Myofascial syndrome: Response to trigger-point injections

HI

I K

DO LI

LO G, M.D., Ph.D.

Myofascial syndrome: Response to trigger-point injections BRA: Electromyographic recording in 18 patient with

hroni m fa cial pain pr vided objecti e evidence for high level f mu Ie ten ion in place of the previou reliance on ubjective reporting of the pain. The e level declined harply after the inje tion of a local anesthetic at the trigger point, howing that mea urable phy iologic change accompanied th ubjecti e relief reported b the patient. Myofa cial ndrome ( ) i a fru trating and baffling affliction ~ r patient and ph ician alike. I xten ive literature on the t pic ha b en available ince the 19th entury 2 et con iderable confuion till exi t . De pite the fact that the c nditi n i extremel common J the pain is often di mi sed a being p chogenic in nature. I·] Travell, who ha devoted many year to stud ing M S, propo ed that the condition i frequent! not dete ted becau e "recognition of the phy ical basi for the symptom from myofa cial trigger point i

difficult because myofascial structure are not vi ualized by the u ual radiologic examination and becau e no blood or urine te t pinpint the pr blem."] he pointed out that other routine laboratory te ts are u ually negative a wei!.] erum enzyme con entration are normal. 4 Cal ium and pho phoru Ie els are within normal limit, a are the red blood cell count and hemoglobin leveLS The leukocyte count i u uall normal,6 but in acute ca es it may be elevated. s onethele it i po sible to diagno e objectively the patient with

Dr. Hendler i a i rant profe or of psychiatr at The John Hopkins niversity hool of Medi ine and clinical director of rhe Men ana Clinic, revenson Md. Dr. Lon is professor and chairman, Department of eurosurgery, also at Johns Hopkins. Ms. Fink i a research as i tant or rhe Men ana linie. Reprim requesrs to Dr. Hendler at the Mensana Clinic, Greenspring Valley Road, reven on, M D 21153.

MFS. To this end, it is imperative that the pathology of the syndrome be understood. A number of alternative descriptions of the underlying pathology have been proposed; everaJ f them are particularly acceptable in the light of various a pect of treatment of MFS. Cailliet describes the pathology particularly well. 7 Damage to soft ti ue either by trauma or operative procedures, produces extravasation of fluid between the fascial plane. Normally, this mixture of bl d and extracellular fluids is aborbed by the body. Other authors 8 ugge t that an inflammatory reaction ccurs, possibly causing adheion to form. 9 These adhesions may inhibit the normal gliding action of one muscle across another, o that muscle activity in one direction creates abnormal tension on an underlying muscle. This tension create pasm, with a subsequent reduction in the range of motion of both muscles. This reduced range of motion limits activity, and if the mu cle i stretched beyond the limited range, pain is worsened. The site of adhesion becomes the focus (continued)

990

PSYCHOSOMATICS

Myofascial syndrome

of a myofascial trigger point. 7 Alternate theories 9 suggest that a site of irritation within a specific muscle causes chronic tension or pain. With the increase in muscle tension, blood vessels that pass through the interstices of the muscles become compressed and several vasoactive agents are released, including serotonin and histamine, which causes further vasoconstriction, inftammation, and pain. 7 Symptoms, diagnosis, and treatments The patient suffering from MFS typically presents with a dull and aching sensation with occasional sharp shooting pains. 9 In addition, that person often reports stiffness and easy fatigability. 10 The pain is worsened by action, cold and wet weather, movement, and excessive use of the area in question. Heat, massage, warm weather, and inactivity seem to afford some relief, as do muscle relaxants and nonsteroidal anti-inftammatory drugs. 10 Frequent locations in which trigger points are found include the cervical and shoulder girdle regions. The lumbosacral area is another site of MFS, as is the anterior chest wall. The most commonly affected muscles are the quadratus lumborum, the pectorals, the latissimus dorsi, the erector muscle of spine, the trapezius, the levator muscle of scapula, the rhomboids, and the gluteal muscles. s.1I Diagnosis of MFS normally involves examination of the suspected muscles. The trigger point is usually found in a palpable band within the muscle and is extremely tender to the touch. 3 When snapped briskly, a local twitch response is produced. In addition, muscles with trigger points exhibit restricted stretch, limited range of

motion, weakness without atrophy, and no neurologic deficit. 3 Also, pressure on trigger points can cause referred pain, which may radiate in a variety of ways not correlated with classic neurologic pathways. II Indeed, trigger-point pressure mimics a variety of associated painful experiences. 3 In zones of referred pain, the following effects may be observed: (I) diffuse deep tenderness and occasionally cutaneous hyperalgesia, (2) vasomotor and secretory autonomic concomitants (pallor and coldness owing to vasoconstriction, coryza, tearing of the eye, sweating, dermatographia, and pilomotor activation), and (3)

