Rev. bras. ortop. vol.49 número6

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

Original

article

Cubital

compressive

neuropathy

in

the

elbow:

in

situ

_neurolysis

versus

_anterior

_{transposition}

_–

comparative

study

夽

,

夽夽

Marco

Sousa

∗

_,

_Ricardo

_Aido,

_Miguel

_Trigueiros,

_Rui

_Lemos,

_César

_Silva

DepartamentodeOrtopediaeTraumatologia,CentroHospitalardoPorto,Porto,Portugal

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received25June2013 Accepted21October2013 Availableonline22October2014

Keywords:

Ulnarnerve Elbow Pain Paresthesia

Ulnartunnelsyndrome

a

b

s

t

r

a

c

t

Objective:Tocomparetheresultsfromtwoofthemostcommonlyusedsurgicaltechniques:

insitudecompressionandsubcutaneoustransposition.Theprocessesofpatientstreated surgicallyinapublicuniversityhospitalbetweenJanuary2004andDecember2011were reviewed.Casesofproximalcompressionofthenerve,angulardeformityoftheelbowand systemicdiseasesassociatedwithnon-compressiveneuropathywereexcluded.

Methods:Ninety-seven cases were included (96 patients). According to the modified

McGowanscore,14.4%ofthepatientspresentedgradeIa,27.8%gradeII,26.8%gradeIIband 30.9%gradeIII.Insituneurolysisofthecubitalwasperformedin64casesandsubcutaneous anteriortranspositionin33.

Results:AccordingtothemodifiedWilsonandKnoutscore,theresultswereexcellentin

49.5%,goodin18.6%,onlysatisfactoryin17.5%andpoorin14.4%.Incomparingthetwo techniques,weobservedsimilarnumbersofexcellentandgoodresults.GradesIIbandIII wereassociatedwithmoreresultsthatwerelesssatisfactoryorpoor,independentofthe surgicaltechnique.

Conclusion: Bothtechniqueswereshowntobeefficientandsafefortreatingcubitaltunnel

syndrome.

Neuropatia

compressiva

cubital

no

cotovelo:

neurólise

in

situ

versus

transposic¸ão

anterior–Estudo

comparativo

Palavras-chave:

Nervoulnar Cotovelo Dor Parestesia

r

e

s

u

m

o

Objetivo:Compararosresultadosdeduasdastécnicascirúrgicasmaisusadas,a

descom-pressãoinsitueatransposic¸ãosubcutânea.Foramrevistososprocessosdosdoentestratados cirurgicamentenumhospitaluniversitáriopúblicoentrejaneirode2004edezembrode2011. Foramexcluídascompressõesproximaisdonervo,deformidadesangularesdocotoveloe doenc¸assistêmicasassociadasaneuropatianãocompressiva.

夽

Pleasecitethisarticleas:SousaM,AidoR,TrigueirosM,LemosR,SilvaC.Neuropatiacompressivacubitalnocotovelo:neuróliseinsitu

versustransposic¸ãoanterior–Estudocomparativo.RevBrasOrtop.2014;49:647–652.

夽夽

WorkdevelopedintheDepartmentofOrthopedicsandTraumatology,PortoHospitalCenter,Porto,Portugal.

∗ _{Corresponding}_author_.

E-mail:marcoguedes81@gmail.com(M.Sousa).

http://dx.doi.org/10.1016/j.rboe.2014.10.005

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Síndromedotúnelulnar Metodos: Foramincluídos97casos(96doentes).SegundooescoremodificadodeMcGowan, 14,4%dospacientesencontravam-senoGrauIa,27,8%noII,26,8%noIIbe30,9%noIII.A neuróliseinsitudocubitalfoifeitaem64casoseatransposic¸ãoanteriorsubcutâneaem33.

Resultados: SegundooescoremodificadodeWilsoneKnout,osresultadosforamexcelentes

em49,5%,bonsem18,6%,apenassatisfatóriosem17,5%epobresem14,4%.Nacomparac¸ão dasduastécnicasobservamosvaloressimilaresderesultadosexcelentesoubons.Osgraus IIbeIIIestãoassociadosamaisresultadosmenossatisfatóriosoumausindependentemente datécnicacirúrgica.

Conclusão: Asduastécnicasserevelameficientesesegurasnotratamentodosíndromedo

túnelcubital.

