trigger points - extracorporeal shock wave therapy€¦ · myofascial trigger points ... who were...

Der Orthopäde 2 2012 113

Key Topic

Orthopäde 2012 41:113-125DOI 10.1007/s00132-011-1860-0Online publication date 18 Feb. 2012 Springer-Verlag 2012

M. Gleitz1 K. Hornig2

1Orthopaedic Surgery, Luxembourg

2Orthopaedic Surgery, Saarbrücken

Trigger points – Diagnosis andtreatment concepts with specialreference to extracorporeal shockwaves

Myofascial trigger points (MTrPs)have had an unsteady history interms of the evaluation of theirmedical significance since theywere first described 70 years ago[73]. Despite its prominence, thetrigger point theory, originallydeveloped for medical diagnosisand therapy, used to be disputedby medical professionals for manyyears on grounds of lack ofobjective verifiability and scientificevidence. Among doctors, triggerpoint therapy was only performedby a small group of specialistswho were highly skilled in manualtechniques and focused on func-tional treatments, improving theprocedure on the basis of varioustherapy approaches [1, 10, 25, 32,53, 71]. At the same time, triggerpoint therapy became a standardprocedure in paramedical symp-tom-oriented treatment, which hasachieved widespread acceptanceamong patients as a result of itsexcellent success rates [24].

Renaissance of trigger pointtherapy

During the last decade, trigger pointtherapy has been increasingly usedby orthopaedists practising conser-vative treatment as a new procedurewith shock wave application. This isthe result of two parallel scientificdevelopments. One is muscle painresearch, which during the last 30years has come to consider musclepain as a form of pain of its own [46]that is distinctly different from nerveand organ pain.

The other is the wider use of extra-corporeal shock wave therapy toinclude the treatment of the mostdiverse types of tissue: tendons [5,18, 51, 56], bones [7], skin [59],cardiac muscle [80] and, morerecently, skeletal muscles.

As a result, shock wave treat-ment of skeletal muscles representsan empirically extended indication forregenerative shock wave therapy.During the last few years, it hascome to be referred to as "triggerpoint shock wave therapy" becauseshock waves – better than any othermethod – are able to induce thereferred pain that is characteristic oftrigger points and treat the clinicalsymptoms associated with thesetrigger points [4, 22, 47].

Myofascial trigger points(MTrPs) and muscle pain

Trigger points are hyperirritablepainful sites in a muscle that occur inthe form of mostly palpable localindurations in a taut band ( Fig. 1).

Trigger points are a specific typeof ischaemic local muscle pain andare frequently associated withreferred pain. Contrary to normalmuscle pain, muscular trigger pointshave a limited self-healing capacity.

Pathophysiology of musclepain

Muscle pain is mediated through theexcitation of nociceptors by vaso-neuroactive substances (bradykinin,prostaglandin, serotonin, histamine)and high concentrations of potassiumand H+.

Fig. 1 Trigger point complex. Left: Macroscopic muscle knot (central trigger point)located in the taut band. Right: Magnified detail with contraction knot resulting fromlocal sarcomere contractures within individual muscle fibres. (modified from [66],courtesy of Level10 Buchverlag, Heilbronn)

Taut band

Muscle knot(centraltrigger point)

Contractionknot

Normalmuscle fibre

114 Der Orthopäde 2 2012

Key Topic

Fig. 2 Convergence-projection theory. By opening ineffectivesynapses (B), the nociceptive excitation of a proximal muscleaffected by trigger points and normally connected with the spinalcord via dorsal horn neuron 1 is centrally transmitted via dorsal hornneuron 2 of the distal muscle. TrP trigger point. (modified from [46],courtesy of Level10 Buchverlag, Heilbronn)

Referred pain is primarily induced inthe trigger point itself. However, itcan also be evoked at a distance ofup to 4 cm from the trigger point,more frequently around active triggerpoints (47 %) than around latenttrigger points (23 % [29]). Thedegree of local and referred painperceived and its extension dependon the extent of trigger point irritationand not on the size of the muscle.Moreover, referred pain is alsodetermined by the external pressureapplied during the examination.

Referred pain is not specific tothe myofascial pain syndrome. It canalso originate in tissue other thanmuscles, such as large joints, facetjoints, ligaments, periosteum,fasciae, tendons, scars andespecially inner organs.

This means that muscularreferred pain is a characteristic butunspecific symptom, which frequentlyrequires extensive differential diag-nosis [46, 60].

Pathophysiology of myo-fascial trigger points

According to the acknowledgedtrigger point hypothesis [66], triggerpoints originate from local sarcomerecontracture caused by an excessiverelease of acetylcholine at the motorend-plate due to overuse or trauma( Fig. 3). Strong muscular con-traction causes intramuscularvascular compression and, conse-quently, local ischaemia, which re-leases vasoneuroactive substancesand causes severe local pain at thetrigger point. The resulting neuro-genic inflammation with tissueoedema aggravates the energycrisis, preventing the uptake of cal-cium into the sarcoplasmic reticulumand, consequently, the elimination ofthe sarcomere contracture. Thisresults in a vicious circle of persistingtrigger points.

