Superior gluteal nerve: a new block on the block? DEANESTESIOLOGIA REVISTABRASILEIRA

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RevBrasAnestesiol.2018;68(4):400---403

REVISTA

BRASILEIRA DE

ANESTESIOLOGIA

^Publicação^Oﬁcial^da^Sociedade^Brasileira^deAnestesiologia www.sba.com.br

CLINICAL INFORMATION

Superior gluteal nerve: a new block on the block?

Miguel Sá

^∗

, Rita Grac ¸a, Hugo Reis, José Miguel Cardoso, José Sampaio, Célia Pinheiro, Duarte Machado

CentroHospitalardeTrás-dos-MonteseAltoDouro,DepartamentodeAnestesiologiaeTerapêuticadaDor,VilaReal,Portugal

Received8July2016;accepted25November2016 Availableonline27December2016

KEYWORDS Superiorgluteal nerve;

Ultrasound;

Pain;

Regionalanesthesia

Abstract

Backgroundandobjectives: Thesuperiorglutealnerveisresponsibleforinnervatingtheglu- teusmedius,gluteusminimusandtensorfascialataemuscles,allofwhichcanbeinjuredduring surgicalprocedures.Wedescribeanultrasound-guidedapproachtoblockthesuperiorgluteal nervewhichallowedustoprovideefﬁcientanalgesiaandanesthesiafortwoorthopedicproce- dures,inapatientwhohadsigniﬁcantriskfactorsforneuraxialtechniquesanddeepperipheral nerveblocks.

Clinicalreport:An84-year-oldfemalewhoseregularuseofclopidogrelcontraindicatedneurax- ialtechniquesordeepperipheralnerveblockspresentedforurgentbipolarhemiarthroplastyin ourhospital.Takingintoconsiderationthesurgicalapproachchosenbytheorthopedicteam,we settouseacombinationofgeneralanesthesiaandsuperﬁcialperipheralnerveblocks(femoral, lateralcutaneousofthighandsuperiorglutealnerve)fortheprocedure.Amonthandahalf post-dischargethepatientwasre-admittedfordebridingandcorrectionofsuturedehiscence;

weperformedthesameblocksandlightsedation.Sheremainedcomfortableinbothcases,and reportednopaininthepost-operativeperiod.

Conclusions:Deepunderstandingofanatomy andinnervationempowersanesthesiologiststo solvepotentiallycomplexcaseswithsafer,albeitcreative,approaches.Therelevanceofthis block inthiscase arises from itsinnervationof thegluteus medius muscleandposterolat- eral portion of the hip joint. Tothe best of ourknowledge, this is the ﬁrst report ofan ultrasound-guidedsuperiorgluteal nerveblock withananalgesic andanesthetic goal,which wassuccessfullyachieved.

∗Correspondingauthor.

E-mail:[email protected](M.Sá).

https://doi.org/10.1016/j.bjane.2016.11.001

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Superiorglutealnerve:anewblockontheblock? 401

PALAVRAS-CHAVE Nervoglúteo superior;

Ultrassom;

Dor;

Anestesiaregional

Nervoglúteosuperior:umnovobloqueioacaminho?

Resumo

Justificativaeobjetivos: Onervoglúteosuperioréresponsávelpelainervaçãodosmúsculos glúteomédio,glúteomínimoe tensordafáscia lata,todospodemserlesadosdurantepro- cedimentos cirúrgicos.Descrevemosumaabordagem guiadaporultrassom parabloqueiodo nervoglúteosuperior,oquenospermitiuforneceranalgesiaeanestesiaeficientesparadois procedimentosortopédicosaumapacientequeapresentavafatoresderiscosignificativospara técnicasneuraxiaisebloqueiosprofundosdenervosperiféricos.

Relatodecaso: Pacientedosexofeminino,84anos,cujousoregulardeclopidogrelcontraindi- cava técnicas neuraxiais ou bloqueios profundos de nervos periféricos, apresentou-se para hemiartroplastia bipolarurgente emnosso hospital.Levandoem consideraçãoaabordagem cirúrgica escolhida pela equipede ortopedia,estabelecemos o usode uma combinaçãode anestesiageralebloqueiossuperficiaisdenervosperiféricos(femoral,cutâneolateraldacoxa e nervoglúteo superior)para o procedimento.Um mêsemeio apósaalta, apaciente foi readmitidaparadesbridamentoecorreçãodadeiscênciadesuturaquandofizemososmesmos bloqueiosesedaçãoleve.Apacientepermaneceuconfortávelemambososcasos,semqueixa dedornoperíodopós-operatório.

Conclusões: Acompreensãoprofundadaanatomiaedainervac¸ãocapacitaosanestesiologis- tasaresolvercasospotencialmente complexoscomabordagensmaisseguras,atécriativas.

A relevânciadessebloqueionestecasoresulta dasuainervaçãodomúsculo glúteomédioe daporçãoposterolateraldaarticulaçãodoquadril.Deacordocomnossapesquisa, esteéo primeiro relatodeumbloqueiodonervoglúteosuperiorguiado porultrassomcomobjetivo analgésicoeanestésicoquefoiobtidocomsucesso.

