Transcutaneous electrical nerve stimulation for acute pain

97 Pages·2016·0.91 MB·English

Citation:
Johnson, MI and Paley, CA and Howe, TA and Sluka, KA (2015) Transcutaneous electrical nerve
stimulation for acute pain: A review. Cochrane Database of Systematic Reviews (6). ISSN 1469-
493X DOI: https://doi.org/10.1002/14651858.CD006142.pub3
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CochraneDatabaseofSystematicReviews
Transcutaneous electrical nerve stimulation for acute pain
(Review)
JohnsonMI,PaleyCA,HoweTE,SlukaKA
JohnsonMI,PaleyCA,HoweTE,SlukaKA.
Transcutaneouselectricalnervestimulationforacutepain.
CochraneDatabaseofSystematicReviews2015,Issue6.Art.No.:CD006142.
DOI:10.1002/14651858.CD006142.pub3.
www.cochranelibrary.com
Transcutaneouselectricalnervestimulationforacutepain(Review)
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
TABLE OF CONTENTS
HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PLAINLANGUAGESUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
AUTHORS’CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
CHARACTERISTICSOFSTUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
DATAANDANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Analysis1.1.Comparison1TENSversusplaceboTENS,Outcome1Painintensity(100mmVAS). . . . . . . 72
Analysis1.2.Comparison1TENSversusplaceboTENS,Outcome2>50%reductioninpain. . . . . . . . 73
Analysis2.1.Comparison2TENSversusnotreatmentcontrol,Outcome1Painintensity(100mmVAS). . . . . 74
Analysis3.1.Comparison3ConventionalTENSversusAL-TENS,Outcome1>50%reductioninpain. . . . . 75
Analysis4.1.Comparison4HighpulseamplitudeTENSversuslowpulseamplitudeTENS,Outcome1Painintensity
(100mmVAS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
ADDITIONALTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
WHAT’SNEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
CONTRIBUTIONSOFAUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
DECLARATIONSOFINTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
SOURCESOFSUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
DIFFERENCESBETWEENPROTOCOLANDREVIEW . . . . . . . . . . . . . . . . . . . . . 94
INDEXTERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Transcutaneouselectricalnervestimulationforacutepain(Review) i
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
[InterventionReview]
Transcutaneous electrical nerve stimulation for acute pain
MarkIJohnson1,CaroleAPaley2,TraceyEHowe3,KathleenASluka4
1FacultyofHealthandSocialSciences,LeedsBeckettUniversity,Leeds,UK.2Research&DevelopmentDepartment,AiredaleNHS
FoundationTrust,Keighley,UK.3GlasgowCityofScience,Glasgow,UK.4GraduatePrograminPhysicalTherapy&Rehabilitation,
UniversityofIowa,IowaCity,Iowa,USA
Contact address: MarkIJohnson, Faculty ofHealthandSocial Sciences,LeedsBeckettUniversity, CityCampus, CalverleyStreet,
Leeds,LS13HE,[email protected].
Editorialgroup:CochranePain,PalliativeandSupportiveCareGroup.
Publicationstatusanddate:Stable(noupdateexpectedforreasonsgivenin’What’snew’),publishedinIssue6,2015.
Reviewcontentassessedasup-to-date: 3December2014.
Citation: JohnsonMI,PaleyCA,HoweTE,SlukaKA.Transcutaneouselectricalnervestimulationforacutepain.CochraneDatabase
ofSystematicReviews2015,Issue6.Art.No.:CD006142.DOI:10.1002/14651858.CD006142.pub3.
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
ABSTRACT
Background
This is a second update of a Cochrane Review originally published in Issue 2, 2009. Transcutaneous Electrical NerveStimulation
(TENS)isanon-pharmacologicalagent,basedondeliveringlowvoltageelectricalcurrentstotheskin.TENSisusedbypeopletotreat
avarietyofpainconditions.
Objectives
ToassesstheanalgesiceffectivenessofTENS,asasoletreatment,foracutepaininadults.
