An active motion compensation instrument for beating heart mitral valve surgery

New 3D ultrasound visualization has enabled minimally invasive, beating-heart intracardiac procedures. However, rapid motion of internal heart structures limits the realization of these new procedures. This paper investigates the concept of using a single actuator to compensate for tissue motions which occur largely in one direction. We characterize mitral valve annulus motion and show that it is well approximated by a ID model. The subsequent development of a motion-compensating tool (MCT) is described. The resulting instrument was tested in user trials under a series of positional error and tracking delay conditions. Results indicate that the MCT provides an approximately 50% increase in dexterity and 50% decrease in applied force in comparison to a solid tool. The study also shows that MCT tracking efficacy is highly dependent on tracking delays, indicating the importance of predictive, cyclical control algorithms.