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Acute Facial Paralysis Sarah Mowry, M.D. March 13, 2012.

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Presentation on theme: "Acute Facial Paralysis Sarah Mowry, M.D. March 13, 2012."— Presentation transcript:

1 Acute Facial Paralysis Sarah Mowry, M.D. March 13, 2012

2 Disclosures None

3 Lecture Objectives Review facial nerve anatomy Identify and classify facial nerve dysfunction List causes of acute facial paralysis Describe presumed etiology of Bell palsy Explain the current treatment recommendations for Bell palsy

4 Facial Nerve Anatomy Right EarLeft Ear

5 Facial Nerve Anatomy

6 Patient Work Up History Physical Audiogram Electrodiagnostic testing Imaging

7 Facial Nerve Exam Elicit history/exam findings of intratemporal branches – Dry eye (Schirmer’s test) – Hyperacusis from stapedius dysfunction (reflex testing) – Dysguesia – Decreased sensation in the EAC (Hitselberger’s sign) Examine all branches of the nerve in the periphery – Degree of weakness – Presence of synkinesis – Presence of spacticity Examine other cranial nerves Examine the EAC, TM and periauricular area

8 Classify House-Brackmann Scale Sunnybrook Sydney Fisch Detailed Evaluation of Facial Symmetry Yanagihara

9 Sunnybrook

10 House Brackmann Scale GradeDescriptionGross functionResting appearance Dynamic appearance 1Normal 2Mild dysfunctionSlight weakness with effort, may have mild synkinesis NormalMild oral and forehead asymmetry; complete eye closure with minimal effort 3Moderate dysfunction Obvious asymmetry with movement, noticeable synkinesis or contracture NormalMild oral asymmetry, complete eye closure with effort, slight forehead movement 4Moderately severe dysfunction Obvious asymmetry, disfiguring asymmetry NormalAsymmetrical mouth, incomplete eye closure, no forehead movement 5Severe dysfunctionBarely perceptible movementAsymmetricSlight oral/nasal movement with effort, incomplete eye closure 6Total paralysisNoneAsymmetricNo movement

11 Imaging in Bell Palsy The literature is filled with case reports of missed diagnoses Contradictory evidence in the literature about the prognostic value of MRI – Most studies performed on 1.5 T magnets and were qualitative in nature Some advocate imaging all patients. – Is this the best use of scarce resources? – If so, what is the timing of imaging?

12 Imaging in Bell’s Palsy Absolute indications – Any patient with symptoms suspicious for stroke – Palsy that progresses after 3 weeks – Palsy that does not start to improve by 3 months – Recurrent facial palsy – Any patient contemplating surgical intervention

13 Facial Nerve Testing Faradic/galvanic stimulation NET MST ENoG EMG Only used for patients with complete paralysis

14 Patterns of Injury Seddon (1940s) Neuropraxia Axonontmesis Neurontmesis Sunderland (1950s) 1 st degree – conduction block and demyelination 2 nd degree – axonal loss 3 rd degree – disruption of the endoneurium 4 th degree disruption of the perineurium 5 th degree – disruption of the epineurium

15 Patterns of Injury Neuropraxia – No wallerian degeneration – Axon and supporting tissue remains intact Axonotmesis – Loss of continuity of the axon – Wallerian degeneration occurs Neurotmesis – Injury involves endoneurium – Wallerian degeneration occurs

16 Pattern and Prognosis Neuropraxia will recover fully Axonotmesis will recover without synkinesis Neurotmesis will develop synkinesis and may not recover fully

17 Ideal Test Be able to distinguish Axontmesis from Neurontmesis – Distinguish 2 nd from 3 rd degree injury All available testing can only distinguish 1 st degree injury from higher levels of injury Must make inferences about higher degrees of injury from specific testing patterns.

18 Faradic/Galvanic stimulation – No longer used – Direct current applied to the stylomastoid foramen – Assess with visual response – Does not predict prognosis

19 Nerve Excitability Test (NET) Electrode over main trunk and then a ground electrode elsewhere Current increased until visual response is elicited from normal side – Threshold testing Same done for diseased side Difference of 3.5mAmp between sides indicates poor prognosis for full recovery Drawback is inter-test variability and subjective nature of response

20 Maximal Stimulation Test (MST) Increase the current on the normal side until “maximal facial twitch” is seen Same level of current is then applied to the diseased side Difference between the 2 sides is then graded as equal, lesser or no response. Drawback is painful exam, very observer dependent

21 Electroneurography (ENoG) Electrodes over the main trunk and then distally Measures the compound muscle action potential Suprathreshold stimulus is applied to both sides Magnitude of the response is compared between sides Not useful until Wallerian degeneration has occurred