Searchmethods
Wesearchedthefollowingdatabasesupto3December2014:theCochraneCentralRegisterofControlledTrials(CENTRAL),inthe
CochraneLibrary;MEDLINE;EMBASE;CINAHL;andAMED.Wealsocheckedthereferencelistsofincludedtrials.
Selectioncriteria
We included randomised controlled trials (RCTs) of adults with acute pain (< 12 weeks) if they examined TENS given as a sole
treatmentandassessedpainwithsubjectivepainscales.TrialswereeligibleiftheycomparedTENStoplaceboTENS,notreatment
controls,pharmacologicalinterventionsornon-pharmacologicalinterventions.Weexcludedtrialsonexperimentalpain,casereports,
clinicalobservations, letters,abstractsorreviews.AlsoweexcludedtrialsinvestigatingtheeffectofTENSonpainduringchildbirth
(labour),primarydysmenorrhoeaordentalprocedures.StudieswhereTENSwasgivenwithanothertreatmentaspartoftheformal
trialdesignwereexcluded.Wedidnotrestrictanyarticlesbasedonlanguageofpublication.
Datacollectionandanalysis
Tworeviewauthorsindependentlyassessedstudyeligibilityandcarriedoutstudyselection,dataextraction,’Riskofbias’assessment
andanalysesofdata.Weextracteddataonthefollowing:typesofparticipantsandpaincondition,trialdesignandmethods,treatment
parameters,adverseeffects,andoutcomemeasures.Wecontactedtrialauthorsforadditionalinformationifnecessary.
Transcutaneouselectricalnervestimulationforacutepain(Review) 1
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Mainresults
Weincluded12trialsintheoriginalreview(2009)andincludednofurthertrialsinthefirstupdate(2011).Anadditionalsevennew
trialsmettheinclusion criteriainthissecondupdate.Intotal,weincluded19RCTsinvolving 1346 participantsatentry,with11
trialsawaitingclassificationeitherbecausethefulltextwasunavailableorinformationinthefulltextfailedtoclarifyeligibility.We
excludedmosttrialsbecause TENSwasgivenincombination withanothertreatmentaspartof theformalstudy designorTENS
was not deliveredusing appropriate TENS technique. The typesof acute pain included in this Cochrane Review were procedural
pain,e.g.cervicallasertreatment,venepuncture,screeningflexiblesigmoidoscopyandnon-proceduralpain,e.g.postpartumuterine
contractionsandribfractures.Wepooleddataforpainintensityforsixtrials(sevencomparisons)comparingTENSwithplacebobut
theI2 statisticsuggestedsubstantialheterogeneity.Meandifference(MD)with95%confidenceintervals(CIs)onavisualanalogue
scale(VAS,100mm)was-24.62mm(95%CI-31.79to-17.46)infavourofTENS.Datafortheproportionofparticipantsachieving
≥50%reductioninpainwaspooledforfourtrials(sevencomparisons)andrelativeriskwas3.91(95%CI2.42to6.32)infavourof
TENSoverplacebo.Wepooleddataforpainintensityfromfivetrials(sevencomparisons)buttheI2statisticsuggestedconsiderable
heterogeneity.MDwas-19.05mm(95%CI-27.30to-10.79)infavourofTENSusingarandom-effectsmodel.Itwasnotpossible
topoolotherdata.Therewasahighriskofbiasassociatedwithinadequatesamplesizesintreatmentarmsandunsuccessfulblinding
oftreatmentinterventions.Seventrialsreportedminoradverseeffects,suchasmilderythemaanditchingunderneaththeelectrodes
andparticipantsdislikingTENSsensation.
Authors’conclusions
This Cochrane Review update includes seven new trials, in addition to the 12 trials reviewed in the first update in 2011. The
analysisprovidestentativeevidencethatTENSreducespainintensityoverandabovethatseenwithplacebo(nocurrent)TENSwhen
administered as a stand-alone treatment for acute pain in adults. The high risk of bias associated with inadequate sample sizes in
treatmentarmsandunsuccessfulblindingoftreatmentinterventionsmakesdefinitiveconclusionsimpossible.Therewasincomplete
reportingoftreatmentinmanyreportsmakingreplicationoftrialsimpossible.
