Rev. bras. ortop. vol.49 número5

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w w w . r b o . o r g . b r

Original

Article

Comparative

study

between

physical

examination,

electroneuromyography

and

ultrasonography

in

diagnosing

carpal

tunnel

syndrome

夽

,

夽夽

Arnaldo

Gonc¸alves

de

Jesus

Filho

a,∗

,

Bruno

Fajardo

do

Nascimento

a

,

Marcelo

de

Carvalho

Amorim

a

_,

_Ronald

_Alan

_Sauaia

_Naus

a

_,

Elmano

de

Araújo

Loures

a

_,

_Lucas

_Moratelli

b

a_University_Hospital,_Universidade_Federal_de_Juiz_de_Fora_(UFJF),_Juiz_de_Fora,_MG,_Brazil

b_Universidade_Federal_de_Juiz_de_Fora_(UFJF),_Juiz_de_Fora,_MG,_Brazil

a

r

t

i

c

l

e

i

n

f

o

Articlehistory: Received9July2013 Accepted27August2013

Availableonline16September2014

Keywords:

Carpaltunnelsyndrome Ultrasonography Electromyography

a

b

s

t

r

a

c

t

Objective:Toevaluatethesensitivityofelectromyographyandultrasonographyin diagnos-ingcarpal tunnelsyndrome (CTS), incomparison withphysicalexamination, whichis consideredtobethegoldstandard.

Methods:Inthiscross-sectionalstudy,themedicalfilesof56patientswith70handsaffected byCTSwhowereattendedbetweenMarch2010andJune2012werereviewed.Thestudy includedpatientswithaclinicaldiagnosisofCTS.Thesensitivityofthecomplementary examinationswasanalyzedandcomparedwithphysicalexamination.

Results:Nocturnalsymptomswerefoundin96.4%, thenaratrophyin 62.5%and abnor-malsenseoftouchin50%.Thesensitivitiesfoundwere:ultrasonography,67.1%(95%CI: 55.7%–78.6%);anassociationofphysicalexaminationtests,95.7%(95%CI:90.0%–100%);and electromyography,98.6%(95%CI:95.7%–100%).Thepresenceofatrophy,abnormalitiesofthe senseoftouchandlonger-durationsymptomsincreasedthesensitivityofultrasonography andphysicalexamination.

Conclusion:ThesensitivityofultrasonographyforCTSwaslowerthanthatof electromyog-raphyandphysicalexamination.

夽

Pleasecitethisarticleas:deJesusFilhoAG,doNascimentoBF,AmorimMC,NausRAS,LouresEA,MoratelliL.Estudocomparativoentre oexamefísico,aeletroneuromiografiaeaultrassonografianodiagnósticodasíndromedotúneldocarpo.RevBrasOrtop.2014;49(5):446–51.

夽夽

WorkdevelopedattheOrthopedicsandTraumatologyService,UniversityHospitaloftheUniversidadeFederaldeJuizdeFora,MG, Brazil.

∗ _{Corresponding}_author.

E-mail:[email protected](A.G.deJesusFilho). http://dx.doi.org/10.1016/j.rboe.2014.09.002

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Estudo

comparativo

entre

o

exame

físico,

a

eletroneuromiografia

e

a

ultrassonografia

no

diagnóstico

da

síndrome

do

túnel

do

carpo

Palavras-chave:

Síndromedotúnelcarpal Ultrassonografia Eletromiografia

r

e

s

u

m

o

Objetivo:Avaliarasensibilidadedaeletroneuromiografia(ENMG)edaultrassonografia(USN) nodiagnósticodesíndromedotúneldocarpo(STC)comparadacomadoexamefísico, consideradopadrão-ouro.

Métodos: Estudo seccional pela análise de prontuários de 56 pacientes com 70 mãos acometidascomSTCentremarc¸ode2010ejunhode2012.Asensibilidadedosexames complementaresfoianalisadaecomparadacomadoexamefísico.

Resultados: Constataram-sesintomasnoturnos em 96,4%, hipotrofiatenar em 62,5% e alteraçãodotatoem50%.AsensibilidadedaUSGfoide67,1%(95%IC,55,7%-78,6%);ada associaçãodostestesdoexamefísico,de95,7(95%IC,90,0%-100%);eadaENMG,de98,6% (95%IC,95,7%-100%).Apresençadehipotrofia,dealteraçõesnotatoeomaiortempodos sintomasaumentaramasensibilidadedaUSGedoexamefísico.

