Facial nerve

DISORDERS OF FACIAL NERVE

Facial nerve

Nerve of second branchial arch

Mixed nerve- Both sensory and motor

Motor- muscles of facial expression* -muscles of 2nd pharyngeal arch

Sensory- Taste from anterior 2/3 of tongue & palate -general somatic sensations - secretomotor fibres

Facial nerve-components

Special visceral efferent

General visceral efferent

Special visceral afferent

General somatic afferent

SVE

GVE

SVA

GSA

Facial nerve-NucleiMotor nucleus

Superior salivatory nucleus

Lacrimatory nucleus

Nucleus tractus solitarius

Facial nerve -course

Facial nerve-Course

Intracranial part

Intratemporal part

Extracranial part

Intratemporal part

Meatal segement

Labrynthine segment

Tympanic segment

Mastoid segment

Labrynthine segment

Shortest segmnet of nerve

Narrowest diameter

Bony canal in this segment – narrowest

Odema or inflammation

BRANCHES

Surgical landmarks

Processus cochleariformisOval window and horizontal canalShort process of incusPyramidTympanomastoid sutureDigastric ridge

Surgical landmarks

Cartilagenous pointer

Tympanomastoid suture

Styloid process

Posterior belly of digastric

Variation and anomalies

Bony dehiscenceProlapse of nerveHump Bifurcation and trifurcation Bifurcation enclosing stapesBetween oval and round window

Structure of nerve

Sunderland classification-nerve injuries

1°-Neurapraxia2°-Axonotmesis3°-Neurotmesis4°-partial transection5°-complete transection

Electrodiagnostic tests

Minimal nerve exitability test

Maximal stimulation test

Electroneuronography

Electromyography

Facial paralysis-causes

CentralIntracranial part(cerebellopontine angle)Intratemporal partExtracranial partSystemic diseases

Intratemporal part

Idiopathic

Infections

Trauma

Neoplasm

IIT-N

Bell’s palsy60-70% of facial paralysis

Both sexes-equal frequency

Any age group- incidence increase with age

Family history-6-8%

Angiopathy and fluid retention

Bell’s palsy- Aetiology

Viral infection

Vascular ischemia

Hereditary

Autoimmune disorder

Bells’s palsy-clinical features

• Onset-sudden

• ‘Bell phenomenon’-attempt to close eye, eyeball turn up & out

• Asymmetry of face,Dribbling of saliva,epiphoria,noise intolerance,

Loss of taste

• Recurrent-3-10%

Bell’s palsy-Diagnosis

Diagnosis by exclusion

History ,complete otological , head & neck examination

Imaging studies,blood test –cbc, ps,ESR,Blood sugar,serology

Bell’s palsy-Diagnosis

• Nerve excitability test

• Topodiagnosis

Bell’s palsy-treatment

general

surgicalmedical

• General-reassure analgesics, care of eye, physiotherapy• Medical-steroids

PREDNISOLONE 1mg/kg/day x 5 days review after 5 days

• If Recovering – taper dose during next 5 days

• If Complete paralysis – continue 10 days thereafter taper the dose

Combined with acyclovir

Other drugs- vitamins , vasodilators, antihistamines, mast cell inhibitors

• Surgical- Nerve decompressionPROGNOSIS85-90% -Recover fully

10-15%- incomplete

Good prognosis- incomplete & recovery within 3 weeks

Melkersson syndrome

Fissured tongue

Swelling lips

Facial paralysis

Infections- Ramsay-Hunt syndrome

Herpis zoster oticus

Facial paralysis along with vescicular rash

Anasthesia of face,giddiness,hearing impairment

Middle ear infections, maligant otitis externa

Trauma

Fractures of temporal bone***

Ear or mastoid surgery

Parotid surgery or trauma to face

Neoplasm

• Intratemporal

• Tumours of parotid

Localisation of facial lesion

• Central facial paralysis CVA, tumor, abcess

-paralysis only lower half of face on c/l side

-involuntary movements and muscle tone retained

• Peripheral facial paralysisLevel of nucleus-6th nerve involement

Cerebellopontine angle- other cranial nerve

Bony canal???

Lesion outside temporal bone- only motor functions affected

Topodiagnostic test- intratemporal part

1.Schirmer test

2.Stapedial reflex

3.Taste test

4.Submandibular salivary flow test

Complications following facial paralysis

Incomplete recovery

Exposure keratitis

Synkinesis

Tics and spasms

Contractures

Crocodile tears

Frey’s syndrome

Psychological & social problems

Hyperkinetic disorders

Hemifacial spasmi)Essentialii)secondary

Blepharospasm

surgery

1.Decompession 2.end-end anastomoses3.Nerve graft4.Hypoglossal facial anstomoses5.Plastic procedures

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