Hemifacial spasm describes unilateral painless intermittent spasms of the muscles involved in facial expression. Typically the spasm begins around the eye and spreads to involve the entire half of the face. The spasms, however, may only involve the upper or lower face, and may be associated with excessive tearing. Also the hemifacial spasms persist during sleep.
What Causes Hemifacial Spasm?
Hemifacial spasm, in most cases, is caused when a blood vessel compresses the facial nerve as it exits the brain stem. Rarely tumors, cysts, or vascular malformations can compress the facial nerve as it exits the brain stem, causing hemifacial spasm. Multiple sclerosis affecting the brain stem can also cause hemifacial spasm.
How Is Hemifacial Spasm Diagnosed?
The patient’s presenting symptoms are unique to the disease and frequently are enough to definitively diagnose hemifacial spasm. An MRI of the brain and brainstem is often obtained to ensure that a tumor, cyst, vascular malformation, or multiple sclerosis is not the cause of the hemifacial spasm.
How Is Hemifacial Spasm Treated?
The treatment for hemifacial spasm is primarily surgical. Medications (such as carbamazipine and phenytoin) generally fail as a treatment for hemifacial spasm. The surgical treatment for hemifacial spasm involves exposing the facial nerve as it exits the brainstem and identifying the blood vessel that is compressing the nerve. This blood vessel is then separated from the nerve using a piece of Teflon felt.