facial nerve paralysis-Dr Parvathi Jayagopal

1. FACIAL
NERVE
PARALYSIS
PARVATHI JAYAGOPALAN
DEPT OF OMFS

2. INTRODUCTION
 Nerve of second branchial arch.
 Mixed nerve
 Course:
 Intracranial
 Intratemporal
 Extratemporal

3. Supranuclear pathway
 precentral gyrus of
cerebral cortex –
genu of internal
capsule- pons –
majority of fibers
cross to reach opp
side nucleus- some
fibers terminate in
ipsilateral nucleus.
 Emerge from lower
border of pons –
motor & sensory root
( nerve of Wrisberg)

5. Infranuclear pathway
 Leaves nucleus with 8th nerve in cerebellopontine
angle- enter IAC
 Motor root:
 Muscles of facial expression
 Scalp
 Auricle
 Stylohyoid
 Stapedius
 Post belly of digastric

7.  Sensory root:
 Special visceral afferent : taste to ant 2/3rd of
tongue via chorda tympani
 General visceral efferent: salivary glands via
petrosal
 Special visceral efferent: to facial muscles

8.  Enter IAC- 7th nerve joins nervus intermedius
– form common trunk- leaves IAC- enters
fallopian canal in temporal bone.
 Total length in temporal bone- 22-33 mm.

10.  Subdivided segments:
 Horizontal segment
from fundus of internal
acoustic meatus to
geniculate gang.- 3-
4mm “
LABYRINTHINE
SEGMENT”
 Acute angle turn to
enter tympanic cavity-
“FIRST GENU”
 Post on medial wall of
middle ear above
promontory- “
TYMPANIC SEGMENT”
( 10-12mm)

11.  Curves down at
pyramid and oval
window at angle- “
SECOND GENU”
 “MASTOID/
VERTICAL
SEGMENT”- from
second genu to
stylomastoid
foramen ( 9-16mm). `

12.  Facial ( fallopian ) canal ( Gerrier 1977):
 Individual sheath of pia mater curves up and
continues with arachnoid.
 Slight constriction of nerve seen just prior to it
labyrinthine segment 0.68 ( Fisch U, 1981) in
diameter.
 Change in direction of the nerve that produces
an angle of 132 deg, open anteriorly and
medially.

14. Branches of facial nerve
 Intracranial:
 Greater superficial petrosal nerve ( secretomotor-
lacrimal gland)
 Intratemporal:
 Nerve to stapedius- from mastoid segment ( supplies
stapedius)
 Chorda tympani nerve- from mastoid segment- joins
lingual nerve to supple ant 2/3rd of tongue,
secretomotor to submand. Gland.
 Sensory branches join auricular branch of vagus to
supply external auditory canal.

15. Branches in head & neck
 Ansa Haller ( inconstant)- immediately below
stylomastoid foramen, anastomses with
glossopharyngeal nerve.
 Posterior auricular nerve- 1-2mm below
stylomastoid foramen.
 Styloid branch- enters styloid muscle.
 Branch to post belly of digastric.

16. Branches in parotid plexus
 Temporal branch
 Zygomatic branch
 Buccal
 Marginal mandibular
 Cervical

18. Landmarks of facial nerve
 Tragal pointer: 1 cm inf to tragal cartilage
 Tympanomastoid suture: angle where the
vaginal process of tympanic portion of
temporal bone meets mastoid process.
 Styloid process: lateral to styloid process.

19.  Tracing terminal branch backwards:
 Ramus frontalis: tragus to lateral canthus
 Ramus buccalis: tragus to alar nose, parallel to
zygoma.
 Ramus mandibularis: angle of mand. at pont 4-
4.5cm from attachment of lobule of pinna.
 Tendon of post belly of digastric
 Post auricular vein/ retromandibular vein

20. • Distance of FN from anatomical structures
• Tragal pointer, 24.3 to 49.2 (mean 34)
• Posterior belly of digastric, 9.7 to 24.3 (mean 14.6)
• External auditory canal, 7.3 to 21.9 (mean 13.4)
• Tympanomastoid suture, 4.9 to 18.6 (mean 10.0)
• Styloid process, 4.3 to 18.6 (mean 9.8)
• Transverse process of the axis, 9.7 to 36.8 (mean 16.9)
• Angle of the mandible, 25.3 to 48.69 (mean 38.1).
• The length of the facial nerve trunk from its point of exit from the
stylomastoid foramen to its bifurcation into upper and lower divisions
ranged from (mm) 8.6 to 22.8 (mean 14.0).
Surg Radiol Anat. 2006 May;28(2):170-5. Epub 2006 Apr 20.
Landmarks of the facial nerve: implications for parotidectomy.
Pather N, Osman M.

