Cerebrovascular Disease

What is Hemifacial Spasm?

Hemifacial Spasm (HFS) is a condition of painless, intermittent, involuntary, spasmotic contractions of the muscles of only one side of the face. These muscles are innervated by the facial, (or seventh), cranial nerve. 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.

What causes HFS?

Approximately eighty-five percent 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 is pressed up against the facial nerve. With each beat of the heart, blood is forced through this artery which causes the artery to bump up against the nerve. With time, this repeat pressure rubs the insulation off the nerve. This injury to the nerve causes it to fire abnormal impulses thereby causing the involved facial muscles to contract involuntarily. Rarely HFS can be caused by other conditions such as tumors, vascular malformations, multiple sclerosis, adhesions, or bony skull deformities. One must be careful not to confuse HSF with facial myokymia (continuous facial spasm), or blepharospasm (bilateral spasmodic closure of the eye muscles). One distinguishing feature of HFS is that the involuntary movements persist during sleep.

What type of work-up should be performed in the evaluation of HFS?

First of all, a good history and neurological exam should be performed by a neurologist. The exam is usually normal except for the obvious unilateral facial spasm.

Imaging studies, such as an MRI of the brain with and without contrast, should be performed prior to any treatment in order to rule out a tumor as the cause of the spasm.

What treatment options are available and what are their risks and benefits?

There are two categories of treatment options available. They are invasive non-surgical and surgical.

Invasive Non-Surgical Treatment

This treatment involves local injections of botulinum toxin (botox) which is typically performed by a neurologist. The toxin is injected into the affected muscles and works by paralyzing or weakening them. This can decrease or completely eliminate the spasm on a temporary basis. Eventually the toxin will wear off and another injection is required.

The most common complication of this treatment involves severe weakening of the muscles which may present itself as obvious facial weakness with asymmetry at rest, inability to close ones eye with possible development of a corneal abrasion as a result, difficulty eating with food leaking out the corner of ones mouth, etc. These symptoms depend on which muscles have been injected.

The patient must understand that if the HFS is caused by the artery pressing on the facial nerve, the botox is not treating the problem, but it may be temporarily improving the symptoms. The drawbacks include the need to repeat the injections periodically and the possibility of some permanent weakness after multiple injections.

The benefits of this treatment option is that the patient does not have to accept the risk of "major" brain surgery and the general anesthesia associated with it.

Surgical Treatment

The surgical procedure performed to treat HFS is called a Microvascular Decompression (MVD). The MVD is recommended for patients who are not happy with the results of the botox and are in good health. With this procedure, a small amount of hair is shaved behind the ear on the affected side. Under general anesthesia, the skin is opened and a small piece of bone is removed. Working under the microscope, the neurosurgeon is able to identify the blood vessel that is pressing against the nerve. The surgeon will then move it out of the way by tacking it up away from the nerve with an insulating sponge. The bone is then replaced and the skin is closed. A MVD takes approximately 1-2 hours in experienced hands. Post-operatively there may be episodes of mild HFS, however they usually begin to diminish 2-3 days following the MVD.

The benefits of this procedure involve the fact that the problem itself is treated if the blood vessel is the offending agent. There is an 85-90% initial success rate and 70% at 10 years post-operatively. The mortality for this procedure is 1%. The most common complications include mild facial weakness (1-3%-usually temporary), hearing loss on the affected side (3%), spinal fluid leakage (5%), and meningitis (less than 5%).

Patient Stories

Anne Katz

Anne Katz is a 45 year old economic development consultant from Long Beach. She first began experiencing twitching in her eye in 1994. Initially botox injections helped ease the spasm, but the condition slowly became worse until the spasms would severely distort one side of her face, almost completely closing her eye and mouth.

"My job requires regular meetings with new clients, and it was very difficult and awkward to meet people when my face was very noticeably twitching," Anne recalls. "In addition, it was getting harder to drive. I became reluctant to leave the house." Anne was referred to Dr. Giannotta in August 1998 and underwent the MVD. Dr. Giannotta located the blood vessel irritating Anne’s facial nerve, moved it out of the way, and held it in place with a piece of Teflon.

"I was hospitalized at USC University Hospital for two days, and the condition was completely corrected. The difference is like night and day", Anne adds. "My face doesn’t twitch at all, and the stares from others have stopped. My friends and family noticed the improvement immediately. My daughter even said, ‘Mom, your eye is open.’ And I have started to socialize again. Dr. Giannotta is an excellent surgeon, very skilled and personable."

For more information, please feel free to call USC Department of Neurological Surgery at (323) 442-5757.