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Facial Nerve Paralysis Dr. Vishal Sharma. Gabriel Fallopius (1523-62)

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Presentation on theme: "Facial Nerve Paralysis Dr. Vishal Sharma. Gabriel Fallopius (1523-62)"— Presentation transcript:

1 Facial Nerve Paralysis Dr. Vishal Sharma

2 Gabriel Fallopius ( )

3 Anatomy of Facial Nerve Motor root: 7000 axons Sensory root (Nervus intermedius / Wrisberg): 3000 axons. Joins motor root at fundus of I.A.C. Motor: predominantly to facial muscles Secretomotor: lacrimal, submandibular, sublingual Taste: anterior 2/3rd of tongue Sensory: Post-aural / concha / ext. auditory canal

4 Course of facial nerve

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10 Parts of facial nerve Intracranial: within cerebello-pontine angle Intra-temporal Meatal segment Labyrinthine segment Tympanic segment Mastoid segment Extra-cranial Extra-parotid Intra-parotid (terminal)

11 1. Supranuclear: Fibers in cerebral cortex to brain stem 2. Brain stem: Motor nucleus of facial nerve (pons) 3. Intra-cranial (12 mm): Brain stem to entry into IAC 4. Meatal (10 mm): Within Internal Auditory Canal 5. Labyrinthine (4 mm): Fundus of I.A.C. to Geniculate gangl. 6. Tympanic (11 mm): Geniculate ganglion to pyramid 7. Mastoid (13 mm): Pyramid to stylomastoid foramen 8. Extra-temporal (15 mm): S.M. foramen to pes anserinus Segments of Facial Nerve

12 Primary branches of facial nerve Intra-temporal: greater superficial petrosal, stapedius, chorda tympani Extra-parotid: post-auricular, stylohyoid, posterior belly of digastric Intra-parotid: temporal, zygomatic, buccal, marginal mandibular, descending cervical

13 Intra-cranial branches

14 Extra-cranial branches

15 Communicating branches to: Meatal: vestibulo-cochlear Tympanic: lesser petrosal otic ganglion Mastoid: auricular branch of vagus Extra-parotid: glossopharyngeal, auriculotemporal, vagus, greater auricular, lesser occipital Terminal: branches of trigeminal

16 Surgical landmarks

17 Cochleariform process: small bony protuberance (from which tensor tympani muscle turns 90 0 to insert into malleus) lies 1 mm inferior to geniculate ganglion at anterior end of tympanic segment. Cog: bony ridge hanging from tegmen tympani lies 1 mm above & posterior to cochleariform process. Incus short process: 2 mm below lies external genu Lateral Semicircular Canal: 2 mm Antero-Infero- Medial lies external genu Oval window: 1 mm above lies external genu

18 Inferior edge of Posterior S.C.C.: 2 mm anterior & lateral lies mastoid segment of facial nerve Tympano-mastoid suture in posterior canal wall: 5- 8 mm medial lies mastoid segment of facial nerve Digastric ridge in mastoid tip: leads antero-medially to mastoid segment of facial nerve Groove between mastoid & bony E.A.C. meatus: bisected by facial nerve Tragal pointer: 1 cm antero-infero-medial is facial nv Root of styloid process: lateral lies facial nerve Superior border of posterior belly of digastric: superior & parallel lies facial nerve

19 Surgical landmarks

20 Lesions of Facial Nerve

21 LesionManifestation Supranuclear C/L hemiplegia, ed jaw jerk Nuclear (pons)I/L 6 th, 7 th palsy + C/L hemiplegia In C.P. AngleI/L 5 th, 7 th, 8 th palsy Supra-geniculate ed lacrimation, hyperacusis, loss of taste Supra-stapedialHyperacusis, loss of taste Supra-chordalLoss of taste Infra-chordalFacial asymmetry only

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24 FeaturesUpper Motor Neuron Palsy Lower Motor Neuron Palsy Forehead wrinklingB/L presentSame side absent Eye closureB/L presentSame side absent Naso-labial foldOpposite side absent Same side absent Drooping of angle of mouth Opposite sideSame side

25 Etiology of Facial Nerve Palsy

26 1. Idiopathic (55%): Bells palsy, Melkersson Rosenthal syndrome 2. Temporal bone trauma (25%): Road traffic accident 3. Infection (10%): C.S.O.M., Herpes Zoster oticus Malignant otitis externa 4. Neoplasm (5%): Parotid tumors, Acoustic Neuroma, Glomus tumors, Malignancy of ear 5. Congenital (4%): Moebius syndrome 6. Iatrogenic (rare): Mastoidectomy, Parotid surgery 7. Metabolic (rare): Diabetes mellitus, Hypertension

27 Sunderlands Classification (1951)

28 Cross section of nerve

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30 Grade NameCharacteristics INeuropraxiaPartial block of axoplasm IIAxonotemesisInjury to axon IIINeurotemesisInjury to endoneurium or myelin sheath IVPartial transection Injury to perineurium VComplete transection Injury to epineurium

31 House Brackmann Classification (1 year post-injury)

32 Grade DescriptionCharacteristics INormalNormal facial function IIMild dysfunction Slight weakness seen only on close inspection IIIModerate dysfunction Obvious asymmetry; complete eye closure IVModerately severe dysfunction Obvious asymmetry; incomplete eye closure VSevere dysfunction Only minimal motion seen; asymmetry at rest VITotal paralysisNo movement

