Facial Paralysis

Facial Paralysis Facial Nerve Subcommittee of the American Academy of Otolaryngology-Head & Neck Surgery Editor: Peter S Roland MD Contributors: Peter S Roland MD, Larry Lundy MD, Jacques Herzog MD, Fred Telischi MD & Gady Har-El MD

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• Idiopathic 57% • Trauma 17% • Herpes zoster 7% • Tumor 6% • Infection 4% • Birth trauma 3% • Central etiology 1%

• Ramsay-Hunt • Bell’s palsy

– Facial paralysis – Idiopathic and therefore a – Otalgia diagnosis of exclusion – Vesicular eruption on auricle – Widely held to be viral – Sensorineural hearing etiology loss (SNHL) / Vertigo – Varicella zoster virus

• History and physical examination

• Audiometry

• Topognostic study

• Radiographic imaging

• Prognostic studies

• Sudden or gradual

• Associated hearing loss – Tinnitus – Pain – Infection

– Trauma Chronic Suppurative Otitis Media

• Hemotympanum • Otitis media • Cholesteatoma • Middle ear mass • Vesicular eruption

Middle ear paraganglioma

• Facial nerve

– Incomplete vs. complete – LMN vs. UMN

• Other cranial nerves

• Tear test

• Stapedial reflex

• Taste test

• Salivary flow

• Asymmetric SNHL

• Complete CN VII palsy

• MRI/CT

Metastatic mass in Internal Auditory Canal

• Viral – Herpes simplex – Herpes zoster

• Vasospasm

• Immunologic injury

• Entrapment

• Compressive neuropathy

• Bell’s palsy • Ramsay-Hunt

– Total paralysis 69% – Greater degeneration – Complete recovery 71% – Complete recovery 16% – Satisfactory outcome 84% – Satisfactory 40-50% – Recurrence 6.8%

Early return = Good prognosis

• Salivary flow

• Electrodiagnostic studies

• Identify reversible vs. irreversible injury

• Prevent progression from second-degree to third-degree injury

• Timing 3-5 days

• ? Reinnervation

• Minimal excitability > 3.5 mAmps

• ENOG > 90% degeneration

• Valcyclovir 1000 mg TID

• Famciclovir 500 mg TID

• > 90% degeneration

• Within 14-21 days of onset

• Expose meatal foramen

• Primary uses of testing

– Assists in prognosis

– Helps determine appropriate treatment options

– Monitors response to treatment

• 1st degree – Neuropraxia

• 2nd degree – Axonotmesis

• 3rd degree – Endoneural disruption

• 4th degree – Perineurial disruption • 5th degree – Neurotmesis

• Basic principles

– Facial nerve is tested distal to site of lesion

– Attempt to determine rate and degree of degeneration

– Need to assess facial nerve function frequently (daily or every other day)

– Need normal function on uninvolved side for comparison of test results

• Basic principles (cont’d)

– Only valid for clinically paralyzed, not paretic, facial nerve – No value once response is lost or recovery begins – Test results lag behind pathologic event by about 3 days

• Test battery

– NET - Nerve excitability test

– MST - Maximal stimulation test

– ENOG - Electroneuronography

– EMG - Electromyography

• NET – Nerve excitability test

– Lowest level of stimulation to get a twitch – Compare this threshold with normal-side threshold – Difference of 3.5 mAmps indicates significant and progressive degeneration – ~ 40% of patients with 3.5 mAmps difference still have complete, spontaneous recovery

• MST - Maximal stimulation test – Increase stimulation level until maximal response is seen – Grade response (compared with normal side) as: • Equal • Slightly decreased • Markedly decreased • Absent

• MST - Maximal stimulation test (cont’d)

– If normal response for 10 days, then 85-90% chance of complete return of function – If markedly decreased or absent, then ~ 85% chance of poor outcome with significant sequela – If response slightly or markedly decreases, expect some synkinesis

• Uses maximal stimulation • Record compound muscle action potential (CMAP) • Measure amplitude of response • Amplitude of waveform is proportional to number of functional axons

