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Facial Nerve
Paralysis
Dr. Vishal Sharma
Gabriel Fallopius (1523-62)
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
Course of facial nerve
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)
Segments of Facial Nerve
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
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
Intra-cranial branches
Extra-cranial branches
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
Surgical landmarks
Cochleariform process: small bony protuberance
(from which tensor tympani muscle turns 900 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-InferoMedial lies external genu
Oval window: 1 mm above lies external genu
Inferior edge of Posterior S.C.C.: 2 mm anterior &
lateral lies mastoid segment of facial nerve
Tympano-mastoid suture in posterior canal wall: 58 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
Surgical landmarks
Lesions of Facial Nerve
Lesion
Manifestation
Supranuclear
C/L hemiplegia, ed jaw jerk
Nuclear (pons)
I/L 6th, 7th palsy + C/L hemiplegia
In C.P. Angle
I/L 5th, 7th, 8th palsy
Supra-geniculate
Supra-stapedial
ed lacrimation, hyperacusis,
loss of taste
Hyperacusis, loss of taste
Supra-chordal
Loss of taste
Infra-chordal
Facial asymmetry only
Features
Upper Motor
Neuron Palsy
Lower Motor
Neuron Palsy
Forehead wrinkling
B/L present
Same side
absent
Eye closure
B/L present
Same side
absent
Naso-labial fold
Opposite side
absent
Same side
absent
Drooping of angle
of mouth
Opposite side
Same side
Etiology of Facial
Nerve Palsy
1. Idiopathic (55%): Bell’s 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
Sunderland’s
Classification (1951)
Cross section of nerve
Grade
Name
Characteristics
I
Neuropraxia
Partial block of axoplasm
II
Axonotemesis
Injury to axon
III
Neurotemesis
Injury to endoneurium or
myelin sheath
IV
Partial
transection
Injury to perineurium
V
Complete
transection
Injury to epineurium
House Brackmann
Classification (1 year
post-injury)
Grade
Description
Characteristics
I
Normal
Normal facial function
II
Mild
dysfunction
Moderate
dysfunction
Moderately severe
dysfunction
Severe
dysfunction
Total paralysis
Slight weakness seen
only on close inspection
Obvious asymmetry;
complete eye closure
Obvious asymmetry;
incomplete eye closure
Only minimal motion
seen; asymmetry at rest
No movement
III
IV
V
VI
Sunderland
Grading
EEMG
response
Recovery
begins in
House Brackmann
grading
I
Normal
1-4 wks
I
II
25 % of
normal
1-2 mth
II
III
< 10 % of
normal
2-4 mth
III or IV
IV
No response
4-18 mth
V
V
No response
Never
VI
Diagnosis

Topo-diagnostic Tests

Electrical Tests

Magnetic stimulation of intra-cranial facial nerve
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CT scan temporal bone: for progressive palsy

MRI brain

Surgical exploration
Topo-diagnostic tests

Audiometry: cochlear nerve function

Vestibulometry: vestibular function

Schirmer’s test: Greater Superficial Petrosal Nerve
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Stapedial reflex test: Nerve to stapedius

Electrogustometry: Chorda tympani

Submandibular salivary flow: Chorda tympani

Examination for terminal facial nerve branches
Schirmer’s 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
Stapedial Reflex
Electrogustometry
Measures minimum amount of current
required to excite sensation of taste
Muscles supplied by terminal branches
Electrical tests
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
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
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% = 85-95 % chance of recovery

Response < 10% = 25 % chance of recovery
Electro-neuronography
Electro-neuronography
Electro-neuronography
Electromyography
Records spontaneous activity of facial muscles
Electromyography Responses
Normal
Fibrillation
Polyphasic
Electrical Silence
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
Bell’s 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
Sir Charles Bell
Clinical Features

Loss of forehead wrinkles
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Inability to close eyes
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Wide palpebral fissure
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Epiphora
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Loss of naso-labial fold
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Drooping of angle of mouth
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Dribbling of food while
chewing on affected side
Medical treatment

Prednisolone (1mg/kg in 2 doses): for 2 - 3 weeks

Acyclovir: 200-400 mg 5 times per day X 7days
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Eye care: Voluntary closure @ 2 / min. Ciplox eye
drops 2 hourly & ointment H.S. Eye cover at night.

Physiotherapy: moist heat + facial massage +
facial muscle exercise
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Electrical stimulation of facial nerve & muscle

Facial nerve decompression: Controversial
Moebius syndrome
Melkersson Rosenthal
Syndrome

Recurrent alternating facial palsy

Fissured tongue

Facio-labial edema

Familial history
Melkersson Rosenthal Syndrome
Surgical Treatment for
Facial Nerve Injury
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
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
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
Barber Pole
Direct repair & Cable Grafting
Nerves used for cable grafting
Nerve Transposition
Nerve Transposition
Temporalis muscle transposition
Masseter muscle transposition
Gold Weight Eyelid Implant
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. Frey’s syndrome: gustatory sweating
 Secreto-motor to sympathetic cross over
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