PLAIN LANGUAGE SUMMARY
TranscutaneousElectricalNerveStimulation(TENS)totreatacutepaininadults
Background
Acutepainispainofrecentonsetandlimitedduration.Acutepainisassociatedwithsurgery,physicaltrauma(e.g.brokenbones,burns
andcuts)andmedicalprocedures(e.g.venepunctureandsigmoidoscopy).TranscutaneousElectricalNerveStimulation(TENS)isa
treatmenttorelievepainbyadministeringmildelectricalcurrentstothebodyusingelectrodepadsattachedtothesurfaceoftheskin.
Reviewquestion
DoesTENSrelieveacutepaininadults?
Studycharacteristics
Weincluded19 clinical trialspublishedupto3December2014, which examined1346 people.The trialsadministered TENSto
produce a strong non painful ’tingling’ sensation at the site of acute pain. The trials assessed TENS for cervical laser treatment,
venepuncture,sigmoidoscopy,ribfracturesanduterinecontractionsafterchildbirth.WedidnotincludetrialsthatassessedTENSfor
painassociatedwithchildbirth,dentalproceduresandmenstruationbecausetheyhavebeenthesubjectofotherCochraneReviews.
Eleventrialsareawaitingclassification.
Keyresults
TENSwasbetterthanplaceboTENS(deliveringnoelectricalcurrent)atreducingtheintensityofacutepainbutthereductioninpain
wasnotconsistentacrossalltrials.Thisfindingwasbasedonananalysisofonlysixofthe19trials.Therewasaninsufficientnumber
patientstomakeafirmconclusion.
AsmallnumberofpatientsexperienceditchingandrednessbeneaththeTENSpadsordislikedthesensationproducedbyTENS.
OverallweconcludedthatTENSmayreducetheintensityofacutepaininsomepatientsbutthequalityofevidencewasweak.TENS
isinexpensive,safeandcanbeself-administered.WerecommendedthatTENSshouldbeconsideredasatreatmentoptiongivenon
itsownorincombinationwithothertreatments.
Transcutaneouselectricalnervestimulationforacutepain(Review) 2
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Qualityoftheevidence
Thequalityoftheevidencewasmoderatetolowbecausesamplesizesweresmallandsomepatientswereawarethattheywerereceiving
TENSorplacebo.
BACKGROUND Atheoreticalfoundationforelectroanalgesia(painreliefbyelec-
tricalmethods)wasestablishedin1965throughthepublication
This Cochrane Review is a second update of Walsh 2009, and
ofMelzackandWall’sgatecontroltheoryofpain(Melzack1965).
replacesthe2011update.
Thistheoryproposedthatametaphoricalgateconsistingofexcita-
toryandinhibitorysynapsesexistedinthedorsalhornofthespinal
cord. The gate could regulate the amount of nociceptive traffic
Descriptionofthecondition (painfulstimuli)beingtransmittedonwardstothebrain.Thisgate
couldbeopenedbynoxious stimulithatexcitedhighthreshold
TheInternationalAssociationfortheStudyofPaindefinespainas
smalldiameterperipheralafferentsandcouldbeclosedbynon-
“anunpleasantsensoryandemotionalexperienceassociatedwith
noxiousstimuli(e.g.touch,pressureandelectricalcurrents)that
actual or potential tissue damage, ordescribed intermsof such
excitedlowthresholdlargediameterperipheralafferents.
damage”(Merskey1994).Acutepainisdefinedaspain“ofrecent
TechnologicaladvanceshaveproducedavarietyofTENSdevices
onsetandprobablelimiteddurationwhichusuallyhasanidentifi-
withawiderangeofstimulationparametersforcliniciansandpa-
abletemporalandcausalrelationshiptotheinjuryordisease”.In
tientstochoosefrom(e.g.pulsefrequency,pulseamplitude,pulse
clinicalpracticeacutepainiscategorisedaspainoflessthanthree
durationandelectrodeplacementsite).TENSinterventionstend
monthsduration(Strong2002).Currentapproachestoacutepain
tobedescribedaccordingtotechnicalcharacteristicsaseitherhigh
managementincludepharmacologicalagents(drugs)andanum-
frequency,lowintensity(conventionalTENS)orlowfrequency,
ber of non-pharmacological agents, one of which is Transcuta-
highintensity(acupuncture-likeTENS,AL-TENS).Thistechni-
neousElectricalNerveStimulation(TENS)(Schug2014).
