Temporal Bone TraumaTemporal Bone Trauma

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Temporal bone traumaTemporal bone trauma

Epidemiology Epidemiology PathophysiologyPathophysiologyEvaluationEvaluationSymptomsSymptomsTreatmentTreatment

EpidemiologyEpidemiology20% of all skull fractures20% of all skull fracturesMechanism of injuryMechanism of injury

Motor vehicle collisionMotor vehicle collisionAssault Assault Falls Falls

GenderGender3 male : 1 female 3 male : 1 female

AgeAge70% in 270% in 2ndnd, 3, 3rdrd, 4, 4thth decadesdecades

PediatricsPediatricsBimodal distributionBimodal distribution22--3 years = falls3 years = falls15 years = MVC15 years = MVC

EpidemiologyEpidemiology

PathophysiologyPathophysiologyApplication of forceApplication of force

Requires 1875 pounds of lateral forceRequires 1875 pounds of lateral forceFractures along structurally weakest points Fractures along structurally weakest points

Structures at riskStructures at riskCranial nerves VII, IX, X, XICranial nerves VII, IX, X, XICochleaCochleaLabyrinthLabyrinthOssiclesOssiclesTympanic membraneTympanic membraneCarotid arteryCarotid arteryJugular veinJugular vein

Open fractures (60%)Open fractures (60%)Bloody Bloody otorrheaotorrhea, brain , brain herniationherniation, or CSF in external auditory , or CSF in external auditory canal, canal, eustachianeustachian tube, or site of penetrating injurytube, or site of penetrating injury

EvaluationEvaluationMultiply injured Multiply injured patientpatient

AirwayAirwayVentilationVentilationCirculationCirculationNeurologicNeurologic statusstatus

•• GlascowGlascow coma scalecoma scale•• Cervical spine Cervical spine

immobilizationimmobilization•• Documentation of Documentation of

movement of face and movement of face and extremitiesextremities

EvaluationEvaluationOtoscopicOtoscopic examinationexamination

•• Tympanic membraneTympanic membrane•• Middle ear Middle ear

Cranial nervesCranial nerves•• Tuning forks Tuning forks

Characterization of Characterization of otorrheaotorrhea if presentif presentRadiologyRadiology

NeuroNeuro--otologicotologicexaminationexamination

SubjectiveSubjective•• DisequilibriumDisequilibrium•• Hearing lossHearing loss•• VertigoVertigo•• Prior Prior otologicotologic historyhistory

Mechanism of injuryMechanism of injury•• Direction of forceDirection of force•• Site of impactSite of impact

External earExternal ear•• LacerationsLacerations•• HematomaHematoma•• OtorrheaOtorrhea•• Bony deformityBony deformity

NeuroNeuro--otologicotologic examinationexaminationNystagmusNystagmusPeripheral vertigo Peripheral vertigo

Horizontal or Horizontal or rotatoryrotatorySuppressible with fixationSuppressible with fixationMost common vertigo after Most common vertigo after head trauma is BPPVhead trauma is BPPV

Central vertigoCentral vertigoVertical or directionVertical or direction--changing changing Fails to suppress with fixationFails to suppress with fixation

ENG ENG As outpatient if symptoms do As outpatient if symptoms do not resolvenot resolve

Fistula test Fistula test Not performed acutelyNot performed acutelyRisk of iatrogenic injury and Risk of iatrogenic injury and introducing contaminants into introducing contaminants into inner ear outweigh benefitsinner ear outweigh benefits

HearingHearingAssess initially with tuning Assess initially with tuning forksforksAudiogramAudiogram

Formal audiogram prior to Formal audiogram prior to surgical intervention surgical intervention Not necessary in acute setting Not necessary in acute setting if symptoms/clinical evaluation if symptoms/clinical evaluation consistent with CHL consistent with CHL

BattleBattle’’s signs sign

ExtravasatedExtravasated blood blood from posterior from posterior auricular arteryauricular artery

