Conventional open surgery on the brain involves drilling openings in the skull through which to access the gray matter. But what if the part of the brain needing to be accessed is located at the bottom of the brain as is the case with treating severe epileptic seizures? Generally it means more drilling. Now engineers at Vanderbilt University have developed a surgical robot that uses an alternative point of entry – the cheek.

Treating those seeking relief from severe epileptic seizures involves drilling through the top of the head and deep into the brain to destroy a small area in the hippocampus where the seizures originate. Inspired by the through-the-cheek technique neuroscientists currently use to implant electrodes in the brain to track brain activity and locate the source of epileptic fits, a team headed by Associate Professor of Mechanical Engineering Eric Barth developed a robotic device that enters through the patient's cheek. This provides a less invasive way to access the desired area, avoiding drilling through the skull altogether.

The working prototype developed by the team features a 1.14 mm needle made from nickel-titanium, which is one of the few common metals compatible with MRIs. The needle works in a similar way to a mechanical pencil, with compressed air used to advance the needle segments a millimeter at a time. Concentric tubes, some of which are curved, allow the robotic platform to steer the needle and follow a curved path into the brain, with surgeons able to track its position by taking successive MRI scans.

"The systems we have now that let us introduce probes into the brain – they deal with straight lines and are only manually guided," says Associate Professor of Neurological Surgery Joseph Neimat. "To have a system with a curved needle and unlimited access would make surgeries minimally invasive. We could do a dramatic surgery with nothing more than a needle stick to the cheek."

Mechanical engineering graduate student David Comber, who is responsible for much of the design, says the accuracy of the system measured in the lab is better than 1.18 mm, which is considered accurate enough for such surgery. To keep costs down, the team also designed it so much of the system can be 3D printed.

The team will now move onto testing the robotic platform on cadavers, with Barth estimating the technology could make its way into operating rooms within the next decade.

Comber recently unveiled the working prototype in a live demonstration at the Fluid Power Innovation and Research Conference in Nashville.

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