Robot-enhanced neurosurgery for nimbler seizure mapping

implanting electrodes for seizure monitoring, with robotic assistance
Scellig Stone and Joseph Madsen in surgery with the robot.

Head shaved, a little boy rests on the operating table, deep under anesthesia. His parents have brought him to Boston Children’s Hospital in hopes of determining the cause of his seizures. Now, neurosurgeons Scellig Stone, MD, PhD, Joseph Madsen, MD, and their colleagues in the Epilepsy Center are performing a procedure designed to monitor seizure activity in the 3-year-old’s brain.

But as the team members crowd around the table, they’re not alone. With the push of a button, a large robotic arm rotates and lowers right next to the boy’s head, helping the physicians pinpoint the precise location to drill. “This is a real game-changer,” murmurs one of the clinicians observing the surgery. “It’s going to transform the way we practice.”

Enhancing minimally invasive seizure monitoring

For patients who don’t respond to anti-seizure drugs, surgery often holds the only hope for managing epilepsy. To identify the area of the brain from which seizures are originating, physicians have traditionally performed subdural intracranial seizure monitoring. This invasive approach involves surgically opening the skull and placing a grid of electrodes on the surface of the brain. It’s a lengthy operation with a long recovery time, and it can’t always locate deep seizure origins.

Stereotactic frames such as this one may no longer be needed with the introduction of the robot. (Image: Wikimedia Commons)

Increasingly, neurosurgeons are relying on stereoelectroencephalography (SEEG), a procedure in which electrodes are instead fed on tiny wires through trajectories drilled into the skull. These electrodes can reach deeper into a child’s brain — and can present a better opportunity for clinicians to determine the source of seizure activity. Boston Children’s is currently a leading destination for pediatric SEEG in the United States.

“SEEG is far less invasive and far better tolerated in children,” says Stone. “There’s a night-and-day difference for patients in terms of recovery after surgery.”

However, to perform SEEG, surgeons have had to employ a stereotactic frame, a halo-like apparatus placed around the patient’s head that uses 3-dimensional coordinates to help map the targets to be drilled. And with the need for multiple measurements comes increased opportunity for human error and more time spent in the operating room (OR).

To address this concern, some neurosurgeons, including those at Boston Children’s, have begun using a stereotactic robotic arm to point to the drilling targets. Used in concert with brain imaging, this technology allows precise placement of the electrodes — eliminating the need for a cumbersome frame and greatly decreasing OR time.

“The robot allows us to place electrodes much more quickly than in the past. When you use a stereotactic frame for this, it can take all day. Now we’re completing the procedure in less than half that time,” says Stone. “As a result, patients spend far less time under anesthesia, which is always a benefit when working with kids.”

New angles on neurosurgery

Stone and his colleagues say they plan on using the robotic assistance for all eligible patients in the future and predict its use will soon become routine at Boston Children’s. Meanwhile, the technology has the potential to further expand seizure monitoring capability.

While stereotactic frames limit the trajectories through which surgeons can place electrodes, the robotic arm provides more angles, allowing surgeons to tackle much more ambitious implantation strategies. This means that previously unreachable brain areas can now be monitored, improving the likelihood of identifying seizure origins.

Scellig Stone, MD, places electrodes for seizure monitoring with the aid of a robotic arm.

This flexibility isn’t limited to diagnostic procedures. The same trajectories that the robot helps create for SEEG can also be used to pass laser fibers deep into the brain and ablate areas of tissue associated with seizures. “This is an area of technology that’s really exploding,” says Stone. “It’s allowing us to build expertise in less-invasive epilepsy surgery.”

Back in the operating room, Stone shows his resident how to guide an electrode’s wire into the patient’s brain. As she finishes up, Madsen pushes another button and the robot’s arm lifts, swivels and lowers again nearly instantaneously at the next insertion site. The same process would have once taken tens of minutes, including adjusting the frame and cross-checking its settings. All that time quickly adds up to hours of extra OR time saved.

“Great; all set,” says Stone. “Now, on to the next.”

Learn more about the Boston Children’s Epilepsy Center.