percutaneous electrical nerve stimulation (pens) … · pens was given using algotec® disposable...

Percutaneouselectricalnerves/mula/on(PENS)therapy

InPENS,oneormoreindividualnervesordermatomesares5mulatedusingneedleprobes.Asingleprobewithagroundingpadorpairsoffine-gaugeneedlesareinsertedintothesubcutaneousplanenearthetargetednervesorintotheaffecteddermatomes.Theneedlesareconnectedtoalow-voltagepulsegeneratorandanelectricalcurrentisthenapplied.Thismaygenerateasensa5onofparaesthesiaandmusclecontrac5on(duetoalterna5nglowandhighfrequencys5mula5on).Thedura5onoftreatmentvariesbuteachsessionofs5mula5ontypicallylastsbetween15-60minutes.

Randomisedcontrolledtrials(RCTs)haveshownthatPENSmaybeeffec5veinchronicpaincondi5onssuchasscia5ca,anddiabe5cneuropathicpain.Keyefficacyoutcomesinthesetrialsincludereduc5oninpain(allevia5onoflocalisedneuropathicpain,reliefofallodyniaandhyperpathia,reduc5oninthefrequencyofsharpshoo5ngpains,reduc5onintheburningsensa5on),andassociatedfunc5onalandemo5onalimprovements.

PENSisgenerallysafeandwelltolerated.Reportsexistofexacerba5onofpain,bruisingandbleedingasimmediateadverseevents.Theore5caladverseeventsincludelocalvascularornervedamage;pneumothorax;possibleinterac5onwithacardiacpacemakerifusedabovethewaistline;possibleepileptogeniceffectifusednearthehead;andpossibleadverseeffectsifusedinpregnancy.Nopublishedreportsexistofanyofthesetheore5calproblemsactuallyarising,however.

Neuromodula/onforheadachedisorders

Headachedisordersarethemostcommonformofneurologicaldisabilityonaglobalbasis,andthesixthmostcommoncauseofdisabilityworldwide.Thecumula5velife5meincidenceofmigraineapproaches50%infemales;the1yearprevalenceforclusterheadache,forwhichthereisnocumula5vedata,isabout0.1%ofthepopula5on;approximately2%ofthepopula5onindevelopedcountrieshavechronicdailyheadaches.Themedicaltreatmentofpa5entswithprimaryandsecondaryheadachesyndromescanbeverychallengingasserioussideeffectsfrequentlycomplicatethecourseofmedicaltreatments,andsomepa5entsproverefractorytonumerousandvariedmedica5ons.

Thelast10-15yearshasseentheexpansionofannewbranchofheadachetreatment:neuromodula5on.Thisgroupoftechniquescomprisesnon-invasivetreatmentswhich,bytarge5ngthecentralorperipheralnervoussystem,aimatmodifyingpainandothermechanismsinvolvedinheadache,andmoreinvasivesurgicalapproachesdirectedtowardsstructuresdirectlyinvolvedinthegenesisofspecificheadachesyndromes.Thefactthattheseapproacheslackthesideeffectsanddruginterac5onscommontomedicaltherapiesmakethemaVrac5vechoicesformanypa5ents.

Theprincipleoftheseapproachesistomodulatethefunc5onofneuronalstructuresthataredirectlyorindirectlyinvolvedindetec5onortransmissionofpainfuls5muli,orintheprocessingofthisinforma5oninthebrain.Neuromodula5onofheadachedisordershasbeenachievedbydirectmodula5onofbrainstructuresinvolvedinthegenera5onofaVacks(deepbrains5mula5onofthehypothalamusinclusterheadache,forexample),modula5onofinhibitoryan5nocicep5vepathways(occipitalnerves5mula5on),modula5onofcor5calexcitability(transcranialmagne5canddirectcurrents5mula5on),anddirectinhibitoryeffectsattheleveloftheperipheralneuronorthespinalcord(TENS).Highqualityrandomisedcontrolledtrialsarefewandfarbetween,however,andfurthercontrolledstudiestovalidate,strengthenanddisseminatetheuseofneuromodula5onforheadachedisordersareneeded.Inaddi5on,newtechniqueswithprovensafetyandefficacyinotherpaindisorders,suchasPENStherapy,shouldbetrialledinheadachedisorders.

PATIENT# AGE SEX YRSCH YRSCCH #PENSRxPREVIOUSPREVENTIVETREATMENTS BESTRESPONSETOGONB RESPONSETO1stPENSRx SUBSEQUENTCOURSE OUTCOME

1 32 F 13 3 7 VER,TOP,LI,MEL,SVP,MTH,VNS 2-3wks,itching&localisedalopecia 6wkspainfree Upto3mthspainfree OngoingPENStherapy&GONB

2 39 M 4 3 2 VER,TOP,LI,MTH,PIZ 3-4days 4wkspainfree Only3dayspainfree ReferredforONS

3 45 F 22 3 1 VER,TOP N/A Unhelpful N/A Ongoingmedicaltreatment

4 49 M 9 9 1 VER,TOP,LI,MEL,DHE,INDO 3-4days 4daysreducedseverity N/A Ongoingmedicaltreatment