EditoraLtda.Todososdireitosreservados.

Introduction

Carpaltunnelsyndrome(CTS)isthecommonestneuropathy ofthe upperextremities.1 _The _incidence_of _the _disease _is estimatedtobebetween0.125%and1%peryearandits preva-lencerangesfrom5%to15%,dependingonthecriteriaused fordiagnosingit.2,3_More_than_80%_of_the_patients_are_over_the ageof40yearsandwomenaremoreaffectedthanmen(5:1). Althoughbilateraloccurrenceiscommon(>50%ofthecases), thedominanthandisusuallythefirsttobeaffectedandis moreseverelyinvolved.4

The following have been described as causal factors: rheumatological and endocrinological diseases; infections; thrombosisofthe medianartery;inflammatoryalterations; bursalfibrotic alterations; bone, muscle and neurovascular abnormalities;trauma;tumorallesions;andpregnancy.CTS hasbeencorrelatedwithmanualactivitiesandtherearealso casesofidiopathicnature.5

Thediagnosisisclinicalanddeterminedfromthehistory andphysicalexamination,6_which_includes_the_Tinel,_Phalen andDurkantests.Tinel’ssign,whichisobservedbymeans oflightpercussiononthewrist,transmitsafeelingof pares-thesiainthedistributionregionofthemediannerve.Phalen’s testconsistsofcompleteflexionofthewristfor60s, with-outapplyingforce.IncasesofCTS,theflexedpositionofthe wristcompressesthemediannerveevenmorethan itwas alreadycompressedintheneutralposition,andalsotransmits afeelingofparesthesiaintheregionofthemediannerve.7

Durkan8_proposed_a_new_test_in_1991,_in_which_the exam-inerusesboththumbstoapplydirectpressuretothecarpal regionfor30s.Thisquicklyproducesthecommonsymptoms ofCTSalongthepathofthemediannerve.

Althoughthediagnosisiseminentlyclinicalandisbased onsymptomsandonthedistributionofsensoryalterations inthehand,itcanbemadebymeansofneurophysiological

methodsforevaluatingtheconductionvelocityofthemedian nerve.7,9_Over_recent_years,_in_the_light_of_the_advent_of high-resolutionultrasonography,ithasbeensoughttodemonstrate theusefulnessofthismethodasanaidtodiagnosingCTS, especiallyincasesinwhichcompatiblesymptomsarepresent together withnormalphysicalandelectroneuromyographic examinationresults.10,11

Thesensitivity ofelectrodiagnostictests onthe median nerverangesfrom49%to84%,whilespecificitiesaround95% havebeenregistered.12 _{Ultrasonography}_has_been_shown_to havesensitivityof77.6%(95%CI:71.6%–83.6%)andspecificity of86.8%(95%CI:78.9%–94.8%)forCTS.13

AmongpatientswithCTS,anatomicalassessmentofthe carpaltunnelisthemostimportantevaluationforthe diag-nosisandtreatment.Chronicfocalcompressionofthemedian nervemayleadtomorphologicalalterationsand demyelina-tion,caused bymechanicalstressthat deformsthemyelin sheath. Ischemia may thecause ofthe intermittent pares-thesia thatgenerallyoccurs duringthe nightor withwrist flexion.14–17

Imaging techniques have gained great importance over recent decades.Buchberger et al.18 _were _the _first _to_report using ultrasonography fordiagnosing this syndrome.Their findingsconfirmedpreviousmagneticresonancestudies.19,20 Thecurrentcriteriausedformagneticresonanceand ultra-sonographyare:edemaofthemediannerveattheentrance tothecarpaltunnelandflatteningofthemediannerve,along with archingofthe flexorretinaculum atits exit from the carpalcanal.21

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Materials

and

methods

This was a cross-sectional study on 56 patients with 70 affectedwristswhowereevaluatedbetweenMarch2010and June2012.Thedatawereobtainedbyreviewingthemedical files.

IndividualswithaclinicalconditionconsistentwithCTS andwithpreviousEMGandUSassessmentsontheaffected wristswereincluded.Patientswereexcludedinthefollowing situations:if theyhad previouslyundergonesurgical treat-mentforneuropathy; if therewere insufficientdatainthe medicalfiles;iftheywerelostfromthefollow-upatthe outpa-tientclinic;andifsomeofthecomplementarytestswerenot done.Complaintsofpainorparesthesiaonthepathofthe mediannerve,withworseningatnight,and presenceofat leastonepositiveclinicalexaminationorevidenceofatrophy inthethenarregion,wereconsideredtobeaclinicalpicture consistentwithCTS.

