand twitch response were dismissed as notvarying from normal in either type of hyper-sensitive spot.

Comments

The authors are to be highly commendedfor their effort to introduce TrPs into the think-ing of sports medicine physicians to help themconsider TrPs as an important differential di-agnosis and to look for them. It effectivelycharacterizes myofascial pain caused by TrPs

and the FMS. Much of the article presented adetailed description of manual and injectiontreatments for TrPs. The authors provided sev-eral guidelines, indications and contraindica-tions for injecting TrPs, without emphasizing

that accurate and reliable identification of TrPsrequires considerable training and practice (15).

The issue of distinguishing myofascial painfrom FMS as diagnoses is one thing, and dis-tinguishingTrPs fromtender points associatedwith FMS as examination findings is quite an-other. There is accumulating evidence that TrPscan be considered a neuromuscular diseasewith a specific pathophysiology that explainsit characteristic symptoms and many of its ef-fective treatments. However, FMS still lacks aspecific pathophysiology that explains any-where near all of its characteristic symptoms

and there is no known curative treatment forthat entity.

Jan Dommerholt proposes that clinicallypatients are perhaps better served focusing onthe diagnosable associated dysfunctions, assuch, without giving them a generic umbrelladiagnosis. David Simons suspects that when theappropriate electroencephalogram and brain-function imaging studies are adequately eval-uated, there will be a core brain dysfunctionthat may account for most of the clinical FMSsymptoms, but may correlate poorly with theestablished diagnostic criteria.

Patients who receive the diagnosis of FMS,whether it fits the established criteria or not,need understanding and appropriate medicalattention. Distinguishing active TrPs from ten-der points ascribed to FMS will help greatly toidentify what is commonly a major and treat-ablecause of muchof the patients symptoms.

The data collected in the authors table sup-port the many papers that characterize TrPs asa regional pain syndrome and FMS as a gener-alized pain syndrome. There is relatively littleliterature that clearly distinguishes TrPs and

FMS, and much progress has been made latelyin the understanding of both of these commonand clinically important conditions. One diffi-culty is that as TrPs persist and become chronic,they frequently also multiply and become morewidespread. It indeed is very likely that manypatients diagnosed with FMS may in fact havechronic myofascial pain syndrome [MPS] (7).Gerwin observed that about 45 percent of pa-



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tients diagnosed with chronic MPShad clinicallyrelevant TrPs in three or four body quadrants(16). Individuals with active TrPs [especiallyacute TrPs] butnotFMS are considerably morecommon than those who meet FMS criteria

but do not have active TrPs.Taut bands and local twitch responses are

important features of TrPs that help to makethe important distinction between TrPs andtender points associated with FMS. Althoughtaut bands are found almost as commonly innormal subjects as in MPS and FMS patients,they are absent in tender points of FMS pa-tients if those tender points are not also TrPs,which sometimes is, and sometimes is not, thecase. All TrPs are tender spots. Local twitchresponses occur only in taut bands and ordi-narily are elicited only by mechanical stimula-

tion of a TrP in a taut band. Therefore, onewould not expect them to be associated withany of the tenderspots of FMS that are not alsoTrPs. There is much evidence (17,18) thatmany FMS patients have both active and latentTrPs, which adds greatly to the confusion. Inthe same way that the diagnosis of TrPs de-pends strongly on the history, a valid diagno-sis of FMS [in the minds of many] dependsstrongly on serious involvement of multipleorgan systems, increased fatigability, and epi-sodes of impaired cortical function. This ap-proach helps greatly to more clearly distin-guish between the two diagnoses [DGS, JD].

BRIEF REVIEWS AND ABSTRACTS

A Novel Microanalytical Technique for As-saying Soft Tissue Demonstrates SignificantQuantitative Biochemical Differences in 3Clinically Distinct Groups: Normal, Latent,and Active: J.P. Shah, T. Phillips, J.V.Danoff, L.H. Gerber (abstract). Arch PhysMed Rehabil 84 (suppl.): A4, 2003.

Dr. Shah and his colleagues at the NationalInstitutes of Health have initiated a very im-portant series of studies sampling the biochem-ical milieu of myofascial trigger points [TrP].This abstract briefly summarizes their earlyfindings. It was established that by using anovel microdialysis needle, it is possible to ac-curately measure concentrations of various

chemicals including substance P, calcitoningene-related peptide [CGRP], bradykinin, nor-

epinephrine, tumornecrosingfactor-, and inter-leukin 1-. The subjects were divided into threegroups: normal, latent TrPs, and active TrPs.

The researchers found increased levelsof eachof the measured chemicals in the active groupcompared to normal subjects andsubjects withlatent TrPs. In addition, the pH of the TrP sitewas significantly lower in the active TrP group.This abstract included very few subjects. Moreextensive studies are needed to draw any firmconclusions from this new technique. Thesestudies promise to identify many of the sub-stances in the immediate vicinity of the TrPthat are responsible for or contribute to theclinical characteristics. It is possible that the

results of future studies by Shah andcolleaguescould expand the current integrated Trp hy-pothesis and provide new insights in the basicpathophysiology of TrPs. For example, the in-creased levels of CGRP combined with thefinding of a lowered pH may shift the focusaway from presumed excessive release of ace-tylcholine towarda possible impaired functionof acetylcholinesterase, as both CGRP and alowered pH can effectively reduce the func-tion of acetylcholinesterase [JD].

