Hemifacial spasm is a rare neuromuscular disease characterized by irregular, involuntary muscle spasms on one side of the face. The facial muscles are controlled by the facial nerve or the seventh cranial nerve, which originates at the brainstem and exits the skull below the ear where it separates into five main branches.
This disease takes two forms: typical and atypical. In typical form, the twitching usually starts in the lower eyelid in orbicularis oculi muscle. As time progresses, it spreads to the whole lid, then to the orbicularis oculi muscle around the lips, and buccinator muscle in the cheekbone area. The reverse process of twitching occurs in atypical hemifacial spasm; twitching starts in orbicularis oris muscle around the lips, and buccinator muscle in the cheekbone area in the lower face, then progresses up to the orbicularis oculi muscle in the eyelid as time progresses. This disorder occurs in both men and women, although it affects middle-aged or elderly women more frequently.
MRI is usually done as part of a patients evaluation, to rule out tumors or other diseases that may cause hemifacial spasm. Medications at times may reduce the facial spasms, but Botox is the most effective treatment. Injecting a few of the facial muscles at 3-6 month intervals is very effective in most patients. A brain operation to relieve pressure on the facial nerve I occasionally done as a last option for some patients.