Robotic Heart Surgery

Robotic heart surgery.

The cardiac surgeon (in a party suit) sits down at a large grey console. Peering into a binocular-like viewer, he adjusts the 3-D picture, grabs two joysticks and calmly proceeds to perform a complex triple bypass on a patient who is thousands of miles away in another continent. The patient wakes up one hour later with only three 5mm keyhole incisions in the side of his chest. He has a hearty meal and is discharged two days later. Space-age-science-fiction imagination? Not really, for robotic cardiac surgery, blended with virtual reality, is already with us in the last year of the fading millennium.

Traditional and minimally invasive endoscopic surgery has been with us for quite some time now. It was realised that the need for big incisions was due to the fact that the surgeon had to insert his hands into the operative field. This was circumvented to some extent by the advent of special and long instruments which were inserted via small holes or “ports” in the patient’s body.

The surgeon would manipulate these instruments to perform surgery. However, the biggest limitation of conventional endoscopic instruments was the limited number of degrees of freedom (DoF) at the tip of the long instrument. In addition, operator tremors and the lack of motion scaling rendered delicate endoscopic bypass surgery impossible. It was like using a one-foot long pen to sign your name.

In order to overcome these limitations computer-enhanced instrumentation systems have been developed.

These are basically spin-offs of the space-age NASA technology (where astronauts are able to remote-control fine instruments to manipulate equipment in outer space) and of the Pentagon Research and Development Wing which aims at putting MASH-style surgeons out of the battlefield and let them operate on injured armymen at the frontline without physically being there.

These have allowed a quantum leap in minimally invasive surgery and are one of the biggest revolutions in cardiac surgery in which robots are becoming the surgeon’s hands. Highly advanced computer systems seamlessly translate the surgeon’s natural hand movements into corresponding micro-movements of the robot placed inside the patient.

The incision on the patient’s chest will be totally unlike that in the over one million patients per year worldwide who undergo bypass surgery. Normally, in a multivessel bypass surgery (the commonest type — the others much less common being single and double vessel bypass), the surgeon approaches the heart by a long midline cut in the sternum or the breastbone. In robotic multivessel bypass surgery there are only three tiny “keyholes” in the left side of the chest. Through these pass in delicate computerised hardware — a light source, a camera and the “robot”. The robot basically comprises two “hands” which have tiny metal fingers with rotating wrists which hold various microsurgical tools such as needles and scalpels. The new robotic wrist has seven DoF including tool function, i.e., the grip available at the tip of the instrument.

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