Measurable physiologic change accompanies the subjective pain relief reported by patients who receive trigger-point injections. skeletal muscle spasm. 3 Additionally, pressure on the trigger point often causes pain at a different, frequently distant (3 to 20 cm) location, consistent with the anatomy of the affected muscle. Many alternative modes of treatment of MFS have been proposed and have met with some degree of success, as measured by patientreported relief. These methods include passive stretching of the muscle while spraying a vapocoolant (ethyl chloride), 3 dry needling, 12 sauna, ice massage, and hydrotherapy. Another method is injection of a local anesthetic into a trigger point. 8 Many papers have been written describing the clinical effectiveness of such treatments. However, most

of these studies have been restricted to analysis of subjective reports from the patient regarding the degree of pain relief. The goal of the present research was to provide a quantitative method, utilizing surface electromyography (EMG), for documenting muscle spasm associated with MFS and for quantifying changes in muscle tension in response to trigger-point injections. This information should be useful for further studies in the treatment ofMFS. Subjects and procedures Eighteen patients from 27 to 56 years old and suffering from chronic myofascial pain served as subjects in the study. They had been originally referred to the Mensana Clinic with a diagnosis of "psychosomatic pain." In an attempt to control the variable of different spasm strength in different muscles, patients with pain in a common muscle group had been selected. Seventeen of the 18 patients sUf,; fered from local and referred pain owing to a trigger point in the trapezius. Fifteen of these 17 patients were women. The 18th subject was a man with myofascial pain in the region of right quadratus lumborum muscle. The patients were diagnosed according to the criteria described above. Each subject was placed in a darkened biofeedback cubicle and was unaware of muscle tension readings so that no feedback could occur. Surface electrodes for EMG were placed on the affected muscle group. Standard Cyborg silverplated electrodes were used, with electrode gel as the conductor. The electrodes were held in place with two-sided adhesive disks. Using a Cyborg BioLab 21 computer, EMG recordings were made with a Cy(continued)