33 Sunderland Grading EEMG response Recovery begins in House Brackmann grading INormal1-4 wksI II25 % of normal 1-2 mthII III< 10 % of normal 2-4 mthIII or IV IVNo response4-18 mthV VNo responseNeverVI

34 Diagnosis Topo-diagnostic Tests Electrical Tests Magnetic stimulation of intra-cranial facial nerve CT scan temporal bone: for progressive palsy MRI brain Surgical exploration

35 Topo-diagnostic tests Audiometry: cochlear nerve function Vestibulometry: vestibular function Schirmers test: Greater Superficial Petrosal Nerve Stapedial reflex test: Nerve to stapedius Electrogustometry: Chorda tympani Submandibular salivary flow: Chorda tympani Examination for terminal facial nerve branches

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37 Schirmers Test Unilateral wetness ed by >30% of total amount of both eyes after 5 minutes = Schirmer test positive lesion at or proximal to geniculate ganglion

38 Stapedial Reflex

39 Electrogustometry Measures minimum amount of current required to excite sensation of taste

40 Muscles supplied by terminal branches

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42 Electrical tests

43 Nerve Excitability Test Stimulating electrode used over terminal branches of facial nerve Minimum current intensity required to produce minimal muscle movement is calculated Normal side compared to paralyzed side Difference > 3.5 mAmp = unfavorable prognosis

44 Maximal stimulation test Stimulating electrode used over terminal branches of facial nerve Minimum current intensity required to produce maximal muscle movement is calculated Normal side compared to paralyzed side Difference > 3.5 mAmp = unfavorable prognosis

45 Electro-neuronography Terminal branch of facial nerve stimulated & action potential recorded in appropriate muscle Paralyzed side compared to normal side (which is taken as 100%) Response > 10% = % chance of recovery Response < 10% = 25 % chance of recovery

46 Electro-neuronography

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49 Electromyography Records spontaneous activity of facial muscles

50 Electromyography Responses Normal Polyphasic Fibrillation Electrical Silence

51 Response Interpretation Normal Motor Unit Action Potentials: Incomplete transection of facial nerve Poly-phasic Motor Unit Action Potentials: Re-innervation of facial muscles Fibrillation potentials: Denervation of muscles (2-3 weeks after trauma) Electrical silence: Atrophy / absence of muscle

52 Bells Palsy Acute onset, idiopathic, unilateral, self-limiting, non-progressive, peripheral facial nerve palsy 85% start recovering within 3 weeks Etiology: 1. Viral: Herpes simplex, Herpes Zoster 2. Ischemia of facial nerve: exposure to cold, emotional stress, nerve compression 3. Hereditary 4. Autoimmune

53 Sir Charles Bell

54 Clinical Features Loss of forehead wrinkles Inability to close eyes Wide palpebral fissure Epiphora Loss of naso-labial fold Drooping of angle of mouth Dribbling of food while chewing on affected side

55 Medical treatment Prednisolone (1mg/kg in 2 doses): for weeks Acyclovir: mg 5 times per day X 7days Eye care: Voluntary 2 / min. Ciplox eye drops 2 hourly & ointment H.S. Eye cover at night. Physiotherapy: moist heat + facial massage + facial muscle exercise Electrical stimulation of facial nerve & muscle Facial nerve decompression: Controversial

56 Moebius syndrome

57 Melkersson Rosenthal Syndrome Recurrent alternating facial palsy Fissured tongue Facio-labial edema Familial history

58 Melkersson Rosenthal Syndrome

59 Surgical Treatment for Facial Nerve Injury

60 A. Facial nerve decompression: till meatal foramen B. Neurorrhaphy (Nerve repair) 1. Direct end to end anastomosis 2. Interposition Cable grafting: sural, greater auricular C. Nerve Transposition: hypoglossal-facial D. Muscle Transposition: temporalis, masseter E. Micro-neuro-vascular muscle flaps F. Static Procedures: eyelid implant, fascial sling

61 Treatment Protocol Up to 3 weeks: Nerve decompression or Nerve repair 3 weeks – 2 year: Nerve Repair or Nerve Transposition > 2 year with fibrillation in Electromyography: Nerve Repair or Nerve Transposition > 2 yr with electrical silence in Electromyography: Muscle transposition / Eyelid implant / Fascial sling

62 Facial Nerve Decompression Cortical mastoidectomy done Facial nerve canal bone thinned in barber pole fashion with diamond burr. Drilling done: Posteriorly at mastoid segment, Laterally at external genu & Inferiorly at tympanic segment Avoids injury to chorda tympani & lateral S.C.C. Labyrinthine segment decompressed by middle cranial fossa approach

63 Barber Pole

64 Direct repair & Cable Grafting

65 Nerves used for cable grafting

66 Nerve Transposition

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68 Temporalis muscle transposition

69 Masseter muscle transposition

70 Gold Weight Eyelid Implant

71 Complications of facial nerve injury 1. Incomplete recovery 2. Exposure keratitis 3. Facial tics & spasms 4. Faulty regeneration of facial nerve a. Synkinesis: Mass movement of facial muscles b. Crocodile tear syndrome: gustatory lacrimation Salivary to lacrimal gland cross over c. Freys syndrome: gustatory sweating Secreto-motor to sympathetic cross over

72 Thank You


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