calapproachfailstospecifythephysiologicalintentionofdeliver-
ingTENS.Inthisregard,thephysiologicalintentionwhenadmin-
isteringconventionalTENSistoactivateselectivelynon-noxious
Descriptionoftheintervention lowthresholdafferentnervefibresintheskin(Aβ-fibres)which
areclaimedtoinhibittransmissionofnociceptiveinformationat
TENSisthedeliveryofpulsedelectricalcurrentsacrosstheintact
thelevelofthespinalcord(i.e.segmentalmodulation)(DeSantana
surfaceoftheskin tostimulate peripheralnervesprincipallyfor
2008).Inpractice,Aβnervefibreactivityisrecognisedbytheuser
painrelief(Johnson2014).InclinicalpracticeTENSisadminis-
reportingstrongelectricalparaesthesia(pinsandneedles)beneath
teredusingaportable,battery-powereddevicethatgenerateselec-
theelectrodes.ThephysiologicalintentionofAL-TENSistogen-
tricalcurrentsthataredeliveredtothebodyviaelectrodesattached
erateamuscletwitchwhichisbelievedtoincreaseactivityinsmall
totheintactsurfaceoftheskin.TENSisinexpensiveandcanbe
diameterafferentnervefibresinmuscles(Aδ)leadingtoactivation
self-administered.ThesafetyprofileofTENScomparespositively
ofdescendingpaininhibitorypathways.Inpractice,AL-TENSis
comparedwithmedication.Safetyguidelinespublishedbyprofes-
achievedbyadministeringlowfrequencyandhighintensity,but
sionalbodiesguidejudgementsaboutwhetheritisappropriateto
non-painful,currentsovermuscles(Francis2011).Interestingly,
useTENS(Houghton2010).ContradictionsincludeTENSfor
experimental evidence toestablish therolesof differentafferent
patientswhoalsohaveelectronicimplants,suchascardiacpace-
fibres in TENS outcome is inconclusive (Garrison 1994; Levin
makersandimplantablecardioverterdefibrillators.Precautionsin-
1993;Radhakrishnan2005).Researchsuggeststhatdifferentfre-
cludepregnancy,epilepsy,activemalignancy,deep-veinthrombo-
quenciesofTENSmayactthroughdifferentneurotransmittersys-
sis,andfrailordamagedskin.
tems. Slukaand colleagues conducted aseries of animal studies
thathaveshownthatlowfrequencyTENS-inducedantihyperal-
gesia(decreasedsensitivity topain) ismediatedbyactivation of
Howtheinterventionmightwork serotoninandmuopioidreceptors,whilehighfrequencyTENS
activatesdeltaopioidreceptors(Kalra2001;Radhakrishnan2003;
Naturalformsofelectricity(e.g.electrogenicfish)havebeenused
Sluka1999). In 2008, a systematic review evaluating frequency
asamethodofpainreliefsincetheEgyptianera(Johnson2014).
Transcutaneouselectricalnervestimulationforacutepain(Review) 3
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
dependenteffectsonexperimentallyinducedpaininhumanswas givenasasoletreatmentonlytoseeifithassufficientefficacyin
inconclusiveduetoaninsufficientnumberofhighqualitytrials itsownright.
