JSAN2017;4(2):81-86

JournalofSocietyofAnesthesiologistsofNepal

OriginalArticleA comparative study of bilateral ilioinguinal and iliohypogastric nerve block forpostoperativeanalgesiainlowersegmentcesareansection.AnjaliPoudel*,PrashantKumarDutta**

*B.P.KoiralaInstituteofHealthSciences,BuddhaRoad,Dharan,56700**NepalgunjMedicalCollege,B.P.Chowk12,Nepalgunj,Banke,21902CorrespondingAuthorDr.AnjaliPoudel,MDB.P.KoiralaInstituteofHealthSciences,BuddhaRoad,Dharan,56700Email:603anjalee@gmail.comORCID:https://orcid.org/0000-0001-8932-4447 AbstractBackgroundModern techniques incorporate regionalanesthesia inpain management and it is the best and safesttechnique. It avoids the side effects that remainwiththe traditional use of opioids. Ilioinguinal andiliohypogastric nerve block can provide a satisfactorypostoperative analgesia in parturients withpfannenstiel incision thereby reducing postoperativeopioidconsumption.ObjectiveTo compare opioid consumption and pain reliefpostoperatively with ilioinguinal and iliohypogastricnerve block in patients undergoing lower segmentcesareansection.MethodsIt is a hospital based comparative study done inNepalgunj Medical College Teaching Hospital,Kohalpur,Banke inaperiodofoneyear.Totalofsixtypatients, thirty in each were randomly allocated intothe twogroups.GroupBreceivedbilateral ilioinguinalandiliohypogastricnerveblockbylandmarktechniquewith 20ml of 0.5% bupivacaine; 10ml in each side.Group NS received ilioinguinal and iliohypogastricnerve block with 20ml of 0.9% normal saline. Inpostoperative period blood pressure, pulse, oxygen

saturation, numerical rating scale score at differentallocatedduration,totaldoseoftramadolconsumptionandtimetofirstdoseoftramadolwererecorded.ResultsThe total postoperative tramadol consumption in thefirst24hrpostoperativelywassignificantlylessingroupB (125 ± 34.11mg) than in groupNS (205 ±37.93mg).The mean effective duration of analgesia measuredfromthetimeofonsetofspinalblockadetothetimeofrequestfortramadolwas264±78.27minutesingroupB and 178.17±30.61minutes in group NS, which wasstatistically significant and also numerical rating scalescoreswere lowatall pointspostoperatively ingroupB.ConclusionBilateral ilioinguinal and iliohypogastric nerve blocksignificantly lowers the consumption of tramadol andalsoprovidesadequatepostoperativepainrelief.

Keywords:Bupivacaine;Ilioinguinalandiliohypogastricnerveblock;LowersegmentcesareansectionArticleHistoryReceived 31stDecember2016 Accepted 19thSeptember2017Published28thAugust2018

©AuthorsretaincopyrightandgrantthejournalrightoffirstpublicationwiththeworksimultaneouslylicensedunderCreativeCommonsAttributionLicenseCC-BY4.0thatallowsotherstosharetheworkwithanacknowledgementofthework'sauthorshipandinitialpublicationinthisjournal.

Howtocitethisarticle:PoudelA,DuttaPK.Acomparativestudyofbilateralilioinguinalandiliohypogastricnerveblockforpostoperativeanalgesiainlowersegmentcesareansection.JournalofSocietyofAnesthesiologistsofNepal(JSAN)2017;4(2):81-86

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Introductiono reliefpainhasalwaysbeen theprimeaimofananesthesiologist.Moreover,pain reliefin a mother has more compelling reasonsbecause high levels of pain interfere withearly infant care and breastfeeding.1 So,

effective postoperative analgesia facilitates earlyambulation, infant care and prevention ofpostoperativemorbidity.2There have been a variety of pharmacologicalalternatives including oral or parenteralacetaminophen, non-steroidal anti-inflammatorydrugs,opioids,intrathecalopioids,epiduraltechniquesand patient controlled analgesia. Traditional use ofopioids though provides adequate postoperativeanalgesia,alsohavewelldocumentedsideeffects likesedation, nausea, pruritus, respiratorydepression andneed continuous monitoring and intervention, whennecessary.Therefore,toovercometheaboveproblemsalternativetherapiesaretobeexplored.

