Neurosurgeons implant new type of electrical stimulator to control seizures

On June 18, neurosurgeons at the University of Alabama at Birmingham implanted a new type of electrical stimulator to control seizures in patients with difficult-to-control epilepsy.

It marked the first time in the Southeast the RNS system by NeuroPace had been implanted since the device gained FDA approval in November 2013. The first patient was a 24-year-old woman from central Alabama.

RNS stands for responsive neurostimulation.

"It is designed to record patient's specific brain activity and recognize patterns that are associated with seizures," said Kristen Riley, M.D., associate professor in the Department of Neurosurgery. "The RNS system then delivers stimulation in order to help modulate and control the seizures."

The system consists of electrodes attached by leads to a generator which can communicate with a computer. The generator is curved so that it can be placed within a patient's skull. It is a little bigger than a flash drive.

"We drill a trough for the device so that it is flush within the skull," said Riley. "There is not a raised area; it's basically hidden within the skull."

The electrodes are placed near the location in the brain where a patient's seizures are triggered. Jerzy Szaflarski, M.D., Ph.D., professor in the Department of Neurology and director of the UAB Epilepsy Center, says the RNS system can be customized for each individual patient so that it learns which patterns of brain activity lead to seizures in that patient. He says data from research studies dating back several years indicate that many patients will respond to the stimulation and have significant reduction in their seizures.

"This is not a treatment that will cure epilepsy," he said. "This is a treatment that will help control seizures in a very specific group of patients who are not otherwise candidates for surgery. I don't expect too many patients to become seizure-free; but if we can decrease their seizures by even half, we can make huge improvements in their lives."

The RNS system is for patients with severe seizures who do not respond to medications and are not candidates for surgery because the location of their seizure onset is at a sensitive part of the brain. It is also only for patients whose seizure onset can be traced to just one or two locations in the brain.

"We're very excited to offer this therapy to our patients who are not candidates for more traditional therapies for epilepsy," said Szaflarski. "We see multiple patients like that every year, and the RNS system could make a huge difference in the lives of those patients. There is already data to show that the quality of life of those patients has improved significantly with RNS."