Comparison between erector spinal plane block and epidural block techniques for postoperative analgesia in open cholecystectomies: a randomized clinical trial

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SCIENTIFIC ARTICLE

Comparison between erector spinal plane block and epidural block techniques for postoperative analgesia in open cholecystectomies: a randomized clinical trial

Thiago Mamoru Sakae

^a^,^b^,∗

, Luiz Henrique Ide Yamauchi

^a^,^c^,^d

, Augusto Key Karazawa Takaschima

^a^,^c^,^d

, Julio C. Brandão

^d

, Roberto Henrique Benedetti

^a^,^b^,^c^,^d

aServic¸odeAnestesiologiaSIANEST,Florianópolis,SC,Brazil

bUniversidadedoSuldeSantaCatarina(UNISUL),Florianópolis,SC,Brazil

cHospitalFlorianópolis,Florianópolis,SC,Brazil

dTSASociedadeBrasileiradeAnestesiologia(SBA),RiodeJaneiro,RJ,Brazil

Received15July2019;accepted1December2019 Availableonline10February2020

KEYWORDS Cholecystectomy;

Analgesia;

Regionalanesthesia;

Randomized controlledtrial;

ESPblock;

Epiduralblock

Abstract

Introductionandobjectives: BlockadeoftheErectorSpinalMuscle(ESPBlock)isarelatively new block, initially described for chronic thoracic pain analgesia, but it has already been described for anesthesia and analgesiain thoracicsurgical procedures and, more recently, forhighabdominalsurgeries.Theaimofthestudywastocomparetwotechniques,ESPBlock andEpiduralBlock,withmorphineandlocal anestheticfor postoperative analgesiaofopen cholecystectomysurgeries.

Methods: Controlledsingle-blindrandomizedclinicaltrialwith31patients(ESPBlock,n=15;

Epidural,n=16),ofbothgenders,agesbetween27and77years.TheESPblockwasperformed attheT8levelwithinjectionof20mLof0.5%ropivacainebilaterally.Theepiduralblockwas performedattheT8---T9spacewith20mLof0.5%ropivacaineand1mgofmorphine.

Results: TheESPBlockgrouppresentedhighermean NumericPainScale(NPS)valuesforpain intheupto2hour(p=0.001)andinthe24hour(p=0.001)assessments.TheESPBlockgroup hadathree-foldincreasedrisk(43.7%vs.13.3%)ofrescueopioiduseinthe24postoperative hourswhencomparedtotheepiduralgroup(RR=3.72,95%CI:0.91to15.31,p=0.046).

Conclusion: ESPBlockdidnotprovetobeaneffectivetechniqueforpostoperativeanalgesia ofopencholecystectomy,atthedosesperformedinthisstudy,havingrequiredmore useof rescue opioid,andwithoutdifferencesinNPS. Morecomprehensivestudiesarerequired to assesstheefﬁcacyofESPblockforthevisceralandabdominalsomaticcomponent,considering thespeciﬁcblockadelevel.

∗Correspondingauthor.

E-mails:thiago.sakae@unisul.br,thiagosakae@gmail.com(T.M.Sakae).

https://doi.org/10.1016/j.bjane.2020.02.014

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PALAVRASCHAVE Colecistectomia;

Analgesia;

Anestesiaregional;

Ensaiocontrolado randomizado;

ESPblock;

Bloqueioepidural

Comparac¸ãoentreastécnicasdebloqueiodoplanodomúsculoeretordaespinhae bloqueioepiduralparaanalgesiapós-operatóriaemcolecistectomiasabertas:um ensaioclínicorandomizado

Resumo

Justiﬁcativaeobjetivo: OBloqueiodoPlanodoMúsculoEretor daEspinha(ESPblock)éum bloqueio relativamente novo, inicialmente descritopara analgesia de dortorácica crônica, porém jádescritoparaanestesia eanalgesiaem procedimentoscirúrgicostorácicose,mais recentemente,para cirurgiasabdominais altas.Oestudoobjetivoucomparar astécnicasde bloqueio ESP block ebloqueio epiduralcom morﬁna eanestésico local para analgesia pós- operatóriadecirurgiasdecolecistectomiaaberta.

Método: Estudoclínicorandomizadocontrolado,unicegocom31pacientes(ESPblock,n=15;

Epidural,n=16),de ambosossexos, idadesentre27e77 anos. OESP blockfoi realizado nonível deT8cominjeçãode20mLderopivacaína0,5%bilateral. ObloqueioEpiduralfoi realizadonoespaçoT8---T9com20mLderopivacaína0,5%e1mgdemorfina.

