SciTech

Robot traverses the surface of the heart

The term “robotics” brings to mind visions of probes that zoom up to the sky and land on the rocky surface of the moon. Carnegie Mellon, however, has introduced a robot of a different kind: one that lands on the slick surface of the heart. HeartLander, barely the size of a finger, is being developed by Cameron Riviere, an associate research professor at the Robotis Institute, and is capable of revolutionizing the way cardiac surgery is done today.

HeartLander’s capabilities are enormous. It can literally “walk” on the heart, allowing surgeons to reach previously inaccessible parts of the heart. It can also inject medications into the muscle of the heart, place pacing electrodes on the surface, and even selectively destroy malfunctioning tissue. Perhaps the best part about the device is that it requires only minimally invasive surgery.
Patients being treated with HeartLander need no more than some local anesthesia and a few minutes of their time to get treated for something that presently requires at least an overnight hospital stay. “You could potentially do outpatient procedures with [HeartLander]. That’s the sort of the thing that the surgeons get excited about,” Riviere said.

Initially, Riviere and his team had a hard time getting HeartLander to move along the heart. Riviere explained that the current prototype of HeartLander uses suction cups to move around the heart. It has one front foot and one back foot that are connected to each other by flexible wires and can hold on to the surface of the heart with the suction cups.

If the suction of the back foot is on, the back foot remains stationary and the front foot can be pushed forward by the wires. For the device to move forward, the front foot is kept stationary with suction pads and the back foot is pulled by the wires up to the front foot. “You can do that in a cycle and get this kind of inchworm motion,” Riviere explained.
Although this seems simple in theory, the reality is not so simple. The surface of the heart is wet and slippery, making it hard for the suction cups to hold on. The suction also cannot be increased beyond a certain degree for fear of causing damage to the heart. When Riviere first tested the device on pigs’ hearts, the device just kept slipping and was not able to move around much. Riviere and his team spent a couple of years trying to solve this problem. “All of a sudden this one prototype we built — boom — it [worked] ... [but getting the device to move properly] was really the big challenge.” With the locomotion technique in place, HeartLander was all set to do wonders on the surgical table.

To fully realize the potential of HeartLander, Riviere started working with Marco Zenati, a professor of surgery at the University of Pittsburgh School of Medicine and adjunct professor at the Robotics Institute. As stated in an article on CarnegieMellonToday.com, Zenati is known for performing the first robot-assisted beating-heart coronary bypass surgery in the country.
With this background, Zenati was definitely able to understand the importance of HeartLander for cardiac surgeries. “[HeartLander] is unique because it qualifies as an organ-mounted robot. So HeartLander actually adheres to the surface of the beating heart.

All the other robots are mounted on a platform, not on the heart itself,” Zenati said. He explained that this feature of the robot allows it to access nearly all parts of the heart, opening the door to a number of opportunities.

This novel characteristic of being able to move around the entire surface of the heart allows HeartLander to provide a different and safer approach to the way surgeries are done. Riviere explained that to get HeartLander on the heart, the surgeon would have to make an incision just below the sternum — the breastbone located at the center of the chest — and place HeartLander on the apex of the heart. HeartLander could then move wherever the surgeon wanted it to go.

Today, the area that allows surgeons to have maximum access to the heart is the space lying below the left lung. Heart surgeries therefore call for the deflation of the left lung. This procedure has a number of drawbacks, including the aforementioned drawback of having to administer general anesthesia, which necessitates an overnight hospital stay. “One of the benefits of HeartLander is that because it is highly flexible and it can crawl wherever you want it to go, you just need an incision in the pericardial sac, but it no longer matters where that incision is; as long as you have one, you can get in,” Riviere explained.

As of now, HeartLander has been tested only on pigs. Before they test it on humans, the team is adding more features to HeartLander to make it even better than what it already is. “[We want] to integrate HeartLander with a navigation system to create a virtual reality environment where the heart will be represented on a three-dimensional matrix [along with] HeartLander. We can basically use this virtual environment to provide model-guided planning and therapy,” Zenati said.