Introduction

After observing that the cubital nerve was compressed at the elbow, in a fibro-osseous space defined by a ligament betweenthe medialepicondyle and theolecranon, Feindel andStratford1_used_the_term_“cubital_tunnel_syndrome”_for thefirsttime.Oneyearearlier,Osborne2_had_described sim-pledecompressionofthenervebymeansofsectioningthis sameligament.However,thefirstpublishedpapersdatefrom 1878,theyearinwhichPanas3_described_the_condition_and Marchand4_described _a_procedure_for_releasing_and stretch-ingthecubitalnerve.Theconditionof“toxicneuritisofthe cubitalnerve” wasalsodescribedbyBuzzard5 _in₁₉₂₂_and, twodecadeslater,Learmonth6_also_described_techniques_for submuscularandintramusculardecompressionand transpo-sition.

Compressionofthecubitalnerveisacommoncondition andmayoccuratseverallevels.Compressionattheelbowis thecommonestformofcubitalcompression7–9_and_is_the sec-ondcommonestcompressionneuropathyoftheupperlimbs. Thediagnosis isbased on symptoms, signs, orthopedic testsandelectrophysiologicalstudies.

Manycasesofcubitaltunnelsyndromecanbetreated con-servativelywithoutsurgery.Nevertheless,somecasesrequire surgicaltreatmentwithaviewtoavoidingpersistenceofthe symptomsandprogressionoftheneurologicaldeterioration. Thesurgicaltreatmentshouldbeguidedbythefollowing prin-ciples: (1) release of all the possible compression sites; (2) preservationofthevascularizationofthecubitalnerveatthe elbow;and(3)earlymobilizationoftheelbow.

Thecommonestsurgicaloptions includesimple decom-pression, medial epicondylectomy, subcutaneous anterior transposition,intramuscularanteriortranspositionand sub-muscularanteriortransposition.

Theelbowisadynamicjoint.Overthecourseoftheday, it flexes and extends to placethe hand in functional pos-itions.Throughthismobility,changestotheshapeandspace ofthecubitaltunneltakeplace.Whentheelbowisflexed,the tunnelbecomesflatter10_and_the_arcuate_ligament_becomes tensioned,11 _which_leads_to_reduction_of_the_space_available forthenerve11,12_and_increased_pressure_inside_the_tunnel.13

FeindelandStratford1 _and_Osborne2_advocated_that sec-tioning the fibrotic band that forms the ceiling of this tunnel would be sufficient for relieving the pressure and

consequentlyrelievingthesymptomsinthemajorityofthe cases.

Undernaturalconditions,thenerveisalsosubjectto trac-tionandexcursionduringthenormalmovementoftheelbow. Anteriortranspositionhastheaimoftransferringthenerve toapointanteriortotheaxisofmobilization oftheelbow. Thisdiminishesthetensionandalsoeliminatesthepressure onthecubitaltunnel.

There is no consensus in the literature regarding the bestsurgicaltreatmentforcubitaltunnelsyndrome.Anterior transpositionisperhapstheproceduremostofteneffected.14 Nonetheless, other authors have defendedthe notion that simple decompression is just as effective as transposition and presentsasimilarsuccessrateandlowercomplication rate.15–17

The present study had the aimof expandingthe infor-mation available on comparisons of results between two techniques thatare widelyusedfortreating cubitaltunnel syndrome:insitudecompressionandsubcutaneousanterior transposition.

Material

and

methods

The records of all patients who were treated surgically at our institution between January 2004 and December 2011 were reviewed. The inclusion criterion was taken to be a diagnosis of idiopathic cubital tunnel syndrome based on physicalexaminationandelectromyographicanalysis.Cases of proximalcompression ofthe nerve, angulardeformities of the elbow and systemic diseases associated with non-compressiveneuropathywereexcluded.

Inthismanner,97caseswereobtained,correspondingto 96patients(56menand40women),withameanageof51.91 years(range:15–84).Therightsidewasinvolvedin51patients

andtheleftsidein46(Table1).

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Table1–Demographiccharacteristicsofthepatientsincludedinthestudy.

