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Design and Comparison of Magnetically-Actuated Dexterous Forceps Instruments for Neuroendoscopy

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Robot assistance brings significant advantages to modern surgery by enabling new, minimally invasive approaches while reducing the physical and mental burden on the surgeon. Though robot assistance has become standard in areas such as urology and general surgery, it remains largely absent in neurosurgery. The primary reason is a lack of dexterous wristed tools that are small and compact enough to maneuver within the confines of the brain. The miniaturization of conventional cable-driven robot tools is limited by cable strength and frictional inconsistencies that only worsen at smaller scales.

Low-frequency magnetic actuation enables unconventional, alternative tool designs that could be the key to new robot-assisted approaches in neurosurgery. Powerful magnetic fields, projected from permanent magnets outside the patient, safely and effectively apply forces and torques to tiny, remote magnetic tools. We demonstrate how the magnetic material on these robot tools can be arranged and optimized to produce a variety of tool designs with unique actuation behaviors.

Using laser welding manufacturing techniques, superelastic nickel titanium components, and neodymium magnets, we fabricated three magnetic robot tool prototypes. These devices can pass through the 3.2 mm diameter tool channel of a standard neurosurgical trocar. In a simulated endoscopic procedure, a human operator used the tools to pluck a mock tumor from the third ventricle of a silicone brain model. If used in combination with clinical-scale electromagnetic coil systems, our models predict these tools will be capable of the forces necessary for many neurosurgical tasks.

While many challenges remain in robot-assisted neurosurgery, these tools represent a major step forward in the design of feature-rich, highly versatile, miniature surgical robots.

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