(Chen 2008). In recent years frequency-dependent effects have
beenconfirmedinhumansubjectsbyhighqualityresearchstudies
(Chen2010a;Chen2010b;Chen2011;Claydon2011;Leonard
2010;Léonard2011;Liebano2011). OBJECTIVES
Whyitisimportanttodothisreview
Primaryobjective
TENSisusedextensivelybypeoplewithacuteandchronicpain
ToassesstheanalgesiceffectivenessofTENS,asasoletreatment,
(DeSantana2008;Johnson2011).Meta-analysesontheeffective-
foracutepaininadults.
nessofTENSforchronicmusculoskeletalpain(Johnson2007)
and for osteoarthritis of the knee (Bjordal 2007) demonstrated
a significant effecton pain over placebo. Cochrane Reviews on
Secondaryobjectives
TENSforspecificchronicpainconditionshavebeenhinderedby
methodologicalweaknessesinrandomisedcontrolledtrials(RCTs) Toassesswhether:
(Bennett2011;Johnson2010;Johnson2014;Sluka2013).Anall- 1. TENSeffectivenessisinfluencedbythetypeofTENS(i.e.
encompassingCochraneReviewonTENSforavarietyofchronic conventionalTENSversusAL-TENS);
painconditions(i.e.pain>threemonths’duration)reportedin- 2. TENSeffectivenessisinfluencedbythetimeofrecording
conclusiveresults(Nnoaham2008).However,thisreviewhasnow theoutcomemeasure,i.e.ifoutcomeisinfluencedby
beenwithdrawnandisbeingreplacedbynewreviewsonTENS measurementstakenwhenTENSisswitchedon(duringTENS
forneuropathicpaininadults,ledbyGibson(protocolinpress) measurement)comparedtowhenTENShasbeenturnedoff
and TENS for fibromyalgia, led by Claydon et al (protocol in afterthetreatment(post-TENSmeasurement);
press).ThereisalsoatitleregisteredforanoverviewofCochrane 3. TENSeffectivenessisinfluencedbydurationofTENS
ReviewsofTENSforchronicpain(protocolinpress). treatment;
CochraneReviewsonTENSforspecifictypesofacutepainhave 4. TENSeffectivenessdiffersfordifferentacutepain
beeninconclusiveforlabourpain(Dowswell2009)anddysmen- conditions;and,
orrhoea(Proctor2002).AnearlysystematicreviewofTENSfor 5. TENSissafeforthetreatmentofacutepain.
post-operativepainfoundTENStobenobetterthancontrolsfor
postoperative pain (Carroll 1996) although pain measures were
takenwhenpatientswere allowedfreeaccesstoanalgesic medi-
cation.Thiscompromisespainscoresbecausepatientsinplacebo
METHODS
andTENSgroupstitrateanalgesicmedicationtoachieveeffective
painrelief,andthereforeexhibitsimilarpainscores.Reviewau-
thorsalsoincludedtrialsthatunderdosedTENSor usedanin-
Criteriaforconsideringstudiesforthisreview
appropriateTENStechnique,orboth.Ameta-analysiswithsub-
group analysis demonstrated a significantly better outcome for
TENSwhenappliedusingadequate(optimal)stimulationtech-
niques whencomparedtonon-adequate stimulation techniques Typesofstudies
(Bjordal2003);optimalTENStechniquesweredefinedasanin- We included all prospective RCTs. Both cross-over and parallel
tensitythatwasstrongenoughtogenerateastrongparaesthesia trialdesignswereacceptable.Weexcludeddatafromthefollow-
andelectrodesappliedatthesiteoftheoperativescar.Recentev- ing:trialsthatwerenon-randomised;studiesofexperimentalpain;
idencefromsystematicreviewssuggeststhatTENSissuperiorto case reports; clinical observations; and letters, abstracts and re-
placeboTENSwhenusedincombination withanalgesic medi- views(unlesstheyprovidedadditionalinformationfrompublished
cationforthoracotomyandpost-sternotomypain(Freynet2010; RCTsthatmetthecriteria).