Total Neurolysis Transposition p

No.ofpatients(n) 97 64 33

Sex(n)

Male 56(58.3%) 38(60.3%) 18(54.5%) 0.373

Female 40(41.7%) 25(39.7%) 15(45.5%)

Meanage(SD) 51.9(14.9) 51.2(14.7) 53.3(15.6) 0.535

Follow-up(months) 10.3(4–33) 9.3(4–29) 11.7(6–33)

Reinterventions 2 2 0

Side 50R;47L 28R;37L 22R;10L

Thus,14.4%(14)ofthepatientswereingradeI,27(27.8%) inIIa,26(26.8%)inIIband30(30.9%)inIII(Table2).

Insituneurolysisofthe cubitalnerve wasperformed in 64cases,whilesubcutaneousanteriortranspositionwas per-formed in 33 cases. Among the patients who underwent neurolysis,12.5%were ingradeI,29.7% inIIA, 28.1%inIIB and29.7%inIII.Amongthosewhounderwentanterior trans-position,18.2%wereingradeI,24.2%inIIA,24.2%inIIBand theremaining33.3%inIII(Table3).Nostatisticallysignificant differencesinthe patients’ preoperativestageaccording to surgerygroupwereobserved(p=0.817).

Thepostoperativeevaluationwasstratifiedinaccordance withthesystemofWilsonandKnout,19_in_which_an_excellent result corresponded to minimal sensory and motor alter-ations,without tension at the incision site; good signified moderatesensoryandmotoralterations;satisfactorysignified improved,butwithpersistentalterations;andpoorsignified noimprovementorevenworseningofthestate.

In the descriptive analysis, the continuous variables were represented by the mean and standard deviation.

Table2–Characterizationofthesampleinabsoluteand relativefrequencies.

n %

Typeofsurgery

Neurolysis 64 66.0

Transposition 33 34.0

Total 97 100.0

Sex

Male 56 58.3

Female 40 41.7

Total 96 100

Postoperativeresult

Excellent 48 49.5

Good 18 18.6

Satisfactory 17 17.5

Poor 14 14.4

Total 97 100.0

Preoperativegrade

I 14 14.4

IIA 27 27.8

IIB 26 26.8

III 30 30.9

Total 97 100.0

Mean (min–max)

SD

Age 51.91(15–84) 14.9

The categorical variables were represented by the

abso-lute frequency (n) and the relative frequency (%). With

the aim of selecting appropriate statistical tests, the

Kolmogorov–Smirnovtestwasusedtoascertainwhetherthe

study variables followed normal distribution. To compare

means,Student’sttestforindependentsampleswasused.

Thechi-square testorFisher’s exacttest(whenapplicable) wereusedtoanalyzeassociationsbetweenpairsofcategorical variables.

The four grades of the modified McGowan scale were

regroupedintotwolevels:gradeIwithIIA;andgradeIIBwith III.ThepostoperativeevaluationusingtheWilsonandKnout systemwasreclassifiedintotwogroups:excellentand satis-factory,goodandpoor. Thestatisticaltestswereconducted bilaterallywithasignificancelevelof5%.Thestatistical anal-ysisonthedatawasperformedusingtheIBMSPSSStatistics 20.0software.

Results

FromthemodifiedWilsonandKnoutclassification,outofthe

97 operations performed, 48 (49.5%)produced an excellent

result,18(18.6%)good,17(17.5%)satisfactoryand14(14.4%) poor.Anewsurgicalinterventionwasonlynecessaryin rela-tiontotwopatients(Table1).

Nodifferencesrelatingtosexwereobservedwithregardto thesurgicaltechnique.Themeanagewas52(14.9)years.The patientswhounderwenttranspositionsurgeryweretwoyears olderthanthosewhounderwentneurolysis(53.3versus51.2). Comparison between the results from the two surgical techniques showed that there were no statistically sig-nificant differences, with similar values for the rates of excellentresults(48.4%forneurolysisversus51.5%foranterior

Table3–Comparisonofpreoperativegradeamongthe patientsaccordingtosurgerygroup(neurolysisor transposition).

PreoperativegradebasedonthemodifiedMcGowanscore

GradeI Neurolysis Transposition p

Preoperativegrade n % n %

I 8 12.5 6 18.2 0.817

IIA 19 29.7 8 24.2

IIB 18 28.1 8 24.2

III 19 29.7 11 33.3

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Table4–Comparisonofthepostoperativeresults accordingtothesurgicaltechniqueused.

