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 Ear
Left 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 Grade Description Gross function
Resting appearance
Dynamic appearance 1
Normal 2
Mild dysfunction
Slight weakness with effort, may have mild synkinesis
Mild oral and forehead asymmetry; complete eye closure with minimal effort 3
Moderate dysfunction
Obvious asymmetry with movement, noticeable synkinesis or contracture
Mild oral asymmetry, complete eye closure with effort, slight forehead movement 4
Moderately severe dysfunction
Obvious asymmetry, disfiguring asymmetry
Asymmetrical mouth, incomplete eye closure, no forehead movement 5
Severe dysfunction
Barely perceptible movement
Asymmetric
Slight oral/nasal movement with effort, incomplete eye closure 6
Total paralysis
None
No 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) Sunderland (1950s) Neuropraxia
Axonontmesis
Neurontmesis
1st degree – conduction block and demyelination
2nd degree – axonal loss
3rd degree – disruption of the endoneurium
4th degree disruption of the perineurium
5th degree – disruption of the epineurium

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

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 2nd from 3rd degree injury
All available testing can only distinguish 1st 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
Most reliable location for distal leads is the nasolabial fold

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

27. Acute Facial Paralysis
Unilateral facial dysfunction is common
20-30 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
Limb C, Niparko JK. The acute facial palsies. In: Neurotology 2nd Edition. Jackler RK, Brackmann DE Eds. Pg 1231.

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

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
20-40 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):1598-607
Prednisolone (85%) better than placebo (63%)
Acyclovir+steroid no improvement over prednisolone alone
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):141-6.
Improved outcome if started within 48 hours
NEJM – 496 patients underwent therapy. Excluded pregnant, DM, zoster, COM. 25mg po bid vor 10 days +/- 400 mg acylovir 5x/day for 10days. At 3 mo the absolute risk reduction was 19% and the NNT was 6. at 9 mo the risk reduction as 12% and the NNT was 8.

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):144-8.
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 1999 37 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 1999 3 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. Gantz et al 1999 Steroids only vs intervention group p=0.0003
Steroids vs surgical controls – not significantly different
<14 days vs >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!