Regionalanesthesiaiswidelyemployedwhichprovidessatisfactory postoperative pain relief and is devoid ofsignificant side effects. The postoperative pain thatfollows a cesarean section (CS) with the pfannenstielincisionhas both a somatic component and a visceralcomponent.3 The somatic pain generated at theincisionsite isconductedby II/IH,which innervatetheL1–2dermatome distribution.4 Because of the II/IHnerve involvement, block of this nerve produces asignificantdegreeofpost-CSpain relief. Incontrast tothe somatic component of postoperative pain, thevisceral pain component is diffusewith no peripheralnerveassociation.5

Sofar,nostudyhasbeendoneonII/IHnerveblock inpatients undergoing cesarean section in ourNepalesepopulation. The various benefits of this regionalanesthesia and its analgesic efficacy in postoperativeperiod are still not known. Therefore, this study hasbeen conducted to assess the efficacy of ilioinguinaland iliohypogastric nerve block in postoperative painrelieftherebyreducingopioidconsumptionamongtheparturients undergoing lower segment cesareansection.

MethodsA randomized comparative study for one year wasconducted in Nepalgunj Medical College TeachingHospital,Kohalpurafterethicalapprovalobtainedfromthe ethical committee, written and informed consentobtainedfromthepatientsorpatient’sattendants.Thestudy was conducted in 60 patients of ASA physicalstatus I and II of age between 20 to 35 yearsundergoing non-emergent lower section ceasereansectionsurgeryunderspinalanesthesia.Thosepatients

belongingtoASAphysicalstatusIII,IVandV,unwillingtoparticipate,preeclampsia andeclampsia, allergic tobupivacaine and contraindicated to spinal anesthesiawere excluded from the study. At the end of thesurgery, bilateral iiliinguinal and iliohypogastric nervewasblockedeitherwithbupivacaineornormal saline.In a time period of one year from Jan 2014 to Dec2014, a sample size of sixty patients was taken anddivided into two equal groups using sealed envelopetechnique.GroupB: Bilateral IliinguinalandIliohypogastricnervewas blocked with 10ml of 0.5% bupivacaine on eachsidewithatotalof20ml.

GroupNS:BilateralIliinguinalandIliohypogastricnervewas blocked with 10ml of 0.9% normal saline with atotalof20ml.

All patients admitted to the hospital before surgeryhad a complete pre-anesthetic evaluation includingdetailedhistory taking, thoroughphysicalexaminationand routine pre-operative investigations. NumericalRating Scale (NRS)6was explained preoperatively in asimple language,which the patient could understand.(0-10whole numbers, starting from 0 = no pain 1-3=mildpain,4-6=moderatepain,7-9=severepainand10=worstpainimaginable).

0: No pain 1-3: Mild pain 4-6: Moderate pain 7-9:Severepain 10:Worstpainpossible

Then, thepatientwas kept in left-lateral position andby using the midline approach at L3-4 vertebralinterspaces a 25-gauze Quincke’s spinal needle wasinserted for spinal anesthesia. Once free flow ofcerebrospinal fluid was recognized, the intrathecalanestheticsolutioninastandardizeddose,of2.5mlof0.5%bupivacaineindextrose(hyperbaric)wasinjectedinto the subarachnoid space at the rate of 0.2ml/sec.Attheendoftheinjection,asmallsteriledressingwasappliedandthepatientimmediatelyturnedintosupineposition, with a pillow under the head.Intraoperatively, continuous electrocardiogrammonitoring was done. Blood pressure was monitoredevery fiveminutes using anoscillometric non-invasiveblood pressure monitor. Oxygen saturation wasmonitoredwiththehelpofapulseoximeter.

The time of start of spinal anesthesia and level ofsensory block and the time of start of surgery wasnoted. If during the surgery hypotension occurred, itwas managed by incremental doses of injectionmephenteramine6mgintravenously.