ModifiedWilsonandKnoutscore

Result Neurolysis Transposition p

n % n %

Excellent 31 48.4 17 51.5 0.957

Good 12 18.8 6 18.2

Satisfactory/poor 21 32.8 10 30.3

Total 64 33

Table5–Comparisonofthepostoperativeresults accordingtopreoperativegradeforthesurgical techniqueofneurolysis.

Result Preoperativegrade p

I/IIA IIB/III

n % n %

Excellent 15 55.6 16 43.2 0.559

Good+satisfactory+poor 12 44.4 21 56.8

Total 27 37

Table6–Comparisonofthepostoperativeresults accordingtopreoperativegradeforthesurgical techniqueoftransposition.

Result Preoperativegrade p

I/IIA IIB/III

n % n %

Excellent 9 64.3 8 42.1 0.208

Good+satisfactory+poor 5 35.7 11 57.9

Total 14 19

transposition) and good results (18.8% versus 18.28%).

Regardingtheresultsthatwereonlysatisfactoryorpoor,the rateswere32.8%forneurolysisand30.3%forsubcutaneous transposition(Table4).

Intheanalysisstratifiedaccordingtotheinitialgradefor thetwotechniques(Tables5and6),itwasseenthat41patients wereingradesIandIIa,ofwhom27 underwentneurolysis and 14,transposition.Amongthe patientswho underwent neurolysis,55.6% achieved anexcellent result and 44.4% a good,satisfactoryorpoorresult.Anexcellentresultwasalso achievedby64.3%ofthe14patientswhounderwent transpo-sition.AmongthepatientsinitiallyclassifiedingradesIIBor III,37underwentneurolysisand19transposition,and excel-lentresultswereattainedby43.2%and 42.1%,respectively, whiletheresultsweregood,satisfactoryorpoorin56.8%and 57.9%,respectively.

Onlytwopatientshadtheneedforfurthersurgical inter-vention.Bothofthesehadundergonesimpledecompression

(Table2).

Discussion

Several surgical techniques have been put forward for treating compression of the cubital nerve in the elbow.

Excellent 0

10 20 30 40 50 60

Good Satisfactory/poor

Neurolysis Transposition 48.4 51.5

18.8

32.8 30.3

18.2

Fig.1–Postoperativeresultsaccordingtothesurgical techniqueused,expressedasrelativefrequencies(%).

Medial epicondylectomy is rarely performed.20,21 Subcuta-neousanteriortranspositionandsimpledecompressionare the proceduresmostused. Inourstudy,onlypatients who underwent operations using these two techniques were included, giventhatbyalargemajority,thesearethe tech-niquesmostperformedinourdepartment.

Inanalyzingtheresults,itseemsthattherewasno pre-ponderanceofonetechniqueovertheother.Independentof thetechnique,therateofexcellentresultsamongthepatients reached48.5%.Whencomparedaccordingtotechnique,the rates of excellent results were close: 48.4% for neurolysis and51.5%fortransposition.Satisfactoryorpoorresultswere obtainedby32.8%and30.3%,respectively,whichreinforced the similarity (Fig. 1).Thisanalysisalsoshowed thatthere wasatendencyforpatientswithhighergradesatthetime ofthe surgery (IIBand III)to havelower rates ofexcellent results(43.2%and42.1%),althoughnostatisticallysignificant differentwasobservedinthisregard(neurolysisp=0.957;and transpositionp=0.559).Thistendencywasshowntobe inde-pendentofthetechniqueandconfirmswhathasbeenwidely disseminatedintheliterature,i.e.thatthechancesof allevi-atingthepainandrecoveringsensitivityandmotorstrength areinverselyrelatedtotheinitialgradeofneuropathy.

The notable study on cadavers by Gelberman et al.22 demonstratedthatintraneuralpressureincreasesmorethan does extraneuralpressure whenflexionisgreater than90◦_.

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pressurevaluesthatwerehighallthetime,eveninextension, andwhichwerearoundfourtimeshigherinflexion.