Sbruzzi2012).Todate,therehasbeennoall-encompassingsys-
tematicreviewonTENSforacutepain.Asystematicreview,which
Typesofparticipants
takesaccountofadequateTENStechniques,isnecessarytoassist
cliniciansandresearcherstomakeinformeddecisionsontheeffec- Study participants were required to be adults (i.e. 16 yearsand
tivenessofthismodalityforacutepain.TENScanbegiveneither over)withadiagnosis ofacutepain(lessthan12weeks)byany
asasoletreatment,i.e.standalonetreatment,orcombinedwith cause includinginjury or surgical intervention. Acutepaincon-
otherinterventions.ThisCochraneReviewwillfocusonTENS ditionsincluded,butwerenotlimitedto,thefollowing:angina;
Transcutaneouselectricalnervestimulationforacutepain(Review) 4
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
back pain; fractures; headache;musculoskeletal pain andproce- Primaryoutcomes
duralpain.Weincludedpostpartumpaintrialsifthepaininves- • Standardsubjectivescalesforpainintensity,painreliefor
tigated was due to episiotomy or Caesarean section irrespective both(e.g.visualanaloguescales(VAS),numericalratingscales
of the presence of uterine cramps. We excluded trialsincluding (NRS);verbalratingscales(VRS)McGillPainQuestionnaire
patientswithpainduetouterinecontractions(i.e.labour)alone (MPQ)).
andtrialsincludingpatientswithacutepainduetoprimarydys-
menorrhoea as these conditions have been covered by previous
CochraneReviews(Dowswell2009;Proctor2002).Inaddition, Secondaryoutcomes
weexcludedtrialsonelectricalstimulationfordentalprocedures • Othermeasuresofpain.
asthisisasubjectforaseparatereview.
Werecordedadverseeventsassociatedwiththeintervention.Also,
wesoughtinformationonthelevelofcompliancewiththeinter-
Typesofinterventions vention,themagnitudeanddurationofeffect.
We only included trials which evaluatedsurface electricalnerve
stimulation for the treatment of acute pain (i.e. transcutaneous
as opposed to percutaneous electrical stimulation). We defined Searchmethodsforidentificationofstudies
appropriatedeliveryofTENSasfollows:
1. A’standardTENSdevice’wasusedwhichdelivered
biphasicormonophasic(typeofwaveform)pulsedelectrical
Electronicsearches
currentsinthemArange.TENShadtobedeliveredusingat
Wedevelopeddetailedsearchstrategiesforeachelectronicdatabase
leasttwosurfaceelectrodes.WeexcludedTENSdeliveredusing
searched. We based these on the search strategy developed for
singleprobes(i.e.TENSpens).Neuromuscularelectrical
MEDLINE but revised each strategy appropriately for each
stimulation(NMES)devicesandInterferentialCurrentdevices
database.Thesearchstrategycombinedthesubjectspecificsearch
wereexcluded;
withphaseoneandtwooftheCochraneSensitiveSearchStrategy
2. TENSwasadministeredtoproduceastrongelectrical
forRCTs(aspublishedinchaptersections6.4.11.1,6.3.2.1and
paraesthesiathatwasfeltbythepatient.WeincludedAL-TENS
6.3.3.2intheCochraneHandbookforSystematicReviewsofInter-
deliveredatstrongintensitiestogeneratemuscletwitches.We
ventions(Higgins2011).Thesubjectspecificsearchusedacombi-
excludedtrialsiftheactiveTENSinterventionwasdeliveredat
nationofMeSH(uppercase)andfreetext(lowercase)termsbased
intensitiesreportedtobe’barelyperceptible’,’faint’or’mild’;
ontheMEDLINEsearchstrategyviaOVIDwhichcanbeseenin
3. TENSwasadministeredonanareaofthebodywhichwas
Appendix1.Weattemptedtoidentifyallrelevanttrialsirrespec-
sensate(wherepainisbeingfelt)ateither(a)thesiteofpainor
tiveoflanguage. Weassessednon-English papersandtranslated
(b)overnervebundlesproximal(ornear)tothesiteofpain.We
articleswhennecessary.
onlyincludedTENSdeliveredatacupuncturestimulationpoints
WeperformedtheliteraturesearchforWalsh2009upto8Au-
ifthepointwaslyingovernervebundlesproximal(ornear)to
gust 2008 and subsequent searches up to 7 January 2011 for
thesiteofpain.Weconsideredanyparametersoftreatment
the 2011 review update. For this second search update we per-
meetingthesecriteriaaswereanydurationorfrequencyof
formedsearchesupto3December2014.Wesearchedthefollow-
treatmentandeitherself-appliedortherapist-appliedtreatments.