Thecharacteristicsofthesamplethatwereevaluatedwere age,sex,maritalstatus,ethnicity,retiredstatus,lengthoftime workingandlengthoftimesincethecurrentsymptomsfirst appeared.Clinically,thefollowingwereevaluated:presenceof hypotrophy;alteredsenseoftouch;lossofthumbopposition; nocturnalsymptoms;affectedunilaterallyorbilaterally;and sideaffectedorwithmoreevidentsymptoms.

ThesensitivitiesoftheEMG,USandphysicalexaminations wereevaluated.ThephysicalexaminationincludedtheTinel, DurkanandPhalentests.

The sensitivity of the diagnostic examinations was assessedbycorrelationwiththepatients’characteristics.For this purpose,the samplewasformed byaffectedwrists in patientswithunilateralalterationsandbywristsofthe half-bodywithgreaterseverityofcomplaints,amongthepatients withbilateraldiagnoses.Followingthis,alltheaffectedwrists werestudiedandthesensitivitiesoftheexaminationswere identifiedandcompared.

Thenumericalvariableswereevaluatedwithregardtotheir centraltrendanddispersionmeasurements(mean±standard deviation)andthecategoricalvariableswerecomparedwith regardtofrequency.Thenumericalvariableswerecompared withthecategoricalvariables bymeansoftheANOVA and Mann–Whitney tests, after conformation of normal distri-butionusing theKolmogorov–Smirnovtest. Thecategorical variableswerecomparedwitheachotherbymeansofthe2 andFisherexacttests.Thestatisticalsignificancelevelwas takentobe5%.

Forthestatisticalanalysis,theSPSSsoftwareversion19.0 wasused.

Results

The individuals presented a mean age (± standard devia-tion)of49.91±9.44years(range:32–67).Higherprevalenceof CTSwasobservedamongwomen(94.6%),marriedindividuals (67.9%)andthewhite-skinnedethnicgroup(64.3%). Individ-ualswhowereoccupationallyactiveaccountedfor98.2%of thecasesandthe meanlengthoftimeforwhichtheyhad beeninworkwas7.40±10.88years.

Sometypeofpainwasreportedby74%ofthepatientsand 50% reportedparesthesia.Unilateral symptomsoccurredin 75%and,amongthese,theleftwristwasaffectedin54.8%. Amongthe patientswithbilateral complaints,theleft side presentedmoreevidentcomplaintsin57.1%.

Nocturnal symptomswere presentin 96.4%and muscle hypotrophyin62.5%.Themeantimefromthestartof symp-toms until access to a consultation was 1.99±1.22 years. Alteredsenseoftouchwasobservedin50%ofthecasesand therewerenocasesoflossofthumbopposition.

Presenceofthenarhypotrophywasassociatedwithgreater sensitivity of the physical examinations. Altered sense of touchwasassociatedwithgreatersensitivityinPhalen’stest. Presenceofhypertrophy,alteredsenseoftouchand greater durationofsymptomswerealsoassociatedwithgreater sen-sitivityofUS(Table1).

TheresultsfromtheTinel,PhalenandDurkantests cor-related with each other and with the result from US. No associationamongtheresultsfromthesethreetestsandthe resultfromEMGwasobserved(Table2).

ThesensitivityofEMGwassignificantlygreaterthanthe sensitivityofUS,incomparisonwiththephysicalexamination tests(Table3).

Discussion

ThesensitivityoftheTinelandPhalentestsandofUSamong the samplestudied was concordant with the literature.1,13 However, the sensitivity of EMG(95% CI: 95.7%–100%) was higherthan thatintheliterature,inwhichvaluesbetween 85%and90%hadbeenestablished.22

ThesensitivityofEMGfordiagnosingCTSwassignificantly greaterthan thesensitivityofbothUSandthethree physi-caltests(Tinel,PhalenandDurkan)whenassessedseparately. Tinel’stestalonehadthelowestsensitivityofallofthetests. InthestudyconductedbyDurkan8 ₍₁₉₉₁₎_on₃₁_patients seenbetween1987and1990,46handswithaconfirmedEMG diagnosisofCTSwereevaluated.Thisauthor’stestwas pos-itive in40 handsoutofthe46evaluated(87%).Inapplying Phalen’stest,32(70%)ofthe46handspresentedthesign,while Tinel’ssignwaspresentin26hands(56%).