• If amplitude of involved side is 10% or less than normal side, then poor chance for spontaneous normal or near normal recovery • If amplitude of involved side is 10% or greater than normal side, expect excellent recovery

NORMAL ABNORMAL LEFT

• EMG – Electromyography

– Requires needle insertion into facial muscles

– Need to test multiple muscle groups (3-5 recommended)

– Does not estimate percentage of degenerated facial nerve fibers

• EMG – Electromyography

– Primary use in acute phase of facial paralysis (first 2 weeks) is confirmatory for other tests

– If other tests (NET, MST, ENOG) show no or little response, and EMG shows voluntary motor unit potentials, then still have good prognosis

– Loss of voluntary motor unit potentials worsens prognosis

• EMG - Electromyography (cont’d)

– Fibrillation potentials occur at earliest at 10-14 days post onset, indicating degenerating motor units

– Polyphasic reinnervation potentials can occur as early as 4-6 weeks post onset, indicating fair recovery (if later, worse recovery)

• Acute otitis media

• Chronic suppurative otitis media

• Cholesteatoma Acute Otitis Media

• Pathophysiology:

– Natural dehiscences?? Hof has localized “block” to dehiscence in 2 cases but 55% of t-bones have dehiscences

– Bacteriology no different than for acute otitis media

– Direct involvement of the facial nerve by infection. (Balance and Duel, 1932; May, 1982)

• Pathophysiology:

– Demyelination secondary to bacterial

toxins (Kettle, 1943; Joseph and Sperling, 1998) – Ischemia secondary to thrombosis of the

vaso-vasorum (Antoni-Candela and Stewart, 1974; Graham,1977)

– Viral reactivation ( Joseph and Sperling, 1998)

– 23 patients – 12 presented with moderate palsy and 11 with severe – 4 had mastoidectomy secondary to persistent infection @ 2-4 weeks – 22/23  HB I. Onset of improvement within 3 weeks in 78%

• Clinical reports: May

– 36 cases – 89% good recovery, 11% poor – All Rxed with antibiotics (abx) + myringotomy (myr) – Surgery if complete paralysis plus no response to maximal stimulation or  salivary flow or coalescent mastoiditis or meningitis – Maximal stimulation testing predicted recovery

• Clinical reports: Elliot

– 10 cases, 8 patients incomplete and 2 complete

– 8/8 incomplete recovered with abx + myr (1 protracted)

– The 2 complete had mastoidectomy and recovered

• Clinical reports: Hof

– 7 pts

– 5 recovered with abx + myr + tube

– 2 had mastoidectomy with decompression secondary to facial nerve FN deterioration, both recovered

• Incidence in preantibiotic era:

– 4 estimates by separate investigators all between 0.5% and 0.7%

• Incidence in postantibiotic era: – 2 estimates by separate investigators between 0.005% and 0.16%

• Clinical reports: Bluestone – 35 cases – 22 partial and 13 complete – All Rxed with abx + myr – 7 needed surgery because of coalescent mastoiditis or ENOG evidence of denervation

• Consensus:

– Facial nerve paralysis secondary to acute otitis media should be Rxed with appropriate antibiotics

– Myringotomy if not already draining

© 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Recommendations • Debated: – A tube should be inserted – Electrophysiological tests should be used to determine if surgery is necessary – Decompression should accompany mastoidectomy – Steroids

• Incidence:

– Preantibiotic • 2.3% (Pollock)

– Postntibiotic • May — 3 cases • Harker — 5 cases

• Pathophysiology:

– Natural dehiscence ??

