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In a development that will not just level the playing field, but raise the whole game, bio-engineers have designed a robot that can navigate autonomously through the chambers of a pig’s heart. Scientists have in the past used external controls or magnetic devices to navigate inside a body, but a robotic device that can do so autonomously and also safely, is something that is set to get the medical community excited.
Bioengineers at Boston Children’s Hospital say this is the first time a robot has been able to navigate autonomously inside the body. In findings published in the journal “Science Robotics,” the scientists programmed a robotic catheter to find its way along the walls of a beating, blood-filled heart to a leaky valve, without a surgeon’s assistance.
The scientists created a map of cardiac anatomy and preoperative scans of 83 individual pigs’ hearts. With that information, the control system was able tell where the device was within the organ, and how it could get to its target.
Senior investigator and chief of Pediatric Cardiac Bioengineering at Boston Children’s Hospital, Pierre Dupont equated the autonomous robotic device to the equivalent of a self-driving car navigating to a desired destination inside the body.
“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,” Dupont explained.
Dupont further said: “This would not only level the playing field, it would raise it. 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.”
In the study that was published in “Science Robotics,” the bio-engineers explained that they had created a robotic catheter that can navigate through the blood-filled heart using wall-following algorithms inspired by positively thigmotactic animals, such as cockroaches.
“The catheter uses haptic vision, a hybrid sense using imaging for both touch-based surface identification and force sensing, to accomplish wall following inside the blood-filled heart. Through in vivo animal experiments, we demonstrate that the performance of an autonomously controlled robotic catheter rivaled that of an experienced clinician,” the study says.
A release accompanying the study’s results further said the researchers’ robotic catheter navigated using an optical touch sensor developed in Dupont’s lab. The touch sensor uses artificial intelligence (AI) and image processing algorithms to enable the catheter to figure out where it is in the heart and where it needs to go.
Dupont explained that the algorithms help the catheter figure out what type of tissue it’s touching, where it is in the heart, and how it should choose its next motion to get where it is wanted for it to go.
For the demo, the team performed a highly technically demanding procedure known as paravalvular aortic leak closure, which repairs replacement heart valves that have begun leaking around the edges. Once the robotic catheter reached the leak location, an experienced cardiac surgeon took control and inserted a plug to close the leak, the press release said.
In repeated trials, the bioengineers said, the robotic catheter successfully navigated to heart valve leaks in roughly the same amount of time a surgeon would take using either a hand tool or a joystick-controlled robot.
In further explaining how the autonomous device works, the researchers said it uses a navigational technique known as “wall following,” where the robotic catheter’s optical touch sensor sampled its environment at regular intervals, in much the way insects’ antennae or the whiskers of rodents sample their surroundings to build mental maps of unfamiliar, dark environments.
The sensor told the catheter whether it was touching blood, the heart wall or a valve (through images from a tip-mounted camera) and how hard it was pressing (to keep it from damaging the beating heart). Data from pre-operative imaging and machine learning algorithms helped the catheter interpret visual features. In this way, the robotic catheter advanced by itself from the base of the heart, along the wall of the left ventricle and around the leaky valve until it reached the location of the leak, the release said.
Uma Duvvuri of the University of Pittsburgh Medical Center, who heads a robotic innovation lab, was quoted saying this was a “pretty exciting” study. “This robot is trying to walk along the wall of the heart until it gets to the valve. That’s a pretty exciting development but this is still very, very preliminary.”
While this technology is still far from being introduced in hospital operating rooms, surgeons are optimistic that an autonomous device could be very useful in other procedures as well.