Inthesamestudy,thesensitivityofPhalen’stestwas70% anditsspecificitywas84%,withafalse-positiverateof16%. Ontheotherhand,Tinel’stestwaslesssensitive:56%ofthe patientsinwhomCTShadbeenconfirmedbymeansof elec-trophysiologicalexaminationswerepositiveinthistest,with specificityof80%forthehands,and20%showedfalse posi-tiveresults.InDurkan’stest,thesensitivitywas87%andthe specificitywas90%,withafalsepositiverateof10%.Inviewof thehighsensitivityandspecificityofthistest,itcanbeused amongsomepatientswithsignsandsymptomstypicalofCTS toidentifycandidatesforsurgicaltreatment,therebyavoiding expenditureoncomplementaryexaminations.8

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Table1–Comparisonofsensitivitiesandmeansensitivitiesoftheexaminationsperformedon56patientswithCTS, accordingtothecharacteristicsofthesample.Forthepatientswithabilateraldiagnosis,thebodyhalfwiththegreater

complaintwasevaluated.

Samplecharacteristics n(%) n(sensitivity%)ormean US EMG

Physicalexamination

Tinel Phalen Durkan Ti+Ph Ti+D Ph+D Ti+Ph+D

Sex p=0.636 p=0.764 p=0.732 p=0.795 p=0.795 p=0.861 p=0.895 p=0.614 p=0.964 Male 2(3.6) 1(50.0) 2(100) 2(100) 2(100) 2(100) 2(100) 2(100) 1(50.0) 2(100) Female 54(96.4) 33(61.1) 47(87.0) 46(85.2) 48(88.9) 48(88.9) 50(92.6) 51(94.4) 34(63.0) 53(98.1) Maritalstatus p=0.834 p=0.422 p=0.813 p=0.290 p=0.508 p=0.844 p=0.854 p=0.864 p=0.789 Single 14(25.0) 8(57.1) 11(78.6) 12(85.7) 11(78.6) 12(85.7) 13(92.9) 13(92.9) 9(64.3) 14(100) Married 38(67.9) 24(63.2) 34(89.5) 33(86.8) 35(92.1) 35(92.1) 35(92.1) 36(94.7) 24(63.2) 37(97.4) Widowed 4(7.1) 2(50.0) 4(100) 3(75.0) 4(100) 3(75.0) 4(100) 4(100) 2(50.0) 4(100) Ethnicity p=0.293 p=0.836 p=0.478 p=0.894 p=0.163 p=0.711 p=0.425 p=0.344 p=0.754 Black 7(12.5) 3(42.9) 6(85.7) 5(71.4) 6(85.7) 5(71.4) 6(85.7) 6(85.7) 5(71.4) 7(100) Mixed 13(23.2) 10(76.9) 12(92.3) 11(84.6) 12(92.3) 11(84.6) 12(92.3) 12(92.3) 10(76.9) 13(100) White 36(64.3) 21(58.3) 31(86.1) 32(88.9) 32(88.9) 34(94.4) 34(94.4) 35(97.2) 20(55.6) 35(97.2) Retiredstatus p=0.607 p=0.875 p=0.857 p=0.893 p=0.893 p=0.929 p=0.946 p=0.375 p=0.982 Yes 1(1.8) 1(100) 1(100) 1(100) 1(100) 1(100) 1(100) 1(100) 0(0) 1(100) No 55(98.2) 33(60.0) 48(87.3) 47(85.5) 49(89.1) 49(89.1) 51(92.7) 52(94.5) 35(63.6) 54(98.2) Nocturnalsymptoms p=0.150 p=0.236 p=0.018a _p₌_0.205 _p₌_0.010a _p₌_0.139 _p₌_0.105 _p₌_0.136 _p₌_0.964

Present 54(96.4) 34(63.0) 48(88.9) 48(88.9) 49(90.7) 50(92.6) 51(94.4) 52(96.3) 35(64.8) 53(98.1)

Absent 2(3.6) 0(0) 1(50.0) 0(0) 1(50.0) 0(0) 1(50.0) 1(50.0) 0(0) 2(100)

Hypotrophy p=0.033a _p₌_0.009a _p₌_0.119 _p₌_0.024a _p₌_0.133 _p₌_0.016a _p₌_0.048a _p₌_0.001a _p₌_0.625