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24 Electromyography Introduced in the 1960s to replace faradic and galvanic stimulation Needle electrodes are placed into the muscle Measures a compound muscle action potential – Fibrillation potentials and polyphasic action potentials Requires 21 days to quantify the degree of denervation Evoked and voluntary EMG

25 Voluntary EMG Used to identify a false positive ENoG Suggests early “deblocking” of the FN Presence of CMAP on voluntary EMG is a sign of good prognosis

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27 Acute Facial Paralysis Unilateral facial dysfunction is common – per 100,000 per year for Bell’s Palsy Bilateral facial dysfunction is not common – Less then 2% of acute palsies are bilateral – Typically associated with systemic diseases – Usually other manifestations of systemic diseases are present

28 Acute Facial Palsy All that palsies is not Bell’s! 70-85% of acute unilateral facial paralysis is idiopathic thus can be termed “Bell palsy”

29 Limb C, Niparko JK. The acute facial palsies. In: Neurotology 2 nd Edition. Jackler RK, Brackmann DE Eds. Pg 1231.

30 Bilateral Acute Paralysis Bell palsy DM Heerfordt’s fever (uveoparotid fever) PAN GBS Myesthenia gravis Skull fracture Bulbar palsy Prophyria Leukemia Myotonic dystrophy Meningitis Botulism Leprosy Polio Lyme disease Syphilis Isoniazid Post vaccine neuropathy

31 Bell Palsy Sir Charles Bell first to attribute facial paralysis to dysfunction of the facial nerve in 1821 Cause has been a source of intense debate From 1930s-1960s felt to be due to vascular insufficiency to the distal portion of the nerve Other theories included autonomic dysfunction, autoimmune injury and viral infection

32 Viral Hypothesis Murakami et al. Ann Int Med 1996;124(1):27 Performed transtemporal facial nerve decompression on 14 patients with Bell’s, 9 pts with HZ oticus and 12 controls Looked for HSV, VZV and EBV in endoneurial fluid and post auricular muscle (PCR) Also drew serological studies on all patients

33 Viral Hypothesis Murakami et al 1996 – Identified HSV-1 DNA in the endoneurial fluid and post auricular muscle of 11 of 14 patients (78%) – Identified VZV in 89% of the Ramsey Hunt patients – No viral DNA was identified in the control patients – No HSV-1 or HSV-2 DNA was found in the Ramsey Hunt or control patients – HSV-1 antibody was present at higher incidence than controls – Viral antibody titers were not different between the groups

34 Viral Hypothesis Murakami et al 1996 – Still not definitive – Need to identify replicated viral particles in the affected nerve

35 Mouse Model Mouse model – Induce a transient facial paralysis by inoculating HSV-1 onto the auricle or tongue of KOS mice (60%) – Inflammatory lesion within the facial nerve similar to that seen in human Bell’s palsy Mixed injury of the facial nerve with extensive demyelination of the distal nerve – Electrical testing is similar to that seen in humans

36 Idiopathic Facial Paralysis AKA Bell Palsy people/100,000 population per year 7-12% have recurrent Bell Palsy <2% have bilateral involvement Most common between age yrs of age Those over 60 yo have worse prognosis for full recovery (30%) Children have very high rates of full recovery (>90%)

37 Natural History of Bell Palsy Peitersen 1982 – 1011 patients in Copenhagen, Denmark over 15 yr period – Examined at onset and then at 1 week intervals for 1 month then bimonthly exams until complete resolution or 1 yr – At presentation, 31% had incomplete paralysis, 69% had complete paralysis (non-standardized scale)

38 Natural History Peitersen 1982 – Approximately half of patients presented with pain in addition to facial palsy 50% had coincident pain 25% had pain precede palsy 25% had pain after palsy manifested – 83% had taste alteration – 71% had hyperacusis – 12% had lacrimal dysfunction

39 Natural History Peitersen 1982 – All patients recovered function to some degree – 71% achieved normal facial muscle function – 80% regained taste function – 97% regained lacrimal function – 86% regained stapedial muscle function

40 Natural History Peitersen 1982 – Risk factors for incomplete recovery Diabetes Pregnancy Return of function beginning >3weeks from onset of paralysis Postauricular pain

41 Treatment Numerous recommended treatments over the years – Medications, surgery, diet, physical therapy, acupuncture Viral etiology treated with antiinflammatory and antiviral therapies Current treatment investigations involves corticosteroids, antivirals and surgery