OtoscopicOtoscopic examinationexamination

HemotympanumHemotympanum

EAC lacerationEAC laceration

TM perforationTM perforation

OssicularOssicular disruptiondisruption

ImagingImagingImaging follows acute Imaging follows acute stabilization of lifestabilization of life--threatening injuriesthreatening injuriesScreening head CT to Screening head CT to rule out intracranial rule out intracranial injuriesinjuriesHighHigh--resolution CT resolution CT scan of temporal scan of temporal bones if fracture bones if fracture suspectedsuspected

HighHigh--resolution CT resolution CT scan of temporal scan of temporal bones required if: bones required if:

Facial paralysisFacial paralysisCSF leakCSF leakDisruption of superior Disruption of superior wall of EACwall of EACSuspected vascular Suspected vascular injuryinjury

ClassificationClassification

Traditional Traditional LongitudinalLongitudinalTransverseTransverseOblique Oblique

Newer classification schemeNewer classification schemeDisruption of Disruption of oticotic capsulecapsuleSparing of Sparing of oticotic capsule capsule

Longitudinal fracturesLongitudinal fractures

7070--90% of temporal bone 90% of temporal bone fracturesfracturesParallel to long axis of Parallel to long axis of petrouspetrousapexapex

Starts in Starts in squamoussquamous part of part of temporal bonetemporal boneThrough posterior/superior Through posterior/superior EACEACThrough roof of middle ear Through roof of middle ear (anterior to membranous (anterior to membranous labyrinth)labyrinth)Into carotid canal, ending at Into carotid canal, ending at foramen foramen lacerumlacerum

Injury to Injury to temporoparietaltemporoparietalregionregion

Longitudinal fractures:Longitudinal fractures:ComplicationsComplications

Facial nerve palsyFacial nerve palsy20% of longitudinal 20% of longitudinal fxfx

Hearing lossHearing lossConductiveConductiveTympanic disruptionTympanic disruptionOssicularOssicularderangementderangementHemorrhage into Hemorrhage into middle earmiddle ear

Transverse fracturesTransverse fractures1010--30% of temporal bone 30% of temporal bone fracturesfracturesPerpendicular to long Perpendicular to long axis of temporal boneaxis of temporal bone

Start at foramen magnumStart at foramen magnumPerpendicularly across Perpendicularly across petrouspetrous pyramidpyramidThrough labyrinthine Through labyrinthine capsulecapsuleInto middle cranial Into middle cranial fossafossaEnd in foramen End in foramen lacerumlacerum

Impact at frontal or Impact at frontal or occipital areaoccipital area

Transverse fractures:Transverse fractures:ComplicationsComplications

Facial nerve palsyFacial nerve palsy50%50%

Hearing lossHearing lossSensorineuralSensorineural

CSF leakCSF leakFracture extends Fracture extends intracraniallyintracranially

Oblique fracturesOblique fracturesInjury pattern similar to Injury pattern similar to longitudinal fractureslongitudinal fracturesFrom superior EAC, From superior EAC, parallel to parallel to petrouspetrous boneboneTurns superior/oblique to Turns superior/oblique to cross cross petrotympanicpetrotympanicfissurefissure

Remains lateral to Remains lateral to oticoticcapsulecapsule

OticOtic capsule sparing fracturescapsule sparing fractures9494--98% of temporal bone 98% of temporal bone fracturesfracturesSquamosalSquamosal portion of portion of temporal bonetemporal bonePosterosuperiorPosterosuperior wall of wall of EACEACThrough mastoid air cells Through mastoid air cells and middle earand middle earFractures Fractures tegmentegmentympani tympani Results from a blow to Results from a blow to temporoparietaltemporoparietal regionregion

OticOtic capsule disrupting fracturescapsule disrupting fractures2.52.5--5.8% of temporal 5.8% of temporal bone fracturesbone fracturesFracture proceeds from Fracture proceeds from foramen magnum across foramen magnum across petrouspetrous pyramid and pyramid and oticoticcapsulecapsuleOften passes through Often passes through jugular foramen, IAC, and jugular foramen, IAC, and foramen foramen lacerumlacerumDo NOT typically affect Do NOT typically affect ossicularossicular chain or EACchain or EACResults from blow to Results from blow to occipital regionoccipital region

