Hemifacial Spasm
Hemifacial spasm is a unique facial movement disorder characterized
by unilateral involuntary contractions of the facial muscles.
It often begins with the muscles around the eye, but with time
will spread to involve the muscles of the cheek and even the
superficial muscles of the neck. The contractions are intermittent,
sudden and unexpected. They may follow one upon the other and
produce a nearly continuous facial contraction but there are
generally long periods during which the contractions are minimal
or absent.
Hemifacial spasm is easily distinguished from blepharospasm
because of its unilateral nature and because the contractions
tend to be coarser and more intermittent. It must be distinguished
from a continuous, undulating, small magnitude contractions
of facial myokymia. Sometimes the most difficult distinction
is from habit tics. These facial movements can simulate hemifacial
spasm but will never be seen during sleep and are generally
more stereotyped than hemifacial spasm.
Hemifacial spasm is painless. Over time, some weakness of the
face on the side of the spasm may develop. A degree of continuous
contraction, or tonus, may be found in long standing cases.
If there is continuing damage to the facial nerve, muscles in
different parts of the face on the involved side may begin to
contract simultaneously, a condition known as synkinesis.
The cause of hemifacial spasm is unknown. However, the fact
that removing pressure on the facial nerve near the point where
it leaves the brain very frequently relieves the spasm suggests
that such pressure is the case of the spasm.
Treatment for hemifacial spasm runs the range of benign neglect
to major surgery. It is important to remember that hemifacial
spasm is not a dangerous or life threatening disease. It does
cause obvious deformity of the face and can be quite embarrassing
and interfere with a persons social interactions. As it becomes
more advanced, involuntary eye closure at times of stress concentration,
such as when reading or driving, can significantly interfere
with a person's functioning. Therefore, many people with hemifacial
spasm choose to have it treated.
Medical treatment. Sometimes, physicians will attempt to treat
hemifacial spasm with medication. The most effective medication
is carbomazepine (also known as Tegretol). Although highly effective
for a similar problem producing intermittent facial pain called
trigeminal neuralgia, Tegretol is only rarely effective in the
long run for hemifacial spasm. In many cases it is not effective
at all. Related medications such as phenytoin and baclofen may
be tried, but are even less effective. Sedatives and muscle
relaxants such as diazepam (Valium) and clonazepam (Klonopin)
are occasionally useful in the treatment of hemifacial spasm.
Botulinum Toxin. For patients with mild spasm restricted to
one part of the face who are willing to have repeated treatments
or for those too ill to undergo surgery, botulinum toxin injections
can effectively eliminate the spasm for a period of several
months. Because of the number of injections that would be required
and a limitation on the total dose of toxin that can be injected,
it is generally not practical to treat the entire face. Repeat
injections every 3-6 months are usually required. Botulinum
toxin is an effective means of achieving partial, temporary
control of hemifacial spasm. For a person whose primary concern
is to reduce spasm around the eye to allow reading and binocular
vision while driving, it may be the most desirable form of treatment.
It is not, however, curative and the young or severely involved
patient will want to give serious consideration to surgical
treatment.
Surgical treatment. Historically, surgical treatment involved
partial or complete damage to the facial nerve. Spasm would
be eliminated by causing weakness. If the nerve was only partially
damaged, as it recovered and facial strength returned, the spasm
would return. This situation changed in the 1950's when a neurosurgeon
in Cleveland, William Gardner, documented cases of hemifacial
spasm associated with bulging from arteries near the point where
the nerve leaves the brain. Relieving the pressure that these
bulging arteries put on the facial nerve relieved the spasm.
This concept was refined and popularized in the 1970's by Dr.
Peter Jannetta of Pittsburgh. He demonstrated that even normal
arteries pushing on the facial nerve where it leaves the brain
were associated with hemifacial spasm. When these arteries were
moved away from the nerve, the spasm would go away. This operation
is called "microvascular decompression". It is now
considered to be the definitive treatment for hemifacial spasm
and is curative in 80% or more of patients who have the operation.
As currently practiced, microvascular decompression is performed
through a quarter sized opening in the skull just behind the
ear. The membranes surrounding the brain and holding in the
spinal fluid are opened, spinal fluid removed and the nerve
exposed. Using a surgical microscope to magnify the region,
the small artery or arteries pushing on the nerve are identified
and moved away from the nerve. A small piece of shredded teflon
felt which looks like cotton is used to hold the arteries in
their new position. During the operation, the function of the
facial nerve is electronically monitored. The abnormal contractions
can be seen in most patients and disappear immediately when
the decompression is completed. Such monitoring guides the surgeon
and increases the chance of a successful operation. After the
decompression is completed the membranes are sewn back together,
the removed bone is replaced (often with a plastic plate) and
the skin is closed.
A typical patient is in the hospital for 3-7 days after surgery,
the patient's age being the best predictor of how long they
will stay. It is a matter of 2-6 weeks before the person has
regained normal levels of energy and functioning.
The operation of microvascular decompression has been curative
in over 80% of the patients who it is performed. Some patients
experience recurrence of the spasm which goes away on its own
and some have required reoperation or have elected to have secondary
treatment with botulinum toxin. The operation has been a safe
one in experienced hands. Nonetheless, it is major surgery near
critical parts of the brain and serious complications including
stroke and even death can and have occurred. The most common
complications, however, are not life threatening. Five to 7%
of patients will experience some permanent decrease in hearing
on the side of the operation. This is because the nerve for
hearing lies right next to the facial nerve and is very sensitive
to any manipulation. Spinal fluid leakage occurs in 5-15% of
patients. While this creates a risk for infection or meningitis,
it generally can be successfully treated without additional
surgery and merely prolongs the hospital stay.
For those patients who desire a permanent solution to their
problem with hemifacial spasm microvascular decompression is
the obvious choice. The small risks of serious complications
must be weighed against the degree of interference with the
person's daily functioning in making a decision regarding surgical
treatment. While many patients who undergo microvascular decompression
after having a series of botulinum toxin injections ask "Why
didn't I have this done right away?", others will choose
to stay with a series of botulinum toxin injections in order
to avoid the discomfort and risk of microvascular decompression.
This is a very individual decision that should be discussed
thoroughly with physicians knowledgeable and experienced with
both types of treatment.
For questions or further information Doctor Patel can be contacted
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