First autonomous robot to operate on soft tissue outdoes human surgeons

Step aside, Ben Carson. The once lauded ability to perform delicate operations with gifted hands may soon be replaced with the consistent precision of an autonomous robot. And—bonus—robots don’t get sleepy.

In a world’s first, researchers report using an autonomous robot to perform surgical operations on soft tissue and in living pigs, where the adroit droid stitched up broken bowels. The researchers published the robotic reveal in the journal Science Translational Medicine, and they noted the new machinery surpassed the consistency and precision of expert surgeons, laparoscopy, and robot-assisted (non-autonomous robotic) surgery.

The authors, led by Peter Kim at Children’s National Health System in Washington, DC, emphasized this feat is not intended to be a step toward completely replacing surgeons. Rather, they want the technology to provide new tools that help every operation go smoothly. “By having a tool like this and by making the procedures more intelligent, we can ensure better outcomes for patients,” Kim said.

Kim and his colleagues aren’t the first to use robotics or even autonomous robots in surgery, of course. But non-autonomous robots have yet to offer the quality assurance for every operation that doctors and engineers had hoped for. And autonomous robots have so far only made themselves useful for digging into rigid body parts, such as bones, while historically failing with slippery, wiggly soft tissue. Those squishy innards pose a particular challenge to autonomous robots because they easily move around and look alike, making it difficult for the machinery to keep track of and manipulate all the bits and slices.

To get around the problem, Kim and his team started with preexisting autonomous robots, which look much like a mechanical arm, and added new imaging features. The new robot is called STAR, for Smart Tissue Autonomous Robot, and it includes a 3D visual tracking system and a custom near-infrared fluorescent (NIRF) imaging system. The 3D system works by having an array of microlenses that triangulate the spatial position of every pixel in an image. And the NIRF system allows the robot to precisely spot and track the tissue in need of surgical work using luminescent markers—those glowing tissue tags are added by doctors prior to the surgery.

With the spatially informed robot, the researchers next boosted the machine’s dexterity by adding an articulated suturing tool, with eight degrees of freedom, that can sew up tissue in tight spaces. They also added an extra sensor that ensures the proper tension for each stitch and fed the robot a suturing algorithm based on expert techniques.

In tests with out-of-body tissues, STAR met or exceeded the performance of other surgical methods in terms of metrics like needle placement, stitch spacing and tension, the number of mistakes, and the potential for the seam to leak. It’s like a “smart sewing machine,” Kim jokes.

In a test on four live pigs, STAR successfully reconnected sliced intestines, a procedure generally called anastomosis. Such a procedure for joining tubular body parts is used in operations like reconstructive bowel surgery and blood vessel repair.

Despite its accuracy, STAR took considerably longer to perform the anastomosis than a human surgeon, averaging around 50 minutes, while a live doctor took about eight minutes. The authors explain that they took their time during the initial tests, which they liken to parents cautiously watching their child learn to walk.

This is a proof-of-concept, Kim said. It will likely be years before STAR shows up in a real operating room, but autonomous robotic soft tissue surgery is on the horizon.