Present 35(62.5) 25(71.4) 34(97.1) 32(91.4) 34(97.1) 33(94.3) 35(100) 35(100) 28(80.0) 34(97.1) Absent 21(37.5) 9(42.9) 15(71.4) 16(76.2) 16(76.2) 17(81.0) 17(81.0) 18(85.7) 7(33.3) 21(100) Senseoftouch(order) p=0.085 p=0.005a _p₌_0.352 _p₌_0.012a _p₌_0.665 _p₌_0.056b _p₌_0.118 _p_<_0.001a _p₌_0.500

Normal 28(50.0) 14(50.0) 21(75.0) 23(82.1) 22(78.6) 25(89.3) 24(85.7) 25(89.3) 11(39.3) 27(96.4) Altered 28(50.0) 20(71.4) 28(100) 25(89.3) 28(100) 25(89.3) 28(100) 28(100) 24(85.7) 28(100) Symptoms p=0.267 p=0.433 p=0.651 p=0.528 p=0.528 p=0.305 p=0.414 p=0.132 p=0.750 Unilateral 42(75.0) 24(57.1) 36(85.7) 36(85.7) 37(88.1) 37(88.1) 38(90.5) 39(92.9) 24(57.1) 41(97.6) Bilateral 14(25.0) 10(71.4) 13(92.9) 12(85.7) 13(92.9) 13(92.9) 14(100) 14(100) 11(78.6) 14(100) Side p=0.569 p=0.091 p=0.207 p=0.023a _p₌_0.154 _p₌_0.392 _p₌_0.162 _p₌_0.529 _p₌_0.446

Right 25(44.6) 15(60.0) 24(96.0) 23(92.0) 25(100) 24(96.0) 24(96.0) 25(100) 16(64.0) 24(96.0) Left 31(55.4) 19(61.3) 25(80.6) 25(80.6) 25(80.6) 26(83.9) 28(90.3) 28(90.3) 19(61.3) 31(100) Age(years) p=0.690 p=0.359 p=0.914 p=0.179 p=0.376 p=0.985 p=0.608 p=0.843 p=0.112

Meanforpositivetests 49.5 49.47 49.85 49.32 49.52 49.9 49.75 49.71 50.18

Meanfornegativetests 50.55 53 50.25 54.83 53.17 50 52.67 50.24 35

Lengthoftimeworking (years)

p=0.162 p=0.870 p=0.888 p=0.850 p=0.375 p=0.311 p=0.510 p=0.738 p=0.262

Meanfornegativetests 9.09 7.29 7.13 8.5 9.5 2 2.67 7.81 15

Durationofsymptoms (years)

p=0.424 p=0.568 p=0.259 p=0.849 p=0.892 p=0.336 p=0.601 p=0.029a _p₌_0.680

Meanfornegativetests 1.91 2 1.5 2.16 2.17 1.38 1.5 1.62 2

TOTAL 56(100) 34(60.7) 49(87.5) 48(85.7) 50(89.3) 50(89.3) 52(92.9) 53(94.6) 36(64.3) 55(98.2)

Ti,Tinel;Ph,Phalen;D,Durkan;EMG,electroneuromyography;US,ultrasonography;+,associationbetweentests.

a _Statistical_{significance.} b _Close_to_statistical_{significance.}

sense of touch and increased sensitivity of US. Posi-tive results from US were correlated with greater dura-tion of symptoms, which suggests progression of the lesion.

ThepresenceofnocturnalsymptomsinfluencedDurkan’s test and increased its sensitivity. However, the number of caseswithoutnocturnalsymptomswastoosmalltovalidate thisobservation.There wasnosignificantdifferenceinthe sensitivityofEMGregardingthecharacteristicsofthesample. The association between the results from the physical examinationtestsandtheresultsfromUSsuggeststhatthis

complementary examination positively identified damage thathadbeenclinicallyperceivedinthephysicalexamination. On the other hand, EMG seemed to be capable of show-ingsubclinicaldamage,giventheabsenceofevidenceofan associationbetweentheothertestsandthehighsensitivity encountered.

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Table2–Evaluationoftheassociationsbetweenthediagnosticexaminationson70handsaffectedwithCTSin56 patientsattendedatauniversityhospital.