NOVEMBER 1983 • VOL 24 • NO II

993

SlNEQUAN Cdoxepin HCI) Reference 1 Barranco SF. Thrash ML Hackell E. Frey J el IlPflzer Pharmaceullcats. PfIZer Inc. New 'lbrk. NY) Early onse 01 response 10 do.ep,n Ireatment J Clm Psych,arry 40 265- 269 1979 BRIEF SUMMARY SlNEOUAN' (doxepln Hel) e-ulea/Oral Concenlr8te ConIraIndlc8tlona. SI EOUAN rS conlralno. led In Ind! dualS whO have shown hypersenSl lo lIle drug F\:)sslb,lity 01 cross sensl ty 'lIl other d benzo eplnes should be eplln mind SINEOUA IS conlralnd,caled In pallents Wllh glaucoma or a lendencYlo Uflnary relenllon These dIsorders shOuld be ruled OUI. paniCUlarly In older p l,enlS w.mIngs. The once-a-day dosage regimen 01 SINEOU In pallenls WIlli In""currenl Illness or pallenlS la Ing olher medic loons should be carefully adJUsled This IS especially pOllanlln patJenls race '"9 other rnedlcallons WIth anllchollnerglC effects lJNge /n CHI/.Ir/OI: The use of SJ EOUAN on a once-aoday dOSage regimen ,n genau,c pallems should be adJUsled carefully based on the pa 'enl's cond,loon lJNge /n Pregnancy: ReproduclJOn studies have been perlormed In rats rabbils. m0nkeys and dogs and I ere was no ""rdence 01 harm 10 !he animal fetus. The ,elevance 10 humans IS not known Srnce thllle IS no expenence In pregnant women whO have reeeived thIS drug. salety ,n pregna.ncy has nol been established There are no data Wllh respecllo lhe secreoon of lhe drug In human mil and lIS elleci on the nurSIng Inlant lJNge In Children: The use 01 SINEOUA in children under 12 years 01 age IS nol recommended because safe condliJonS for 115 use have not bean eslablished MAO /nh/bItorI: Senous SIde elleelS and even dealll have been repO(s Thetelore. MAO ",hibnors should be dlSConllnued alleasllwo weeks prior 10 Ihe cautiOUS Inillaloon 01 lherapy Wllh SINEOUAN The exaci leng 01 lime may vary and 's dependenl upon !he patllcular MAO onhlbllor being used. lhe tenglh 0 lime II has been adrntmstered and the dosaQe ,nvolved UDge with AJcollol: II should be borne ,n mind Ihal alcol1ollngesl,on may Increase lIle danger Inherenl III any ImemlOllal or un,menllonal SINEOUAN overdosage. This 's especially ,mporlant,n pallenlS whO may use alcOhOl excessively. Pr_utlona. S,nce drl7NSlness may occur Wllh Ihe use of this drug. pallenls shOuld be warned of !he posSibility and caullOl1ed aga,nsl drIVIng a ca' or operatIng dangB/OUS machinery whIle la ng lhe drug Pallents should also be caulooned !hal Ihe~ response 10 alcohol may be potentlaled Since sUJclde IS an ."heren risk In any dePfessed patient and may remaIn so until slg"'ficanl Improvemer1 has occurred, pallenls should be closely SUpeMSed dunng lIle early course 01 Iherapy PrescHptlOnS should be '1mllen tor Ihe smallest feasible amount. Should Increased symploms of psychOSIS or shlfl to .manIc symplomatology occur. II may be necessary 10 reduce dosage or add a malOr ltanqUilizer 10 !he dosage 4'

regimen Advwae Reectlona. NOTE: Some of the adverse reacllOOS noled below have nol been specifically reported Wllh 51 EOUA use However. due 10 !he close pharmacological Slmi!anl1es among lIIe lnCychcs Ihe reaClJOllS shOuld be considered when prescroblng SI EOUAN

Anr,chO!IIl
RoeRIG. A division of Pfizer Pharmaceuticals New York, New York 10017

Myofascial syndrome

borg 133 biofeedback machine. Average microvolt readings for ten-second intervals were integrated over the five minutes immediately prior to the trigger-point injections. These. were recorded and retained for comparison with postinjection microvolt readings. Injections were then administered in the following manner: a 24-mm 2 I-gauge needle was inserted directly into the trigger point, which was determined by manual palpation for firm tense bands of exquisite tenderness in the suspect area. A dose of I to 4 cc of 0.5% bupivacaine, a local anesthetic, was then injected into the muscle. As has been noted by other authors, II the patient reacts with an involuntary jump or grunt as the needle impales the trigger point. This re'ponse indicates that the trigger point has been struck at a suitable spot for injection. The instantaneous reaction is often followed by patient-reported relief of some myofascial pain. The corresponding change in muscular activity that accompanies this postinjection relief was recorded in two consecutive five-minute periods immediately following the injection, and compared with the control muscle-tension readings recorded for the five minutes immediately prior to the injection.

Results The results were analyzed with a Student I test for correlated means, since each patient was used as his own control (preinjection vs postinjection muscle tension). The average muscle tension in the conlrol period was compared with that in the five minutes immediately following injection and with that in lhe five to ten minutes postinjeclion. When the control tension was PSYCHOSOMATICS

compared with that in the five minutes after injection, the average value had dropped from 14.47 ,."V ± 8.66 ,."V (range = 4.38 ,."V to 51.58 ,."V) to 5.81 ,."V ± 3.74,."V (range = 2.36,."V to 19.06 ,."V), for a change of 8.66 ,."V (P<.OO2). Occasionally, there was a transient rise in muscle tension, lasting 30 to 150 seconds after the injection. When the control values were compared with the results at five to ten minutes postinjection, the change was even greater: it went from 14.47 ,."V ± 8.66,."V to 4.72,."V ± 3.21 ,."V, for a change of 9.75 ,."V ± 8.14 ,."V

