422 LETTERSTOTHEEDITOR
2.Simmons ST, Scheich AR. Reg Anesth Pain Med. 2002;27(2): 180---92.
3.Gil KSL. Fiber-optic intubation:tips from the ASA Workshop. AnesthesiolNews.2012.
4.Casta˜neda Pascual M, Batllori Gastón M, Unzué Rico P, et al. Comparación de las cánulas VAMA y Berman para la intubación fibroscópica orotraqueal en pacientes anestesiados. Rev Esp Anestesiol Reanim. 2013;60: 134---41.
MarceloSperandioRamos
HospitalUniversitário,UniversidadedeSãoPaulo,São Paulo,SP,Brazil
E-mails:marcelo.ramos@hu.usp.br,
marcelosramos@terra.com.br
Availableonline7March2015
http://dx.doi.org/10.1016/j.bjane.2013.11.004
Comparison
between
continuous
thoracic
epidural
and
paravertebral
blocks
for
postoperative
analgesia
in
patients
undergoing
thoracotomy:
meta-analysis
of
clinical
trials
夽Comparac
¸ão
entre
bloqueios
peridural
e
paravertebral
torácicos
contínuos
para
analgesia
pós-operatória
em
pacientes
submetidos
a
toracotomias:
meta-análise
de
ensaios
clínicos
DearEditor:
Thearticleentitled‘‘Comparisonbetweencontinuous tho-racic epidural and paravertebral blocks for postoperative analgesia in patients undergoing thoracotomy: a system-atic review’’, recently published in the Brazilian Journal of Anesthesiology, demonstrates the authors’ concern to showthetherapyeffectivenessforanestheticmanagement ofpostoperativepaininchestsurgeries.1
Reading the scientific article arouses greatinterest to readers; however, some points need to be considered, such as: the softwareused for calculations, the sensitiv-ity analysis method by successive meta-analysis, the use ofmixed-effectmodelanalysis,andthesearchtoidentify statisticalheterogeneity.
Thesoftwareusedinthesearchwasdescribedinthe sec-tionsMethodandReferences,butthelatterisincorrect,and itisimpossibletoidentifytheplacewhereitisavailableand tohaveaccesstothesoftwareforfuturesearchessimilarto this.
Themethodofsuccessivemeta-analysiswasusedbythe authorsatsomepointofthesystematicreviewexecutionto performthesensitivity analysis;however, theoutcome of thisanalysiswasnotreportedintheresults ordiscussion, which did not clarify its realcontribution in this system-aticreview.Thismethodallowstheidentificationofalikely sourceofstatisticalheterogeneityandtheexclusionornot ofthearticle,inanattempttoconsolidatetheresults.2
夽 UniversidadeFederaldeAlagoas,Maceió,AL,Brazil.
Theauthorsreportedtheuseofrandomandfixedeffect modelfor meta-analysiscalculation;however,therandom model was chosen to calculate the meta-analysis when-ever I2 was greater than 30%. Inthe analysis of variables
‘‘assessment of pain at rest after 24h and ‘‘incidence of hypotension’’, the value of I2 was lower than that
pro-posed by the authors, notmatching theresearch method description,andtheresultswerealsodescribedbythe ran-dom insteadof fixed effectmethod. The article does not indicatewhetherthisdescriptionoftheresultswasdueto consensusdecisionoftheauthorsorafailuretoconductthe research.
Theauthorsconsideredthepresenceofheterogeneityas aresearchbiaswhentheyreported‘‘(...)theseresultsmay have beenbiasedbytheincludedstudies heterogeneity’’; however, thepresence ofheterogeneity does notindicate biasinasystematicreview.Testsofheterogeneityareused to determine whether differences between the included studies are genuine (heterogeneity) or if it occurred ran-domlyduringtheanalysis(homogeneity).3Ifthedifferences occurredrandomly,theresultsfoundinsystematicreviews have more credibility, and if heterogeneity is found, the reasonsshouldbecarefullyevaluatedbytheauthorsto con-solidatetheresultsandnotonlybeconsideredaresearch bias.
It is noticed that the statistical heterogeneity present inmost analysiswaslittleexploredbythe authors,andit is possible to disagree with part of their conclusion that says:‘‘Fromthissystematicreview,itisclearthatepidural analgesia isassociated withahigher incidenceof arterial hypotensionandurinaryretention whenit is usedfor lat-eralpaincontrolafterthoracotomyinadultpatients,with evidencelevel1A’’,aslevel1Arequiresminimalorabsent heterogeneityorthatitisproperlyexploredwhile perform-ingasystematicreview.
In short, I congratulate the authors for the article, which brings important results for the understanding of post-operativepainin thoracicsurgery. Systematicreview conclusions are less incisive regarding the clinical signifi-canceofitsresultswhenthoseoftheincludedstudiesdiffer fromeachother.3
Conflicts
of
interest
LETTERSTOTHEEDITOR 423
References
1.Júnior AdP, ErdmannTR, Santos TV,et al. Comparac¸ão entre bloqueios peridural e paravertebral torácicos contínuos para analgesia pós-operatória em pacientes submetidos a toraco-tomias: revisão sistemática. Rev Bras Anestesiol. 2013;63: 433---42.
