Nerve Injuries1 / orthodontic courses by Indian dental academy

Nerve injuriesNerve injuries INDIAN DENTAL ACADEMY

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Contents Contents Neuroanatomy Neuroanatomy Classification Classification Etiology Etiology Clinical featuresClinical features Evaluation Evaluation Treatment Treatment


Neuroanatomy Neuroanatomy Function unit of nerve - neuronFunction unit of nerve - neuron


NeuroanatomyNeuroanatomy Sensory nerveSensory nerve Motor nerveMotor nerve


NeuroanatomyNeuroanatomy Nerve fibreNerve fibre EndoneuriumEndoneurium Fascicles Fascicles PerineuriumPerineurium Epineurium Epineurium


NeuroanatomyNeuroanatomy EndoneuriumEndoneurium External layer – collagen fibres, fibroblastsExternal layer – collagen fibres, fibroblasts endoneurial capillariesendoneurial capillaries Internal layer – basal lamina Internal layer – basal lamina


NeuroanatomyNeuroanatomy PerineuriumPerineurium Diffusion barrierDiffusion barrier Resistant to mechanical forcesResistant to mechanical forces


NeuroanatomyNeuroanatomy EpineuriumEpineurium Resistant to compressive and mechanical Resistant to compressive and mechanical Intraneural epineuriumIntraneural epineurium


Classification Classification Seddon Seddon Sunderland Sunderland


ClassificationClassification Seddon classificationSeddon classification Neuropraxia Neuropraxia Axonotemesis Axonotemesis Neurotemesis Neurotemesis


Neuropraxia Neuropraxia Cause – compression or retractionCause – compression or retraction Nerve sheath – intact Nerve sheath – intact Axons – intact Axons – intact Wallerian degeneration – noneWallerian degeneration – none Conduction failure – transitory Conduction failure – transitory Spontaneous recovery – completeSpontaneous recovery – complete Time of recovery – with in 4 weeksTime of recovery – with in 4 weeks


Axonotmesis Axonotmesis Cause – more significant injuryCause – more significant injury Nerve sheath – intact Nerve sheath – intact Axons – interrupted Axons – interrupted Wallerian degeneration – yes, partialWallerian degeneration – yes, partial Conduction failure – prolongedConduction failure – prolonged Spontaneous recovery – partialSpontaneous recovery – partial Time of recovery – monthsTime of recovery – months


NeurotemesisNeurotemesis Complete severence of the nerveComplete severence of the nerve Nerve sheath – interruptedNerve sheath – interrupted Axons – interrupted Axons – interrupted Wallerian degeneration – yes, completeWallerian degeneration – yes, complete Conduction failure – permanentConduction failure – permanent Spontaneous recovery – poor to noneSpontaneous recovery – poor to none Time of recovery – begun by 3 months, if anyTime of recovery – begun by 3 months, if any


Classification Classification SunderlandSunderland Class I – VClass I – V Class I = neuropraxiaClass I = neuropraxia Class II – IV = axonotmesisClass II – IV = axonotmesis Class V = neurotemesisClass V = neurotemesis


Classification Classification Open injuryOpen injury Closed injuryClosed injury


Etiology Etiology Impacted tooth removalImpacted tooth removal OsteotomiesOsteotomies FracturesFractures Dental implant placementDental implant placement Tumor or cyst resectionTumor or cyst resection Salivary gland excisionSalivary gland excision Gunshot injuriesGunshot injuries Local anesthetic injection Local anesthetic injection


Clinical featuresClinical features Numbness of the lipNumbness of the lip Numbness of the anterior tongueNumbness of the anterior tongue Loss of sensation of teethLoss of sensation of teeth


Evaluation Evaluation Loss of sensation, pain or other abnormal Loss of sensation, pain or other abnormal

sensation, or functional impairment?sensation, or functional impairment? Trauma or surgical procedureTrauma or surgical procedure Date, return of sensationDate, return of sensation Area of sensory deficitArea of sensory deficit Character of sensory deficitCharacter of sensory deficit


Evidence of recent injury or surgeryEvidence of recent injury or surgery Palpation, percussionPalpation, percussion Pain without radiation – nerve severance withPain without radiation – nerve severance with proximal stump neuromaproximal stump neuroma Pain with radiation – nerve tissue distal to the Pain with radiation – nerve tissue distal to the injuryinjury Pulp testing Pulp testing


RadiographsRadiographs Static light touchStatic light touch Brush directional strokesBrush directional strokes Two point discriminationTwo point discrimination Pinprick detectionPinprick detection Local anesthetic injectionsLocal anesthetic injections


Management Management Nerve anastomosis Nerve anastomosis Nerve decompressionNerve decompression Nerve grafting Nerve grafting


Nerve anastomosisNerve anastomosis Direct suture Direct suture

anastomosisanastomosis Immediate repair – free Immediate repair – free

of foreign materialof foreign material Delayed repair – 3 to 4 Delayed repair – 3 to 4

weeksweeks Without significant Without significant

tension and stretchingtension and stretching Mono or polyfasicularMono or polyfasicular


decompressiondecompression ExternalExternal Internal Internal


External decompression External decompression Microdissection and release of the epineural Microdissection and release of the epineural

sheath from surrounding scar tissues, foriegjn sheath from surrounding scar tissues, foriegjn bodies, bone or its fragmentsbodies, bone or its fragments

Communition of bone across the NV bundleCommunition of bone across the NV bundle


Internal decompressionInternal decompression Signs of intraneural pathologySigns of intraneural pathology Release the adhesions between the Release the adhesions between the

perineurium perineurium


Grafting Grafting

IndicationsIndications Reanastomosis with tension Reanastomosis with tension Neurotemesis and axontemesisNeurotemesis and axontemesis Evidence of symptomatic neuromaEvidence of symptomatic neuromaGrafts used areGrafts used are Greater auricularGreater auricular Sural nerveSural nerve


Success or failureSuccess or failure Age Age Nature of the injuryNature of the injury Timing of repair Timing of repair Presence of secondary pathologiesPresence of secondary pathologies



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