(P<.OOI). (See the Table). Subjec-

tive onset of pain relief varied from nearly immediately (two to three seconds) to five to seven minutes. This effect was not systematically recorded. Discussion It is clear that a measurable physiologic change accompanies the subjective pain relief reported by patients who receive trigger-point injections. Normal resting muscle potential in our experience is 2 ,."V or less. However, the average value for pretreatment muscle tension in

Teble-A In

the Mu.cle Ten

Ion Reedings· Trapezius Muscle

I

Control period Pllllent

..... SD

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17t 18

5toOmin before Injection

010 5 min 8fter Injectton

5 to 10 min after Injection

7.55 22.93 5.64 5.03 11.37 8.50 11.78 15.12 12.57 4.38 51.58 9.50 20.69 22.12 9.82 6.10 26.04 9.82

4.92 3.23 4.47 7.77 5.61 3.79 4.43 9.29 2.44 4.51 19.06 5.28 6.27 2.36 4.46 4.61 4.93 7.16

3.54 3.15 4.49 3.26 4.21 15.84* 3.50 8.71 1.83 3.21 5.55 3.45 4.08 1.31 5.96 3.57 5.04 4.19

14.47

5.81

4.72

± 8.66

± 3.74

±3.21

• Measured 111 microvolts
*

I

our patients suffering from MFS was seven times as high (14.47 ,."V). Values as high as 77.73 ,."V were recorded, probably because of spasm in the affected muscle groups. Injection of bupivacaine reduced the average value by 60% (to 5.81 ,."V) almost immediately, and by five to ten minutes later reduced it even more, to 4.72 ,."V, a value closer to that of the normal resting muscle potential. This seems to indicate that much of the pain deriving from myofascial syndrome correlates with abnormally high muscle tension in the affected muscle, and that injection of bupivacaine is an effective means of obtaining analgesia and reducing spasm. The mechanism for this relief is not well documented, but it has been postulated to derive from relief of transient muscle contractions severe enough to cause microscopic contracture if sustained. 9 The injection of 0.5% bupivacaine may cause moderate to total nerve blocks of peripheral motor nerves,13 even though its major action is thought to be that of sensory nerve block alone, with attendant analgesia. The relief of pain in itself may cause muscle relaxation. The effects of saline injection or sham injection were not tested. While it has been widely accepted that pain is a subjective experience, the use of electromyographic documentation lends objective corroboration to the subjective complaint of pain seen in MFS. Additionally, the objective reduction of muscle tension recorded after trigger-point injections substantiates their value as an effective treatment for what can be a persistent and difficult condition. 0 (continued)

NOVEMBER 1983 • VOL 24 • NO II

~1YJfv1GCAPSUl.ES fAMANTADNE HOI BRIEF SUMMARV OF PRESCRIBING INFORMATION INDICATIONS. Parkmson s D,sease/Syndrome and Drug· Induced ExtrapyramIdal Reac· lIons SVMMETREL IS Indicated ,n the treatment 01 Idiopathic Par"nson's disease (Paral. YSIS Agitans) pos[encephal1flC parkinsonism drug-Induced extrapyramidal reactions and symptomatiC parkinsonism wnreh may fOllOW Injury to the nervous system by carbon monO),loe IntQ)(.lcat,on It 1$ InOlcated In those elderly patIents oel,eved to aevelOP parkinsonism ,n aSSOciation \VIm cereoral arteriOsclerOSIS In [he treatment of Pafll(,lnson 5 disease SYMMETREL ,s ;ess effective than 'evOdopa (·)-3-(3 4·0IhydrOxypnenylj-L·a1an,ne ana Its efficacy In comparison \'olin the anticnOIlnerg1c anti parkinson drugs nas not yet Deen estab·

Iisned AllhOugh antiChOlinergiC type sloe effects have oeen noted With SVMMETREL when

used In patients 'J\;ltn drug-Inducea extrapyramidal reaCtions mere IS a lower InCidence of t/1ese SIde effects than that Observed wITh antiChOlinergiC anti parkinson drugs

CONTRAINDlCATlONS. SVMMETREL IS conl,a,na,cateO In patients ""th ,nown hypersen. Slt,Vlty 10 tne orug WARNINGS, Pat,enlS WIIn a nlSlory of epilepSy or Orner seizures ShOuld oe Observeo closeiy for OOSSIOle ,nCreaseO seizure aC:I .... ,iy Patients With a r"lstOry of congeSllve neart failure or perlpneral edema snould be fOlloweo Closely as the~e are patIents whO oe.... elopec congestive neart failure wnlle recel'.'lng

