Understanding Hemifacial Spasm

Hemifacial spasm (HFS) is a condition of painless, intermittent, involuntary spasmodic contractions of the muscles in only one side of the face.  The contractions may involve either the upper or lower half of the face, or may begin with rare spasms of the eyelid muscles and slowly progress to involve the entire half of the face.

Most of the cases of HFS are caused by a normal artery near the brainstem in an abnormal position. This artery has a loop in it which can press against the facial, (or seventh), cranial nerve.  Repeated pressure rubs insulation off the nerve, causing the involved facial muscles to contract involuntarily.  IN rare cases, HFScan  develop from other conditions such as tumors, vascular malformations, multiple sclerosis, adhesions or bony skull deformities.

Diagnosing HFS

A physician from the USC Neurosurgery team will conduct a thorough neurological exam.  Often, the results are normal except for the obvious unilateral facial spasm.  One distinguishing feature of HFS is that the involuntary movements persist during sleep.  Imaging studies, such as an MRI of the brain, should be performed in order to rule out a tumor prior to any treatment.

Treatment Options

Both surgery and an invasive, non-surgical treatment are available. 

Invasive Non-surgical Treatment

This treatment involves injections of botulinum toxin (Botox) into the affected muscles, and works by paralyzing or weakening them.  This can decrease, or completely eliminate the spasm on a temporary basis by improving the symptoms.  Eventually, the toxin wears off and further injections are required.  A complication of this treatment could be weakening of the muscles.  A patient may experience obvious facial weakness, inability to close an eye and possibly develop a corneal abrasion. Some patients may also find eating difficult.  These symptoms depend on which muscles have been injected.

Surgical Treatment

The surgical procedure is called Microvascular Decompression (MVD).  It is recommended for patients who are not happy with the results of the Botox, and are in good health.  A highly skilled neurosurgeon from USC will remove a piece of bone from behind the ear on the affected side.  Using a surgical microscope, the doctor can then identify the blood vessel that is pressing against the nerve and move it by tacking it up, away from the nerve, with Teflon felt and fibrin glue.  The bone is then replaced and the skin is closed. 

This procedure treats the problem instead of the symptoms.  There is an 85 – 90% initial success rate and 70% success 10 years after treatment.  Complications are minimal but should be discussed with a neurosurgeon.

Fight On!
Contact Us

Learn more about our neurosurgery physicians at Faculty.

Keck Hospital of USC
Department of Neurosurgery
(323) 442-6290
nsmessage@med.usc.edu