Morerecentstudies,29 _also_conducted_on_cadavers,_have demonstratedthatelongationofthenerveoccursespeciallyin thesegmentproximaltotheepicondyleandbetween30◦_and

90◦_and_then_the_length_remains_constant_until₁₃₅◦_._However,

ataround135◦_,_the_area_and_sagittal_curvature_of_the_tunnel

decreaseand forcethe nerveinto aflattenedshape.These findingssuggestthatthecompressionisgreatestat135◦_.

BasedonthefindingsofGelbermanetal.,22_many ortho-pedistsabandonedthesurgicaltechniqueinitiallydescribed byOsborneand started toperformanterior transpositions. However,overthelastfewyears,severalstudieshave demon-stratednotonlythatsimpledecompressionmay bejust as effective as anterior transposition, but also that the latter maybeassociatedwithagreater numberofcomplications. Oneofthefactors maybethepossibilitythat blood vascu-larizationmight bedisturbed duringthe transposition.30–32 Ogataet al.33 _demonstrated_in _an_experimental_study _that thistranspositionisassociatedwithdecreasedregionalblood flowforatleastthreedaysafterthesurgery.Inarandomized prospectivestudyon44patients,BiggsandCurtis16_concluded thattherewere no differencesinthe resultsbetween sim-pleneurolysisandanteriortranspositionandrecommended theformerbecauseofthelowernumberofcomplications.In anotherrandomizedprospectivestudyon152patients, Bar-tels et al.15 _compared_subcutaneous _anterior _{transposition} andsimpledecompression andalsoconcludedthat simple decompressionhadequalefficacybutwithalower compli-cationrate(23versus 7,amongatotalof30), whichwould alsobeassociatedwith lower cost.In another randomized studyon70patientsand48monthsoffollow-ups,Gervasio etal.17_also_did_not_find_any_{statistically}_significant_differences betweensimpledecompressionandsubmuscular transposi-tion.Inafourthprospectivestudy withafollow-upof63.1 months,Keineretal.34_concluded_that_the_two_techniques_led tosimilarresultsandthatsimpledecompressionshouldbe preferredbecause itwasless invasive.Nabhanet al.35 _also prospectivelycomparedsimpledecompressionand subcuta-neousanteriortranspositionandreportedthattherewereno differencesinthe resultsand thereforealsorecommended simpledecompressionasthepreferredtreatmentbecauseit isasimplerprocedure.Furthermore,twometa-analyses con-ductedbyMacadametal.36_and_Zlowodzki_et_al.37_did_not_find anystatisticallysignificantdifferences betweenthevarious techniques.

Ourstudyseemstobeconcordantwithmostoftherecently publishedpapersonsurgicaltreatmentofthispathological condition.Despite the needforreinterventioninthe cases oftwopatientswhowereinitiallytreatedbymeansof sim-pledecompression,mostofthe patientstreated usingthis techniqueachievedthesameresultasthosewhounderwent subcutaneoustransposition,independentoftheinitialgrade. Theabsenceofcomplicationsinourstudy,incomparisonwith theotherscited,can beexplainedbythe factthatinsome oftheseotherstudies,anteriortranspositionthatsometimes wasintraorsubmuscularwasusedasthecomparison.Thisis generallyassociatedwithahighercomplicationrate.

From the analysis on the literature, it also seems that medial epicondylectomy has an increasingly limited role.

Muermans et al.38 _analyzed _their _results _from ₆₀ epi-condylectomyproceduresperformedon51patientsandfound excellent resultsin 75% ofthem. However, 21 of these 51 patients reported pain in the medial epicondyle after the operation. This was similar to the result obtained by Efs-tathopoulos et al.,39 _in_which_45% _of_the _patients_operated continuedtopresentpainsixmonthsafterwards.

Conclusion

Thisstudywaslimitedbyitsretrospectivenatureandbythe smallnumberofpatientsinsomeofthesubgroupsanalyzed. The postoperative results did not present any correlation withthesurgicaltechniqueused,giventhatindependentof the technique, most ofthe patients achieved an excellent result. This reinforcesthe ideathat simple decompression enablesresultssimilartothosefromsubcutaneousanterior transposition.Therefore,withdueregardforthegreater tech-nicalsimplicityofsimpledecompression,wewouldreserve transposition only forcases ofnerves with a potentialfor subluxation,post-traumaticstiffness,valgusinstability,late paralysisofthecubitalnerveorfailureofsimple decompres-sion.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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