21. Variations in course
DINGMAN & GRABB,1962
Type I-no anastomosis occurred
between branches of the facial
nerve.
Type II presence of an
anastomotic connection between
branches of temporofacial
division.
Type III-a single anastomosis
between the temporofacial and
cervicofacial divisions

22. Type IV a combination of
type II and type III
Type V two anastomotic
rami passed from the
cervicofacial division to
interwine with the branches
of temporofacial division.
Type VI plexiform
arrangement, the
mandibular branch sent
twig to join any members of
the temporofacial division.

24. Neurophysiology & nerve
regeneration
 Facial expression depends
on 7000 motor fibres- muscle
contractions.
 Degree of nerve injury:
 Neuropraxia
 Axontemesis
 Neurontemesis

25. Seddon classification
 Seddon, 1978
 1st degree: compression, reversible,
recovery complete.
 2nd degree: interruption of axoplasm &
myelin, persistent compression,
recovery 1-2 months
 3rd degree: increased intraneural pressure,
loss of myelin tubes, recovery
2-4 months, incomplete recovery

27.  4th degree: partial transection, recovery-
poor
 5th degree: complete transection, no
recovery
 Bells palsy & herpes zoster- 1-3 deg
 Trauma, tumour or cholesteatoma- 4th- 5th
deg

28. Nerve regeneration
 Def: “ complex interactions of neurons,
schwann cells, extracellular matrix &
neurotrophic substances.
 Regeneration follows degeneration
 Sprouting at axonal end

29.  3 major changes:
 Distance bet node of Ranvier is altered
 Myelin covering axon is thinner
 Slitting & crossing of axons

30.  Factors affecting regeneration:
 Site of lesion
 Duration of injury
 Age
 Nutrition
 Blood supply
 Associated injury/ infection

31.  Gangliosides: agents used invivo for
aiding regeneration
 2 properties:
 Neuronotrophic
 Neuritogenic
 Bovine origin- used in peripheral neuropathies

32.  Immunomodulators:
 Nerve injury- release of nerve proteins –
‘foreign antigens’- leads to neuritis.
 Azathioprine, Hydrocortisone- aid nerve
regen.

33.  Growth factors:
 NGF- nerve growth factor
 NPF- neurite promoting factor
 NGF: inc. axonal branching
inc. dentritic branching
prevention of death of neurons

34. Grading system of facial nerve
 HOUSE & BRACKMAN’S:
1984- Facial Nerve Disorder Committee of American
Academy of Otolaryngology
 Grade 1: normal
 Grade 2: mild dysfunction
slight weakness
normal symmetry & tone
motion in forehead- moderate to good,
eye closure- complete
slight asymmetry of mouth

35.  Grade 3: moderate dysfunction
no disfiguring difference
Motion of forehead- slight to
moderate
Weakness of angle of mouth
Eye closure- incomplete
Grade 4: moderately severe dysfunction
obvious asymmetry
Rest- normal symmetry & tone
No motion in forehead
Eye closure- complete
Mouth movement with max effort

36.  Grade 5: severe dysfunction
barely perceptible motion at rest
Forehead motion-none
Eye closure- incomplete
Very slight mouth movement
o Grade 6: total paralysis
no movement

37. Causes of facial palsy
 BIRTH:
 Forceps delivery
 Moebius syndrome
 Dystrophia
myotonica
 TRAUMA
 Accidental
 Skull base #
 Penerating injury to
middle ear
 Barotrauma
 Scuba diving
 Iatrogenic
 Mastoid surgery
 Parotid surgery
 Postaural LA
 Antitetanus serum
 Rabies vaccine
 Embolization

38.  INFECTIONS:
 Bacterial
 Malignant otitis
externa
 Otitis media
 Tuberculosis
 Botulism
 Lyme disease
 Mostoiditis
 Viral
 Herpes zoster
cephalicus
 Poliomyelitis
 Encephalitis
 Fungal
 Mucormycosis
 NEOPLASTIC
 Cerebellopontine angle
tumours
 Vestibular schwannoma
 Facial nerve tumours
 Cochlear neuromas
 Meningioma
 Ependymoma
 Arachnoid cyst
 Temporal bone tumours
 Primary
 Glomus jugulare
 Von Recklinghausen’s
disease
 Hans- Schuller-
Christian disease
 Secondary
 Teratoma
 Leukemia
 Sarcoma

