Navigating the complex blood vessels of the brain using traditional surgical instruments is an intricate task, even for highly skilled surgeons. Robotic assistance has the potential to help neurosurgeons operate much more easily. Now, researchers have developed a foundational model for a soft robotic tool and control system that could give surgeons better control and precision within the brain while performing difficult neurosurgeries. Recent studies have shown that this system is intuitive and highly accurate. Preliminary findings indicate that this robot could potentially make minimally invasive brain surgeries for critical conditions like aneurysms more efficient and effective.

One standard way to treat a brain aneurysm — a weakened blood vessel that bulges and fills with blood —is to guide a plastic tube, known as a catheter, through an artery usually starting at the groin. The aim is to reach the aneurysm and seal it without damaging any other vessels along the way. Surgeons traditionally bend the catheter tips for better navigation and then manually turn them as they move toward the aneurysm. After studying surgical procedures and gathering insights from neurosurgeons, researchers at Johns Hopkins University (Baltimore, MD, USA) and the University of Maryland (College Park, MD, USA) concluded that a steerable robotic tool could greatly improve the process.

The researchers engineered a catheter tip controlled by air pressure, often referred to as pneumatic. They used 3D printing to create the tip from a soft, flexible resin and included two hollow channels along its length. When individually pressurized, these channels cause the tip to bend either left or right. While the idea of a bendable catheter tip is not new, the researchers focused on an unmet need—integrating a control system that aligns with existing clinical practices. They developed a hand-operated dial that allows surgeons to adjust the catheter tip’s position with more precision, as well as providing haptic feedback to indicate the bending of the tip. This system allows surgeons to advance the catheter with one hand while precisely controlling its angle with the other.

To evaluate the new tool, the researchers had two participants—one experienced neurosurgeon and another without surgical experience—maneuver the robotic tip to hit an array of tiny targets. They used one hand to advance the catheter and the other to control the dial, bending the tips closer to each target. Both were successful in achieving sub-millimeter precision, which is less than the diameter of brain vessels and aneurysm openings. The neurosurgeon was naturally faster and more accurate, but the novice showed matching accuracy levels over time. Encouraged by these positive results, the research team is keen to further develop the robotic tool. The researchers plan to reduce its size to make it more clinically applicable and test it in more anatomically accurate settings. Additionally, they aim to expand the tool's capabilities by adding a series of tips, allowing it to form more complex shapes and better navigate the complex brain vasculature.

“The soft microcatheter tip is highly innovative and could be key for widespread use of robotics in endovascular surgery,” said Moria Bittmann, Ph.D., director of the NIBIB Robotics Program. 

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