Background and objectives

Thesuperiorglutealnerve(SGN)isresponsibleforinnervat- ingthegluteusmedius,gluteusminimusand tensorfascia lataemuscles, all ofwhich canbe injuredduringsurgical procedures.Theindividualblockofthisnerveismaderedun- dantbytheuseofneuraxialtechniquesordeepperipheral nerveblocks(PNB)suchasthesacralplexusblock;however, notallpatientscanbesubjected tothesetechniques.We describeanultrasound-guidedapproachtoblock theSGN, which allowed ustoprovide efﬁcientanalgesia andanes- thesiafortwoorthopedicproceduresinapatientwhohad signiﬁcant risk factors for neuraxial techniques and deep PNBs.

Case report

Wepresentthecaseofa60kg84-year-oldfemalewhopre- sentedforurgentbipolarhemiarthroplastyduetoleftfemur hipfracture after fallingin ourhospital’s medicine ward, whereshehadbeenundergoingantibiotherapyfor7daysto treatacommunity-acquiredpneumonia.

She hada knownhistory of atrial ﬁbrillationwithcon- trolledventricularresponse,myocardialinfarctionin2015 (for which she underwent percutaneous coronary inter- vention), NYHA class II heart failure, controlled arterial hypertension, dyslipidemia, depression, and had previ- ously undergone mitral valvuloplasty in 1988 due to

rheumaticfever.Sheregularlytookacenocumarol,clopidogrel,digoxin,carvedilol,ramipril,furosemide,rosuvastatin and sertraline, and had no history of tobacco or alcohol abuseor knownallergies.Shewaspreviously independent forherdailyactivities.

There were no relevant ﬁndings on her pre-operative exams, aside from and discrete lung bilateral inﬁltrates onher chestX-ray.Her hemoglobinlevel was13.9g.dL⁻¹, plateletcount335.000per ␮L,andcoagulationstatushad been promptly corrected with vitamin K. A transthoracic echocardiogram performed after her infarction episode showedmoderate mitralstenosis andmild mitralregurgi- tationwithsevereleftatrialdilation,borderlinecriteriafor pulmonaryhypertension,moderatetricuspidregurgitation, preservedleftventricleejectionfractionandloweredright ventriclefunction.

Afterdiscussingtherisksandsurgicalplanwiththeortho- pedicteamandpatient,we obtained herconsent.Seeing asneuraxialtechniquesordeepPNBswerecontraindicated by her regular usage of clopidogrel, our anesthetic plan consistedof acombination of superﬁcial peripheralnerve blocksandgeneralanesthesia.The patientwasmonitored accordingto AmericanSociety of Anesthesiology monitor- ing standards. Her vitals were BP of 150/92mmHg and HRof 88bpm. We performed a femoral and lateral cuta- neous nerve of thigh block using a 21G 80mm needle (Stimuplex^® Ultra 22gauge, B. Braun, Melsungen, Ger- many) under ultrasound guidance (Venue 40 Ultrasound, GE Healthcare, with a 5---13MHz wide-band linear array

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402 M.Sáetal.

transducer) with an in-plane approach, totaling 15mL of 0.5%ropivacaine.

The surgical team opted for a lateral (Hardinge) approach, whichinvolves the incisionofthe fasciae latae and gluteus medius muscle 5cm proximal to the great trochanterextendingcaudallydownthelineofthefemur.

Inordertoprovideadequate analgesiafor theseincisions, weexecutedaSGNblockwith10mLof0.375%ropivacaine, usingthesameequipmentbyputtingtheultrasoundprobe inatransverseplanecaudallytotheiliaccrestandcephal- icallytothegreatertrochanter,andidentifyingthefascial planebetweenthegluteusmediusandminimus(wherethe SGNtravels) asour targetpoint of injection. We usedan in-planeapproach,fromlateraltomedial.

Afterperformingtheblock,eventlessanestheticinduc- tion was performed with 75␮g of fentanyl and 60mg of propofol.General anesthesia wasmaintainedunder spon- taneousventilationwithanumber3laryngealmaskat0.5 MACofsevoﬂuraneandamixtureofO2:Air40:60.TheBIS valueswerekeptaround50throughouttheprocedure.The procedurelasted90minutes,duringwhich shewashemo- dynamicallystable(BParound120/70mmHgandHRaround 70bpm).Urinaryoutputremainedwellabove1mL.kg⁻¹.h⁻¹. Post-operativenauseaandvomitingprophylaxiswasensured with4mgdexamethasoneandadditionalanalgesiaconsisted solelyof 1gparacetamol.Afteremergingfromanesthesia andforthefollowingdays,thepatientreportednopainat restormovement norside-effects.Shewasprescribed1g Paracetamoland100mgTramadol8hourlyforthefollowing days.

Post-surgical recovery was complicated by methicillin- resistant Staphylococcusaureus bacteremia and complete dehiscenceof the surgical wound, which wassuccessfully managed withantibiotherapyand negativepressure therapy. She was discharged 44 days after surgery, able to immediatelyresumehernormallife.

