Researchers at Samsung Medical Center (SMC) have discovered that intraoperative motor-evoked potential (MEP) monitoring can eliminate the risk of complications during temporal lobe epilepsy (TLE) surgery, the hospital said Friday.

Professor Seo Dae-won

Temporal lobe epilepsy surgery is an essential treatment for patients with refractory epilepsy, offering the opportunity to maximize seizure freedom as well as prevent untimely death. Although the temporal lobectomy is far from the motor nerve system, the operation can cause complications such as hemiplegia in 1 to 3 percent of patients who undergo surgery.

The SMC team, led by Professor Seo Dae-won, aimed to analyze whether MEP was effective in preventing complications.

The team compared postoperative neurological deficits in patients who underwent TLE surgery with or without transcranial MEPs combined with somatosensory evoked potential (SSEP) monitoring between January 1995 and June 2018.

The team performed the transcranial motor stimulation using subdermal electrodes and recorded the MEP responses in the four extremity muscles. Professor Seo made a decrease of more than 50 percent in the MEP or the SSEP amplitudes compared with baseline a warning criterion.

As a result, in the TLE surgery group without MEP monitoring, postoperative permanent motor deficits newly developed in seven of 613 patients, while no permanent motor deficit occurred in 279 patients who received transcranial MEP and SSEP monitoring.

Ten patients who showed the fall of more than 50 percent in the MEP amplitude recovered completely, although two cases indicated transient motor deficits that recovered within three months after the operation.

“Intraoperative MEP monitoring is being used in a variety of surgeries related to the nervous system, including cerebrovascular, brain tumor, spine, and functional brain surgery,” Professor Seo said. “As the research proved that the MEP monitoring eliminates the risk of complication for TLE surgeries, the team expects the method to be more widely used to treat epilepsy patients safely.”

The results of the research were published in the July issue of the Journal of Clinical Neurology.

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