The facial nerve controls the muscles of facial expression, tearing of the
eye and taste. It does not control the muscles of mastication or
chewing. Injury to the facial nerve can cause facial paralysis
producing an inability to close the eyelids and drooling due to loss of
function of the lip muscles (obicularis oris). Injury to the eye
may occur due to loss of the protective function of the eyelids and
drying of the eye due to the loss of tearing.
The Facial Nerve and Facial
Paralysis - Bell's Palsy
Facial paralysis can be caused by infections such
as herpes zoster (Ramsey
Hunt Syndrome), trauma, and tumors. Patients with Ramsey Hunt
Syndrome may have hearing loss and dizziness and viral blebs on their ear canal
and eardrum. Treatment with acyclovir and steroids has been shown to be
beneficial with a recovery rate of 82.6%
Most often no cause is found and Bell's Palsy is
diagnosed. An MRI scan to visualize the facial nerve and an audiogram to
test the hearing nerve (runs along with the facial nerve) may be ordered by your
doctor. The facial paralysis from Bell's Palsy is rapidly progressive over
24 to 48 hours, that from a tumor is usually slowly progressive, over many weeks
or months. Treatment may include use of
steroid and
anti-viral medications.
Surgical decompression of the nerve is debated
in medicine. Many feel that in order for surgery to be of benefit, the
facial nerve must be decompressed at the entrance of the internal auditory
canal, deep within the
inner ear
(middle fossa decompression). This is a very
difficult operation, which in itself carry significant risks.
Smouha et al. reported that a survey of 86 neurotologists that 2/3 would
recommend surgery if electrophysiologicc criteria is meet but only half believed
that surgical decompression should be the standard of care and only half would
use a middle fossa decompression.
View Abstract
Axeisson et. al reported that valacyclovir and prednisone produced complete
recovery in 10 of 10 treated patients as compared to a complete recovery rate of
50% in untreated patients.
View Abstract
Up to 90% of cases of Bell's palsy will have full
or partial recovery of facial function, with over 50% of the cases having close
to 100% recovery. Recovery may be rapid over a few weeks or take several
months to up to one year. The longer the time of recovery, the more sever
the injury and the more likely some residual weakness or synkinesis will be present.
ALL PATIENTS WITH BELL'S PALSY NEEDS TO CONSULT A HEALTH CARE PROVIDER FOR
PROPER DIAGNOSIS AND TREATMENT !!!!
One of the most important aspects in the treatment
of facial paralysis is care of the eye. If the eye dry out the cornea may
become damaged and vision may be lost. Use of liquid tears during the day,
lacrilube during the night and at times taping the eye shut at night will help
to prevent damage. Also, protective glasses should be worn when exposed to
dust since the eye cannot blink to protect itself.
This program will grade the degree and stage of facial paralysis
using all or any one of 10 different grading systems. The physician
enters the patient's physical findings and the program calculates the
degree of facial function impairment.
To
start the program:
Click
on the New File Box.
Enter
the patient's demographic data.
Select
the RGS Grading System to be used.
Then
enter the patient's physical findings.
Select
the "Evaluate" button at the bottom of the screen.
Reference: Ahrens A, Skarada D, Wallace M, Cheung
JY, Neely JG.
Rapid simultaneous comparison system for subjective grading scales
grading scales for facial paralysis. Am J Otol. 1999
Sep;20(5):667-71.
Note: The RGS
program is provided free of charge with permission of the author.
Reference: House JW, Brackman
DE. Facial nerve grading system. Otolaryngol Head Neck
Surg. 1985:93,146-147.
Grade
Description
Measurement*
Function %
Estimated
Function %
I
Normal
8/8
100
100
II
Slight
7/8
76 - 99
80
III
Moderate
5/8 - 6/8
51 - 75
60
IV
Moderately
Severe
3/8 - 4/8
26 - 50
40
V
Severe
1/8 - 2/8
1 - 25
20
VI
Total
0/8
0
0
*
"Measurement" is determined by measuring the superior movement of
the mid-portion of the superior eye brow and the lateral movement of the oral
commissure. A scale point of 1 is assigned for each 0.25 cm of motion up
to 1 cm. for both eye brow and commissure movement. The points are then
added together. Thus, a total of 8 points can be obtained, if each
structure moves 1 cm.
**
"Description" is defined as follows:
Grade
Description
Characteristics
I
Normal
Normal facial
function in all nerve branches
II
Slight
Gross: Slight
weakness on close inspection, slight synkinesis.
At Rest:
Normal tone & Symmetry.
Motion:
Forehead: Good to moderate movement.
Eye: Complete closure with minimum effort.
Mouth: Slight asymmetry.
III
Moderate
Gross: Obvious
but not disfiguring facial asymmetry. Synkineisi is noticeable but
not severe. May have hemi-facial spasm or contracture.
At Rest:
Normal tone & Symmetry.
Motion:
Forehead: Slight to moderate movement.
Eye: Complete closure with effort.
Mouth: Slight weakness with maximum effort.
IV
Moderately
Severe
Gross: Asymmetry
is disfiguring and/or obvious facial weakness.
At Rest:
Normal tone & Symmetry.
Motion:
Forehead: No movement.
Eye: Incomplete eye closure.
Mouth: Asymmetrical with maximum effort.
V
Severe
Gross: Only
slight, barely noticeable, movement.
At Rest:
Asymmetrical facial appearance.
Motion:
Forehead: No movement.
Eye: Incomplete closure.
Mouth: Slight movement.
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