2.BuenoNB.Explorandoaheterogeneidade.In:BarbosaFT, edi-tor.Introduc¸ãoàrevisãosistemática:apesquisadofuturo.2013. Availableat:http://bit.ly/lrs01[accessed02.01.14].
3.Higgins JP, Thompson SG, Deeks JJ, et al. Measur-ing inconsistency in metaanalyses. BMJ. 2003;327: 557---60.
FabianoTimbóBarbosaa,∗,
TatianaRosaBezerraWanderleyBarbosab, RafaelMartinsdaCunhac
aUniversidadeFederaldeAlagoas(UFAL),Maceió,AL,
Brazil
bCentroUniversitárioUnisebInterativo,Maceió,AL,Brazil cHospitalUnimed,Maceió,Maceió,AL,Brazil
∗Correspondingauthor.
E-mail:fabianotimbo@yahoo.com.br(F.T.Barbosa). Availableonline12August2015
http://dx.doi.org/10.1016/j.bjane.2014.02.015
Foot
drop
following
spinal
anaesthesia
Queda
do
pé
após
raquianestesia
DearEditor,
Wereportacaseoffootdropfollowingspinalanaesthesia. The incidence of nerveinjury relatedtospinal anaesthe-siaislessthan1:10,000,andmostincidenceshaveunknown aetiology.1,2However,ifpatientscomplainofpainor paraes-thesia during spinal anaesthesia they must be watched for any unwanted neurological deficits. We report a case involvingapossibleneedletraumaorlocalanaesthetic drug-relatedneuralstructureinjuryandsubsequentfootdrop.
A healthy 31-year-old adult female was scheduled for anal fissurectomy surgery. She had no medical comorbid-ity.Completebloodcountandcoagulationparameterswere normal.Afterobtaininginformedwrittenconsentandafter overnight fasting, she was prepared for the operation. Routinemonitorization(non-invasiveblood pressure, elec-trocardiography,andpulse-oximeter)wasperformedinthe operatingroom.
Onceallasepticprecautionshadbeencompleted,a27g QuinckeneedlewasinsertedintheL4-L5interspace.Asthe needleenteredthesubarachnoidspace,thepatient exhib-itedajerkyreactionthatwasfollowedbyparaesthesiaand pain.The needlewasimmediately withdrawnslightly and oncethepainhadsubsidedspinalanaesthesiawasachieved with 10mg (2mL) 0.5% bupivacaine (heavy marcaine®,
AstraZeneca, Istanbul, Turkey) In orderto achieve saddle block, the patient was kept in a sitting position for five minutesandwasturnedtoapronepositiontooperation.
Intermsofperioperativesedation,midazolam(3mg)was given intravenously. The operation lasted for 30minutes. Thepatientwaslightlysedatedandwascomfortableduring theprocedure.
Atthepostoperativesixthhour,thepatientnoticedthat she was unable to move her left foot. After light touch neurological examination, pin prick and vibration senses were all reported to be absent. All reflexes were brisk exceptfortheleftknee,theankleandtheplantarreflexes, whichwere absent.Therewasalsoa persistentfootdrop involvingwithleftfootplantar flexion(0/5),although the
rightfootwasnormal.BecausetheMRIwasnormal,surgical intervention was not scheduled. Methylprednisolone (250mg) and vitamin B complex treatment (Bemiks®,
Zentiva,Istanbul,Turkey)werestarted.2,3Dexamethazone (16mg) and B complex therapy were continued for five days. Physiotherapy was scheduled, and the patient was discharged.After3monthsof physiotherapy,thepatient’s symptomsweremarkedlyimproved.
Followingspinalanaesthesia,mechanicaltrauma result-ingfromaneedleoraccidentallyunsuitabledrugplacement arethemostprobablecausesofneurologicalcomplications. Asinmany ofthereportedcases,1---3we couldnotexplain the exact aetiological factor that led tothe neurological complications,whichincludedparaesthesiaandpain.
Orientationoftheneedleisalsoanimportantfactorin termsofthedepthandextentofnerveinjury.Atransverse needle insertion is associated with greater nerve injury, while a horizontal insertion is less dangerous. During the spinalanaesthesiaprocedure,paraesthesiaassociatedwith needlemovement maycausenervedamage.The intensity oftheparaesthesiaisastrongindicatorof nervedamage. Theweaknessandsensorialdefectsmaybelonglasting.4
Werecommendabriefneurologicalexaminationofthe lower limbs before a spinal anaesthesia protocol and, in an acute developed spinal anaesthesia-related foot drop situation, an urgent diagnose is needed and a treatment procedureiscrucialforimprovedlongtermoutcomes.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
References
1.NirmalaBC,GowriKumari.Footdropafterspinalanaesthesia:a rarecomplication.IndianJAnaesth.2011;55:78---9.
2.GhaiA,HoodaS,KumarP,KumarR,BansalP.Bilateralfootdrop followinglowerlimborthopedicsurgeryunderspinalanesthesia. CanJAnesth.2005;52:550.
3.Reynolds F. Damage to the conus medullaris following spinal anaesthesia.Anaesthesia.2001;56:238---47.