Recent in-vivo examinations ofhuman tissue have revealed in-creased levels of vasoneuroactivesubstances in the immediate vicinityof trigger points, which can be con-sidered to confirm the trigger pointhypothesis [61].

The vasoneuroactive substances arereleased by subjectively painful andobjectively tissue-damaging stimuli.

Muscle nociceptors, once acti-vated, release neuropeptides (sub-stance P, calcitonin-gene-relatedpeptide [CGRP] and somatostatin),which lead to the formation of localtissue oedema. This phenomenon,which is referred to as neurogenicinflammation [79], does not causeany severe spontaneous pain, butrather dysaesthesia and a feeling ofweakness.

In most cases, painfulness endswith the formation of local tissueoedema, and the lesion is repaired.In adverse conditions, however, theoedema may grow in size and thuscause a vicious circle. According toTravell and Simons [72], this mecha-nism is co-responsible for the forma-tion of trigger points.

Longer-lasting sensitisation ofmuscle nociceptors gives rise to twoclinical phenomena: hyperalgesiaand allodynia. Persistent muscle painis characterised by a high degree ofsubjective suffering. If it persists forover six months, it often becomestherapy-resistant and frequentlyresults in pain chronification [46].

Referred pain

A peculiarity of muscle pain is itsability to induce referred pain inremote deep subcutaneous tissue(muscles, tendons, fasciae, joints –excluding the viscera) or in the skinwithout any primary nociceptiveirritation. Pain referral is character-istic of muscular trigger points. It isexplained on the basis of the conver-gence-projection theory [57] whichstipulates that afferent nociceptiveinformation from the muscle takes awrong path in the spinal cord andreaches somatotopically unrelateddorsal horn neurons ( Fig. 2). Inpatients, this results in erroneouspain localisation in the brain. Thereare characteristic pain referralpatterns for almost all muscles of themusculoskeletal system.

» A peculiarity of muscle

pain is its ability to inducereferred pain.

Referred pain primarily occurs whenlocal muscle pain is very intense orwhen it has persisted for a longperiod of time or has been triggeredrepeatedly.

Ascendingdorsal hornneurons

Spinal cord

LesionTrP

Proximalmuscle

Distalmuscle

A Regular connection with dorsal horn

B New connection of distal musclewith dorsal horn


Abstract

Activators

Trigger points are found to a higherdegree in people who engage in littlephysical activity in their everydaylives, but have occasional intervals ofsevere physical strain. Musclesprimarily affected by trigger pointsinclude the postural muscles in theneck, shoulder and pelvic girdle.

In most cases, trigger points areactivated by acute, persistent orrepeated mechanical overstrain. Inaddition to this, there are perpetu-ating and aggravating factors, whichare frequently different from triggerpoint activators.

Acute muscular overstrain occursas a result of direct trauma (sprain,torn muscle fibres, crush) or eccen-tric and concentric contractions andcauses damage to the muscle cellmembrane. Persistent overstrain iscaused by postural anomalies.Repeated overstrain occurs in caseof weak muscle contractions(repetitive strain injury). It isexplained with the "Cinderellahypothesis" [26] which postulatesthat selective overloading of thesmall type 1 muscle fibres occurs.

Moreover, trigger points are aconcomitant of the following dis-orders:

― postural anomalies,

― osteoarthritis,

― tendinitis,

― discopathy,

― radiculopathy,

― peripheral nerve compressionsyndromes,

― blood circulation disorders.

Other activators and perpetuatingfactors include visceral, rheumatic,endocrinological and oncologicaldisorders, nutritional deficits (lack ofvitamins B1, B6, B12, folic acid,vitamins C and D, iron, magnesium,zinc) as well as general pain syn-dromes. Moist and cold climaticconditions have an additional nega-tive effect. Since the severity oftrigger point symptoms is primarilymodulated by the autonomic nervoussystem [16], stress, lack of sleep andpsychological and psychiatric dis-orders also play a key role.

Orthopäde 2012 41:113-125 DOI 10.1007/s00132-011-1860-0 Springer-Verlag 2012

M. Gleitz K. Hornig

Trigger points – Diagnosis and treatment concepts with specialreference to extracorporeal shock waves

AbstractThe 70-year-old trigger point theory hasexperienced a growing scientific con-firmation and clinical significance as aconsequence of recent muscle painresearch. The trigger point pain forma-tion is caused by high levels of vaso-neuroactive substances. Depending onintensity and duration of the musclestimulus the central pain processing ismodified and leads to characteristicreferred pain patterns. The most effec-tive conventional forms of treatment areaimed at a direct mechanical manipula-tion of the trigger point as are newforms of therapy with focused andradial shock waves. By using highpressures the focused shock waves inparticular are suitable to provoke local

and referred pain and thus simplify thetrigger point diagnosis. The empiricallyfound therapeutic effect of shock waveson muscles is hypothetical and can beexplained in analogy with validatedreactions of shock waves in non-muscle tissues. Overall, the shockwave therapy on muscles represents aconfirmation and extension of theexisting trigger point therapy. It seemsto be suitable for treating functionalmuscular disorders and myofascial painsyndromes within the locomotorsystem.

