Accuracy study on a fluoroscopic image guided robotic system for removal of femoral bone cement in RTHR

摘要

Introduction: During RTHR the removal of femoral bone cement can be a major problem, often leading to complications due to the additional time needed and possible damage of the remaining bone. In conventional RTHR position and orientation of the instruments like chisels are being observed using iterative multiplanar X-ray imaging resulting in a high radiation dose for the patient as well as for the OR staff. Within the MINARO project (Minimal Invasive Navigation and Robotics), funded by the German Research Foundation (DFG), we developed a new approach for computer assisted removal of the bone cement. A method for the intraoperative reconstruction of the bone cement has been developed and its validity been shown in previous work [1,2]. Beneath a hand-navigated milling device an active robotic device has been developed, whose intrinsic accuracy has already been proven to be sufficient for the task [3]. In this paper we report on our work regarding the overall system accuracy, including the intraoperative image acquisition, 3-D reconstruction of the cement body, milling path generation with collision detection, the navigated prepositioning and the mechanical components, consisting of the robot itself, the milling device and the bone fixation.