SNUBH finds electrophysiological test to predict hemifacial spasm surgery success

Seoul National University Bundang Hospital (SNUBH) researchers have developed an electrophysiological test method that predicts the cure rate of microvascular decompression surgery, a representative treatment for hemifacial spasms.

A Seoul National University Bundang Hospital team, led by Professors Ji So-young (left) and Han Jeong-ho, has developed a new test method to determine the success rate of hemifacial spasm surgery.

Hemifacial spasm is a disease in which the cerebral blood vessel compresses the facial nerve, the seventh cranial nerve responsible for facial movement, and the movement of blood vessels such as pulse stimulates the facial nerve, causing convulsions on one side of the face regardless of the patient’s will, the hospital said. Symptoms include cramps in the eyelids and cheekbones muscles and, in severe cases, even the corners of the mouth from time to time.

If a patient suffers from hemifacial spasm even once, it is difficult to heal naturally, and as time goes by, the symptoms worsen, and the number of occurrences increases.

Therefore, receiving treatment promptly is important as the absence of treatment can worsen the convulsions, making it increasingly difficult for patients to open their eyes and expose them to risks such as social phobia or depression as symptoms such as blurred vision or chronic and severe facial distortion appears.

“To fundamentally treat the illness, it is necessary to find the causative cerebral blood vessel, reduce the pressure on the facial nerve, and undergo a microvascular decompression surgery, which physically separates the cerebral blood vessel from the facial nerve,” the hospital said. “To determine whether the microvascular decompression surgery was successful, hospitals currently use a test method to check whether the abnormal electrical signal between the causative blood vessel and the facial nerve has disappeared by inserting a needle into the facial muscles during surgery.”

While the test method is traditional, surgical environment or anesthesia may affect the test results as hospitals perform it during surgery. There is also a limitation that symptoms may recur in about 5 to 10 percent of patients even if the abnormal electrical signal disappears during the operation.

To resolve this issue, the team, led by Professors Ji So-young and Han Jeong-ho of the Department of Neurosurgery, proposed an electrophysiological test method that changes the needle-type test performed during surgery to a non-invasive method and additionally performs cross-validation after surgery.

The method involves predicting the surgical result by performing an electrical signal test on the skin after a certain period after surgery so that the effect of anesthetics disappears and then comprehensively analyzing it with the test results during surgery.

As a result of verifying the accuracy of the test method, the team was able to confirm a recovery rate of about 98 percent in patients who lost electrical signals in both tests and showed significantly higher predictive power than the conventional test method.

Through this, patients could check the recovery rate more quickly and accurately after surgery, the hospital said. Also, the test results helped objectively determine the need for reoperation, thereby minimizing unnecessary treatment and side effects.

“The significance of the test method is that it can predict more accurately the cure rate of hemifacial spasm surgery by combining the follow-up test results with the existing test method and objectively determining whether reoperation is necessary for each patient based on the test results when symptoms recur,” Professor Han said.

The results of the research were published in the latest issue of the Journal of Neurosurgery.