A month and a half post-discharge, the patient was re-admittedfor debriding and correction of suture dehis- cence.Becauseitwaspredictablyasimpleprocedure,we onceagain obtained the patient’s consent and replicated thePNBsmentioned abovewithamixtureof 15mL mepi- vacaine 1.5% and 10mL ropivacaine 0.375%. The patient remainedcomfortablewithonlylightsedation(30mgpropo- fol throughout the hour-long procedure) and reported no painduringsurgeryorinthefollowingday,whenshewasdis- chargedfromourhospital.Therewerenonoteworthyevents duringtheintra-operativeandpost-operativeperiod.

Discussion

Ultrasound-guidedPNBsarebecominganincreasinglypop- ularoptionforanalgesiaandanesthesia,particularlyinthe elderlywhosecomorbiditiesmight pose significantthreats to their safety. Traumatology, in particular, challenges anesthesiologists to optimize patients and find solutions withinalimitedtime-frame formaximum patientbenefit.

Thesefacts notwithstanding,proﬁciency inPNBs demands morethanimagerecognitionandneedle-eyecoordination:

deepunderstandingofanatomyandskin,muscleandbone innervationempowersanesthesiologiststosolvepotentially complexcaseswithsafer,albeitcreative,approaches.

Figure1 ProbepositionfortheSGNblock.Withthepatientin lateraldecubitus,placetheprobeinatransverseplanecaudally totheiliaccrestandcephalicallytothegreatertrochanter.

Inthis case,the block ofthe SGNallowed for painless incisionofthegluteusmediusmuscleintwodifferentcir- cumstances,withouttheresorttoneuraxialapproachesor deep PNBs in a patient under anti-platelet therapy, rep- resenting an excellent option for pain-control and safe anestheticmanagementofapatientwithsigniﬁcantcomor- bidities.

TheSGNarisesfromthesacralplexusandhasitsorigins onthedorsalramiofL4,L5andS1;afterdescendingthrough the great sciatic foramen it courses over the piriformis and between the gluteus medius and minimus, supplying branchesforthesemusclesbeforereachingthetensorfas- cia latae, which is also innervates.¹ These muscles work

GMed GMax

GE

1

2

3

4cm

GMin

Figure 2 Sonoanatomy of the SGN nerve (GMax, Gluteus MaximusMuscle;GMed,GluteusMediusMuscle;GMin,Gluteus MinimusMuscle).Thearrowpointstothefascialplanebetween GMedandGmin,wherethehyperechoicsuperiorglutealnerve andthepulsatingsuperiorglutealarterycanbeseen.

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Superiorglutealnerve:anewblockontheblock? 403 toconcentricallyabductthethigh,stabilizeofstancehip,

andmaintainthehorizontalpelvicpositionduringsingleleg stance.²Somereferencesalsomentionacontributiontothe posterolateralsectionof thehipjointcapsule.^1,3 TheSGN doesnotinnervatecutaneousorbonestructures.

Hadthesurgicalteamoptedforthemorecommonlyper- formed posterolateral (Moore or Southern) approach, the gluteusmediusmusclewouldhavebeenspared(inexchange forthegluteusmaximusmuscle,whichisinnervatedbythe inferiorglutealnerve).Bothapproachesinvolveaskininci- sionofthelateralaspectofthethigh(coveredbythelateral cutaneousofthighnerve,providedthattheincisionisnot ascephalad soastoaffect subcostal nerveterritory) and dissection of the vastus lateralis muscle (covered by the femoralnerve).Innervationofthehipjointcapsuleisstill controversial,meaningitisdifﬁculttodetailtheroleofeach nerve; nevertheless, as mentioned above, the SGN might contributetotheposterolateralsection.³

InordertolocatetheSGN,theprobewaspositionedin a transverse plane caudally totheiliac crestand cephal- icallytothegreater trochanter(Fig.1).Thesereferences correspondtotheoriginandinsertionofthegluteusmedius muscle,respectively.Superﬁciallytotheiliacbone,theglu- teusmediusandminimusmusclesareidentiﬁable(Fig.2).

The nervetravelswithin thefascialplane between them, andisaccompaniedbythesuperiorglutealartery;thepul- sationofthisarterycanaidinthecorrectidentiﬁcationof thetargetpointofinjection,butshouldalsobeasourceof

concern in regards to safety. Furthermore, care should be taken because permanent injury to the SGN could compromisefunctionof thegluteusmedius,minimus,and tensorfascialate,causingTrendelenburggait.

To the best of our knowledge, this is the ﬁrst report of ultrasound-guided SGN block with an analgesic and anestheticgoal. There have been some scarce reports of blockade of this nerve for chronic pain (superior gluteal neuralgia).Asanatomyandsonoanatomyknowledgethrives withinthemedicalcommunity,itistobeexpectedthatnew blockswillbedescribedandthatanestheticpracticesevolve andchangeaccordingly.

Conﬂicts of interest

Theauthorsdeclarenoconﬂictsofinterest.

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