SVMMETREL Patients ~'llh Pa'kinson s olsease ImprOving on SYMMETREL S'10uIO reSur"1e normal actiVities graoually and cautiously conSistent With orner medical cons,oerat,ons Sucn as tne presence 01 osteoporOSIS or phleoothrombOSIS Patients rece, .... ,ng SYMMETREL wno f'\ote central fler\iOUS s,;'Slem effects or 0 uHlng of VISion snOuld be cauiloned against driVing Or work.lng In Siluat,ons wnere alertness IS Imporrant PRECAunONS, SYMMETREL lamantadlne hydrOChlor,del snOUla 'lOf De dISCD";lnuea aorupt'y Since a few patlenlS ",,"ttl Park.'nson s disease e"per,enceo d park.,nson,an CriSIS I e a sudden markea CliniCal deler,orat,on when tnlS mea,catlon ,-,as Sudden,y stopped The dose of antiChOlinergiC drugs Or Of SYMMETREL snou,o De reduceo II arrcP·ne·llk.e eHeclS appear wnen tnese drugs a'e used concurrently The dose of SYMMETREL may need carelul adJuslment In patients wl\h renal Impalrment congestive hearl tatlure per.pheral edema or orthostatiC nypotenSlon Since SYMMETREL IS nOI rnetaoo:lzeo anOls 'TIaln'y e ... creteo In tne lJflne IT rnJy aCCUmli ate 'Nnen rena, lunCllon IS InaoeQuale Cafe snOuld oe e ... erclSec wnen adm,nls:er,ng SYMMETAEL to pallenls wtn !· .... e' diSease a nlSlory of 'ecu-rent eczematolO rasn or 10 patients WI!h PSyCnOSIS 0' sevele psy· c'oneurOSIS nOI COfltrOlled by cnemotne'apeu!IC agents CarefUl ObServal,on IS requlrec wnen SYMMETREL·s administered conCurrently wltn central nervouS system stlmu:ants No long-term stuoles In animals nave been performed to e.... aluate {ne carCinogeniC potential of SYMMETREL The mulagenlc potential ot me orug n,15 nOI yet oeen delelfTl ned In experimental sys1ems

Pregnlncy CltegOry C: SVMMETREL ,amantaolne hyOrocn,ofloel nas oeen shown

\0

oe emoryoto ... ,c and tpratogenlc In rats alSO mg/k.g/Cay aUOuT 12t,mes me recommended numan cose Out nOI a: 37 mg/kg/Cay ErnbryotO~lc and teratogeniC drug eftec!~ werp flO! seen In rdOOlts >;Vllch reCeived up 10 25 times me 'ecommenoea ~uman cose Tnere are no adequate ana well-controlled studies In pregnanl 'o'\,o""en SYMMETAEL snOUIO oe used during p'egnanc',' on:,.,..,t rne potential oeneflt Jusllf,es me potential fiSk, 10 tne emoryo or {ne 'elus Nursing Mother.: SYMMETREllS e"creleo ,n ndman milk, CdullOr" snOulO oe e,e'C!seo wnen SYMMETAEL IS administered 10 a nurSing ~'omar'\ Pediatric Use: The safety and efficacy of Sy'MME TREL In newborn Inf.1nlS and ,n/anTs Del ow rne age 01 1year have not oeen established ADVERSE REACnONS. The most trequently OCCurring seriOUs aoverse reactions are depreSSion congesllve tlear! la,lure or(tlos{atlc nVpolellslve episodes PS..-CtlO$IS and urina'y'€,lentlon Rarely convulSions '€ul<.OOenl<1 Jnd neutropenia n,l.... €' Deen 'cportea Orner ad.... e'se 'eaC,Qns of 'ess seriOUS nJture ',\Inlcn ndve oeen ouserveo Cl'e the fol, OWing ha:!uClnaflons confUSion an'(Iet~ cind IH'!,:Wdil.,.. cinore),la n~1used and const,p
Myofascial syndrome

REFERENCES 1. Simons 00: Myolascialtrigger points: A need lor understanding. Arch Phys Med Rehabil

62:97-99, 1981.

