LONDON (TIP): Doctors have found a new way to treat epilepsy – through the cheek. For those most severely affected, treating epilepsy means drilling through the skull deep into the brain to destroy the small area where the seizures originate – invasive, dangerous and with a long recovery period. Five years ago, a team of Vanderbilt engineers wondered: Is it possible to address epileptic seizures in a less invasive way? They decided it would be possible. Because the area of the brain involved is the hippocampus, which is located at the bottom of the brain, they could develop a robotic device that pokes through the cheek and enters the brain from underneath which avoids having to drill through the skull and is much closer to the target area.

To do so, however, meant developing a shape-memory alloy needle that can be precisely steered along a curving path and a robotic platform that can operate inside the powerful magnetic field created by an MRI scanner. The engineers have developed a working prototype. The business end of the device is a 1.14 mm nickel-titanium needle that operates like a mechanical pencil, with concentric tubes, some of which are curved, that allow the tip to follow a curved path into the brain.

Unlike many common metals, nickel-titanium is compatible with MRIs. Using compressed air, a robotic platform controllably steers and advances the needle segments a millimeter at a time. The needle is inserted in tiny, millimeter steps so the surgeon can track its position by taking successive MRI scans. According to associate professor of mechanical engineering Eric Barth, who headed the project, the next stage in the surgical robot’s development is testing it with cadavers.

He estimates it could be in operating rooms within the next decade. Associate professor of Mechanical Engineering Robert Webster had developed a system of steerable surgical needles. “The idea for this came about when Eric and I were talking in the hallway one day and we figured that his expertise in pneumatics was perfect for the MRI environment and could be combined with the steerable needles I’d been working on,” said Webster. The engineers identified epilepsy surgery as an ideal, high-impact application.

They learned that currently neuroscientists use the through-the-cheek approach to implant electrodes in the brain to track brain activity and identify the location where the epileptic fits originate. But the straight needles they use can’t reach the source region, so they must drill through the skull and insert the needle used to destroy the misbehaving neurons through the top of the head. “The systems we have now that let us introduce probes into the brain – they deal with straight lines and are only manually guided,” the doctors said.