After completion of surgery II/IH nerve was blocked

T

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bilaterally for postoperative analgesia. The ilioinguinaland iliohypogastric nerve block injection wasperformedbylandmarktechniqueasdescribedbyBellet al.3 in a standardized fashion for all parturientsfollowing wound closure. A landmark of 2cm medialand 2cm superior to anterior superior iliac spine wastaken, pointing towards the midpoint of inguinalligament.Theneedlewasthenadvanceduntilfirstlossof resistance and drug was deposited in betweenexternal oblique and internal oblique muscle. It wasfurther advanced and on second loss of resistanceagaindrugwasdeposited inbetween internalobliqueand transverse abdominus muscle. The needle wasthen withdrawn to the skin and redirected mediallyand later laterally in a fan-shaped manner and sameprocedurerepeated.Thiswayatotalof10mlofeither0.5% bupivacaine or normal saline was deposited inone side and same procedure repeated on thecontralateral side with total of 20ml. After the blockthe patient was transferred to post anesthesia careunit.

The time of great toe movement in post-operativeroom was noted which indicated the regression ofspinalanesthesia.Atthatpointoftime,thesuccessofilioinguinal and iliohypogastric nervewas assessed bypinprick at the site of incision and adequacy andpresenceofblockwasnotedandconfirmed.With theprimaryoutcomevariablebeingtheassessmentofpainrelief with the II/IH nerve block with bupivacaine orwithout bupivacaine and duration of analgesia thepatientswerefollowedsubsequentlyand levelofpainwasassessedbyusingtheNRSscores.Itwasrecordedinitially at 30mins postoperatively, then at 2hrs, 4hrs,8hrs,12hrs,16hrs,20hrsand24hrs.Thedurationwasanalgesiawasassessedbythetimeforfirstdoseoftramadol and total consumption of tramadol wascalculated. Blood pressure, pulse and oxygensaturation by pulse oximeter were also recordedalong with the NRS score in post anesthesia careunit. If the pain score was more than 3 thenintravenoustramadol50mgwasgivenandtimetofirstdose of tramadol was noted. Regardless of theirNRS score on frequent intervals, patients wereenquired wheather they require additionalanalgesia and intravenous tramadol 50mg wasgiven if required. Patients were also instructed torequestpainmedication fromthenursewheneverthey required pain relief and not towait for theirnextscheduledpainassessment.Patientswerenotallowed to view their previous pain responses.Adverse effects and complications of opioids likenausea,vomiting,pruritusanddrowsiness ifanywererecorded.

The primary outcome variable was decrease in totalconsumptionoftramadolwithin24hrspostoperatively

in parturients receiving ilioinguinal and iliohypogastricnerve block with bupivacaine. A sample size of 25 ineachgroupwas required toevaluate30%decrease intotalconsumptionoftramadolwithapowerof90%at5% significant level.7 To account for the dropouts 30patients were included in each group. All data soobtained was compiled in Excel worksheet softwareand statistical analysis was done using StatisticalPackage for Social Science (SPSS 19.0). All thecontinuous and categorical data were compared.Studentt-testwasusedforcontinuousdata.Ifpvalueequals to 0.05 or less, then it was consideredstatisticallysignificant.

ResultsOver one year of study period a total of 73 patientsenrolled for non-emergent cesarean section underspinal anesthesia were assessed for eligibility and atotalof60patients thirtypatients ineachgroupwereincludedinourstudy.CONSORT2010FlowDiagram

Assessed for eligibility (n= 73)

Excluded n= (13) ♦Not meeting

inclusion criteria (n=

Analysed (n= 30 ) ♦Excluded from analysis (give reasons) (n=0 )

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

Lost to follow-up (n= 0) Discontinued

Analysed (n= 30) ♦Excluded from analysis (n= 0 )

Analysis

Follow-Up

Randomized (n= 60)

Enrollment

Allocation

Allocated to intervention (n= 30) ♦Received allocated

intervention (n= 30)

Allocated to intervention (n= 30) ♦Received allocated

intervention (n= 30)

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Table1Demographicprofileofthestudypatientsanddurationofsurgery

Variables Group B;n=30

Group NS;n=30

Pvalue

Age 25.50±4.10 26.20±4.36 0.525Weight 57.73±3.90 56.80±4.21 0.377ASAI:II 27:3 27:3 -Duration ofsurgery(minutes)

52.33 ±14.84

56.00 ±14.59

0.338

ASA:AmericanSocietyofAnaesthesiologist

The demographic profiles of the patients in both thegroups were comparable with regards to age andweight. ThedistributionasperASA statuswas similarin both the groups and duration of surgery wascomparableinboththegroups[Table1].Therewasnosignificantdifferenceinmeanheartrate,systolicbloodpressureanddiastolicbloodpressureintwogroupsatpostopertive period at 30mins, 2 ,4,8,12,16, 20 and24hr.(Figures1,2and3).

