Augmented reality for safer coronary artery bypass

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 sternum and the tissues surrounding it. Intraoperatively, the sternum is located and the tissues surrounding the LIMA are tracked using a stereo videoscope held by a robotic arm. Knowing the position of the videoscope relative to the sternum now makes it possible to calculate where in the videoscopic images the LIMA is located. This information is then used to generate an augmented reality showing the tissues surrounding the LIMA as transparent, thus revealing the position of the LIMA within them. (C) 2003 Published by Elsevier Science B.V.