nerve problems and causes
The most common condition resulting in facial
nerve weakness or paralysis is Bell’s palsy,
named after Sir Charles Bell who first described
the condition. The underlying cause of Bell’s
palsy is not known, but it may well be due to an
infection or inflammation of the nerve. We know
that the nerve swells in its tight bony canal.
This swelling results in pressure on the nerve
fibers and their blood vessels. Treatment is directed
at decreasing the swelling and restoring the circulation
so that the nerve fibers may again function normally.
Herpes Zoster Oticus
A condition similar to Bell’s palsy is herpes
Zoster Oticus or "shingles" of the facial
nerve. In this condition, there is not only facial
weakness but also often hearing loss, unsteadiness,
and painful ear blisters. These additional symptoms
usually subside spontaneously but some hearing
loss and discomfort may remain.
Injuries of the Facial Nerve
The most common cause of facial nerve injury is
due to a skull fracture. This injury may occur
immediately or may develop some days later due
to nerve swelling.
Injury to the facial nerve may occur in the course
of operations on the ear. This complication, fortunately,
is very uncommon. It may occur, however, when the
nerve is not in its normal anatomical position
(congenital abnormality) or when the nerve is so
distorted by mastoid or middle ear disease that
it is not identifiable. In rare cases it may be
necessary to remove a portion of the nerve in order
to eradicate the disease.
Delayed weakness or paralysis of the face following
reconstructive middle ear surgery (myringoplasty,
tympanoplasty, stapedectomy) is uncommon, but occurs
at times due to swelling of the nerve during the
healing period. Fortunately, this type of facial
nerve weakness usually subsides spontaneously in
several weeks and rarely requires further surgery.
Acoustic Tumors: The most common tumor to involve
the facial nerve is a nonmalignant fibroid tumor
of the hearing and balance nerve called an acoustic
neuroma. Although there is rarely any weakness
of the face before surgery, tumor removal sometimes
results in weakness or paralysis due to the close
proximity of the facial nerve. This weakness usually
subsides in several months without treatment.
Facial Nerve Neuroma: A nonmalignant fibroid growth
may grow in the facial nerve itself, producing
a gradually progressive facial nerve paralysis.
It may be necessary to server or remove a portion
of the facial nerve in order to remove an acoustic
tumor or a facial nerve neuroma. An attempt is
made to sew the nerve ends together at the time
of surgery or to insert a nerve graft. The nerve
used in grafting is taken from a skin sensation
nerve in the neck. Total paralysis will be present
until the nerve regrows through the graft, usually
a period of 6 to 24 months. At time, a nerve procedure
is necessary later, connecting a tongue nerve to
the facial nerve (hypoglossal-facial anastomosis).
In all of these situations there will be some permanent
Removal of a facial nerve neuroma may necessitate
removal of the inner ear structures. If this is
necessary, it results in a total loss of hearing
in the operated ear and temporary severe dizziness.
Persistent unsteadiness is uncommon.
Acute or chronic middle ear or mastoid ear infections
occasionally cause a weakness of the face due to
swelling or direct pressure on the nerve. In acute
infections, the weakness usually subsides as the
infection is controlled and the swelling around
the nerve subsides.
Facial nerve weakness occurring in chronically
infected ears is usually due to pressure from a
cholesteatoma (skin-lined cyst). Mastoid surgery
is performed to eradicate the infection and relieve
nerve pressure. Some permanent facial weakness
Tumors and circulatory disturbances of the nervous
system may cause facial nerve paralysis. The most
common example of this is a stroke. As opposed
to other conditions listed here, in brain diseases
there are usually many other symptoms, which indicated
the cause of the problem. Treatment is managed
by the neurotologist in conjunction with an internist,
neurologist, or neurosurgeon.
Hemifacial spasm is an uncommon disease which
results in spasmotic contractions of one side of
the face. Extensive investigation is necessary
at times to establish the diagnosis correctly.
In some cases, a hemifacial spasm is caused by
an irritation of the facial nerve by a blood vessel
near the brain. Examination of the nerve and correction
of the irritation, if present, is possible by a