2. Simons 00: Special review: Muscle pain syndromes. I. Am J Phys Med 54:291-300, 1975. 3. Travell J: Identilication 01 myolascial trigger. point syndromes: A case 01 atypical lasclal neuralgia. Arch Phys Med Rehabil 62: 100-

106, 1981. 4. Ibrahim GA. Awad EA. Kottke FJ: Interstitial myolibrositis: Serum and muscle enzymes and lactate dehydrogenase-isoenzymes.

Arch Phys Med Rehabil55:23·28. 1974.

5. Abel O. Siebert WJ. Earp R: Fibrositis. J Miss State Med Assoc 36:435·437. 1939.

6. Long C: Myolascial pain syndromes: I. General characteristics and treatment Henry

Ford Hosp Med Bull 3: 189·192. 1955.

7. Cailliet R: Soft Tissue Pain and Disability. Philadelphia. FA Davis. 1977, pp 32·37.

8. Awad EA: Interstitial myofibrositis: Hypothesis 01 the mechanism. Arch Phys Med Rehabil

54:449-453. 1973. 9. Simons DG: Special review: Muscle pain syn· dromes. II. Am J Phys Med 55: 15·42. 1976. 10. Hendler N: Commonly misdiagnosed pain syndromes: Detection and treatment. in Hendler N (ed): DiagnosiS and Nonsurgical Management ot Chronic Pain. New York, Raven Press. 1981, pp 218-225. II. Brown BA: Diagnosis and therapy 01 common myolascial syndromes. JAMA 239:646-648.

1978. 12. Melzack A: Myolascial trigger points: Relation to acupuncture and mechanisms 01 pain. Arch Phys Med Rehabi/62:114-117. 1981. 13. Physicians· Desk Reference. ed 36. Oradell. NJ. Medical Economics, 1982, pp 711·713.

,i

DOSAGE AND ADMINISTRATION. Adult Oollgelor Plrklnsonism: Tt,e usual aose 01 SYMMETREL I amanli1dlr')e nydlachlo'lde)IS 100 mg twice a day ""nen usee alone> SYMMETREL nas an onset 01 action usually Within 48 nOurs Tne Inlt,a, dose Of SYMMETREL IS 100 mg dCllly for pat,en!s .....,Ih sellOUS aSSOCiated medlGi' I'lnesses Or whO dre recel .... lnO high doses of orner antlpark,lnson drLJg~ Alief one to se.... ('rdl weeks at 100 m::-l once daily rtle dose may De Increaseo 10 100 mCj lWlce aa,ly It 'l€CeSsary OCC,lslonally pat,enls whose responses dre not OQ!lmal ......11h SYMMETREL at 200 mg dad~' may benetl! frOIn an Increase up to 400 mg dally In dr"lded doses Howevel SuCtl paTients SrlOuld oe supen,i1sed clOsel~ by their pnyslclans P,lllents Inlll£1l:y C1€'r1 .... ,nq benefl! from SYMMETAEL not uncommonly e.perlence a tall-olt of elfeCli'lie('leS5 alter .-ltew monftls Benetl! rncly oe fegalned 01' IncreJSlflg me dose to 300 'llg dally ,,\ lern:11lvely Tempofary dlscontlnUa!lon ot SYMMETAEl fOI severa' ..veeks !ol;O'o"o'ed hy reIniTiaTion Of Tne (1rug may reSUI!ln regaining beneflf In some patients A decl~Ior. ro use otner antlpark"nson drugs m.1y oe necessary Dosage 'or Concomitant Therapy: Some patients whO dO no! respond to anl'CnOllner OIC ,lnliparl
me

With the addition ot SVMMETREL Oosege lor Drug·lnduCed Extrlpyramidll Relcllons: Adult The usual dose 01 SYMMETAEL (amantadine nydrochlOflde) IS 100 mg tWice a day OccaSionally patIents whose responses are not opllmal With SYMMETREl al 200 mg dally may benefit tram an Increase up to 300 mg dally In diVided doses 6043-10BSP Capsules manufJClured lly A P SCherer·NOrih Ameflca St PeTersburq FlorIda 33702

lor

Du Pont Phannaceuticals

Bloch_ Depertment E.!. duPont de l'Iemours £, Co. (Inc.) Wllmln(ll_. DeII.lre 191M

999