Resultados: OgrupoESPblockapresentouvaloresmédiosdedorpelaEscalaVisualNumérica (EVN)maioresnasavaliac¸õesaté2horas(p=0,001)eem24horas(p=0,001).OgrupoESP blockapresentouumriscotrêsvezesmaior---43,7%vs.13,3%---deusodeopioidederesgatenas 24horaspós-operatóriasdoqueogrupoepidural(RR=3,72;95%IC0,91a15,31;p=0,046).

Conclusão: Nasdosesrealizadasnesseestudo,oESPblocknãosemostrouumatécnicaefetiva paraanalgesiapós-operatóriadecolecistectomiaaberta,commaisusodeopioidederesgatee semdiferenças naescalavisual numéricadedor.Necessita-sedeestudos maisabrangentes avaliando aeficácia do ESP block para o componente viscerale somático abdominal, con- siderandooníveldobloqueioespecífico.

Introduction

Post-operativeanalgesiaformediumandlargethoracicand upper abdominal surgeries stillpose a challenge to mod- ernanesthesiology.^1,2 Neuraxialblocktechniques(thoracic epiduralblock,spinallumbaranesthesia)forthisregionare usuallyassociatedwithgeneralanesthesia.Adjuvantsaimto extendpostoperativeanalgesiatimeandpromoteimproved qualitytoanesthesia,inadditiontodecreasingconsumption ofanestheticsandofopioids(intraandpost-operative),with allthepositiveconsequences,includingearlymobilization andreductionintheincidenceandextensionofatelectasis intheimmediatepost-operativeperiod.^1,2

Multipleultrasoundguided (USG)procedureshavebeen described as single or associated techniques, and also for treating chronic thoracic and abdominalpain.Erector Spinae Plane Block (ESP) is a relatively new ultrasound- guidedtechnique,originallydescribed tomanagethoracic painwhenperformedattheT5vertebralevel,^3,4butithas alsobeen successfully usedfor abdominalanalgesia when performedatthelowerT8---10levels.^5,6

ESPhasalsobeendescribedasrelativelyeasiertoper- formwhencomparedtootherconventionalblocks,suchas epiduralanesthesiaandparavertebralblock.^5---7

Clinical ﬁndings of previous studies^3---7 have been sup- portedby studiesin cadaversthathave shownthe spread oftheanestheticsolutioninjectedinthedeepinterfascial planeoftheerectorspinaemuscle,neartheintervertebral foramen,surroundingthedorsalandventralbranchesofthe thoracicspinenerveroots.^8---10

Thepost-operativepainthatfollowsacholecystectomy using a Kocher incision has both a somatic and visceral component.Morerecently,theerectorspinaemuscleplane block(ESP)hasproveditseffectivenessbyprovidingample thoracic,^1,2,7,10 high abdominal^5,6,8,9 somatic and visceral analgesia,whenperformedatthelevelofT5---T6,inaddition toanalgesiaforvertebralspineprocedures.^11---13Therefore, bilateralESPblockonthetransverseprocessofT8maypro- videeffective post-cholecystectomy analgesiaand reduce the incidence of excessive opioid use-associated adverse effects.^6---9

Theeffectivenessoftheblockhasbeenshowninseveral studies,and thishas made thesame pattern ofblocks to beperformedinthelumbarandevencervicalregions.^11---13 ESPblockisexpectedtoresultinlesscomplications,such asnerve paralysis, hematoma, pulmonary lesions, among others,given the injection target in the ESP block is the transverse process of the vertebra, which is not close to morevulnerableanatomicalstructures.³

The comparisonwithwell-established techniques,such as the epidural block, is mandatory. The epidural block, due to possible counterindications, opens the possibility to other safe alternatives that provide appropriate analgesia, without approaching the neuroaxis and decreasing likelihood of epidural anesthesia-associated sympathetic blocks.^8,14,15

Theobjectiveofthepresentstudywastocompareerec- tor spinae plane block and epidural block techniques in relation to post-operative analgesia in open cholecystectomies.

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Methods

A single-blind, non-inferiority, randomized clinical trial was performed after approval by the Research Ethics Committee of Universidade do Sul de Santa Catarina (CAAE 96216918.7.0000.5369) and registration on the BrazilianClinicalTrialRegistry(ReBEC---RegistrodeEnsaios Clínicos Brasileiros) registry RBR-29r8nr http://www.

ensaiosclinicos.gov.br/rg/RBR-29r8nr/.