Physicaltest Physicaltest US EMG

Tinel Phalen Durkan Ti+Ph Ti+D Ph+D Ti+Ph+D Positiveresultinbothtestsinrelationtothetotal(%)

Tinel – 61.400 58.6 62.9 62.9 61.4 62.9 52.9 61.4 Phalen 0.003a _– ₈₀ _88.6 _82.9 _88.6 _88.6 _65.7 _87.1

Durkan 0.026a _0.012a _– _80.0 _85.7 _85.7 _85.7 _61.4 _84.3

Ti+Ph 0.001a _0.000a _0.055b _– _84.3 _88.6 _90.0 _65.7 _88.6

Ti+D 0.001a _0.028a _0.000a _0.019a _– _88.6 _90.0 _64.3 _88.6

Ph+D 0.141 0.000a _0.000a _0.002a _0.002a _– _94.3 _65.7 _92.9

Ti+Ph+D 0.047a _0.001a _0.002a _0.001a _0.001a _0.0a _– _65.7 _94.3

USG 0.000a _0.001a _0.057b _0.004a _0.035a _0.1 _0.25 _– _67.1

EMG 0.629 0.886 0.857 0.900 0.9 0.943 0.957 0.329 –

Significanceofthecorrelation(p-value)

Ti,Tinel;Ph,Phalen;D,Durkan;US,ultrasonography;EMG,electroneuromyography;+,associationbetweentests.

a _Statistical_{significance.} b _Tendency_toward_{significance.}

Table3–Sensitivityofthetestsinrelationtothe70handsaffected.

Physicaltest US EMG

Tinel Phalen Durkan Ti+Ph Ti+D Ph+D Ti+Ph+D

s(%) 62.9 88.6 85.7 90 90 94.3 95.7 67.1 98.6 95%CI 50.0–74.3 80.0–95.7 77.1–92.9 81.5–97.1 82.9–95.7 88.6–98.6 90.0–100 55.7–78.6 95.7–100

Ti,Tinel;Ph,Phalen;D,Durkan;US,ultrasonographyEMG,electroneuromyography;s,sensitivity;+,associationbetweentests.

ThefalsenegativerateforEMG(95%CI:0%–4.3%)forthe samplestudiedherewassignificantlylowerthaninthe liter-ature.WernerandAndary22_reported_that_false_negative_rates forEMGof10–15%werepossibleindiagnosingCTS (sensitiv-ityof85–90%).Thiscanbeexplainedbythefactthatthereare patientswithintermittent symptomsinwhom demyelinat-ingoraxonallesionsdonotoccur.Dhongetal.24_and_Pádua etal.25_pointed_out_that_there_were_false_negative_results_in theirstudiesand statedthat giventhepatients’symptoms andtheresultsfromtheelectrophysiologicalexaminations, thelattershouldbeconsideredtobethereferenceandthe diagnosis should be confirmed through the typical symp-toms.

Nonetheless, the significantly higher sensitivity of EMG that was observed (95% CI: 95.7%–100%) can partly be explainedbythelongperiodwithsymptomsthatthepatients experienced before gaining access to the healthcare sys-tem.

BecauseUSisanobserver-dependentexamination,itmay give rise to conflicting resultsand opinions.26 _Researchers warnthatinformationbiasmayexist,giventhatUSimages thatareevaluatedwereproducedbydifferentprofessionalson differentequipment.Moreover,thepossibilitythatlabor-law orsocial-securityinterestsmightinfluencetheresultscannot bedismissed.

On the other hand, US providesthe possibility of diag-nosticevaluationbothofassociateddiseases andofneural anatomicalvariations.Inaddition,itcanbedonequicklyand dynamically,atarelativelylowcostinrelationtoEMG.26

Conclusion

ThesensitivityofEMGfordiagnosingCTSwassignificantly greater than the sensitivities ofUS and the threephysical examinationtests(Tinel,PhalenandDurkan),whenevaluated separately.Whenusedtogether,thethreeclinicaltests pre-sentedsensitivitythatwasgreaterthanthatofUS.Inaddition, the results from the physicalexamination tests(evaluated bothseparatelyandtogether)andfromUSDdidnotshowany correlationwiththeresultsfromEMG.

EMGwasshowntobeavaluablecomplementary examina-tioninthecasesstudied.Itwasnotinfluencedbythevariables considered and showedsensitivitygreater than thatofUS. Prospective studies with larger samples that evaluate the specificityandpredictivevalueofcomplementary examina-tionsandclinicaltestsshouldbeenvisagedsothatdefinitive conclusionscanbereached.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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