Bioengineers have reported the first example of a robotic device navigating itself inside a living body.
The autonomous robot catheter moved through the beating blood-filled hearts of live pigs to locate leaky valves, with no human intervention.
Once in position, a surgeon took over to close the leak using an external joystick controller.
The US team reporting on the advance in the journal Science Robotics said the device was the equivalent of a self-driving car.
Lead researcher Dr Pierre Dupont, from Boston Children’s Hospital, said: “The right way to think about this is through the analogy of a fighter pilot and a fighter plane.
“The fighter plane takes on the routine tasks like flying the plane, so the pilot can focus on the higher-level tasks of the mission.”
The robot navigated by feeling its way through the heart’s internal chambers with an optical touch sensor.
The “wall following” technique is similar to that adopted by rodents that use their whiskers to build mental maps of unfamiliar dark environments.
A link to an artificial intelligence (AI) system enabled the catheter to work out its location and where it needed to go using the most efficient pathway.
For the experiment, the team performed a demanding procedure known as a paravalvular aortic leak closure.
The surgery repairs replacement heart valves that have started to leak around the edges.
In 83 trials on five pigs, the robot catheter was able to reach the site of valve leaks in about the same time as a surgeon using a hand tool or remote-controlled device.
Dr Dupont envisioned future autonomous surgical robots pooling their data to continuously improve performance over time.
“This would not only level the playing field, it would raise it,” he said. “Every clinician in the world would be operating at a level of skill and experience equivalent to the best in their field.
“This has always been the promise of medical robots. Autonomy may be what gets us there.”