Samplesizewascalculatedaccordingtonon-inferiority trials,¹⁶ theparametersadoptedwere0.05alfa,0.20beta, 7.9z²errors,measurementstandarddeviationof3.0,anda clinicallyimportant difference onthe Numeric Pain Scale (NPS) for pain over 4 points. Thus, the number required fornon-inferioritybetweentheepiduralblockanderector spinaeplaneblockgroupswas15patientspergroup.

Patientsover18yearsofage,bothsexes,ASAIandII,sub- mittedtoopencholecystectomysurgeryandelectiveKocher incision were included. Patients with urgent/emergency indicationcholecystectomy,intraoperativecholangiography orposteriorbiliarytracthandling,ASAIIIorhigher,history of allergy to any study medication, use of anticoagu- lants,blockfailure,useofanticonvulsantsorpostoperative cognitive deﬁcit that prevented the patient from under- standing/answeringthequestionnairewereexcluded.

Surveyors inthepostoperative wereblindtothegroup towhichpatientsbelongedandtointraoperative manage- mentandcomplications (hypotension,bradycardia, useof vasoactivedrugs).

Patientswerechosenrandomlybyrandomnumberdraw oftheEpiinfo6softwareEpitablefunction,forgroupsam- ples:1---‘‘Positivecontrol’’groupwithepiduralanesthesia;

and2--- InterventiongroupwithErectorSpinaePlaneBlock (ESPblock).

Variables assessed were sex, age, BMI, ASA classiﬁca- tion, 0 to 10 (2 hours and 24 hours) Numeric Pain Scale (NPS),intraoperativecomplications(bradycardia,hypotension,vasoactivedrug required),postoperativenauseaand vomitingandadversereactions(pruritus,urinaryretention).

Urinaryretentionwasdeﬁnedasrequiringurethralcatheter in24hours.

Both block groups (epidural --- Group 1 or ESP block --- Group2)weresubmittedtoaseptictechnique,aftervenous access,monitoring (pulseoximetry, cardioscopy and non- invasivepressure)andlightsedation(1to5mgmidazolam and25 to75 mcgintravenousfentanyl), receivingoxygen supplementation and duly positioned withthe help of an assistant.

The positive control group was submitted to epidural anesthesiawith20mL 0.5%ropivacaineand1mgof mor- phine.EpiduralanesthesiawasperformedwithaTuohy18G medianneedle,T8---T9level,inadditiontoadministrationof 2%lidocainewithvasoconstrictor,4mLgivenastest-dose.

Theinterventiongroupwassubmittedtobilateralerector spinaeplaneblock(ESPblock).TheESPblockwasperformed withpatientsitting,andahighfrequency,5---13MHzlinear transducer(LOGIQe;GEHealthcare)wasusedinthelongi- tudinalparasagittaldirectiontoidentifytheT8transverse process,countingtheﬁrsttoeighthrib.Thedevicewasthen pulledmedially untilthe tip of the transverse process of T8 wasidentiﬁed. The 22G 5 cm needle (BBraun, Stimu-

Table1 Clinicalcharacteristics.

Variable ESPblock group

Epidural group

p

Sex

0.886

Male 6(40%) 6(37.5%)

Female 9(60%) 10(53.5%)

Age(mean;SD) 56.40(16,21) 57.38(11.69) 0.848 BMI(kg.m^-2)

0.803 18---24 4(26.7%) 5(31.2%)

25---29 10(66.7%) 10(62.5%)

>30 1(6.7%) 1(6.2%)

ASA

0.902

I 5(33.3%) 5(31.2%)

II 10(66.7%) 11(68.8%)

BMI,BodyMassIndex;ASA,AmericanSocietyofAnesthesiology classiﬁcation;p,p-value.

plex A50,22G) wasinserted into the plane, craniocaudal direction,goingthroughskin,subcutaneousandmusclelay- ers(trapezemuscle,greaterdorsalmusclefasciaandspinal erectormuscle)untilthetipwasbetweentheanteriorfas- ciaofthespinal erectormuscleandtransverse processof T8.Theplane wascheckedwithdispersionof0.5to1mL salinesolutionandvisualizationoflineardispersionofﬂuid inthespinalerectormuscleplane,followedbyinjectionof 20mLof0.5%ropivacaine.Thetechniquewasbilateral.