ClassificationClassificationWhy change classification Why change classification scheme?scheme?OticOtic--capsulecapsule--disrupting disrupting fractures have: fractures have:

SNHL SNHL Higher incidence of CN VII Higher incidence of CN VII palsy (30palsy (30--50% v. 650% v. 6--13%)13%)22--4X higher risk of CSF 4X higher risk of CSF leakleakHigher risk of delayed Higher risk of delayed meningitis meningitis

DahiyaDahiya: J Trauma, Volume : J Trauma, Volume 47(6).December 1999.107947(6).December 1999.1079

Penetrating traumaPenetrating trauma

Mostly GSWMostly GSWInjuries depend on Injuries depend on direction/velocity of direction/velocity of missilemissile

ComplicationsComplications

SensorineuralSensorineural hearing losshearing lossConductive hearing loss Conductive hearing loss CholesteatomaCholesteatomaCSF fistulaCSF fistulaFacial nerve injury Facial nerve injury Vascular injury Vascular injury

SensorineuralSensorineural hearing losshearing lossSevereSevere--Profound SNHLProfound SNHL

OticOtic--capsulecapsule--disrupting disrupting fracturesfractures

Mixed hearing lossMixed hearing lossIncusIncus dislocation dislocation 50% of patients with 50% of patients with incusincusdislocation have >10dB dislocation have >10dB SNHL SNHL

PrognosisPrognosisProfound SNHL has poor Profound SNHL has poor prognosisprognosisModerate SNHL may have Moderate SNHL may have some recovery some recovery

MechanismMechanismDisruption of membranous Disruption of membranous labyrinthlabyrinthAvulsion /trauma to Avulsion /trauma to cochlear nervecochlear nerveInterruption of cochlear Interruption of cochlear blood supplyblood supplyHemorrhage into cochleaHemorrhage into cochleaPerilymphaticPerilymphatic fistula fistula

•• May be suggested by May be suggested by fluctuating or progressive fluctuating or progressive HL HL

Conductive hearing lossConductive hearing loss80% CHL resolves 80% CHL resolves spontaneously spontaneously HemotympanumHemotympanumResolution of Resolution of hemotympanumhemotympanumaffected by affected by

EndotrachealEndotracheal intubationintubationAssociated facial fracturesAssociated facial fracturesPresence of CSF leakPresence of CSF leak

OssicularOssicular discontinuity (20%)discontinuity (20%)Common injuriesCommon injuries

IncudostapedialIncudostapedial joint (82%)joint (82%)Dislocation of Dislocation of incusincus (57%)(57%)Fracture of stapes Fracture of stapes cruracrura (30%)(30%)

Suggested by residual CHL Suggested by residual CHL following resolution of following resolution of hemotympanumhemotympanum

Exploratory Exploratory tympanotomytympanotomyindications: 30dB CHL indications: 30dB CHL persisting > 2m after injury persisting > 2m after injury Contraindications: CHL in only Contraindications: CHL in only hearing earhearing earRelative contraindication: Relative contraindication: mixed hearing loss mixed hearing loss

CholesteatomaCholesteatoma

Delayed complicationDelayed complicationPathogenic mechanismsPathogenic mechanisms

Epithelial entrapment in fracture line Epithelial entrapment in fracture line •• EpitympanumEpitympanum, , antrumantrum

IngrowthIngrowth of epithelium through fracture lineof epithelium through fracture line•• EpitympanumEpitympanum, , antrumantrum

Traumatic implantation of TM skin into METraumatic implantation of TM skin into ME•• MesotympanumMesotympanum

Trapping of epithelium medial to Trapping of epithelium medial to stenosisstenosis of EACof EAC•• EAC EAC

CSF fistulaCSF fistulaComplicates 17% of temporal bone fracturesComplicates 17% of temporal bone fractures

CSF CSF otorrheaotorrhea•• With TM disruptionWith TM disruption

CSF CSF rhinorrhearhinorrhea•• If TM intact If TM intact

OticOtic capsule sparingcapsule sparingFloor of middle cranial Floor of middle cranial fossafossa