39.  Parotid tumours
 Benign
 Pleomorphic
adenoma
 Adenolymphoma
 Oxyphil adenoma
 Malignant
 Mucoepidermoid
carcinoma
 Acinic cell
carcinoma
 Adenocarcinoma
 Eoidermoid
carcinoma
 Neurological
 Opercular syndrome
 Milliard- Gabler
syndrome
 Encephalitis
 Multiple sclerosis
 Myasthenia gravis
 Charot- Marie- Tooth
disease
 Miscellaneous
 Toxic
 Tetanus
 Diphtheria
 Metabolic
 Diabetes

40. Testing of facial nerve
 Depends upon:
 Determining degree of axonal degeneration- “
electrodiagnosis”
 Function of accessory branches –
“ topognosis”

41.  Topognostic tests
 Lacrimation tests (
Schirmer’s test)
 Stapedial reflex
 Salivary flow test
 Sensation test
 CT
 Prognostic tests
 EMG
 NET
 NCT
 MST
 ENoG
 Diagnostic
assessment
 Blink reflex
 EMG
 EnoG
 Intraoperative
monitoring
 Electrically evoked
potential
 Mechanically
evoked potential

43. Topognostic tests
 Lacrimal flow test: (
Schimer’s test)
 Tschiassny ( 1953)
 Filter paper 5cmx
0.5cm
 Lower conjuctival
fornix- 5mins
 <30% / 25mm

45.  Salivary flow test:
 Magielski & Blatt
(1958)
 No. 50/60
polyethylene catheter-
Whartons papilla
 Lemon drops- suck for
1 min
 1-5 mins- monitor
 <25%

46.  Stapedial reflex:
 Objective test
 Called ‘ Otologists EMG ‘
 Taste sensation
 Ant 2/3rd

47. Electrodiagnostic tools
 2 types:
A) Orthodromic conduction tests: nerve
stimulated proximally, muscle response
distally
B) Antidromic conduction test: nerve stimulated
in retrograde manner
Disadv- artifacts, difficult to detect

48.  EMG:
 Weddell & colleagues (1944)
 Measures electric response during needle
insertion at rest & voluntary movement (
Crumley, 1982)

49.  Merits:
 Detect subclinical evidence of early regeneration
 Differentiate birth trauma from embryological
etiology
 Determine completeness of neural blockade
 Demerits:
 Use only after 14- 21 days of nerve injury
 False response

50.  Nerve conduction time:
 ~ to EMG
 Tests latency response of a muscle
 EMG- stimulates nerve at stylomastoid
foramen.
 ‘latency’- time bet onset of stimulus & onset of
response
 Reliable

51.  Nerve excitibility test:
 Stimulating nerve at stylomastoid foramen-
twitch reflex
 Easy to perform, easily available, inexpensive.
 Difference of 3.5 mA bet sides- poor prognosis.
 Dermertis: small fibers- higher threshold
50% fibers have to be lost – best
results

52.  Maximal stimulation test:
 Modified NET
 Uses max stimulation to peripheral branches
 Current 5mA- increased slowly
 Electroneurography:
 Esselen, 1977
 Bipolar electrodes used
 2 techniques:
 Standard lead placement ( Hughes, 1981)
 Optimized lead placement ( Kartush, 1985)
 OPL more reliable- better subject tolerance
 Alar nasi- optimum site

53.  Magnetic stimulation:
 Barker (1985)
 Stimulate motor cortex by time varying magnetic fields
to induce electrical depolarization.
 At REZ- by transcranial penetration
 Blink reflex:
 Overend (1896)
 Tapping glabellar surface
 Electrically- stimulating supraorbital foramen- response
of orbicularis oculi
 Trigeminal- afferent, facial- efferent
 Test for intracranial & intratemporal portion

54. Bell’s palsy
 Sir Charles Bell, 1829
 Def: “ acute idiopathic lower motor neuron
palsy of facial nerve, usually unilateral, self-
limiting, non-progressive, non-life threatening,
spontaneous remitting by 4-6 months, always
by 1 yr.

55.  THEORIES:
 Vascular ischemia theory
 Viral theory
 Hereditary theory

56.  Vascular ischemia theory:
 Dec circulation to facial nerve.
 Interruption of major vessels/ sec to
compression within fallopian canal
 Primary: vasospasm of blood vessels
 Opposition: rich supply from stylomastoid &
petrossal vessels.
 Proponents: lack of anastomosis, dec vascularity
of horizontal segment, embolization of middle
meningeal artery

57.  Secondary: arterial constriction- capillary
dilatation- inc permeability- transudation
 Capillary dilatation- ischemic damage/ reflex from
fall in venous pressure
 Pressure from transudate- walls of lymph
capillaries- closed by compression.
 Fluid accumulates- compressed venules &
capillaries within fallopian canal- “ zonal ischemia”
 Teritiary: strangulation effect produces residual
facial paresis.