5 42 F 2 1 8 VER,TOP,LI,MEL,MTH,INDO Upto5wks,butlesseffec/veover/me 5dayspainfree Upto2mthspainfree RevertedtoepisodicCH

6 63 M 7 5 3 VER,TOP 3-4days 6wkspainfree Upto3mthspainfree OngoingPENStherapy

7 33 F 6 6 4 VER,TOP,LI,MEL,MTH,PRG,AMI,INDO,VNS 3-4days,painful 6wkspainfree 6-8wkspainfree OngoingPENStherapy&referredforONS

8 32 F 1 1 2 VER,TOP,LI,INDO Unhelpful 6mthsreducedseverity 3mthspainfree OngoingPENStherapy

9 29 M 12 12 1 VER,TOP,LI 3-4days 6mthsreducedseverity N/A(declinedfurtherPENSRx) Ongoingmedicaltreatment

ResponsetoPENStherapyinchronicclusterheadache

DrMarkWWeatherall&MrDipankarNandiDepartmentsofNeurology&Neurosurgery,CharingCrossHospital,ImperialCollegeNHSHealthcare,London,UK

PERCUTANEOUSELECTRICALNERVESTIMULATION(PENS)THERAPYFOR

REFRACTORYPRIMARYHEADACHEDISORDERS

MethodsOuraimwastodemonstratewhetherpercutaneouselectricalnerves5mula5on(PENS)therapyhasaroletoplayinthemanagementofrefractoryheadachedisorders.Aretrospec5vereviewoftherecordsof36pa5entswhohavebeentreatedwithsupraorbitaloroccipitalPENStherapyatourcentrebetweenSeptember2012andJune2016wasundertaken.Follow-updatawasavailablefor33pa5ents.Ofthese,26hadaprimaryheadachediagnosis,ofwhom14hadchronicmigraine(CM),9hadchronicclusterheadache(CCH),2hadnewdailypersistentheadache(withmigrainousfeatures),andonehadhemicraniacon/nua.Thesecondaryheadachescomprisedoccipitalneuralgia,cervicogenicheadache,andtrigeminalneuropathy.

Technicaldetails

PENSwasgivenusingAlgotec®disposable21gaugePENStherapyprobes(50mm)totheoccipitalnerveipsilateraltothepain(orbilaterallyincasesofbilateralpain).InsomecasessupraorbitalPENSwastriedonasecondorsubsequentoccasionifthepa5enthadfailedtorespondtooccipitals5mula5on.S5mula5onwasdeliveredat2Hz/100Hz,at3cycles/second,between1.2-2.5Vdependingonpa5enttolerability,for25-28minutes.Noimmediatecomplica5onswererecordeddurings5mula5on,apartfromonepa5entwhoexperiencedpaindurings5mula5on,andinmostcasesthetrea5ngneurosurgeon(DN)recordedgoodcoverageandradia5onofeffectdurings5mula5on.

Results

Sixoutoftheninepa5entswithCCHimprovedsignificantly(seethetablebelow);thesepa5entshadpreviouslyfailedtorespondtobetweentwoandeightoralpreven5vemedica5ons,andhadatbestexperiencedtemporarybenefitfromnerveblockswithlocalanaesthe5cagents.Inallpa5entswithCCH,PENStherapywaswelltolerated,withnosignificantadverseeventsreported.Onepa5entwithCCHrevertedtotheepisodicformofthedisorder;thisimprovementhasbeenmaintainedformorethantwoyearsfollowingthecessa5onoftherapy.Onlythreeofthepa5entswithCMexperiencedanyno5ceablebenefitwithPENStherapy;onepa5entwithCMexperiencedpaindurings5mula5on,twopa5entswithCMexperiencedsevereneckpain,andthreepa5entswithCMexperiencedanexacerba5onoftheircondi5onlas5ngdaystoweeks.Theseadverseeffectsarepossiblyduetothepresenceofsignificantallodynia,notimprovedbyPENStherapy.

Conclusion

PENStherapyshowsgreatpoten5alasarela5velynon-invasive,low-risk,andinexpensivecomponentofthetreatmentop5onsforrefractoryprimaryheadachedisorders,par5cularlychronicclusterheadache.Furthertrialsofthetechniqueinthisdebilita5ngcondi5onarewarranted.

Acknowledgements

TheauthorsaregratefulfortheassistanceofthenursingstaffofWard10N,CharingCrossHospital,indeliveringPENStherapytoourpa5ents,andtoCoralWinslow-LlewellynandSusanDanielsofAlgotec®fortheirsupport.

CH:clusterheadache;CCH:chronicclusterheadache;VER:verapamil;TOP:topiramate;LI:lithium;MEL:melatonin;SVP:sodiumvalproate;MTH:methysergide(nolongeravailable);VNS:vagalnerves5mula5on(non-invasive);PIZ:pizo5fen;DHE:dihydroergotamine(IVinfusion);PRG:pregabalin;AMI:amitriptyline;INDO:indomethacin;GONB:occipitalnerveblockade(withDepoMedrone&lidocaine);ONS:occipitalnerves5mula5on.