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 DISCLAIMER: The American Academy of Otolaryngology-Head and Neck Surgery Foundation (AAO-HNS/F) is providing these resources for historical purposes only. The information is provided AS IS, and the Academy makes no representations or warranties about the suitability of this information for any purpose. The information contained in this publication represents the views of those who created it at the time it was created, and does not necessarily represent the official views or recommendations of the American Academy of Otolaryngology — Head and Neck Surgery Foundation, Inc. All materials are subject to copyrights owned or licensed by the AAO-HNS/F, and all rights are reserved. The names, trademarks, service marks, and logos of the AAO-HNS/F may not be used by any other party without prior, express written permission of AAO-HNS/F. © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Facial Paralysis Etiology • Idiopathic 57% • Trauma 17% • Herpes zoster 7% • Tumor 6% • Infection 4% • Birth trauma 3% • Central etiology 1% © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Bell’s Palsy and Ramsay-Hunt • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Diagnosis • History and physical examination • Audiometry • Topognostic study • Radiographic imaging • Prognostic studies © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation History • Sudden or gradual • Associated hearing loss – Tinnitus – Pain – Infection – Trauma Chronic Suppurative Otitis Media © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation House-Brackmann Grading © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Physical Otoscopy • Hemotympanum • Otitis media • Cholesteatoma • Middle ear mass • Vesicular eruption Middle ear paraganglioma © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Physical Examination Neurological • Facial nerve – Incomplete vs. complete – LMN vs. UMN • Other cranial nerves © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Topognostic Testing • Tear test • Stapedial reflex • Taste test • Salivary flow © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Radiography Air contrast CT • Asymmetric SNHL • Complete CN VII palsy • MRI/CT Metastatic mass in Internal Auditory Canal © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Etiology • Viral – Herpes simplex – Herpes zoster • Vasospasm • Immunologic injury © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Pathophysiology • Entrapment • Compressive neuropathy © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Natural History • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Prognostic Studies Identify within 14 days of onset • Salivary flow • Electrodiagnostic studies © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Prognostic Studies • Identify reversible vs. irreversible injury • Prevent progression from second-degree to third-degree injury • Timing 3-5 days • ? Reinnervation © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Prognostic Studies Poor prognosis • Minimal excitability > 3.5 mAmps • ENOG > 90% degeneration © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Treatment Medical • Prednisone 1 mg/kg/day X 5-14 days, slow taper • Valcyclovir 1000 mg TID • Famciclovir 500 mg TID © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Treatment Surgical • > 90% degeneration • Within 14-21 days of onset • Expose meatal foramen © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • Primary uses of testing – Assists in prognosis – Helps determine appropriate treatment options – Monitors response to treatment © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Nerve Injury - Sunderland Classes • 1st degree – Neuropraxia • 2nd degree – Axonotmesis • 3rd degree – Endoneural disruption • 4th degree – Perineurial disruption • 5th degree – Neurotmesis © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • Test battery – NET - Nerve excitability test – MST - Maximal stimulation test – ENOG - Electroneuronography – EMG - Electromyography © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation ENOG - Electroneuronography • Uses maximal stimulation • Record compound muscle action potential (CMAP) • Measure amplitude of response • Amplitude of waveform is proportional to number of functional axons © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation ENOG -Electroneuronography • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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 © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Electrophysiologic Testing • 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) © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Facial Paralysis Secondary to Otitis Media • Acute otitis media • Chronic suppurative otitis media • Cholesteatoma Acute Otitis Media © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation 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) © 2003 The American Academy of Otolaryngology – Head and Neck Surgery Foundation Acute Otitis Media • Pathophysiology: – Demyelination secondary to bacterial toxins (Kettle, 1943;