OticOtic capsule disruptingcapsule disruptingFrom posterior cranial From posterior cranial fossafossa through through oticotic capsulecapsule

Delayed CSF leakDelayed CSF leakHerniationHerniation of of duradura/brain into defect/brain into defectHematomaHematoma obstructing outflow of CSFobstructing outflow of CSF

CSF fistulaCSF fistulaOther Other

IntrathecalIntrathecal fluoresceinfluoresceinUsed for localizing fistulas Used for localizing fistulas when all other methods when all other methods have failed have failed

SymptomsSymptomsClear watery drainage from Clear watery drainage from the nose or ear the nose or ear

•• Flow increases when Flow increases when patient leans forward with patient leans forward with neck flexedneck flexed

Headache Headache Laboratory testsLaboratory tests

GlucoseGlucoseProteinProteinPotassium Potassium

ββ--2 2 transferrintransferrinRadiology Radiology

HRCT HRCT CT CT cisternographycisternography

CSF fistula CSF fistula Meningitis Meningitis

22--88%88%Duration of leak Duration of leak

< 7 days 5< 7 days 5--11% 11% > 7 days 33> 7 days 33--88% 88%

Prophylactic Prophylactic antibioticsantibiotics

No benefit without No benefit without CSF fistula CSF fistula Questionable benefit Questionable benefit with CSF fistula with CSF fistula

Risk of meningitis Risk of meningitis increases with increases with concurrent infection concurrent infection Pathogens Pathogens

H. H. influenzaeinfluenzaeS. S. pneumoniaepneumoniae

CSF fistulaCSF fistulaTreatment Treatment Conservative Conservative management 7management 7--10 days10 days

Total Total bedrestbedrestHOB elevatedHOB elevatedStool softenersStool softenersNo No noseblowingnoseblowing, sneezing, , sneezing, strainingstrainingRepeat lumbar punctures Repeat lumbar punctures or lumbar drainor lumbar drain

Operative managementOperative managementApproach depends on Approach depends on hearing status, location of hearing status, location of fistula, and presence of fistula, and presence of brain brain herniationherniationOticOtic capsule disruptingcapsule disrupting

•• Obliteration of mastoid Obliteration of mastoid and middle ear and middle ear

OticOtic capsule sparing capsule sparing •• Lateral Lateral –– complete complete

mastoidectomymastoidectomy•• Medial Medial -- combined middle combined middle

cranial cranial fossafossa approach approach

Facial Nerve InjuryFacial Nerve Injury

Complicates 7% of temporal bone fracturesComplicates 7% of temporal bone fractures25% of injuries are complete facial paralysis25% of injuries are complete facial paralysisOnset Onset

ImmediateImmediate-- 27%27%•• Patients examined in ER before muscle relaxantsPatients examined in ER before muscle relaxants

DelayedDelayed-- 73%73%•• Crucial to differentiate between Crucial to differentiate between ‘‘delayed onsetdelayed onset’’ and and ‘‘delayed delayed

diagnosisdiagnosis’’

UnestablishedUnestablished onset onset •• Should be treated as immediate onset Should be treated as immediate onset

Facial nerve injury Facial nerve injury HouseHouse--BrackmannBrackmann

I I –– Normal Normal II II –– Mild dysfunctionMild dysfunction

Normal symmetry at restNormal symmetry at restSlight weakness on close Slight weakness on close inspection inspection Slight Slight synkinesissynkinesis

III III –– Moderate dysfunction Moderate dysfunction Normal symmetry at rest Normal symmetry at rest Noticeable (but not severe) Noticeable (but not severe) synkinesissynkinesisObvious (but not Obvious (but not disfiguring) weakness disfiguring) weakness *COMPLETE eye closure *COMPLETE eye closure

IV IV –– Moderately severe Moderately severe dysfunction dysfunction

Normal symmetry at restNormal symmetry at restObvious and disfiguring Obvious and disfiguring weaknessweakness*INCOMPLETE eye *INCOMPLETE eye closureclosure

