[Development of a planned and monitoring robotic assistance and automation for application in orthopedics and trauma surgery]

Abstract

Robot-assisted surgery offers many advantages with respect to precision and facilitation in medicine, whereby the physician controls the system externally by guiding the movement of the robot during the operation. Despite training and experience, operating errors by the user cannot be excluded. In addition, for the established systems the precise guidance of instruments along complexly shaped surfaces, e.g. for milling or cutting, depends on the skills of the operator. This article presents an expansion of the established robotic assistance for smooth movement along randomly shaped surfaces and introduces a movement automation which goes beyond the assistance systems used so far. Both approaches aim to improve the accuracy in surface-dependent medical procedures and avoid operator errors. Special applications with these requirements are, for example the execution of precise incisions or removal of adhering tissue in cases of spinal stenosis. A segmented computed tomography (CT) or magnetic resonance imaging (MRI) scan serves as the basis for a precise implementation. For robotic assistance externally guided by the operator the commands given to the robot are tested and monitored without delay so that adaptation of the movement exactly corresponding to the surface can be carried out. In contrast, the automation for the established systems differs in that the movement along the desired surface is roughly planned by the surgeon preoperatively by marking prominent points on the CT or MRI scan. From this a suitable track, including the appropriate instrument orientation, is calculated and, after checking the results, the robot finally carries this out autonomously. Based on this procedure, which is planned by humans and carried out by robots, errors are minimized, respective advantages are maximized and costly training on correct steering of robots becomes obsolete. The evaluation is carried out both in simulation and also experimentally on a complexly shaped 3D-printed lumbar vertebra from a CT scan with a Stäubli TX2-60 manipulator (Stäubli Tec-Systems GmbH Robotics, Bayreuth, Germany); however, the procedures are also transferable to and applicable on every other robotic system that covers the necessary working space, such as the da Vinci system.

Keywords: Complex surfaces; Instrument orientation; Movement automation; Operating error; Precision.