KeywordsTrigger point Extracorporeal shockwave Muscle Myofascial pain Referred pain

Differentiation of triggerpoints

Different types of trigger points aredistinguished by the clinical symp-toms they present.

― Active trigger points are symp-tom-producing trigger points thatmay cause spontaneous local orreferred pain and paraesthesia.Active trigger points generallydevelop at middle age and causepain.

― Passive (latent) trigger points areclinically inapparent triggerpoints, but have the same poten-tial as active trigger points whenprovoked by pressure or tension.They usually develop at an ad-vanced age in life and manifestprimarily through limited mobility.

― Satellite trigger points develop inthe area of pain referred by aprimary trigger point.

― Secondary trigger points occur inmuscles that are adjacent to aprimary trigger point location(synergists, antagonists). Theydevelop as a result of a motiondisorder caused by a primarytrigger point.


Key Topic

Fig. 3 Integrated hy-pothesis of trigger pointformation: this hypothesispostulates that the energycrisis causes nociceptionby the release of sensi-tising substances andprevents actin-myosinseparation. CGRP "calci-tonin-gene-related pep-tide". (modified from [66],courtesy of Level10 Buch-verlag, Heilbronn)

Symptoms

The clinical symptoms of triggerpoints are manifold. Most impor-tantly, they cause pain perceived asdeep local tissue pain or referredpain, which may be partly disablingand which is similar in intensity to aheart attack, bone fracture or colic.Besides pain, trigger points alsocause sensory, motor and auto-nomous disorders. Sensory distur-bances imitate neurological loss withtemporary numbness and paraes-thesia (dysaesthesia, hypaesthesia).Owing to central and peripheralsensitisation, trigger points also leadto hyperalgesia and allodynia.

Motor deficits manifest ashypertonia, stiffness, muscle short-ening, muscle weakness (reflexinhibition without atrophy), coordi-nation disorders, excessive activity,early fatigue and delayed recoveryafter strain [46].

In very rare cases, autonomousdisorders may be accompanied bychanges in skin temperature result-ing from vasoconstriction or vaso-dilation, lacrimation, piloerection andproprioceptive deficits with unsteadygait, vertigo and tinnitus. Finally,direct pressure on trigger pointsduring sleep may cause sleep distur-bance.

Long-term sequelae

If the disorder persists for a longtime, the trigger point may experi-ence structural, partly irreversiblealterations. Biopsies of muscularcontraction knots have revealed aloss of myofibrils and an empty sar-colemma [54, 77].

Disorders resulting from muscleoverload occur in the areas sur-rounding the trigger points. Thesefunctional deficits spread from onemuscle to another and thus give riseto muscle chain reactions [40].

Where tendons are affected, theoverload will cause insertional tendi-nitis [25] and attachment triggerpoints [50].

The point in time at which thesesequential changes occur is impos-sible to predict.

Prevalence

Muscle pain, besides joint pain, isone of the main causes of muscu-loskeletal diseases requiring treat-ment [58]. It is the main reason whypeople need to see a doctor, takesick leave or file disability claims [67]and affects up to 85 % of the popu-lation [64]. Owing to its high preva-lence, the treatment of muscle painposes both a medical and a socio-economic challenge. Myofascialtrigger points play a key role in thegenesis of muscle pain [65].


Advertising space Diagnosis

Muscular trigger points are diag-nosed primarily by history and on thebasis of clinical criteria [10, 32, 53].Laboratory diagnosis, currentlyavailable imaging techniques andelectromyography are not suitable foridentifying trigger points in dailyclinical practice.

So far, no uniform internationalstandards have been established forthe diagnosis of muscular triggerpoints [70]. The criteria generallyadopted are the localisation of triggerpoints by palpation of painful spots intaut bands and the recognition of theinduced pain. Characteristics includereferred pain, twitch response,restriction of mobility by muscleshortening, muscle weakness withoutneurological loss and diagnosedautonomous disorders.

Owing to the subjective nature ofpalpatory examination, the majorityof examiners find it difficult to diag-nose trigger points [30]. This hasalso been confirmed by recent reviewarticles which criticise the quality ofstudies that paint a positive picture ofthe reliability of manual palpation [42,48]. Trigger point specialists, how-ever, attribute high intertesterreliability to the manual examinationmethod [11].