After being submitted to epidural anesthesia or ESP block, bothgroups were submittedtogeneralanesthesia, and anesthesia induction wasperformed with3 mcg.kg⁻¹ offentanyl,0.4mg.kg⁻¹ofatracuriumand1to2mg.kg⁻¹ propofol.Allpatientsreceivedprophylacticantibioticswith 2 g cefazoline, analgesiawith 100 mg ketoprofen, 10 mg dexamethasoneand8mgondansetronintraoperativelyfor prophylaxisofpostoperativenauseaandvomiting.

Mean, median and standard-deviation for continuous variablesandproportionsforcategoricalvariableswerecal- culated. Pearson Chi-Square test or Fisher exact test to checkassociationamongcategoricalvariableswereused,as appropriate.Fortheassociationofnumericalvariables,Kol- gomorovSmirnovorWilcoxontestswereused.Thelevelof signiﬁcanceadoptedwas95%.Cut-offpointsofindependent variables were based on conceptual models. Data stored wereanalyzedontheSPSS20.0program.

Results

The study included 31 patients submitted to open cholecystectomy,ofwhich15patientsintheinterventiongroup (ESP block) and 16 patients in the positive control group (epidural)(Fig.1).Meanagerangedbetween27and77years (mean:57.23years),withaslightpredominanceofwomen (61.3%).BMIranged between18and 38kg.m⁻²,withpre- dominanceofBMIbetween25---29(64.5%).ASAclassiﬁcation waspredominantlyASA2(67.7%)(Table1).

Therewerestatisticallysigniﬁcantdifferencesbetween thegroupsinthepost-surgicaluptotwo-hourand24-hour assessmentsontheNumericPainScale(NPS).Theinterven- tion grouphad mean painNPS valueshigher in the upto

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Assessed for eligibility (n=33)

Excluded (n=2)

♦ Do not meet inclusion criteria (n=0)

♦ ESP failure (n= 1)

♦ Epidural Failure (n= 1)

Analyzed (n=15)

♦ Excluded from analysis (give reasons) (n=0) Lost to follow-up (give reasons)(n=0) Discontinued intervention (give reasons) (n=0) Allocated to Epidural intervention (n=15)

♦ Received allocated intervention (n=15)

Lost to follow-up (give reasons) (n=0) Discontinued intervention (give reasons) (n=0)

Allocated to ESP intervention (n=16)

♦ Received allocated intervention (n=16)

(n=16) Analyzed

♦ Excluded from analysis (give reasons) (n=0) Allocation

Analysis Follow-Up

Randomized (n=31) Enrollment

Figure1 Studyﬂowchart(CONSORTstandard).

Table2 Comparisonofnumericpainscalebetweengroups.

Group Pain2hours p Pain24hours p

ESPblock

Mean:6.00

0.001

Mean:3.69

0.001

Median:5.50 Median:3.00

Standard-deviation:1.89 Standard-deviation:2.44 Epidural

Mean:3.00 Mean:0.53

Median:3.00 Median:0.00

Standard-deviation:2.29 Standard-deviation:1.23

two-hour(p =0.001)and 24-hour(p =0.001) assessments (Table2).

The useof opioid required in the post-anesthetic care unit wasseven-foldhigher in the intervention group(ESP block) (RR = 7.87; 95% IC: 1.08 to 57.25; p = 0.026).

Regardingrescueopioiduseinpost-operative24hours,the interventiongrouphadathree-foldhigherrisk---43.7%vs.

13.3%---thantheepiduralgroup(RR=3.72;95%IC:0.91to 15.31;p=0.046).The mostfrequentlyusedopioidamong thesepatientswastramadol,atadoseof100mg(18.1%of patients),followedbymorphine(9.1%ofpatients).

There were no statistically signiﬁcant differences in theincidenceof intraoperativecomplications (p= 0.277), adversereactions (p= 0.381)orpostoperativenauseaand vomiting(p=0.531).

Discussion

TheresultsofthepresentstudyshowinferiorityofESPblock associated analgesic plane, when compared to the group submittedtoepiduralanesthesia.