42 Medical Therapy N Engl J Med. 2007;357(16): – Prednisolone (85%) better than placebo (63%) – Acyclovir+steroid no improvement over prednisolone alone Cochrane Database Syst Rev Mar 17;(3):CD Cochrane Database Syst Rev Mar 17;(3):CD – >1500 pts in 8 randomized studies – Corticosteroids significantly reduced residual weakness and synkinesis when compared to placebo Otol Neurotol Jan;32(1): – Improved outcome if started within 48 hours

43 Steroids Currently no consensus treatment regimen for Bell’s palsy – Prednisone 1mg/kg (QD or divided TID) for 10 days followed by a rapid taper – Other studied regimens are: Prednisolone 25 mg BID x 10 days (NEJM) Cortisone 200mg QD x3d, 100mg QD x3d, 50mg QD x2d Methylprednisolone 1mg/kg/day x 10 day with 3-4 day taper

44 Antivirals Multiple RCT and meta-analyses have failed to demonstrate improved function with antiviral monotherapy or in combination with steroids – Acyclovir 400mg 5x/day – Valacyclovir 1g BID x3-10days Cochrane review of 7 studies and 1987 patients did not demonstrate benefit with the addition of antivirals to steroid therapy

45 Antivirals de Almeida, J. R. et al. JAMA 2009;302:

46 Is Medical Therapy the Only Option? 10-15% of patients will have some facial nerve sequelae despite maximal medical therapy How do we identify these patients? Is there anything that we can do to improve their outcome?

47 Surgery for Bell’s Palsy Controversial First described distal FN decompression in 1932 by Ballance and Duel. – Distal 1 cm of the mastoid segment – Presumed etiology was vascular congestion at the stylomastoid foramen Chorda tympani neurectomy Progressed more proximally along the nerve until the mid 1960s

48 Surgery for Bell’s Palsy 1961 William House described the MCF technique to approach the IAC and FN 1965 Crabtree and House described the MCF for FN decompression in Bell’s palsy and trauma 1972 Fisch and Esslen reported on 12 patients undergoing total FN decompression for Bell’s palsy

49 MCF approach for Bell’s Fisch and Esslen 1972 – 11 of 12 had involvement of the labyrinthine segment and geniculate ganglion – 8 of 12 had involvement of the meatal segment – 5 of 12 had involvement of the tympanic segment – 3 patients tested with intraoperative EEMG demonstrated conduction block proximal to GG at the meatal foramen Confirm by Gantz et al (‘82) 15/16 had block at meatal foramen

50 Anatomic Findings Ge and Spector 1981 – Anatomic study of the meatal foramen demonstrating passage way of 0.68mm at the meatal foramen due to tight arachnoid band

51 ENoG Less than 90% degeneration prognosis for HB 1-2 is excellent (90-95%) Greater than 95% degeneration within 21 days prognosis for HB 1- 2 is only 40-50%. Those who progress to 90% degeneration will continue to worsen to the >95% degeneration more than 90% of the time. 85% may be prognostic of poor outcome – Clin Otolaryngol Apr;31(2): – Otol Neurotol 2011; 32(6):

52 ENoG Cannot distinguish between axonontmesis and neurontmesis Daily testing until day 14 of paralysis Rapid progression of degeneration suggests worse degree of injury Progression to >95% degeneration after 3 weeks still have good prognosis

53 Gantz et al patients over 15 yrs Inclusion criteria – Complete facial paralysis – ENoG >90% degeneration – Absent voluntary EMG CMAP – Presentation within 14 days Early in study presentation within 21 days

54 Gantz et al arms – Medical controls (n=11) Steroids 80 mg prednisone x 7 days with taper from days 8-14 – Surgical controls (n=7) Group of patients operated on early in the study between days from onset of paralysis – Study group (n=19) Underwent subtemporal craniotomy with decompression of the distal IAC, labyrinthine, GG and tympanic segments

55 Gantz et al 1999

56 Steroids only vs intervention group p= Steroids vs surgical controls – not significantly different 14 days at time of surgery was significantly different p=0.001 Patients who meet the inclusion criteria and undergo surgery have a 91% chance of a good outcome at 7 mo

57 MCF decompression Right Ear Left Ear

58 MCF decompression Right ear Left ear

59 MCF decompression

60 Indications for MCF decompression Complete facial nerve paralysis (HB 6/6) Electroneuronography – >90% difference between the affected side and the normal side Voluntary electromyography – Absence of voluntary CMAP Presentation within 14 days of onset of complete paralysis Patient desires operative intervention

61 Conclusions Differential diagnosis for acute unilateral facial paralysis includes more than just Bell Palsy Majority of patients with Bell palsy do well with “masterly inactivity” Corticosteroids DO significantly improve facial nerve outcomes (HB 1 or 2) over placebo Maybe the jury is still out on antivirals Surgery significantly benefits a small group of patients with severe Bell palsy

62 Thank you!


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