After the introduction of extra-corporeal shock wave therapy in thetreatment of myofascial syndromes,diagnostic options have also in-creased. According to the experiencegathered by the authors of thisarticle, especially focused shockwaves, which can reach peakpressures of between 10 and 100megapascals (MPa), enable easyand precise induction of local andreferred pain. This is attributable tothe fact that the intensity of localmuscle pain and the strength of thepressure applied determine theseverity of referred pain (see"Referred pain" section for details).

Trigger points and acupunc-ture

Over 90 % of trigger points coincideanatomically with acupuncture pointstreated for musculoskeletal painrelief. The clinical correspondence oftrigger points and acupuncture pointsin terms of the local pain indication is70 to 80 % [12, 45].

Muscles affected by pain referralfrom trigger points and the paths ofacupuncture meridians have an over80 % overlap rate [13]. These inves-tigations suggest that the modernapproach to myofascial pain and the2000 years old system of meridiansdescribe an identical pain mecha-nism [13, 32, 53].

Classic MTrP therapies

Trigger point therapy has a twofoldpurpose: to alleviate pain and topermanently eliminate the triggerpoint complex. To achieve theseobjectives, trigger point therapy usestreatment modalities aimed atbreaking the vicious circle describedin the integrated trigger pointhypothesis through

― separation of fixed actin-myosinlinks [71],

― elimination of contraction knots[46],

― improvement in local blood circu-lation through reactive hyper-aemia and resolution of theischaemia-induced energy crisis[63],

― reduced concentration of vaso-neuroactive substances [61],

― muscle relaxation.

Among the non-invasive proceduresemployed, manual therapy tech-niques, including massage, trans-verse friction, ischaemic compres-sion, release, spray and stretch andauto-stretching, play a dominatingrole [9, 39, 71).

Invasive treatments performedare trigger point injections with localanaesthetics [73], normal salinesolution [15], corticosteroids [52],botulinum toxin A [78] and dryneedling [69]. Invasive treatmentsare described to be more effectivethan non-invasive methods [35].Injections generally give betterresults than dry needling [36]. Acombination of lidocaine with corti-costeroids provides fast pain relief[74]. As far as dry needling is con-cerned, the deep method has shownto be more effective than superficialdry needling [33].

The methods used to reduce painsymptoms include ultrasound, elec-trotherapy (TENS, microcurrent) andlaser.


Key Topic

Fig. 4 Pressure graph of different types of shock waves. Left: focused shock waves(f-ESWT). Right: radial shock waves (r-ESWT). (courtesy of Level10 Buchverlag,Heilbronn)

Based on the knowledge andinformation gathered to date, thefollowing mechanisms of action ofshock waves in muscle treatmentcan be discussed:

― separation of fixed actin-myosinlinks by the input of mechanicalenergy perpendicular to themuscle fibre direction [61, 71],

― improvement of blood circulationthrough reactive hyperaemia andangioneogenesis [38, 61, 76],

― dilution of vasoneuroactive sub-stances as a result of reactivehyperaemia [46, 61],

― pain modulation through releaseof substance P [28, 43] andCGRP [68],

― pain modulation through releaseand synthesis of nitric oxide [44,49],

― selective degeneration of C-fibres[27],

― pain modulation according to thegate control theory [23, 75],

― biological mechanotransduction[31, 34, 49].

Research conducted by Shah et al.[61, 62] provides extensive informa-tion on the trigger point phenomenonand indirectly confirms the previouslycited theories. In fact, these studiesrevealed a significant reduction invasoneuroactive substances andneuropeptides after dry needling.These changes were similar to thoseassociated with the pain modulationeffect of focused shock wavesapplied to non-muscular tissue [27,28, 43, 49, 68, 76].

Focused (f-ESWT) and radialshock waves (r-ESWT)

Shock waves are acoustic wavescharacterised by high peakpressures (10 – 100 MPa forf-ESWT; 0.1 – 1 MPa for r-ESWT),short rise times (10 – 100 nano-seconds [ns] for f-ESWT; 0.5 – 1milliseconds [ms] for r-ESWT), shortduration (0.2 – 0.5 microseconds [s]for f-ESWT; 0.2 – 0.5 milliseconds[ms] for r-ESWT) and a low tensilewave component (negative pressure)which is 10 % of the peak pressure( Fig. 4). Shock waves propagatethrough a medium without any lossand without any changes in theacoustic impedance and release theirenergy at acoustic interfaces.

Medication-based treatment withparacetamol, NSAIDs, metamizol,muscle relaxants, tricyclic anti-depressants and opioids is effectiveas adjuvant therapy, but alone is notsufficient to ensure successful triggerpoint treatment.

Various follow-up measures arerecommended: repeated slightmovement over the full range ofmotion, moist heat, electric stimu-lation aimed at slight cyclic musclecontraction and biofeedback.

Overall, the clinical evidence ofthe various treatment options fortrigger point therapy is not strongenough to allow evidence-basedguidelines to be established. Judgingby the results of a questionnairesurvey, the majority of medicaltherapists are not satisfied with thetherapy options available at themoment [14].