Technically,basedonanatomicalstudiesonfreshcadav- ers, the likely site of action of the ESP block covers an extensive area after the injection of local anesthetics, spreadboth throughthedorsal andventralregions ofthe thoracicspinal bundles andnervebranches.2,3,15---18 There- fore, the effective block of the ventral branch and the sympatheticﬁbersconcomitantlyisexpectedtooccur,and maypromote effective anesthesiaand analgesia,control- lingsomaticandvisceralpain.Inpracticalterms,however, we have perceived this satisfactory analgesia response in

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thoracicandsomeabdominalwallsurgeries,withstillsome limitedevidenceintheliteratureonthevariableresponse astothecontrolofabdominalvisceralandsomaticpain.^15---19 Aftertheinjectionofefﬁcaciousconcentrationsandvol- umes of local anesthetics using ESP, although there have beenreports showingreliefof visceralandsomaticpains, thereisstillsomevariabilityinthemanagementofvisceral pain,withoutseemingtobeaconsensusestablishedonthe control of this kind of pain when anesthesia with ESP is performed.^8,19,20Somestudiesperformedoncadavershave shownthatspreadoflocalanestheticsinjectedthroughESP toventralbranchesatmultiplelevels,totheneuralforamen andtoepiduralspaceswerenotwellestablished.^19,20

InastudybyYangetal.,²¹ thereachoflocalanesthet- icswas limited only toventral branches when performed at multiple levelsand hardly spread to the thoracic par- avertebralspace.TherearestudiesreportingthattheESP blockwasmorelimitedtodorsalbranchesandonlyroughly 10%involvedtheventralbranchordorsalrootganglion,^18,20 corroboratingtheﬁndingsofourstudy.

AstudyincadaversdesignedtosimulateESPbyIvanusik etal.¹⁸ documentedanextensivecraniocaudalandmedial- lateralspread of dye, both deepand superﬁcial tospinal erectormuscles.However,therewasnospreadofthedye anteriortotheparavertebralspacewhereitsurroundsthe ventralanddorsaloriginsofthoracicspinalnervebranches.

Theinvolvementofthedorsalbranchwasmostlyposteriorto thecostotransverseforamen. Therewaspotentialinvolve- mentofthelateralcutaneous branchesandofthelateral intercostalnervesattheangleoftheipsilateralribs.^18,21

Among the limitations of the study, the choice of the volume of ropivacaine, 20 mL instead of the higher vol- umes used in other studies may have interfered in wider spreadoftheanestheticandinﬂuencedtheblock levelin theESPgroup.Intheory,thevolumeof3mLtoblockeach dermatome¹⁷ wouldprovideappropriatedispersionforthe volumeadoptedin thepresent study.The impossibilityto controlmoredorsalorcaudaldispersioncouldalsoinﬂuence results. Moreover,using adjuvants (corticosteroids, alfa 2 agonists,ketamine),alreadywell-establishedinothertypes ofblock,hasnotbeendescribedfortheESPblockyet,and couldimprovethepotentialoftheblocktocontrolvisceral painthatapparentlydidnotoccurinthepresentstudy.

The small sample size, with characteristics of non- inferiorityclinicaltrials,andthelowstatisticalpowerofthe study,mayrevealmajordifferencesbetweentreatmentsin whichthenullhypothesisisnotrejected,duetotheinsuf- ﬁcientnumberofpatientsortotheovervariabilityofdata.

ThismayleadtoamorelikelytypeIIerror(notfindingadif- ferencewherethereactuallyis),oneofthecharacteristics includedinthe currentstudy,notbeingable,however,to finddifferenceswherethereactuallyare,whichwouldbe moreharmfulfromthescientificandethicalpointofview.

Thisinferenceerrorhasbeen,frequently,underscoredwith theexpression‘‘Theabsenceofevidenceisnotanevidence ofabsence’’.¹⁶

Thiscanexplainstatisticallysigniﬁcantdifferencesbeing foundbetweengroupsforadversereactions,complications andpostoperativenauseaandvomiting.

Conclusions

The fact that ESP does not seem to block the visceral abdominalcomponent well maybe effectivelyone of the limitationsforusingESPforsometypesofabdominalsurg- eries,unlikewhatisperceivedforthoracic,breastsurgeries andothersurgeriesofthethoracicandabdominalwallsand evenhiparthroplasties, dependingonthelevel wherethe blockisperformed.

Morecomprehensive studies arerequired toassess the efﬁcacyofESPforthevisceralandsomaticabdominalcom- ponent,consideringthespeciﬁcblocklevel.

Conﬂicts of interest

Theauthorsdeclarenoconﬂictsofinterest.

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