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.