Shock wave application tomuscles

Muscle treatment with focused shockwaves (f-ESWT) was first discussedin individual publications in the late1990s [37, 41]. This method wasdeveloped as an alternative tomanual trigger point treatment, whichbasically consisted in applying exter-nal mechanical energy to the muscle.The objective of these treatmentswas to alleviate pain and to reducemuscle tone and muscle shortening.

The consistent use of shockwaves in orthopaedics for the treat-ment of myofascial syndromesstarted in early 2000. Initially, radial

shock waves (r-ESWT) were used forthese applications [2, 19], butfocused shock waves (f-ESWT)followed shortly after [3, 4, 22, 47].

The shock wave systemsemployed in muscle treatment arethe same as those originally devel-oped for traditional indications ofshock wave therapy. Based on theresults of scientific studies into thetissue compatibility of shock waves,the recommended energy level forshock wave application should bebelow 0.5 mJ/mm². All other treat-ment parameters and applicationtechniques have been determinedempirically so far [20, 21].

In order to maximise treatmentsafety and standardise shock wavetherapy, DIGEST e. V. (German-speaking International Society forExtracorporeal Shockwave Therapy,www.digest-ev.de) has establishedguidelines for the treatment of differ-ent types of tissue, includingmuscles. These guidelines have alsobeen adopted by the ISMST (Inter-national Society for Medical Shock-wave Treatment, www.ismst.com).

Hypothetical mechanisms ofaction

The mechanisms of action of shockwaves in skeletal muscle treatmenthave not been fully established. Toexplain the clinical success of thistherapy, the validated effects ofshock waves on non-muscular tissueare taken as a basis [17, 55] andassociated with the pathophysi-ological mechanisms of painful spotsin muscles.


Fig. 5 Comparison between focused (f-ESWT) and radial (r-ESWT) shock waves.Left: f-ESWT with deep focus in tissue. Right: r-ESWT with radial shock wave propa-gation, small penetration depth and maximum energy at the skin surface whichdecreases with depth. (courtesy of Storz Medical AG)

After pain has been reduced by over50 %, treatment is continued in thesame manner on the next painfulspot. Treatment frequency variesbetween 1 or 2 sessions a week forchronic disorders and daily sessionsfor acute pathologies. In general, 4 to10 sessions are necessary permuscle region.

Radial shock waves are usedprimarily for therapy purposes, espe-cially for the local treatment of triggerpoints at high energy levels and forlarge-area muscle smoothing atlower energy settings.

After preliminary palpation, hard-ened muscle regions are treatedlocally with 500 to 1000 shockwaves. Again, the energy level useddepends on the patient's level ofperceived pain intensity. Smallermuscles are treated with 2.0 to2.6 bar, larger muscles with 3.0 to4.0 bar. The shock frequency is 4 to20 Hz.

Large-area muscle treatment inmuscle fibre direction after the localtreatment of several painful spots isperformed at low energy levels ofbetween 1.2 and 1.8 bar. Dependingon the size of the muscle, 1000 to4000 shock waves are applied bymoving the shock transmitter slowlyin muscle fibre direction from thedistal to the proximal end. The shockfrequency is 10 to 20 Hz. The treat-ment frequency per muscle region isthe same as for f-ESWT.

Contraindications and diag-nosis

According to DIGEST (www.digest-ev.de) and ISMST (www.ismst.com)guidelines, the structures listedbelow should not be in the shockwave focus for longer periods andare therefore to be consideredabsolute contraindications to shockwave therapy:

― malignant tumours,

― pulmonary tissue,

― epiphysial plate

― large vessels,

― nerves.

Antithrombotic therapies repre-sent relative contraindications.

In view of the cited contraindi-cations, recommended basic diag-nostic procedures include an X-ray ofthe target region and ultrasoundexamination of the local soft tissue. Ifnecessary, additional imaging tech-niques must be used.

Focused and radial shock wavesdiffer in the way they are generated.Focused shock waves are generatedelectrically in a therapy head (elec-trohydraulic, electromagnetic orpiezoelectric principle) and thenconcentrated in a therapeutic focuslocated in the tissue by opticalreflection ( Fig. 5 left).

This explains the beneficialproperty of focused shock waves toirritate trigger points with high localtissue pressures and to induce localand referred pain. Their disadvan-tage is that they can only be appliedto a small treatment zone.

In physical terms, radial shockwaves are ballistic pressure waves.They are generated by the collisionof solid bodies. A projectile isaccelerated by compressed air andhits a shock transmitter. At the skinsurface, this transmitter transmits itskinetic energy in the form of a radialpressure wave which propagatesdivergently in the tissue. The energyintensity reduces with the square ofthe distance from the skin surface( Fig. 5 right; [8]).

Radial shock waves can be usedon extensive muscle regions.

The disadvantages are their minimalpenetration depth and the fact thatthey cannot be focused in the tissue,which explains the lower frequencyof pain referral.