Figure1:ComparisonofHeartRate(HR)

Figure2:ComparisonofSystolicBloodPressure(SBP)

Figure3:ComparisonofDiastolicBloodPressure(DBP)

In both the groups time to great toe movement i.e.time to wear off from spinal anesthesia, inpostoperativeperiodwascomparable[Table2].Atthispoint of time success of block was 100% in patientsreceivingII/IHnerveblockwithbupivacaine,whichwasconfirmedbydullness at incision site. TheNRS scoreswere lower at all points in postoperative period inGroupB[Table3].

Table2:TimetoGreattoemovementfromSAB

Table 3: Numerical Rating Scale (NRS) at varoiusduration

Group(Median±InterQuartileRange)NRS Group B

(n=30)NS(n=30)

30mins 0.00 0.00±12hr 2.00±3 4.00±14hr 3.50±1 4.00±08hr 3.00±1 4.00±112hr 3.00±1 3.00±116hr 3.00±2 4.00±120hr 3.00±2 3.50±124hr 3.00±1 4.00±1

Time to first dose of tramadol inGroup Bwas longeri.e.264±78.27ascomparedto178.17±30.611inGroupNSand thisdifferencewasstatistically significant.Thetotal consumptionof tramadol inGroupBwas lower;125± 34.11 mg versus 205± 37.93 mg in NS and thisdifferencewasalsostatisticallysignificant.[Table4andFig4]

74757677787980818283

Mea

n H

R

GroupB(permin)GroupNS(permin)

104106108110112114116118120122124

SBP

GroupB(mmHg)

GroupNS(mmHg)

646668707274767880

Preoperati…

Postoperat…

2hr

4hr

8hr

12hr

16hr

20hr

24hr

DBP

GroupB(mmHg)

GroupNS(mmHg)

Group B(n=30)

Group NS(n=30)

Pvalue

Time inminutes

148.33 ±41.28

130.00 ±38.26

0.080

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Table 4: Comparison ofmean value of time for firstdoseofTramadolandtotaldoseof tramadol inboththegroups

Group B(n=30)

Group NS(n=30)

p-value

Mean±SD Mean±SD

Time to 1stdose oftramadol(min)

264.00 ±78.27

178.17 ±30.611

0.000

Total dose oftramadol(mg)

125.00 ±34.11

205.00 ±37.93

0.000

Figure4:Timeto1stdoseofTramadolandtotaldoseofTramadolbetweentwoGroups

Nausea was noted in two patients in group B and 6patients ingroupNS(pvalue0.133).Onepatientwithnausea ingroupBalsohadvomitingand6patients ingroup NS had vomiting (p value 0.045) which isstatistically significant. Nausea and vomiting in thepostoperative periodwasmanagedwith a bolus doseofintravenousondansetron4mg.

DiscussionIn past, illioinguinal nerve blocks have been used forhernialrepairwitheffectivepostoperativepainrelief.Astudywhich corelateswith the use of ilioinguinal andiliohypogastric nerve block for hernial repair resultingin effective pain relief was carried out in past byAndersen,NielsenandKehlet.8However,potentialrole

of combined illioinguinal and illiohypogastric nerveblock in the setting of cesearean delivery patientsremainedunclear.The main finding of our study was a significantdifference in the total dose of tramadol consumptionby partiurients receiving the II/IH nerve block withbupivacaine than without. Also there was a longerperiod of analgesia and lower pain scores in patientsreceivingtheblockwithbupivacaine.

