Facial nerve palsy

Slides prepared and compiled by highly experienced ENT teacher, Dr. Krishna Koirala from Nepal , for teaching undergraduate and postgraduate ENT students in the field of otorhinolaryngology.
A clear and concise explanation of the basic concepts in the subject matter concerned.
He is the Head of department with a sound knowledge in the field of ENT to teach both undergraduate and postgraduate ENT students

1. Disorders of the facial
nerve
Dr. Krishna Koirala
2018--09-04

2. Surgical Anatomy
•Mixednervehaving10,000neurons(7,000
motorand3,000sensory)
•Threenuclei
–Motornucleus:CaudalPons
–Superiorsalivatorynucleus:Dorsaltomotor
nucleus
–Nucleusofsolitarytract:Medulla

4. •Superioraspectofmotornucleushasbothcrossed
anduncrossedinput
–Uppermotorneuronlesions-onlythelowerpartof
thefaceonthecontralateralsidewillbeaffected
duetobilateralcontroltotheupperfacialmuscles
(frontalisandorbicularisoculi)
•Inferioraspect–Contralateralinput
–Lowermotorneuronlesions-bothupperandlower
facialweaknessoccursonthesamesideoflesion

7. Features Upper Motor
Neuron Palsy
Lower Motor Neuron
Palsy
Forehead wrinklingB/L presentAbsent on same side
Eye closure B/L presentAbsent on same side
Naso-labial fold Absent on
opposite side
Absent on same side
Drooping of angle of
mouth
Opposite side Same side
Differences between UMN and LMN facial palsy

8. Facial Nerve Trunk (5 fiber types)
•Special visceral efferent : Muscles of facial expression,
stapedius, stylohyoid, posterior belly of digastric
•General visceral efferent : Lacrimal, nasal mucosa,
sublingual and Submandibular glands
•Special sensory : Taste from anterior 2/3 of tongue
•Somatic Sensory : EAC and concha
•Visceral afferent : Mucosa of nose, pharynx , palate

9. Course / parts of facial nerve

11. F. N .SegmentLocation Length
(mm)
Supranuclear Cerebral cortex NA
Brain stem Motor nucleus , superior
salivatory nucleus
NA
Meatal segmentBrain stem to IAC 13-15
Labyrinthine
segment
Fundus of IAC to geniculate
ganglion
3-4
Tympanic segmentGeniculate ganglion to pyramidal
eminence
8-11
Mastoid segmentPyramidal eminence to
Stylomastoid foramen
10-14
Extratemporal
segment
Stylomastoid foramen to pes
anserinus
15-20

12. •Intracranial : Pons to porous of IAC (24 mm)
•Intratemporal
–Meatal
–Labyrinthine
•Shortest (4mm), narrowest (0.68 mm)
•From fallopian canal to geniculate ganglion (1
st
genu)
•Branch –greater superficial petrosal nerve
•Lacks anastomosing arterial cascades : Involved in nerve
edema in fracture temporal bone and vascular
compression,embolic phenomena, low-flow states

13. •Tympanic(Horizontal)-(13mm)
–GeniculategangliontoPyramidalprocess(2
nd
genu)
–Commonlydehiscent(Damagedduringsurgery)
•Mastoid(Vertical)-20mm
–Pyramidtostylomastoidforamen
–Secondgenulieslateralandposteriortothepyramidal
process
–Branches:NervetoStapedius,Chordatympani,Posterior
auricularMuscular

14. •Extracranial /
Extratemporal
–Peripheral branches
•Temporal
•Zygomatic
•Buccal
•Marginal mandibular
•Cervical

15. •Processuscochleariformis:(smallbonyprotuberance
fromwhichtensortympanimuscleturns90
0
toinsert
intomalleus)lies1mminferiortogeniculate
ganglion
•Cog:bonyridgehangingfromtegmentympanilies1
mmabove&posteriortoprocessuscochleariformis
•Shortprocessofincus:2mmbelowitliesthe
externalgenu
Surgical Landmarks of facial nerve

