Transcript Facial Nerve Disease

Facial Nerve Disease
Shankai Yin Prof
Dept of Otolaryngology, the sixth hospital
affiliated to Shanghai jiaotong university
Otolaryngology institute at Shanghai
jiaotong university
上海市第六人民医院
Shanghai Sixth People’s Hospital
Anatomy
 Facial nerve is a mixed
nerve, having a motor
root and a sensory root.
 Motor root supplies all
the mimetic muscles of
the face which develop
from the 2nd brachial
arch.
上海市第六人民医院
Shanghai Sixth People’s Hospital
 Sensory root “nerve of Wrisberg” carries taste
fibers from the anterior 2/3 of the tongue and
general sensation from the concha and
retroauricular skin.
 Also it carries secretomotor fibers to the
lacrimal, submandibular and sublingual glands
as well as those in the nose and palate.
上海市第六人民医院
Shanghai Sixth People’s Hospital
Anatomy: Parts
 Intracranial part
 Intratemporal part
 Extracranial part
上海市第六人民医院
Shanghai Sixth People’s Hospital
Course of the Facial Nerve
 Intracranial
 Arises at the pontomedullary junction
and courses with CNVIII to the internal
acoustic meatus
 12mm
上海市第六人民医院
Shanghai Sixth People’s Hospital
 Intratemporal
 Meatal
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Anterior to the superior vestibular nerve and superior to
the cochlear nerve – 10mm
 Labyrinthe segment
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Passes through narrowest part of fallopian canal - 12mm
Narrowest part of facial nerve. The most susceptible to
compression secondary to edema.
 Tympanic segment
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From geniculate ganglion to pyramidal turn – 11mm
 Mastoid segment
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Exits the stylomastoid foramen – 13mm
上海市第六人民医院
Shanghai Sixth People’s Hospital
 Extracranial
 From stylomastoid foramen to pesanserinus
上海市第六人民医院
Shanghai Sixth People’s Hospital
Anatomy: Branches
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Greater superficial petrosal nerve
Nerve to stapedius
Chorda tympani
Comunicating branch
Posterior auricular nerve
Muscular branches
Peripheral branches: “Pes anserinus”
上海市第六人民医院
Shanghai Sixth People’s Hospital
上海市第六人民医院
Shanghai Sixth People’s Hospital
3-D t bone
Presentation
 Functional and cosmetic problems
 Upper lid fails to drop down and close
 Lower lid loses tone and sags downward
 May evert leading to ectropion
 Produces lagophthalmos and consequent
corneal exposure.
 Interruption of the tear film
 Leads to drying of cornea
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Ocular discomfort
Corneal ulcers
Infection
Perforation
上海市第六人民医院
Shanghai Sixth People’s Hospital
 Upper motor neurone (UMN)
 can wrinkle their forehead (unless bilateral
lesion)
 sagging of the face seen with lower motor
neurone palsies is not as prominent.
 Lower motor neurone (LMN)
 can't wrinkle their forehead
上海市第六人民医院
Shanghai Sixth People’s Hospital
上海市第六人民医院
Shanghai Sixth People’s Hospital
House-Brackmann Facial Nerve
Grading Scale
I
II
Normal
Normal tone and symmetry at rest. Slight weakness on close
inspection
Good to moderate movement of forehead. Complete eye closure with
minimum effort. Slight asymmetry of mouth with movement
III Normal tone and symmetry at rest. Obvious but not disfiguring facial
asymmetry. Synkinesis may be noticeable but not severe .+/hemifacial spasm or contracture. Slight to moderate movement of
forehead
Complete eye closure with effort. Slight weakness of mouth with
maximum effort.
IV Normal tone and symmetry at rest. Asymmetry is disfiguring or
results in obvious facial weakness. No perceptible forehead movement.
Incomplete eye closure. Asymmetrical motion of mouth with
maximum effort
V Asymmetrical facial appearance at rest. Slight, barely noticeable
movement. No forehead movement. Incomplete eye closure.
Asymmetrical motion of mouth with maximum effort.
上海市第六人民医院
Shanghai Sixth People’s Hospital
Degree of Lesion
 Sunderland classification
1° Partial block: Neuropraxia
2° Loss of axons: axonotemesis
3° Injury to the endoneurium: neurotemesis
4° Injury to the perineurium: partial
transection
 5°Injury to the epineurium: complete
transection
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上海市第六人民医院
Shanghai Sixth People’s Hospital
上海市第六人民医院
Shanghai Sixth People’s Hospital
Diagnosis
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History
Presentation
Hearing test
Vestibular function
MRI / CT
Topognostic - Where is the lesion?
Qualitative -Degree of the lesion
上海市第六人民医院
Shanghai Sixth People’s Hospital
Topodiagnostic Diagnosis
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Schirmer’s tear test
Stapedius reflex
Taste test
Submandibular salivary flow test
上海市第六人民医院
Shanghai Sixth People’s Hospital
上海市第六人民医院
Shanghai Sixth People’s Hospital
Qualitative Diagnosis
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Nerve Excitability Test: NET
Maximum stimulation Test: MST
Electroneurography: ENoG
Electromyography: EMG
上海市第六人民医院
Shanghai Sixth People’s Hospital
Bell’s Palsy
 60-70% cases
 Pathophysiology – Impaired “axoplasmic” flow from
edema of facial nerve within fallopian canal
 Rapid onset and evolution < 48 hours
 May be associated with acute neuropathies of cranial
nerves V- X
 Pain or numbness affecting ear, mid-face, tongue and
taste disturbances
 Recurrences are more likely (2.5x) in patients with
family history, immunodeficiency or diabetes
上海市第六人民医院
Shanghai Sixth People’s Hospital
Pathophysiology
 Main cause of Bell's palsy is latent herpes
viruses (herpes simplex virus type 1 and
herpes zoster virus), which are reactivated
from cranial nerve ganglia.
 Polymerase chain reaction techniques have
isolated herpes virus DNA from the facial
nerve during acute palsy.
上海市第六人民医院
Shanghai Sixth People’s Hospital
Treatment
 Oral antivirals - Acyclovir - 10mg/kg
(500mg) q8hrs x 7 days
 Corticosteroid taper 1mg / kg / day for 10
days
 Eye protection - lacrilube
 Follow progression with serial exams
 Facial nerve decompression
 Progression to > 90% degeneration on ENOG
 Performed before irreversible injury to the
endoneurial tubules occurs (two weeks), will allow
for axonal regeneration to occur
上海市第六人民医院
Shanghai Sixth People’s Hospital
Herpes Zoster Oticus
(Ramsay Hunt syndrome)
 10-15% of acute facial palsy cases
 Lesions may involve the external ear, the skin
of EAC or soft palate
 Associated symptoms – hearing loss,
dysacusis and vertigo
 Additional involvement of CN V, IX and X and
cervical branches 2, 3 and 4
 Pathogenesis – Neural injury due to edema at
point between the meatal foramen and the
geniculate fossa in the labyrinthe segment
上海市第六人民医院
Shanghai Sixth People’s Hospital
上海市第六人民医院
Shanghai Sixth People’s Hospital
Thanks！
上海市第六人民医院
Shanghai Sixth People’s Hospital