Extracorporeal shock wavetherapy of skeletal muscles

Focused shock waves can be usedfor both diagnosis and therapy. Afterinitial palpation, the muscle to betreated is examined with shockwaves to identify local and referredpain. The objective is to enablepatients to recognise the inducedpain as part of the pain that hascaused them to seek medical treat-ment. The actual therapy sessiontakes place immediately afterwardsto keep track of the identified painregions. Treatment is performedapplying 300 to 600 shock waves atan energy level of 0.1 – 0.35 mJ/mm²and a frequency of 4 Hz. Theselected energy level depends on thepain intensity perceived by thepatient in the target area. Pain israted on the basis of a VRS (verbalrating scale) from 0 to 10, and theenergy level used should notproduce pain exceeding levels 5 to 8on the VRS.


Key Topic

Fig. 6 Haema-toma colour changesin gluteal muscleregion after radialshock wave appli-cation (r-ESWT)

Fig. 7 Dorsal painreferral from de-scending part oftrapezius muscle.Yellow stars: triggerpoint sites frequentlyidentified with shockwaves. Yellow rec-tangles: typical re-gions of referred painidentified with shockwaves. Blue clouds:regions of referredpain described byTravell. (courtesy ofLevel10 Buchverlag,Heilbronn)

Adjuvant stretching treatmentsshould be performed after the shockwave therapy session in order tomaintain the reduction in muscletone. In the treatment of joint block-age, manual therapy may provebeneficial after the first 2 to 3 shockwave treatments and initial muscletone reduction. Moreover, manycolleagues suggest combination withacupuncture and osteopathy.

Medical strengthening therapy(MST) performed 1 to 2 days after ashock wave treatment session isanother possible option. However, itis important that during the entireshock wave therapy period and up tosix weeks after its terminationpatients should not train at theirmaximum strength level and maxi-mum muscle shortening to avoidactivation of new trigger points [6].

Insertional tendinitis, which fre-quently develops in chronic syn-dromes, requires separate treatmentbecause its nociceptive activity wouldinterfere with the muscle therapy.

Patients suffering from chronicpain syndromes and severe painshould use NSAIDs or paracetamolshortly before and the day aftershock wave therapy. Where neces-sary, adjuvants such as myore-laxants, antidepressants or neuro-leptics can be used.

Local anti-inflammatory infil-trations at the target sites prior toshock wave therapy should beavoided.

Clinical examples

According to the experience gath-ered by the authors of this article,shock wave therapy has proved toprovide good results in the treatmentof all acute and chronic conditions ofmuscular dysfunction with increasedmuscle tone and muscle shortening,provided that there is no dominantpathology that permanently irritatesthe muscle and that the muscle doesnot present any structural damage.Indications include:

― chronic and acute medial andlower cervical syndrome withbrachialgia, dorsalgia andcephalalgia,

― periarticular shoulder pain withrestricted mobility,

― tendomyopathy of forearmextensors and flexors with andwithout radial epicondylopathy,

Side effects and complications

If the energy level selected for shockwave therapy is too high andlocalisation is incorrect, compli-cations such as pneumothorax,tissue and organ bleeding or neuraldamage may occur. This appliesespecially to focused shock wavetherapy.

Still, serious complications areunlikely to develop during shockwave therapy if the correct appli-cation technique, energy level andpenetration depth are used.

However, temporary side effectshave been found to occur in manycases, and patients should be madeaware of them before treatment isstarted. During the first 1 or 2 daysafter the treatment, local pain mayworsen temporarily.

In many patients, the applicationof radial shock waves causes imme-diate local skin reddening, pressuremarks caused by the shock trans-mitter and haematoma colourchanges ( Fig. 6) which usuallypersist for 1 to 2 weeks. When shockwaves are applied to the upper cervi-cal region, headache and temporaryear sounds may occur or worsen.

Concomitant therapies

In general, no concomitant muscletreatments are necessary duringshock wave therapy. Wheneveradditional treatment methods beyondshock wave application are used,any risk of muscular "overtherapy"should be avoided. This is crucialbecause shock waves already pro-duce a strong tissue stimulus.


Fig. 8 Pain referral pattern fromdescending part of trapezius muscle tothe lateral and ventral aspects. (cour-tesy of Level10 Buchverlag, Heilbronn)

― dorsalgia,

― chronic and acute lumbago withand without pseudoradicularirradiation,

― adductor tendinopathy andshortening,

― shortening of thigh extensors andflexors in cases of patellarchondropathy and patellartendinitis,

― peroneal muscle and anteriortibial stress syndrome,

― shin splint,

― calf muscle shortening withtendency to cramp, with andwithout achillodynia,

― shortening of plantar foot mus-cles with and without plantarfasciitis,

― metatarsalgia,

― sports injuries without structuralmuscular discontinuity.

Cervical syndrome withbrachialgia, dorsalgia andcephalalgiaCervical syndromes are among themost frequent indications forsuccessful shock wave therapy.Muscular disorders associated withthese syndromes manifest as painand restricted mobility.