ingdatabases:
Theinterventionstobecomparedincludedthefollowing:
• TENSversusplaceboTENS(i.e.useofashamTENS • CochranePain,PalliativeandSupportiveCareGroup
(PaPaS)SpecializedRegister(4August2008;asdataarecaptured
device).WedefinedashamTENSdeviceasadevicesimilarto
inCENTRAL,wedidnotincludethisdatabaseinthe2011or
theoneusedintheactivegroupbuttheoutputwasmodifiedin
2013updatesearch)Appendix2;
somewaysothateithernoelectricalcurrentorabarely
• CochraneCentralRegisterofControlledTrials,CENTRAL
perceptibleelectricalcurrentisdeliveredthroughtheelectrodes;
• TENSversusnotreatmentcontrols; (theCochraneLibrary,Issue11of12,2014)Appendix3;
• TENSversusapharmacologicalintervention; • MEDLINE(1950toNovweek32014)Appendix1;
• EMBASE(1980to2Dec2014)Appendix4;
• TENSversusanon-pharmacologicalintervention.
• CINAHL(1982to6Dec2014)Appendix5;
WeexcludedtrialsifTENSwasgivenincombination withany • AMED(1985to6November2014)Appendix6;
other treatment as partof the formal trial design, e.g. analgesic • PEDro(www.pedro.org.au)accessed7January2011.We
medication,exercise. excludedthisdatabasefromthe2013updatesearchAppendix7;
• OTseeker(www.otseeker.com)accessed7January2011.We
excludedthisdatabasefromthe2013updatesearchAppendix8;
Typesofoutcomemeasures
and,
Transcutaneouselectricalnervestimulationforacutepain(Review) 5
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
• OpenSIGLE(http://opensigle.inist.fr)accessed7January eration,allocationconcealment,blindingofparticipantsandout-
2011.Weexcludedthisdatabasefromthe2013updatesearch come assessors, incomplete outcome data, and other sources of
Appendix9. bias(fundingandsizeoftrial).Weresolvedanydisagreementby
consensusorbyconsultingathirdreviewauthor.
Searchingotherresources
Measuresoftreatmenteffect
Wesearchedthereferencelistsofallincludedtrials,keytextbooks
andprevioussystematicreviewsforadditionaltrials. Whereavailableandappropriate,wepresentedquantitativedata
for the outcomes listed in the inclusion criteria. For each trial,
wecalculatedrelativeriskand95%confidenceintervals(CI)for
Datacollectionandanalysis dichotomousoutcomes.Forcontinuousoutcomesreportedusing
thesamescale,wedeterminedmeandifferences(MD)and95%
CIs.Whereresultsforcontinuousoutcomeswerepresentedondif-
ferentscales,wecalculatedstandardisedmeandifferences(SMD)
Selectionofstudies
and95%CIs.Weplannedtocalculatethenumberneededtotreat
Fromthetitle,abstract, anddescriptors, pairsofreviewauthors
foranadditionalbeneficialoutcome(NNTB)fortreatmenteffect.
independently reviewed the results of the literature searches to
identifypotentiallyrelevanttrialsforfullreview.Weresolvedany
disagreementsbyconsensus.Wedidnotblindthereviewauthors Dealingwithmissingdata
fromauthors’ names, institutions, and journal name or trial re- Incasesofmissingdataduetowithdrawalsordropouts,weonly
sultsatthisstage oranystageofthereview.Afterscreeningfull usedthe dataanalysed inthe trial for analysis inthisCochrane
textarticles,weincludedtrialsthatmettheinclusioncriteria.We Review.
sought additional information or clarification fromtheprimary
trialauthorifincompletelyreported.