58.  Viral theory:
 Titer to herpes simplex virus/ herpes zoster
 Adour et al- acute benign cranial polyneuritis caused
by reactivation of herpes simplex virus.
 Virus replicates in ganglion cells causing local
damage & hypofunction of nerves.
 Passes down to axons- Radiculitis
 Infects schwann cells causing inflammation &
autoimmune response
 Lymphocytic infiltration- fragmentation of myelin-
demyelination

59.  Hereditary theory:
 Osteoporosis- fallopian canal – abnormal
small diameter
 Prone to ischemia/ viral infections

60.  C/F:
 h/o exposure to cold draught wind
 Pain in post auricular region
 Inability to gargle
 Facial asymmetry
 Deviation to opp. side
 Acute & unilateral
 Numbness/ weakness
 Dec lacrimation & salivation
 90% absence of stapedial reflex
 Chorda tympani- red on otoscopic exam. Within 10
days of onset

61.  Upward movmnt of
eyeball on
attempting to close
eye- “Bell’s
phenomenon”
 Epiphora
 Collection of food in
cheek
 Inability to blow/
whistle
 Loss of taste
 Hyperacusis –
involvement of
chorda tympani

62.  Management:
 Medical:
 Steroids: prednisolone, 60 mg for 3 wks (tapering)
 Acyclovir- 200- 400mg, 5 times /day
 Vasodilators: xanitol nicotinate, ascorbic acid,
multivitamins (B1,B6, B12)
 Eye care
 Active/ passive physiotherapy

63.  Surgical decompression:
 Criteria ( Marsh & Coker)
 Complete denervation
 Paralysis >4-6 wks
 Incomplete return of function in 60 days
 Recurrent facial palsy
 NET diff of 3.5mA bet both sides

65. Facial nerve in Temporal bone
fractures
 Longitudinal
 Transverse
 Mixed

66.  Longitudinal fractures:
 Results from blows ( temporal/ parietal)
 Fracture line: ant to otic capsule, involves
external & middle ear
 Bleeding from ear
 Conductive hearing loss- ossicular disruption
 Does not involve otic capsule
 No sensorineural hearing loss
 Facial nerve canal spared.
 Delay onset- nerve edema

67.  Transverse fractures:
 Frontal/ occipital blows
 Fracture line: through otic capsule
 Damages inner ear
 Hemotympanum
 Tympanic membrane intact- no bleeding from
ear
 Sensorineural hearing loss
 Tinnitus, nausea, vomiting, vertigo, facial palsy

68.  Mixed fractures:
 Comb of longitudinal & transverse
 Fragments of bone lies over facial nerve
 Comminuted fractures
 Brain edema/ pneumocranium
 Prolonged unconsciousness
 CSF leakage

69.  C/F:
 Deafness- conductive/ sensorineural/ mixed
 Hemotympanum/ bleeding from ear
 Facial palsy- lower motor neuron type
 Vertigo- subside in 2-3 wks
 Lateral rectus palsy- on opp side, intraorbital
hematoma
 CSF otorrhea & otorhinorrhea
 Discoloration of skin over mastoid- Battle’s sign
 Unconsciousness, neurological deficit.

70.  Management:
 HRCT
 X rays
 Facial nerve decompression
 Canal wall down technique

71. Iatrogenic injury of facial nerve
Methods to restore functional continuity:
a) Nerve intact but edematous- nerve
decompression , widening of fallopian canal-
slitting of nerve sheath- drain intraneural
hematoma.
b) Partial cut- suturing with 8-0 nylon/prolene

72. c) Complete transection- length of damage < 5mm,
re-routing, end to end anastomosis.
d) Complete transection- cut ends are apart- nerve
grafting with greater auricular nerve.
 keep upper end of anastomotic site more stable-
axonal nerve regeneration from above
downwards.
 Remove 1mm of neurilemmal sheath at
anastomotic ends, bevel cut ends.

