Recall from the NIWeek 2010 Day Three Keynote: Dr. Michio Kaku, theoretical physicist, predicted the next 20 years of technology development, describing tiny robots that would travel throughout the body, taking readings, administering medication and performing tiny microscopic procedures, all while we go about our daily routines.
Researchers at the Carnegie Melon Robotics Institute are one step ahead of us, delivering the HeartLander, a miniature robotic device that can crawl around the surface of the heart, taking measurements and performing simple surgical tasks, all while the heart continues to pump blood throughout the body. We read Nicholas Patronik’s Ph.D. thesis describing this project (and we encourage everyone to check it out).Here is what we learned.
NI technologies have been used for robot-assisted surgeries before, but the HeartLander robot addresses two major challenges of cardiac therapy and surgery:
• Gaining access to the heart without opening the chest
• Operating on the heart while it is beating
Several options for tackling these challenges exist today. Thoracoscopic techniques use laparoscopic tools inserted through the chest cavity to operate on the beating heart (think DaVinci Robot). While this avoids cracking open the rib cage (ouch!), even less invasive methods exist for accessing the heart and performing simpler procedures, like dye injections. Percutaneous transvenous techniques access inner organs through main arteries and veins. For example, a doctor can guide a heart stent through the veins in your thigh to treat blockages, and this procedure is performed on an outpatient basis. While these transvenous procedures are easier to recover from, thoracoscopic techniques offer much more flexibility in the complexity of surgical operations that can be performed.
Illustration of HeartLander concept. Image reproduced from Nicholas Patronik, Carnegie Melon University.
The HeartLander robot is considered a hybrid of these two approaches in that it can achieve fine control of thoracoscopic techniques while maintaining the ability to be performed on an outpatient basis, like the percutaneous transvenous techniques. It adheres to and traverses the heart’s surface, the epicardium, providing a tool for precise and stable interaction with the beating heart. Even better, it can access difficult to reach locations of the heart such as the posterior wall of the left ventricle (the side of your heart that faces your back).
How it works
The HeartLander is launched onto the surface of the beating heart through a small puncture underneath the bottom of the sternum. From there, the robot steadily traverses the epicardium like an inchworm. Offboard linear motors actuate the robot forward while solenoids regulate vacuum pressure to suction pads. Watch a video of early prototypes inching across an inflated balloon, a synthetic beating heart and a porcine beating heart to see HeartLander’s motion in action (warning: the video clips get progressively graphic in nature).
An umbilical tether sends and receives information between the HeartLander and the control station, where the pressure to the suction pads is monitored and controlled to maintain grip at all times. The mobility of the robot is semiautonomous: it uses a pure pursuit tracking algorithm to navigate to predetermined surface targets, and can also be controlled via teleoperation.
Photograph of the HeartLander crawling robot. Two drive wires transmit the actuation from off-board motors for locomotion. A 6-DOF electromagnetic tracking sensor is mounted to the front of the body. Image reproduced from Nicholas Patronik, Carnegie Melon University.
It can navigate to any location on the epicardium, with clock speeds up to 4 mm per second, and acquire localization targets within 1 mm. But our favorite part about this application is that the robot’s motion is controlled entirely with LabVIEW software and NI data acquisition hardware.
So far, the HeartLander has been successfully demonstrated through a series of closed-chest, beating-heart porcine studies. We don’t have tiny robotic heart worms crawling around in us just yet. But we’re certainly excited to see how the HeartLander project progresses and we’re proud that NI technologies are helping pave the way for incredible, futuristic innovations like this.