Working Sideways with Concentric Tube Robots: A System for Natural Orifice Intrauterine Surgeries

Concentric tube robots delivered through endoscopes have thus far been deployed approximately straight ahead of the endoscope's tip, which requires relatively low curvatures and strains, and a single fixed view angle. However, in tight spaces in the body (such as the interior of the uterus), it is often desirable to work close beside the endoscope tip, approximately perpendicular to the endoscope axis. Doing this requires two advancements: (1) a way to angle the camera, ideally without physically moving it, to prevent collisions with anatomy or other tools in the constrained space, and (2) the ability to reach points approximately perpendicular to the endoscope axis, that are close to its tip. We address the first challenge by integrating a variable view angle endoscope designed for arthroscopy. We address the second with highly curved concentric tube robots, designed to undergo higher strains than have previously been reported in the literature. We experimentally demonstrate working sideways from the endoscope tip with such a system by tracing the periphery of simulated uterine fibroids at multiple angles. We also demonstrate the use of electrosurgery to cut around the periphery of a simulated lesion made from animal tissues, while working in a direction approximately perpendicular to the endoscope axis.