In this study, classic landmark approach of blocktechniqueinafan-shapedmannerwasused.Belletal.also used the same technique with success rate of>95%.3OtherregionalblocksoftheanteriorabdominalwalllikeTransverseAbdominalPlaneblock,(TAP)blockcouldalsobeusedinthisstudy.ButTAPblockcoversalarge area, T7-L2 dermatomes whereas II/IH nerveblock cover the same two lowest nerves blocked byTAP block. So it can be said that Ilioinguinal andiliohypogastricnervesblockcomprisesonepartofTAPblock. Since the pfannestiel incision lieswithin the L1dermatome, bilateral ilioinguinal and iliohypogastricnerve block should adeqately provide analgesia afterlowtransversecaesareansection.9

Further, although TAP block technique is apparentlysafe, it may be difficult, especially in obese patientsbecause of failure to identify the landmark of thetriangleofPetitresultinginanincorrectlocationoftheneedle.Inaddition,damagetoviscera(liverandbowel)mayoccasionallyoccur.10

During our study patients who received II/IH nerveblockwithbupivacainealsoreportedtohavepainandreceived tramadol on demand, although totalconsumption were in low doses in comparison withpatients who received II/IH block with normal saline,thatcanbeexplainedby the fact thatwhileprovidinganalgesiaoftheskinanddeeperlayersoftheanteriorabdominalwall,II/IHnerveblockadewouldnotprovideanalgeisa for visceral pain which is diffuse and notassociatedwithperipheralnervesupply.

Inourstudy,inboththegroupsthedurationofsurgerywas almost equal andpostoperatively, themovementof great toe in both the groups were approximately3hr. As spinal anesthesia donot end abruptly after afixedpeiodoftime;rather,theyrecedegraduallyfromthemostcephaladdermatometothemostcaudad.So,themovemetofgreattoewastakenapointwhenthespinal anesthesia has completely resolved from thesurgical site i.e. from L1 dermatome. At this point ofgreat toe movement, success and adequacy of theilioinguinal and iliohypogastric nerve block wasassessedbydullnesstopinprickat thesurgicalsite. InallthepatientswithII/IHnerveblock,successofblock

0

50

100

150

200

250

300

GroupB GroupNS

264

178.17

125

205

Timeto1stdoseoftramadol(min)

Totaldoseoftramadol(mg)

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with bupivacaine was 100% and the low pain scoreswere noted in this group. The higher pain scores inGroupNSthaninGroupBindicatedabetterqualityofanalgesiainGroupB.

There were few limitations in our study. Use ofultrasoundguidedilioinguinalandiliohypogastricnerveblockwould help us to confirm the block success butthis was not feasible in our institution. Other limitingfactor inour study is theuseofneuraxialblockade toperform lower segment caesarean section surgerieswhich otherwise provides a considerable residualanalgesiawithadifficultyinassessingasuccessfulII/IHnerveblocktherebyaddingconsiderablytotheexistingconfounding factors if any. Another limitation is thatthe postoperative pain involved both somatic andvisceral component.The IL/IHnerveblock treated thesomatic pain that is conducted by the incision sitewhereas the visceral pain related to the peritonealtraumaandirritationandpainarisingfromuterusaftersurgerystillexist.

ConclusionBilateral ilioinguinal iliohypogastric nerve block inparturients undergoing LSCS using bupivacainesignificantly decreases opioid consumption andprovidesadequatepainrelief.Conflict of interests:Allauthorshave filled the ICMJEconflict of interest form and declare that they havenothingtodisclose.Acknowledgment:NoneSourcesoffunding:NoneReferences1.KarlstromA,Engstrom-OlofssonR,NorberghKG,SjolingM,HildingssonI.Postoperativepainaftercesareanbirthaffectsbreastfeedingandinfantcare.JObstetGynecolNeonatalNurs.2007Sep-Oct;36(5):430-40.https://doi.org/10.1111/j.1552-6909.2007.00160.xPMid:178803132.FlaifelAH,MuhalhilAH.Postoperativeanalgesiaoftransversusabdominisplaneblockaftercesareandeliveryundergeneralanaesthesia.BasJSurg,2013March;19.

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8.F.H.Andersen,K.NielsenandH.Kehlet.Combinedilioinguinalblockadeandlocalinfiltrationanaesthesiaforgroinherniarepair,adoubleblindrandomizedstudy.BritishJournalofAnaesthesia2005;94(4):520–3.https://doi.org/10.1093/bja/aei083PMid:15695545

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