73.  Complete transection with upper stump not
available for re-innervation, duration of palsy>
18 months – “facio-hypoglossal anastomosis”
 Disadv: mass movmnt, lack of emotion, paralysis
of tongue.
 Regeneration- 1mm/ day

74.  Other techniques:
 Sling operation using tendon/fascia
 Free neurovascular repair
 Muscle transposition
 Protection of eye:
 Dark goggles
 Tarsorrhaphy
 Gold weight for upper eyelid
 Eyelid spring

75.  Technique of nerve repair:
 Suturing:
 No loss of facial nerve segment
 Bleeding granulation- difficult identification
 8-0 nylon/prolene- no knots
 Tagged under nerve sheath- reposited back over
nerve
 Supported by temporalis fascia graft.
 Serves as splint- nerve ends stable, in approximation
 Scaffolding- guide cut ends to re-unite

77. Choice of procedure
 Dynamic & neuronal reconstruction
 Static methods

78. Dynamic reconstruction
 NEURAL REPAIR:
1) Direct nerve repair & grafting:
 Direct approximation/ autogenous nerve grafting
 Main trunk re-approximated with no tension
 Autografting- branches from cervical plexus
ipsilateral/ contralateral
 Sutured to terminal branches
 Alternative- sural nerve
 Recovery- 6 to 24 months

80. 2) Cross- face nerve
grafting ( facio-facial
anastomosis)
 From non- paralysed side
by sural nerve grafts.
 Length of graft 6-8 cm
 2 stage procedure
 Operative technique: FN
of non- paralysed side (
buccal branches) sutured
microsurgically to
branches on paralysed
side using sural nerve
graft.

81.  Disadv:
 Long operating time
 Muscles undergo atrophy
 Only 50% fibers from normal side can be used
 2 suture lines of each graft

82. 3) Nerve crossover:
 Adv: only one anastomosis
 Used when direct anastomosis is not feasible
 Nerves used: glossopharyngeal, accessory,
phrenic, hypoglossal
 Hypoglossal- facial cross over- most popular.
 Adv: simple, single suture line, powerful
innervation
 Disadv: uncooradinated movmnts, loss of
emotion, loss of function of donor nerve.

84.  MUSCLE REPAIR:
 Muscle transfer:
 Long standing muscle atrophy
 To mimetic muscles
 In combination with nerve graft
 Masseter & temporalis- commonly used

85. a) Masseter muscle transposition:
 Ideally suited to give motion of lower face (
De Castro & Zani 1993)
 3 muscle slips sutured to dermis of lower lip,
oral commissure & upper lip.
 Over correction- must be accomplished

87. b) Temporalis muscle transposition:
 Facilitate grater excursive movements.
 Adaptibility to orbit
 2 temporal musculofacial trips- reconstruct
upper lip, lower lip & eyelids
 Adv:
 good muscle bulk, compensate lack of fullness
 Direct muscular insertion- greater range of
motion.
 Best suited for ocular paralysis
 Transfer muscles- from trigeminal nerve
 Facial movmnt on chewing, clenching &
moving mandible.

89. c) Free muscle graft:
 Muscle denervated 14 days before
transplantation
 Full length of muscle is preserved
 Denervated mucle is placed in direct contact
with normal vascularized muscle at recepient
site.

90. d) Free microneurovascular muscle
transfer:
 In combination with cross- face nerve graft/
ipsilateral nerve graft/ split hypoglossal
anastomosis.
 Provide new, vascularized muscle of face.
 Adv: transferred muscle reinnervated by cross
face nerve graft.

92.  Choices of donor muscles:
 Gracilis muscle
 Pectoralis minor
 Latissimus dorsi
 Serratus
 Rectus abdominis
 Platysma

93.  2 stage:
 1st stage- one/ more cross face nerve graft
 2nd stage- 9-12 months later vascularized
muscle transferred, neuronal element sutured
to distal end of cross face nerve graft
 Disadv:
 2 donor site scars
 2 yrs elapse before return to normal movmnt

94. Static methods of reconstruction
a) Suspension : fascia lata sling to support
orbicularis oris & lower eyelid
b) Mechanical devices: gold weights, springs,
magnets for eye closure
c) Selective neurectomy: sectioning of intact FN
d) Selective myectomy

96. e) Surgery for correction to camouflage
deformity: excision of nasolabial skin, face
lift, brow lift
f) Botulinum toxin: interfere ACH release
from motor nerve endplates causing
paralysis, 4-6 months

97.  Fascio- hypoglossal jump anastomoses
 End – to end anastomosis- no epineurium.
 Skin incision from insertion of lobule of ear,
curved backward & downward distance of 4 cm.
 Greater auricular nerve- identified, dissected,
obtain graft of 6cm length.
 FN stump identified & transected near
stylomastoid foramen.
 Hypoglossal nerve- identified, beneath digastric
muscle

100.  Distal end of graft of greater auricular nerve
interpositioned, end- to end to distal stump of
FN.
 Other end end- to side to obliquely transected
hypoglossal nerve.
 10-0 nylon sutures used- tension free approx.