Augmented reality for safer coronary artery bypass

Abstract

The standard procedure for left anterior descending (LAD) coronary artery bypass requires a sternum split. The internal mammary artery (IMA), most typically the left one (LIMA), is dissected free from behind the sternum and is then anastomosed onto the heart below the occlusion of the LAD. Totally Endoscopic Coronary Artery Bypass (TECAB) is a less invasive alternative to the standard procedure. This procedure results in heavily reduced invasiveness, but also leads to loss of precision, reduced force feedback and loss of overview. The purpose of this work is to alleviate the problems related to loss of overview by generating an augmented reality for the surgeons in which they are given the impression of 'seeing through' the tissues surrounding the LIMA thus making localization of the LIMA a simple matter. Using preoperative CT or MR data, the LIMA is located with respect to the tissues surrounding it. Intra-operatively tissues surrounding the LIMA are tracked using a stereo endoscope held by a robotic arm (AESOP). Knowing the position of the endoscope relative to the visible surface inside the chest cavity now makes it possible to calculate where in the endoscopic video stream the LIMA is located. Positioning of the endoscope is also possible using an optical tracking system. This information is then used to generate an augmented reality where the LIMA is superimposed on it's correct position in the video stream. The thesis is using artificial models to test and experiment on the described problem.