US scientists have made a mini prototype robot that crawls over the surface of a beating heart and performs simple repairs without major surgery.
A report in this week’s New Scientist magazine describes how the HeartLander, invented by robotics experts Dr Cameron Riviere and colleagues at Carnegie Mellon University in Pittsburgh, Pennsylvania, has injected dye and attached pacemaker leads to beating hearts inside live pigs.
The surgeon controls the caterpillar-like device, which weighs about the same as an egg and is half the length of a thumb, using a joystick, and tracks it with a visual monitor that uses either X-ray video or a magnetic tracker.
It is hoped that one day such robots will help heart surgeons remove damaged tissue or even inject stem cells directly into the heart without having to stop it beating.
The prototype has yet to be tested on humans, which will take several years, so it is unlikely to be in general use by heart surgeons before 2013.
HeartLander is 20 millimetres long and resembles two nose-shaped end-pieces (these are feet with tiny sucker holes) joined by a short tube which continues through one of the end-pieces to emerge eventually outside of the body.
A vacuum holds the robot in place as all the air is sucked out through the tube and the 20 holes in each sucker foot.
The long tube also contains wires which allow the surgeon to control the robot by making it “crawl” along the surface of the heart at up to 18 cm per minute.
Because the robot is small and flexible, it can be inserted using keyhole surgery; its inventors are hopeful that one day it could be used without a general anaesthetic, which would reduce hospital stays.
They suggest it would be feasible to insert the robot and its connecting tube through a small cut below the ribcage and another cut in the membrane around the heart.
At the moment, open heart surgery needs a very large cut to give surgeons sufficient access, and the heart usually has to be stopped.
Heart experts have welcomed the news and praise the creativity and novelty of the idea. However, they say it will be some years before testing in humans will prove it is safe and effective, and they wonder whether in practice it will be as useful as its inventors hope.
Also, many heart procedures need access to the inside of the heart, whereas HeartLander only accesses the outside surface.
Andrew Rankin, a cardiologist at the University of Glasgow in the UK, says in the New Scientist article that although the heart can be accessed non-invasively through blood vessels, it is not always possible to do this when there is damaged or diseased tissue near the surface of the heart. He suggests that HeartLander could be useful for such cases.
Future developments of the robot include attaching a camera and treating arrhythmias by selectively destroying malfunctioning heart tissue.
Click here for the article in New Scientist (includes video footage of creeping HeartLander).
Written by: Catharine Paddock
Writer: Medical News Today