Caterpillar robot performs heart operations

Apr 19 2007

Scientists in the United States have designed a device which is able to crawl across the surface of the heart and perform precision heart operations.

The tiny robotic caterpillar is a mere two centimetres long when contracted and can move across the surface of the heart at up to 18 centimetres per minute.

The robotic device "walks" by attaching a suction foot to the surface and then extending its body, attaching a second suction foot and pulling the back foot forward.

Movements are controlled outside the body by using a joystick and surgeons can move the caterpillar across the surface of the heart in order to deliver treatment.

The device, called HeartLander, is designed to attach to the surface of the heart and to move around to positions where treatment is needed.

The team hope that the crawling robot will be much less traumatic for both surgeons and patients as precision heart operations could be performed under local anaesthetic without invasive surgery.

The scientists at Carnegie Mellon University Robotics Institute in Pittsburgh, Pennsylvania, have already tested the device on the heart of a living pig where a shot of dye intended to mimic a drug injection was given and pacemaker leads were attached.

The caterpillar device is inserted below the ribcage by keyhole surgery and is attached to the heart via a vacuum line to the suckers.

The robot is manoeuvred on to the heart via a small incision under the patient's ribcage and once attached by its suckers it is controlled by three rigid wires which are pushed and pulled by motors outside the body.

The robot also carries a needle, which could be used to inject stem cells and growth factor genes and to take tissue samples from the heart's surface and it could possibly be used with an added radio-frequency probe to treat faulty heart rhythms by killing damaged tissue.

A camera added to the device, rather than relying on the magnetic tracker on the skin which is currently being used, would help surgeons see specifically where the robot was on the heart's surface.

Dr. Cameron Riviere who led the research, says the device avoids having to stop the heart, disturb the ribcage, or deflate the left lung to access the heart, thereby reducing the risk of illness linked to heart bypass procedures.

Dr. Riviere however says that using the robot on humans would be a much more difficult step and the device is years away from clinical use.

Dr. Riviere says the next stage will be to do similar tests using a sheep's heart; he hopes the HeartLander will be available for surgical use within three to four years.

Although the research has been welcomed by many experts most say it's application on humans is a long way off and some are unsure that it will be able to deliver useful treatments to human patients.