This condition results in the facial muscles on one side suddenly contracting, twitching or jerking (especially around the eye). This problem most commonly results from irritation of the facial nerve within the skull by a loop of an artery which has moved with aging into a position that causes the pulsations to repeatedly strike the nerve. This eventually creates the situation where spontaneous electrical “sparks” originate and travel down the nerve to activate the muscles on one side of the face to contract.
This condition can also arise following trauma or Bell’s palsy to the face, which damages the connections between the facial nerve and the muscles of the face. Rarely, this condition can occur in patient with multiple sclerosis if the brain cells from which the facial nerve arises from (in the brainstem) are damaged.
Medications – carbamazepine, benzodiazepines, or baclofen. Can be used to treat this condition, but the success rate is appoximately 30%, and often there are intolerable side effects.
Botulinum toxin injections – will control the spasms > 90% of the time, but only provide temporary relief and need to be repeated every 3-4 months to maintain control. Side effects are minimal usually, and include dry eye, tearing, or drooping of the eye lids. Double vision is rare. These side effects are temporary and completely reversible, as they recover as the injection wears off. It may not be possible with this treatment to stop the spasm around the cheek or corner of the mouth without some transient facial drooping. Weakness affecting the face may gradually develop over the years, not due to the botulinum toxin injections but due to ongoing damage to the nerve by the pulsating blood vessel compressing the nerve.
Surgery (microvascular decompression) – can cure this condition. The procedure involves a general anesthetic. The Neurosurgeon through a opening in the skull behind the ear (under microscopic guidance) moves the offending artery away from the facial nerve and/or places protective padding between the nerve and artery. The success rate and complication rate depend on the expertise and experience of the surgeon. Success rates of 70 to 90% have been reported. Risks include deafness or loss of hearing on the side of the operation in up to 3%, and rarely, a permanent facial droop, or a stroke due to injuring a blood vessel during the surgery.
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