– Many of the same inflammatory mediators found in cholesteatomas are found in chronic suppurative otitis media

• Clinical reports: Harker

– 6 ears – 4 partial, 2 complete – Surgery within 10 days after onset

– 5 recovered to HB I and 1 to HB II

• Clinical reports: Hartley

– 1 case

– Immunosuppressed

– Required graft

• Incidence:

– May: 13 ears over 20 yrs

– Sheehy: 1.0% of 1,024 Primary ear operations

– Hof: 2 cases in 3 yrs

• Pathophysiology:

–Pressure –Inflammation

• Clinical reports:

– May: 7 pts with normal electrophysiology  HB I pt with no response max. stimulation  all had incomplete recoveries

– Magliulo: 10 pts with facial paralysis secondary to very large cholesteatomas. 7 had grafts, 1 7-12. 2 had compression only — partial recovery

• CONSENSUS:

– Urgent surgical intervention is the most appropriate therapy for facial nerve paralysis secondary to cholesteatoma or chronic suppurative otitis media

• DEBATED:

– CWU versus CWD; decompression

General considerations

• Most commonly injured cranial nerve

• Protected by longest bony nerve canal • Second leading cause of facial paralysis after Bell’s palsy • Location (intra- vs. extratemporal facial nerve) • Timing of paralysis

Iatrogenic injury

• Anticipated or not • Knowledge of anatomy • Intraoperative monitoring • Local anesthetic effects • Early exploration

• ENOG for delayed paralysis

• Mechanism of injury

• Paralysis vs. paresis (HB grading scale)

• Immediate vs. gradual paralysis • Electrical testing

• Imaging

• Associated findings • Hearing loss • Cerebrospinal fluid (CSF) otorrhea • Mastoid ecchymosis (Battle’s sign) • Hemotympanum • External canal disruption

Fracture through mastoid cortex

• High-resolution CT

• Transverse vs. longitudinal orientation

• Mechanisms of injury • Stretch (50%) • Transection (30%) • Compression (20%)

Transverse

Longitutdinal

• 4 times more common than transverse • Facial nerve injury in 20% of cases • Stretch or bony compression more common • Perigeniculate area most common site

• Conductive hearing loss typical Longitudinal fracture

• Frequent severe brain injury/mortality • 50% associated with facial nerve injury • Labyrinthine segment most common site • Transection common • Sensorineural hearing loss typical

Transverse fracture

• Paralysis only

• After 3 days • ENOG appears most accurate initially

• EMG during recovery for prognostication

• Nerve conduction for peripheral injuries

• Steroids

• Decompression • Exploration • Removal of bone fragments

• Neurorrhaphy

• Early exploration • Neurorrhaphy • Grafting • Mobilization • >30-50% injury

Bullet lodged in Temporal Bone

• No tension (grafting when necessary)

• As soon as possible – Barring infection/contamination

• Fresh nerve endings

• Approximation in fallopian canal or with several sutures

• Total facial rehabilitation – neural procedures

• Segmental rehabilitation

• Primary neurorrhaphy (+ rerouting)

• Cable grafting

• Crossover procedures

• Cross-face nerve grafts

Prereanimation After interposition graft

• Distal nerve function? • Neuromuscular junction function? • Muscle atrophy? Types • Hypoglossal - Facial • Spinal accessory - Facial • Phrenic - Facial

1 yr after 12-7 crossover

• Upper face

• Midface

• Lower face

• Tarsorrhaphy • Gold weight • Spring • Cartilage • Blepharoplasty • Silastic encircling • Temporalis muscle transposition • Free muscle transfer (+ Cross-face nerve graft)

Gold weight Intraop after surgery Good eye closure post-op

• Tarsorrhaphy • Lid shortening • Lateral canthoplasty • Medial canthoplasty (+ adhesion) • Cartilage graft augmentation • Temporalis muscle transposition • Free muscle transfer

Lid shortening Canthoplasty

• Cosmesis • Breathing • Static • Dynamic

• Temporalis muscle transfer

• Masseter muscle transfer

• Cross-face nerve graft

• Free muscle transfer

• Facelift • Suspension procedures (fascia, palmaris longus, Alloplastic materials) • Rhinoplasty • Nasal valve reconstruction (+ grafts) • Alar suspension to orbital • Springs, dilators

• Temporalis muscle transfer • Masseter muscle transfer • Digastric muscle (anterior belly) transfer • Free muscle transfer • Cross-face nerve graft

• Facelift

• Oral commissuroplasty (primary, secondary) • Lip wedge resection • Suspension procedures (fascia, tendon, Alloplastic materials) • Anti-drooling procedures