The robotic platform heaves, as if breathing. Atop it stretches a piece of white gauze with a blue line painted down the middle. Along this line another robot snips with little surgical scissors, waiting for the platform to come to a brief rest before making a cut. And another snip, and rest. And another, and rest, on down the line.
This could be you one day. Not that you’ll turn into a robot—you may go under the knife of a machine working as a surgical assistant. And it’s machines like this heaving robotic platform—actually adapted from the technology that powers flight simulators—that you’ll have to thank.
A subtle challenge of operating on humans is that their lungs keep breathing and their hearts keep beating—that is, if the surgeon is doing their job right. When the chest heaves or blood pumps, the surgeon has to compensate for that movement.
This new robot mimics that movement. It’s a kind of a Stewart platform, a normally hefty pneumatic device that powers things like immersive flight simulators. But for this study, the researchers took the concept and shrunk it down to a 6-inch-wide device, opting for servo motors instead of pneumatic power. The machine costs just $250.
Fake patient in hand, the researchers first had a human practice cutting on it in a straight line with the da Vinci surgery robot. “We had this nice sinusoidal motion of this platform, something mimicking a heartbeat, and we expected him to follow the motion,” says UC Berkeley computer scientist Sanjay Krishnan. “Instead he would wait for the platform to return to a certain position and then do something really quickly, and then wait again.” Meaning, instead of constantly cutting, the surgeon waited for the machine to reach a lull, then cut.
The researchers took the data from watching the surgeon's movements and developed algorithms that could mimic his strategy for cutting along a line. They also developed algorithms for cutting continuously, without waiting for lulls. “If you were to design an algorithm to exactly track the motion, first it fails a couple times where it outright misses the line,” says Krishnan. This method of continuously cutting is also more than twice as inaccurate as what the surgeon demonstrated. (The system can also grab grains of rice off the platform, by the way, as you can see above.)
But the surgeon’s way does come at a cost: For the robot it’s about twice as slow as constantly cutting because the algorithm is waiting to time its cuts right. Good news, though: one of the great promises of robotics is the potential for speed. Algorithms will only get better, as will the capabilities of the hardware.
Surgery robots won’t just have to worry about the body’s natural motions, either. Breathing lungs and beating hearts produce relatively consistent motions compared to, say, a nurse bumping the patient while the robot is working. That’s a particularly pressing problem because these robots wouldn’t be designed to replace surgeons, but to work alongside them. “I don't think we'll ever replace surgeons,” says UC Berkeley roboticist Ken Goldberg, who helped develop the new system. “I don't want to overstate this at all, but I think it's a step toward being able to do more subtasks in more realistic settings.”
To do more subtasks, a surgery robot would have to get more flexible. For example, it’d need to eyeball different kinds of tissues that transform as the procedure progresses. “In surgery, you’re not only dealing with deformable objects, where they sort of change shape, they change color, all sorts of things based on how your camera is looking at them,” says Krishnan. Context is paramount—training the machines to parse a dynamic environment.
And even if robots are up to the challenges of such a sensitive job, their creators will have to convince surgeons that they need the machines. “Surgeons by definition, we're creatures of habit,” says pediatric surgeon Peter Kim, who studies surgical robots. “At the same time under the pretext of wanting what's best, what's safest for the patient, we tend to be somewhat conservative.”
“I think as we gain more and more confidence and trust in these technologies, we will accept that yes, we will work with the machines,” Kim adds. “And possibly in the not too distant future the machines will do significant parts of it and do it better.”
For now, though, the robots remain in the early days of medical school. But if you’re a piece of gauze, at least, the doctor is in.
More medical robots
—A soft robot that fits around the heart helps the organ keep pumping.
—Few procedures are as precise as ear surgery, but this medical robot can help.
—Here's an idea: Why don't we make mini medical robots squirm like maggots?
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