Facial Palsy

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BANDAR AL-QAHTANI, M.D. KSMC. Facial Palsy. Etiology. Past theories: vascular vs. viral McCormick (1972) – herpes simplex virus Murakami (1996) 11/14 patients with HSV-1 in neural fluid None in controls or Ramsay-Hunt syndrome Temporal bone section at autopsy
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BANDAR AL-QAHTANI, M.D.KSMCFacial PalsyEtiologyPast theories: vascular vs. viralMcCormick (1972) – herpes simplex virusMurakami (1996)11/14 patients with HSV-1 in neural fluidNone in controls or Ramsay-Hunt syndromeTemporal bone section at autopsyAnimal model inoculated with HSV-1Evaluation
  • Careful history – timing
  • HX of present illness Associated symptoms (pain, dysgeusia)
  • SNHL, vesicles, severe pain
  • Trauma, acute or chronic OM, recurrent
  • Exposures
  • Physical exam
  • Audiometry
  • CT/MRI/other
  • Topographic
  • Electrophysiology
  • Anatomy
  • Intracranial
  • Meatal
  • Labyrinthine (2-4 mm)
  • Tympanic (11 mm)
  • Mastoid (13 mm)
  • Extracranial
  • AnatomyTraumatic facial nerve palsy/paralysisBirth trauma Penetrating injuryIatrogenic Temporal bone #Longitudinal vs transverse or mixed Transection vs edema injuryImmediate or delayed Infection Herpes virus,TB ..etcOtitis media ,cholesteatoma,mastoiditis Metabolic & systemic DMGuillian barre syndromeAutimmune Bell’s PalsyFacial paralysisAcute onset, limited duration, minimal symptoms, spontaneous recoveryIdiopathic in pastDiagnosis of exclusionMost common diagnosis of acute facial paralysisPathophysiologyHSV viral reactivation leading to damage of facial nerveNeuropraxia– no axonal discontinuityAxonotmesisWallerian degeneration (distal to lesion)Axoplasmic disruption, endoneural sheaths intactNeurotmesisWallerian degeneration (distal to lesion)Axon disrupted, loss of tubules, support cells destroyedElectrophysiologyTreatment plan based on 16% of patients who do not fully recoverSeveral tests used for prognosisMeasure amounts of neural degeneration occurred distal to injury by measuring muscle response to electrical stimulusNET, MST, ENoG, EMGAble to differentiate nerve fibers undergoing Wallerian degenerationElectrophysiologyNET (nerve excitability test)Compares current thresholds to elicit minimal muscle contraction3.5 mA difference significantMST (maximum stimulation test)Compares responses generated with maximal electrical stimulation judged as difference in facial movementElectrophysiology
  • ENoG (electroneuronography)
  • Most accurate, objective
  • Records summation potential
  • Degree of degeneration is directly proportional to amplitudes of measured potentials
  • Done after Wallerian degeneration starts (3-4 days)
  • Compare each day
  • ElectrophysiologyENoGEsslen (1977) – over 90% degeneration on ENoG prognosis worsens90-97%: 30% recover fully98-99%: 14% recovery fully100%: none recovered fullyFisch (1981)50% with 95-100% degeneration by 14 days have poor recoveryHigh likelihood of further degeneration if reaches 90%Thus, if ENoG reaches 90% within 2 weeks: 50-50 recovery ElectrophysiologyEMG (electromyography)Not useful in acute phase except as complementary testWill be flat with neuropraxia, 100% degeneration, and early regenerationKey in long-term evaluation (over 3 weeks)Fibrillation potentials– degenerationPolyphasic motor units– regenerating nerveMedical ManagementEye protectionSteroidsMedical ManagementAntiviralsAdour (1996)– double blindOnly 20% progressed to complete paralysisAcyclovir had less degrees of facial weaknessAcyclovir had lower incidence of House 3-5Surgical Managementdebate over yearsNo surgeryImmediate decompression when completeSurgical ManagementFisch and Esslen (1972)– 12 patientsTotal facial nerve decompression via middle cranial fossa and transmastoidFound conduction block at meatal foramen (94% patients)Fisch (1981)Decompression within 14 days for 90% degeneration for maximum benefitMay (1979)Transmastoid decompression beneficial (decreased SF, Schirmer’s, MST reduced)May (1984)No patients benefited from surgery within 14 daysSurgical ManagementGantz (1999)– multi-institutional reviewAssess if patients with degeneration over 90% within 14 days would benefitMiddle cranial fossa (meatal foramen to tympanic segment)If conductive block not identified (6%)– transmastoid added92% with surgery recovered to House 1-245% without surgery to House 1-2ANY QUESTIONS
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