Acupuncture in the Management of Myo-fascial Pain and Headache: J.F. Audette,R.A. Blinder. Current Pain and HeadacheReports 7(5):395-401, 2003.

Drs. Audette and Blinder provide an exten-sive review of the basic principles of variousschools of acupuncture. They explain some ofthe difficulties researchers encounter when try-ing to study the mechanisms and effects ofacupuncture. Considering the conclusions ofMelzack and colleagues that there is a 71 per-cent overlap between acupuncture points and

myofascial trigger points [TrP] and the de-scription of so-called ah shi points, the au-thor suggests that acupuncture should be con-sidered in the treatment of TrPs, especially forthose patients who do not experience completerelief from allopathic treatment or who have apreference for alternative approaches to theirhealth care. According to the theory of ah shipoints, an ah shi acupuncture point can be



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found whenever there is local soreness or pres-sure in the body, irrespective of the classicalacupuncture meridians. Audette and Blindersuggest that unknowingly acupuncturists mayalready treat TrPs, whenever they treat ah shi

points. The efficacy of acupuncture in myo-fascial pain conditions has been not studiedover time. The article by Birch reviewed aboveoffers support for the notion to consider thetreatment of ah shi points, but rejects the find-ings of Melzacks study [JD].

REFERENCES

1. Travell JG, Simons DG: Myofascial Pain andDysfunction: The Trigger Point Manual. Vol. 2. Wil-liams & Wilkins, Baltimore, 1992.

2. Zermann DH,Ishigooka M,Doggweiler R,SchmidtRA: Chronic Prostatitis: A Myofascial Pain Syndrome?Infect Urol. 12(3): 84-92, 1999.

3. Weiss JM: Pelvic Floor Myofascial TriggerPoints:Manual Therapy for Interstitial Cystitis and the Ur-gency-Frequency Syndrome. J Urol. 166(6): 2226-2231,2001.

4. Simons DG, Mense S: Understanding and Mea-surement of Muscle Tone as Related to Clinical MusclePain. Pain. 75(1): 1-17, 1998.

5. Simons DG, Travell JG, Simons LS: Travell andSimons Myofascial Pain and Dysfunction; The TriggerPoint Manual. Vol. 1, 2 ed. Williams & Wilkins, Balti-more, 1999.

6. Baldry PE: Acupuncture, Trigger Points and Mus-

culoskeletal Pain. Churchill Livingstone, Edinburgh, 1993.7. Dommerholt J, Issa T: Differential Diagnosis:

Myofascial Pain, in Fibromyalgia; A Practitioners

Guide to Treatment, (L Chaitow, Editor), Churchill

Livingstone: Edinburgh, 149-177, 2003.8. Melzack R, StillwellDM,Fox EJ: Trigger Points

and Acupuncture Points for Pain: Correlations and Im-

plications. Pain. 3(1): 3-23, 1977.9. Birch S, Felt R: Understanding Acupuncture.

Churchill Livingstone, Edinburgh, 1999.10. Birch S, Ida J: Japanese Acupuncture; A Clinical

Guide. Paradigm, Brookline, 1998.11. Birch S, Jamison RN: Controlled Trial of Japa-

nese Acupuncture for Chronic Myofascial Neck Pain:

Assessment of Specific and Nonspecific Effects of

Treatment. Clin J Pain. 14(3): 248-255, 1998.12. Dworkin SF, LeResche L: Research Diagnostic

Criteria for Temporomandibular Disorders: Review, Cri-

teria, Examinations and Specifications, Critique. J Cranio-

mandib Disord Facial Oral Pain. 6: 301-355, 1992.13. Baker BA: The Muscle Trigger: Evidence of

Overload Injury. The Journal of Neurological & Ortho-

paedic Medicine and Surgery. 7(1): 35-44, 1986.14. Schuller E, Eisenmenger W, Beier G: Whiplash

Injury in Low Speed Car Accidents. J Musculoskeletal

Pain. 8(1/2): 55-67, 2000.15. Gerwin RD, Shannon S, Hong CZ, Hubbard D,

Gevirtz R: Interrater Reliability in Myofascial Trigger

Point Examination. Pain. 69(1-2): 65-73, 1997.16. Gerwin R: A Study of 96 Subjects Examined

Both for Fibromyalgia and Myofascial Pain (Abstract).

J Musculoskeletal Pain. 3(Suppl 1): 121, 1995.17. Donaldson CCS, Sella, GE, Mueller HH: Fibro-

myalgia, a Retrospective Study of 252 Consecutive Re-

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18. Donnelly JM: 2002 Physical Therapy ApproachtoFibromyalgiawith Myofascial Trigger Points: A Case

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