Fig. 9 Pain referral from dorsalgluteal muscles. (courtesy of Level10Buchverlag, Heilbronn)

» Cervical syndromes are

frequent indications for suc-cessful shock wave therapy.

The referred pain induced by shockwaves is mostly consistent with thepain information provided by patientsand has a high level of recognition.Shock waves are applied bothlocally, using focused shock waves,and to larger target areas, usingradial shock waves.

Owing to the great number ofpotential target regions, the musclesto be treated must be selected care-fully. The descending part of thetrapezius is among the most fre-quently affected muscles. It isresponsible for local pain as well asfor pain referral to the thorax, armand head. Trapezius muscle short-ening causes restriction of rotationon the affected side and reducedlateroflexion on the opposite side.

Localisation of trigger points. Inthe neck angle and in lateral direc-tion. Paravertebral region at the C4-7level and in lateral direction up to theacromioclavicular (AC) joint. In theentire ventral muscle portion. Sincetrigger points are distributed over theentire muscle, systematic musclescanning with shock waves is neces-sary.

Fig. 10 Pain referral from lateralgluteal muscles. (courtesy of Level10Buchverlag, Heilbronn)

Referred pain induced by shockwaves is different from the painresulting from manual provocation.Contrary to reports in many medicalpublications dealing with the triggerpoint phenomenon, pain is hardlyever referred to the head. In manycases, the severity and frequency ofoccurrence of headache diminish asa result of the muscle treatment.

Pain referral patterns. (see( Figs. 7, 8).

The most frequent pain referral isto the dorsal interscapular region upto the level of the medial and inferiorscapula, occasionally up to the tho-racolumbar junction. Potential re-ferred pain can be induced in allmentioned locations.

The second most frequent painreferral, which primarily originatesfrom the ventral aspect of the trape-zius muscle, is to the medial lateralthorax along the axillary line andventrally to this line.

The third most frequent painreferral is to the supraclavicular andsubclavicular regions of the ventralthorax, to the medial aspect of thepectoralis muscle and to the para-sternal region. Pain referral to thethorax is suspected to originateprimarily in the free ventral musclemargin and in the dorsal paraverte-bral region at the C7 level.


Key Topic

Fig. 11 Regional painreferral from the gluteusmuscles: to the iliosacraljoint (1), ischial bone (2)and inferior lumbar spine(3). (courtesy of Level10Buchverlag, Heilbronn)

Fig. 12 Painreferral fromexternal rotatormuscles. (cour-tesy of Level10Buchverlag,Heilbronn)

Clinical diagnosis: muscle-relatedheadache with trigger points in thedescending part of the trapeziusmuscle.

Therapy: in this case onlyr-ESWT with a total of 6000 shockwaves (3000 per side) to the freemargins of the horizontal anddescending parts of the trapeziusmuscle, applied at a pressure of2.4 bar. 400 to 500 shock waves areapplied to the spots in which pain ismost severe (possible induction ofreferred pain) until pain has beenreduced by about 50 %. Followed bylarge-area muscle smoothing in fibredirection. Total number of therapysessions is 4 to 6 at weekly intervals.

Results: reduced pain and im-proved mobility already after the firstsession; complete pain relief after 6sessions.

Concomitant therapies: optionalacupuncture, thermotherapy.Strengthening exercises after com-pletion of treatment.

Lumbago and glutealgia withand without pseudoradicularsciaticaChronic lumbago has shown to re-spond exceptionally well to shockwave therapy. In general, shockwaves are applied to the uppergluteal region.

The forth most frequent pain re-ferral is to the dorsolateral upper armat the level of the posterior part of thedeltoid muscle or at the infraspinatusmuscle level. In general, it can beinduced in the lateral aspect of thetrapezius muscle from the ventral ordorsal side. In many cases, pain isreferred up to the ulnar or radialepicondyle, rarely up to the wrist onthe same side.

Treatment example. Anamnesis:pain in the neck and temple regions,occurring regularly during computerwork and aggravated by stress.

High sensitivity to cold and draft.Occasional pain radiation to the arm,not dermatome-related. Previouslyinterpreted as tension headache andtreated with muscle relaxants andmassage without any significantimprovement of symptoms.

Clinical findings: severe restric-tion of cervical spine rotation, softtouch at range of motion limit,myogelosis in the free margins of thetrapezius muscle in a palpable tautband. Strong pain when affectedarea is pinched; pain radiates to theside of the head. Pain is recognisedby patient as the pain complained of.No neurological loss.


These muscles are involved in mostchronic pain syndromes in the lum-bar/pelvic/hip region. Their irritationis attributable to diverse causativefactors, among which functionaldisorders or structural pathologies ofthe lumbar spine and hip joint. Clini-cally speaking, the pain discussedhere is gluteal pain, which causespain referral to the inferior lumbarspine and to the leg, primarily inlaterodorsal direction and thereforereferred to as "pseudoradicular" pain.Referred pain can be induced with ahigh degree of recognition.