16. •LateralSemicircularCanal:2mmanteroinfero-
mediallyliestheexternalgenu
•Ovalwindow:1mmaboveliestheexternalgenu
•InferioredgeofPosteriorS.C.C.:2mmanterior&
lateralliesmastoidsegmentoffacialnerve
•Tympano-mastoidsutureinposteriorcanalwall:5-8
mmmedialliesmastoidsegmentoffacialnerve
•Digastricridgeinmastoidtip:leadsantero-mediallyto
mastoidsegmentoffacialnerve

19. Classification of Nerve injury
•Seddon (1943) : Neuropraxia, Axonotmesis ,
Neurotmesis
•Sunderland (1951)
–1
0
-Neuropraxia -Complete recovery
–2
0
-Axonotmesis -Usually complete
–3
0
-Neurotmesis -Incomplete
–4
0
-Partial transection
–5
0
-Complete transection

22. Causes of Otogenic Facial Nerve paralysis
•Traumatic
–Fracture temporal bone
–Penetrating injury to middle ear/ mastoid
–Facial injuries
–Iatrogenic
•Infective
–Herpes Zoster Oticus (Ramsay Hunt syndrome)
–Acute suppurative otitis media
–Chronic suppurative otitis media Atticoantral type
–Malignant otitis externa

23. •Neoplastic
–Glomus tumors / Schwannoma
–Middle ear malignancies
–Metastatic carcinoma
•Idiopathic
–Bell’s Palsy

24. Diagnostic Tests
•Topodiagnostic Tests
–Hearing and balance
–Schirmer’s test
–Stapedial Reflex
–SM salivary flow rate
–Taste
•Electrodiagnostic Tests
–Maximal nerve stimulation
–Electromyography
–Evoked EMG
•Radiological
–CT Scan
–MRI
•Immunological
–ANA
–RA Factor
–VDRL / Monospot
•ESR
•Bone marrow ( Leukemia,
lymphoma)

25. Topodiagnostic tests
•To determine the anatomical level of a peripheral
lesion
•Principle:Lesionsdistaltothesiteofaparticular
branchofthefacialnervewillsparethefunctionof
thatbranch
–Hearingandbalance:DefectsattheIAC
–Schirmer'stest
•Quantitativeevaluationoftearproduction
•Lesionatorproximaltogeniculateganglion

26. –Significantwhenunilateralwetnessisreducedby
morethan30%ofthetotalamountofbotheyes
after5minutesorwhenbilateraltearingis
reducedtolessthan25mmaftera5-minute
period
•Stapediusreflextest
•Absenceofthereflex-lesionproximalto
stapediusnerve
•Submandibularflowtest
•Tastetest

27. Electrodiagnostic Tests
•Nerve Excitability Test
–Technique : using a stimulating electrode over the
terminal ramifications of the facial nerve, increase
the current (milliamperes) until movement in the
appropriate muscle group is just visible
–Normalvalues(unaffectedsideofface)compared
tothesideofparalysis
–Interpretation:A difference of 3.5 mamp or more -
unfavorable prognosis

28. •Electromyography(EMG)
–Prognosticvalueintraumaticfacialnerveinjury
–Principle:Adenervatedmuscleproduces
spontaneouselectricalpotentials(fibrillations)
after14-21days
–Presenceofvoluntarymotorunitactionpotential
(VMAP)–signofincompleteparalysis
–EarlypresenceofVAMP(10-14days):Better
clinicaloutcomesuggestingnoneedforsurgical
decompression

29. •Electroneurography(EvokedElectromyography)
–Interpretation:Thedifferenceinamplitudeofthe
potentialsoftheintactandinvolvedsideoftheface
correlatewiththepercentageofdegeneratedmotor
fibers(denervation)
–Advantage:Quantitativeanalysisofamountof
degeneration
–Disadvantage:Amplitudesarea24-48hour
delayedrepresentationofactualeventsoccurring
atsiteoflesion

30. Clinical applications
•Facialnervesubjectedtotraumaticinjuriesofa
magnituderequiringsurgicalrepairundergo90%
degenerationwithinsixdaysofinjury
•IncasesofBell'sPalsy,apoorprognosiscanbe
anticipatedinpatientsreaching95%ormore
degenerationwithin14daysofonsetofthepalsy