V V –– Severe dysfunctionSevere dysfunctionAsymmetry at rest Asymmetry at rest Barely perceptible motion Barely perceptible motion

VI VI –– Total paralysis Total paralysis

Facial nerve injury Facial nerve injury PrognosisPrognosis

Important factors Important factors Onset Onset Degree of paresis Degree of paresis

Incomplete paresis rarely fails to resolve Incomplete paresis rarely fails to resolve spontaneouslyspontaneouslyDelayed onset >95% return to HouseDelayed onset >95% return to House--BrackmannBrackmann I or II without intervention I or II without intervention

Facial nerve injuryFacial nerve injurySunderland classificationSunderland classification

NeuropraxiaNeuropraxia11st degreest degree-- Anatomically intact Anatomically intact nerve with conduction nerve with conduction blockadeblockade

AxonotmesisAxonotmesis22ndnd degreedegree-- TransectionTransection of of axons but axons but endoneuriumendoneurium intactintact

NeurotmesisNeurotmesis33rdrd degreedegree-- Transects axon Transects axon and and endoneuriumendoneurium but but perineuriumperineurium intactintact44thth degreedegree-- Transect entire Transect entire nerve trunk but nerve trunk but epineuralepineuralsheath intactsheath intact55thth degreedegree-- Complete Complete transectiontransection of entire nerve of entire nerve trunk and trunk and epineuriumepineurium

Facial nerve injury Facial nerve injury

Nerve excitability test (NET) Nerve excitability test (NET) Compared to healthy sideCompared to healthy sideThe lowest current eliciting a twitch is the The lowest current eliciting a twitch is the threshold of excitement threshold of excitement Difference of 3.5 Difference of 3.5 mAmA = severe degeneration = severe degeneration Can only be used after 3 days and before 2Can only be used after 3 days and before 2--3 3 weeks weeks Determines (in total paralysis) whether Determines (in total paralysis) whether degeneration is occurringdegeneration is occurring

Facial nerve injuryFacial nerve injury

Maximum stimulation test (MST) Maximum stimulation test (MST) Increasing current is delivered until maximal Increasing current is delivered until maximal movement is seenmovement is seenCompared to healthy side Compared to healthy side Subjectively expressed as percentage of Subjectively expressed as percentage of healthy side healthy side

Facial nerve injuryFacial nerve injury

ElectroneurographyElectroneurography (ENOG) (ENOG) Bipolar stimulating electrode at Bipolar stimulating electrode at stylomastiodstylomastiod foramenforamenResponses to maximal electrical stimulation of 2 Responses to maximal electrical stimulation of 2 sides comparedsides comparedRecorded electrically (not subjective) Recorded electrically (not subjective) Normal < 3% difference between sides Normal < 3% difference between sides

Facial nerve injury Facial nerve injury Surgical decompression Surgical decompression

> 90% degeneration within > 90% degeneration within 6 days 6 days > 95% degeneration within > 95% degeneration within 14 days 14 days

Site of injury Site of injury PerigeniculatePerigeniculate ganglion in ganglion in 8080--93%93%

Surgical approach Surgical approach Decompression, nerve Decompression, nerve rerouting with direct rerouting with direct anastamosisanastamosis, cable grafting , cable grafting TranslabyrinthineTranslabyrinthine approach approach Combined Combined transmastoidtransmastoid/middle cranial /middle cranial fossafossa

Vascular injury Vascular injury Carotid injuryCarotid injury

5% chance of carotid injury if 5% chance of carotid injury if canal intactcanal intact18% chance of carotid injury if 18% chance of carotid injury if canal disrupted canal disrupted

Carotid Carotid ligationligation or embolismor embolismIndicated if hemorrhage from Indicated if hemorrhage from EAC cannot be controlled by EAC cannot be controlled by packing packing

•• Packing ONLY indicated with Packing ONLY indicated with significant hemorrhage! significant hemorrhage!

ArteriographyArteriographyIndicated if Indicated if neurologicneurologic deficits deficits