RevBrasAnestesiol.2017;67(6):655---658
REVISTA
BRASILEIRA
DE
ANESTESIOLOGIA
PublicaçãoOficialdaSociedadeBrasileiradeAnestesiologiawww.sba.com.br
CLINICAL
INFORMATION
Intractable
intraoperative
brain
herniation
secondary
to
tension
pneumocephalus:
a
rare
life-threatening
complication
during
drainage
of
subdural
empyema
Li
Lian
Foo
a,∗,
Sook
Hui
Chaw
a,
Lucy
Chan
a,
Dharmendra
Ganesan
b,
Ravindran
Karuppiah
caUniversityofMalaya,FacultyofMedicine,DepartmentofAnesthesiology,KualaLumpur,Malaysia
bUniversityofMalaya,FacultyofMedicine,DepartmentofSurgery,KualaLumpur,Malaysia
cUniversityMalayaMedicalCentre,DepartmentofSurgery,KualaLumpur,Malaysia
Received25December2014;accepted28January2015 Availableonline3October2015
KEYWORDS
Intraoperativebrain herniation;
Tension
pneumocephalus; Hydrogenperoxide; Brainamputation
Abstract Tensionpneumocephalusisrarebuthasbeenwelldocumentedfollowingtraumaand neurosurgicalprocedures.Itisasurgicalemergencyasitcanleadtoneurologicaldeterioration, brainstemherniationanddeath.Unlikepreviouscaseswheretensionpneumocephalus devel-opedpostoperatively,wedescribeacaseofintraoperativetensionpneumocephalusleadingto sudden,massiveopenbrainherniationoutofthecraniotomysite.Thepossiblecausativefactors areoutlined.Itisimperativetorapidlyidentifypossiblecausesofacuteintraoperativebrain herniation,includingtensionpneumocephalus,andinstituteappropriatemeasurestominimize neurologicaldamage.
©2015SociedadeBrasileiradeAnestesiologia.Publishedby ElsevierEditoraLtda.Thisisan openaccessarticleundertheCCBY-NC-NDlicense( http://creativecommons.org/licenses/by-nc-nd/4.0/).
PALAVRAS-CHAVE
Herniac¸ãocerebral nointraoperatório; Pneumoencéfalo hipertensivo; Peróxidode hidrogênio;
Amputac¸ãocerebral
Herniac¸ãocerebralintratávelsecundáriaapneumoencéfalohipertensivono intraoperatório:umacomplicac¸ãoraracomriscoparaavidaduranteadrenagem deempiemasubdural
Resumo Opneumoencéfalohipertensivo éraro,mas foibemdocumentadoapóstraumae procedimentos neurocirúrgicos. Trata-se de uma emergência cirúrgica porque podelevar à deteriorac¸ãoneurológica,herniac¸ãodotroncocerebralemorte.Aocontráriodecasos anteri-oresnosquaisopneumoencéfalohipertensivosedesenvolveunopós-operatório,descrevemos um caso de pneumoencéfalo hipertensivo desenvolvido no período intraoperatório levando
∗Correspondingauthor.
E-mail:[email protected](L.L.Foo). http://dx.doi.org/10.1016/j.bjane.2015.01.005
656 L.L.Fooetal.
aumaherniac¸ãocerebralsúbita,macic¸aeabertaparaforadolocaldacraniotomia.Os pos-síveisfatorescausaissãodestacados.Éimperativoidentificarrapidamenteaspossíveiscausas daherniac¸ãocerebralagudanointraoperatório,incluindoopneumoencéfalohipertensivo,e instituirmedidasapropriadasparaminimizarosdanosneurológicos.
©2015SociedadeBrasileiradeAnestesiologia.PublicadoporElsevierEditoraLtda.Este ´eum artigoOpen Accesssobumalicenc¸aCCBY-NC-ND( http://creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction
Tensionpneumocephalusisrarebutwelldocumented,with studiesshowingan incidenceof2.5---16%1 sinceitwasfirst
described in 1962. Most cases occur postoperatively and presentwithneurologicaldeterioration.Toourknowledge thisis the firstsuchcase report of intraoperativetension pneumocephalus which presented with immediate conse-quences---massivebrainherniationfromtheoperativesite. Anestheticandsurgicalconsiderationsinthemanagementof tensionpneumocephalusandintraoperativebrainherniation areoutlined.