31. Common disorders

32. Bell’s Palsy
•Most common cause of LMN facial palsy (80%)
•Acute, idiopathic, unilateral, peripheral LMN facial
paralysis
–? Viral prodrome ( Herpes simplex) , ? Vascular
•No sex predilection ,no side predilection
•5
th
-6
th
decade-Common
•10% family history
•Pathophysiology
–Nerve swelling within the facial canal

33. Clinical Features
•UnilateralLMNFacialParalysis:Progressestomaximaldeficit
over3to72hours
•Pain(50%):Nearthemastoidprocess
•Excesstearing(33%),hyperacusis,dysgeusia
•Facialweakness
–Allbranchesofnerve:Upper&Lower,Unilateral
–Degree:Partial(30%);Complete(70%)
–Affectedside-flatandexpressionless,twistedintactside,
palpebralfissurewide,eyedoesnotclose

34. •Stapediusdysfunction(33%):Hyperacusis
•Lacrimation:Mildlyaffectedinsomepatients
•Taste--Noclinicallysignificantchangesinmost
patients
•Sensoryloss
–MildorNone
–Maybepresentonfaceortongueonsideof
paralysis

36. •Natural History
–Complete / Incomplete
–Recovery begins within three weeks
–Full recovery by 6 months in 84% ( 60% in HZO )
–Recurrence: 12% ( Rare IN HZO)
–Decrease in Response to electrical testing
-Peaks in 5-10 days(10-14 days In HZO)

37. •Herpes Zoster Oticus (Ramsay Hunt
syndrome)
•Acute LMN facial paralysis caused due to Herpes
zoster virus infection of the geniculate ganglion of
the facial nerve
•Viral prodrome
•Severe pain in and around the ear
•Vesicles in pinna, face , neck ,oral cavity (100%)
•SNHL and /or vertigo (40%)

39. Treatment
1)For all cases of facial paralysis
–Reassurance
–Physical Therapy: Heat, massage
–Psychosomatic Therapy
–Physiotherapy of the face
–Eye care

40. •Eye care
–Cornealprotection
•Antibioticeyedropse.g..Ciprofloxacin2dropsinthe
eyeTDS
•Antibioticointmentatnight
•Naturaltears,isotonicsalineandmethylcellulosedrops
•Stripsofskintapetohelpclosetheeye
•Temporarypatching
•Tarsorraphy
–Comfort

41. 2)For Bell’s Palsy
•Steroid Therapy
–Prednisone1mg/kg/day(60-80mg)tobegin24
to48hafteronsetandgivenfor1wk,then
decreasedgraduallyoverthe2ndwk
•Helpstoreduceresidualparalysis
•Improvesrecovery
•Antiviralagents
–Acyclovir,famciclovir

42. 3)For HZO (Ramsay-Hunt)
•Antiviral agents
–Acyclovir800mg5timesadayfor7days
–Bestresults-treatmentstartedwithinthreedays
aftersymptomsappear
•Steroids
•Carbamazepine:200-600mgTDS
•Vaccines
–Varicellavaccine
–Zostavax(helpfulinpreventingviralreactivation)

43. 4) Other modalities
•Cosmeticrestoration(StaticProcedures)
–Fascialslings:FasciaLata
–Tarsorraphy
–Goldweightprosthesis
–Temporalismuscletransposition
–Eyelidsprings/implants

44. Fascial Slings

45. Surgical treatment of facial nerve palsy
•FacialNerveDecompression(tillmeatalforamen)
•NerveRepair(Neurorraphy)
–Endtoendanastomosis
–Cablegrafting(Sural,greaterauricular)
•NerveTransposition
–Facial-Hypoglossalanastomosis
•MuscleTransposition:Temporalis,masseter
•Micro-neurovascularmuscleflaps

47. Treatment Protocol
•Up to 3 weeks : Nerve decompression or repair
•3 weeks –2 years
–Nerve repair or nerve transposition
•> 2 year with fibrillation in Electromyography
–Nerve repair / nerve transposition
•> 2 yr with electrical silence in Electromyography
–Muscle transposition / Eyelid implant / Fascial
sling