A Novel Robot with a Toroidal Workspace for Coring Applications

Removing a volume of tissue as a single mass can be a complicated operation, and in many cases it would be advantageous to be able to remove more complex geometries and preserve nearby critical regions. In this paper, we present a novel robot with 2 degrees of freedom, designed for cutting around a parametric torus-shaped volume. The kinematics of this system make it possible to drive the tip of the linkage such that it does not collide with any point not on the surface of the specified torus. Two types of tool paths can be followed, with the torus geometry defined to fit a target region of material. Three bone tumor cases were used for simulating the approach. Compared to more standard tri-planar cutting approaches, a toroidal resection could improve upon the amount of healthy bone resected, and reduce surgical access requirements.