Assessmentofheterogeneity
Wehadintendedthat,whereappropriate,wewouldpoolresults
Dataextractionandmanagement
ofcomparablegroupsoftrialsusingthefixed-effectmodelandcal-
Pairsofreviewauthorsindependentlyextracteddatausingacus- culate95%CIs.Weplannedtotestheterogeneitybetweencom-
tomiseddataextractiontooltestedpriortouse.Weresolvedany parable trials using a standard Chi² test considered statistically
disagreementsbyconsensusorbyconsultingathirdreviewauthor. significant at a P value < 0.1, after due consideration of the I2
Wecontactedtrialauthorswheretherewasincompletereporting statisticvalue.WeinterpretedtheI2statisticvalueaccordingtothe
ofdata.Weextracteddataonthefollowingtrialcharacteristicsfor followingthresholds(Higgins2011):0%to40%,mightnotbe
entryintoRevMan2014: important;30%to60%,mayrepresentmoderateheterogeneity;
• Studyparticipants:age,gender,condition,inclusion/ 50%to90%,mayrepresentsubstantialheterogeneity;and75%
exclusioncriteria,numberofparticipantsrandomised,number to100%, considerable heterogeneity.Weplannedtoinvestigate
of,andreasonsfor,withdrawalsordropouts; anyevidenceofheterogeneitytodetermineiftherewereobvious
• Study:designandlocation,methodsofsequence differencesinthetrialsthatwerelikelycausesoftheheterogeneity.
generationandallocationconcealment,blinding,intention-to- Iftheheterogeneitywasregardedaslikelytohaveseriouseffects
treat(ITT)orperprotocolanalysis,outcomemeasuresforpain, onthevalidityoftheresults,thenwedidnotcombinethedata.
andresultsofstatisticalanalysis; Where there was significant heterogeneity,we intended to view
• Interventionsused:whereTENSwasappliedandby theresultsof therandom-effectsmodeland presentthesewhen
whom,stimulationparameters(frequency,waveform,pulse appropriate.
amplitude/intensity,pulseduration),electrodedetails,treatment
timeandfrequency,andadverseeffects.
Subgroupanalysisandinvestigationofheterogeneity
Where the data allowed, we planned separate outcome analyses
Assessmentofriskofbiasinincludedstudies
totestthefollowingnullhypothesesthatthereisnodifferencein
Weoriginallyintendedtoassessthemethodologicalqualityoftri- analgesia:
alsusingthescaledevisedbyJadad1996asdetailedintheprotocol. 1. BetweenAL-TENS(visiblephasicmusclecontractions)and
However,withthelaunchofReviewManager(RevMan)in2008, conventionalTENS(novisiblemusclecontraction);
wedecidedtousetheCochraneCollaboration’s’Riskofbias’as- 2. IftheoutcomemeasureisrecordedduringTENS
sessmenttoolasdescribedinChapter8ofHiggins2011.Twore- application;
viewauthorsindependentlyassessedthefollowing:sequencegen- 3. BetweendifferentTENStreatmentdurations;and,
Transcutaneouselectricalnervestimulationforacutepain(Review) 6
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
4. Betweendifferentacutepainconditions. these1065reports,1038wereremovedbecausetheywerenotrel-
evant,didnotmeettheinclusioncriteria,hadadministeredTENS
incombinationwithanothertreatmentaspartoftheformaltrial
design (n=120) or hadnot administeredTENSusing appropri-
RESULTS atetechniqueasdefinedintheTypesofinterventionssection(n=
32).Hencethisupdateincludedsevennewtrials(Amer-Cuenca
2011; de Sousa 2014; Ekblom 1987; Gregorini 2010; Keskin
2012;Kim2012;Pitangui2012),includingtwoofthetrialsthat
Descriptionofstudies
were awaiting classification in the 2011 update (Ekblom 1987;
Gregorini2010).Intotaltherewere19trialsincludedforreview
(Characteristicsofincludedstudies)andallwerepublishedinEn-
Resultsofthesearch
glish.Eleventrialswereawaitingclassification(Cambiaghi2013;
Forthe2011updateweidentified1775reportsintheliterature dePaivaTosato2007;França2012;Hsueh1997;Liebano2013;
searches. For this update, 1421 records were identified through Park2014;Rajpurohit2010;Salvador2005;Salvino2013;Silva
databasesearchingbetween2011and2014.Afterremovalofdu- 2012;Treacy2011).
plicateswescreenedtheabstractsof1065reports(Figure1).Of
Transcutaneouselectricalnervestimulationforacutepain(Review) 7
Copyright©2015TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.