What is hemifacial spasm?
Hemifacial spasm, also known as tic convulsif, is a rare disorder of the nervous system that causes the muscles on one side of the face to twitch involuntarily. The twitching is typically uncomfortable rather than painful, and is more common in middle-aged and older women as well as those of Asian ethnicity.
What causes hemifacial spasm?
Hemifacial spasm may be the result of:
- A blood vessel touching a facial nerve
- A tumor
- Another underlying condition, such as multiple sclerosis
- Facial nerve injury
In some cases, the cause of the twitching may be unknown.
What are the symptoms of hemifacial spasm?
Symptoms of this condition, which commonly occur on one side of the face and often continue during sleep, include:
- Tiny twitch of one eyelid that may pull the eye completely closed and cause it to tear
- More intense twitching that affects the cheek and mouth
- Pain behind the ear
- Changes in the ability to hear
- Large twitches that run across the face from the eye to the chin
How is hemifacial spasm diagnosed?
Following a detailed history and examination, diagnostic testing may be used to confirm a diagnosis. Tests may include:
- Angiography. X-ray imaging of the blood vessels is performed after a contrast agent is injected into the body to check for any compression or abnormality
- Computed tomography (CT) scan. During a CT, X-ray images are taken to produce cross-sectional images of the bone, blood vessels and soft tissues in the face to check for any compression or abnormality
- Magnetic resonance imaging (MRI) scan. With this test, magnetic fields and radio waves are utilized to produce images of the soft tissues in the face to check for any compression or abnormality
How is hemifacial spasm treated?
Initially, hemifacial spasms are treated with Botox® injections (approximately every six months) to freeze the muscles in the face to stop the twitching. However, surgical treatment may be considered in conjunction with the injections or as an alternative treatment solution.
Hemifacial spasms are surgically treated with a procedure known as microvascular decompression (MVD) to relieve pressure on the affected facial nerve.
With MVD, the goal is to relocate or remove the blood vessel(s) coming into contact with the nerve. During the procedure, an incision is made behind the ear and in the skull. If an artery is placing pressure on the nerve, the artery is moved aside and a pad is placed in between it and the nerve. If a vein is causing the compression, it may be completely removed.