Case
report
A27year-oldfemalepresentedwithright sidedweakness andblurringofvision.CTscanshowedaleftparietaltumour andsheunderwentcraniotomyandexcision.Sherecovered wellandwasdischargedwithpersistent rightsided weak-ness.
Three weeks later, she presented again with wound breakdownandpusdischargefromthecraniotomysite.CT (Fig.1)revealedasubduralempyemainbothfrontalregions measuring1.3cmindepthwithpost-surgical encephaloma-lacicchangesintheleftparasagittalregion.Shewasposted foranemergencycraniectomyandwounddebridement.
Figure1 PreoperativeCTscan.
Pre-operatively,shewasafebrilewithGCSof15/15.Her baseline blood pressure (BP)was 115/75mmHg and heart rate was 105 beats per minute (bpm). In the operating theatre,understandard monitoring,inductionof anesthe-siaproceededwithintravenousfentanyl2mcg.kg−1andIV propofol2.5mg.kg−1.MuscleparalysiswasachievedwithIV rocuronium1mg.kg−1.Herairwaywassecuredwithasize 7.5cmcuffedPVCendotrachealtubeandshewaspositioned supine withher head ona horseshoe headrest. We main-tained general anesthesia withSevoflurane in oxygen: air (FiO2of0.5).
Her previous incisionwound over the frontal areawas opened andbone flap removed. Sloughand pus discharge wasnotedonthe brainsurface.The wound wasdebrided andthenirrigatedwithapproximately10mLof3%hydrogen peroxidemixedwithnormalsalineinabulbsyringe.Upon completionofirrigation,profoundbrainherniationoccurred throughtheoperativesite.Ithappenedacutelyandwound closure was impossible. There was no obvious bleeding seen.
Physiological parameters prior to herniation were all within normalrange (BP: 100/50mmHg; HR:95---115bpm, saturation: 99---100%, end tidal CO2: 33---36mmHg).
Mini-mumAlveolar Concentration had been maintainedat 0.9. Shehadbeen givenintermittentbolusesofrocuroniumfor musclerelaxation.Analgesiawasachievedwithintravenous morphine 4mg and an IV alfentanil 1mg bolus was given duringtheincident.Duringacutebrainherniation,transient hypotensionandtachycardiawereobservedwhichresolved withafluidbolus.
Immediate measures to decrease brain bulk included hyperventilation to decrease the PaCO2 to 30---35mmHg
andadministrationofintravenousmannitol(0.5g.kg−1).IV phenytoin1gwasgivenfor seizureprophylaxis. The head position was checked to ensure the neck veins were not compressed.However,the brainherniationpersisted.The surgeonthenproceededwithamputationof theherniated brainfordecompressionandclosure.
Anurgent CTbrainpost-operation showedleftparietal brain herniation and cerebral oedema of herniated brain andpartoftheleftparietallobe.Extensivesubdural pneu-mocephalus was seen in both frontal regions (Fig. 2). A newsubduralcollectionwasalsonotedintheleft parieto-temporo-occipitalregion.
Shewascerebralprotectedpost-operativelyandanother wounddebridementandburrholewasdonetwodayslater forpersistentdischargeandthepresenceofextensive sub-duralpneumocephalusfromCTscan.
Intractableintraoperativebrainherniationsecondarytotensionpneumocephalus 657
Figure2 PostoperativeCTscan.
Discussion
Acute intraoperative brain herniation through the cran-iotomy site is uncommon. It has been described during traumaticbraininjuriesandexcisionofbraintumour.2The
exactincidenceisunknown,butWhittleetal.estimateda 0.7%incidenceinhispractice.2
Herniation of brain tissue leads to tension on crossing vesselsattheduraledge.Thisresultsinvenousthenarterial compression,impairedperfusionandeventualinfarctionof theherniatingbraintissue.3
The causes of herniation include malignant brain oedema,3 hyperemia,4,5 andhaemorrhage2 (subdural,
sub-arachnoid or intraventricular) at a site distant to the craniotomy, acutely increasing intracranial pressure and forcing brain tissue out of the dural defect.2,3,6 In this
patient, extensive subdural tension pneumocephalus was the main cause as shown in the post operative CT Scan (Fig. 2).Several factorsmay have led toits rapid devel-opmentwhichisoutlinedbelow.