Localisation of trigger points.Primarily along and ventrally to aconnecting line between the posteriorsuperior iliac spine and the greatertrochanter and in the upper third ofthe gluteus medius and minimusmuscles towards the iliac crest.Additional trigger points in the glu-teus maximus muscle in the para-sacral region and above the ischialbone. If pain is perceived at thegreater trochanter, the trigger pointsare located in the dorsal region of thegluteus medius and maximusmuscles and in the external rotators.

Pain referral patterns. Pain is re-ferred from the dorsal aspect of thegluteus medius muscle ( Fig. 9) tothe buttocks, iliac bone, dorsolateralthigh up to the knee and from therein distal direction along the dorso-lateral lower leg down to the ankleand foot. Pain referral is also fromthe middle gluteus medius and mini-mus muscles to the buttocks andlateral aspect of the thigh to justbelow the knee ( Fig. 10), whilepain radiates from the anterior glu-teus medius and minimus muscles tothe inguinal region and adductors.Only in very rare cases is referredpain regionally confined to the centreof the inferior lumbar spine, ischialbone and iliosacral joint ( Fig. 11).The external rotators ( Fig. 12),which are always included in thetreatment of the dorsal gluteus mus-cles, often refer pain to the inguinalregion and ventrally to the hip, thighand adductors.

Treatment example. Anamnesis:pain in the lower lumbar spine area,in the paravertebral and glutealregions and occasionally in thelateral aspect of the thigh, radiatingapproximately to the knee region.

No loss of sensitivity. Pain caused bystrain while standing or after pro-longed sitting or lying down (insupine or lateral position). Severesleep disturbance.

Clinical findings: basically norestriction of lumbar spine mobility,slight restriction of internal rotation ofhip joints, negative facet provocation.Deep palpation by exerting thumbpressure on the gluteus musclescranially from the greater trochanter(gluteus minimus muscle) and alonga connecting line between thegreater trochanter and the posteriorsuperior iliac spine (gluteus mediusmuscle) causes strong local painwhich radiates towards the sacrumdistally to the greater trochanter andtowards the inguinal region. Uponprovocation with f-ESWT, the patientrecognises the radiation and per-ceives maximum pain. No neuro-logical loss.

Diagnostic imaging: the lumbarMRI image reveals slight degenera-tive changes of the facet joints andintervertebral disks without nerveroot or spinal canal compression.

Clinical diagnosis: lumbago withpseudosciatica caused by triggerpoints in the gluteal muscles.

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Key Topic

Therapy: f-ESWT for diagnosiswith provocation of pain referral,immediately followed by therapy.Thanks to the penetration depth ofup to 12 cm, the deep externalrotators (primarily the piriformismuscle) are treated at the same time.Treatment with f-ESWT with 1000 to2000 shock waves (0.15 to 0.25mJ/mm²), of which about 200 to 300per trigger point area until pain hasbeen reduced by about 50 %.Followed by r-ESWT. Total numberof shock waves per side: 3000, withlarge-area gluteal muscle smoothingin fibre direction. r-ESWT reachesprimarily the superficial muscles(gluteus maximus and medius mus-cles). Total number of therapysessions is 4 to 6 at weekly intervals.

Results: almost complete elimi-nation of sleep disturbance after thefirst session and substantial reduc-tion of pain radiation to the leg.Complete absence of symptoms after4 sessions.

Conclusions for practice

― Muscle pain research con-ducted during the last fewyears and the experiencegathered in the use of shockwave therapy of skeletal mus-cles confirm the important roleof myofascial trigger points.

― The use of shock wave therapyallows the diagnostic andtherapeutic options of conser-vative orthopaedics to be ex-tended because it is primarilyconcerned with functional dis-orders and pain syndromes.

― Knowledge of muscle-specificpain referral is important toensure correct differentialdiagnosis of disorders mani-festing as dysaesthesia ormuscle weakness, which inmany cases cannot be diag-nosed neurologically, andbring the muscle in the focusof medical treatment.

― Surgeons can refine indica-tions for surgery and improvepost-operative results bytreating residual muscle pain.

― Effective treatment requiresadequate differential diagno-sis, precise local diagnosisand early trigger point therapy.

Correspondence address

Conflict of interests. Dr Gleitz is a consult-ant to Storz Medical AG, Lohstampfestrasse8, 8274 Tägerwilen, Switzerland, providingtherapy recommendations for the use offocused and radial shock waves.Dr Hornig declares that there is no conflict ofinterests.

(English translation of the article in German:“Triggerpunkte – Diagnose und Behand-lungskonzepte unter besonderer Berücksich-tigung extrakorporaler Stosswellen“, M.Gleitz, K. Hornig, in: Orthopäde 2 / 2012)

Dr M. GleitzOrthopaedic Surgery30, Grand RueL-1660 [email protected]


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