Robotic motion compensation for beating intracardiac surgery

The use of 3D ultrasound imaging for both imaging and tracking has enabled minimally-invasive, beating heart intracardiac procedures. However, the rapid movements of internal heart structures pose a serious challenge to the surgeon that is compounded by the presence of significant time delays in 3D ultrasound imaging. This paper investigates the concept of using a one-degree-of-freedom motion compensation system to synchronize instruments with tissue motions that are approximately one-dimensional. We first describe the motion of the mitral valve, which is well approximated by a 1D model. The subsequent development of a motion compensation system is described, which comprises a motion compensation instrument as well as an extended Kalman filter that can compensate for system delays. The benefits and robustness of the resulting system are demonstrated in user trials under tracking conditions with measurement noise, delay, and heart rate variability.