Firstly, irrigation of the operative field after drainage of subdural empyema may have introduced air into the subduralcavity.Twopreviousstudiesshowedahigher inci-dence of post-operative pneumocephalus after drainage with irrigation for chronic subdural hematomas as com-paredtodrainagealone.7,8Airinthebulbirrigationsyringe
mayhavebeenflushedathigh pressuresintothesubdural space.
Secondly, the use of hydrogen peroxide may have introduced air intracranially. Hydrogen peroxide is com-monly used in neurosurgery for hemostasis and for disinfection. It decomposes to water and oxygen in an exothermicreaction,catalyzedbytissuecatalase.1mLof 3%H2O2releasesapproximately10mLofoxygen.9This
lib-eratedoxygencanleadtowelldocumentedcomplications suchasvenousoxygenembolism,pneumocephalusand car-diacdysrhythmias.10
Lastly,airfromthetwomechanismsabovemayhavebeen trappedin thesubdural spaceby aduralflapproducing a ball valve mechanism, leading to the development of an intraoperativetensionpneumocephalus.
Preexisting cerebral oedema, combined withnew sub-duralcollectionintheleftparieto-temporo-occipitalregion mayalsohavecontributedtoincreasedintracranialpressure (ICP).
Pneumocephalusisacommonfinding,with100%ofpost craniotomy patients having pneumocephalus on the first postoperativeday,1,11 reducingto26%bythethird
postop-erativeweek.11Tensionpneumocephalus,however,israre,
andoccurswhenintracranialairexertsapressureeffectand manifests with neurological deterioration.1,12 It has been
reportedfollowingtrauma,orasacomplicationofsurgery ---commonlydrainageofchronicsubduralhaemorrhage,shunt surgeries,craniofacialandtranssphenoidalprocedures,and posteriorfossacraniotomiesinthesittingposition.1
Thefollowingmechanismshavebeenproposed1:
1. Invertedsodabottlephenomenon
LeakageofCSFcausesnegativeintracranialpressure andsucksairin.
2. Ballvalvemechanism
Airentersintracranialcavitythroughadefect.Raised intracranial pressureforcesbrainparenchyma toblock theentrysiteandtrapstheintracranialair.
3. Expansion of intracranial air-filled spaces by nitrous oxideanesthesia.
4. GasformingorganismssuchasEscherichiacoli.13
Tensionpneumocephalusshouldbemanagedasasurgical emergencybyimmediatereleaseofairthroughaburrhole, needleaspirationorinsertionofadrain.1,12
All published reports of tension pneumocephalus have occurred post operatively except for one case of cardiac arrestwhichoccurredattheendofoperationasthedural edges were sutured.14 In this case the tension
pneumo-cephalusdevelopedintraoperatively andwassoextensive astocauseanacuteexternalbrainherniationthroughthe craniotomysite.
Anestheticandsurgicalconsiderations
Thefirstconsiderationshouldbetoavoidfurtherincreases inICP.Thisincludesensuringadequatedepthofanesthesia, adequate analgesia, avoiding hyperthermia, hypertension andstoppingalldrugsknowntoincreaseICPsuchasnitrous oxide,ketamineandsuxamethonium.Thenextstepshould betoreduce ICPby simplemeasures ---headuptilt, neck in neutral position to avoid venous obstruction. Cerebral oedema can be reduced by diuretics including frusemide andmannitol and moderate hyperventilation as a tempo-rarymeasure.Barbiturates or propofolhave been usedto reducethecerebralmetabolicrate.
658 L.L.Fooetal.
of the brain with a sterile silicone sheet has also been reported.15 In our case, the brain herniated at such high
pressuresthatthesurgeonwasunabletomanuallyreduceit. Thereforebrainamputationwasperformed.Thisisamatter ofcontroversyasamputationofhealthybrainwillinevitably resultinneurologicaldeficits.
Ahybridoperatingtheatrecontainingadvancedimaging facilitiessuchasCTandMRIwouldhavebeenbeneficialin thisscenario,enablingtimelyintra-operativediagnosisand appropriateinterventions.
Conclusion
Wepresentthefirstcasereporttoourknowledgeofan intra-operativetensionpneumocephalusleadingtocatastrophic openbrainherniation.Duetotherarityofthiscomplication, the diagnosis was not immediately recognized intraoper-atively.Timely diagnosis, immediateaspirationof air and closure of the scalp may have prevented the distressing alternativeofabrainamputation.
Consent
Publishedwiththewrittenconsentofthepatient.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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