Imagine this scenario: A surgeon is set to suture pieces of soft tissue on a patient, but instead of doing the whole procedure by himself, he turns to a surgical robot for assistance.

This picture may indeed become reality in the not-to-distant future, thanks to a team of researchers from Children’s National Health System and Johns Hopkins University. The scientists, whose work was recently published in Science Translational Medicine, have developed a robot surgical system, dubbed the Smart Tissue Autonomous Robot, or STAR.

Suturing soft tissue presents a challenge for surgeons in that the tissue can move and change shape in complex ways. Surgeons must be skilled enough to respond to these changes and suture as tightly — and evenly — as possible. The researchers found that a robot surgeon can adjust to the subtle movement and deformation of soft tissue to perform precise and consistent suturing.

So, how does STAR work? STAR has a 3-D imaging system and a near-infrared sensor to spot fluorescent markers along the edges of the tissue to keep the robotic suture needle on track.

Simon Leonard, assistant research professor at Johns Hopkins University, who worked with five co-authors, said the team started working on the project four years ago with lead investigator, and surgeon, Dr. Peter Kim.

“Robots have taken a lot of the work on assembly lines because they can repeat the same task with the same amount of quality. Most of the time the quality is good,” Leonard said.

“The idea behind the robot was to bring this idea into the surgical environment, where a robot could do something with the same level of consistency with good quality, and reduce the amount of variability that can be found among surgeons. The main reason was obviously to have good outcomes, but also to have consistent outcomes across different patients and different procedures,” Leonard explained.

Emphasizing that bones are rigid — and therefore easier to work with than soft tissue — Leonard said that soft tissue can compress, expand, or stretch. “This is something that is challenging for people who have been working with surgical robots for a long time. The amount of formation is very complex,” he said.

“In order for robots to interact with these tissues, you need to be able to know what the current state of the tissue is. Is it open, or closed?”

The researchers addressed this problem by using markers. “We were essentially suturing intestines back together,” Leonard said.

“To accurately detect the edges of the intestines, we put little drops of liquid, like glue, on the rim, or the edges of the intestine. The glue has a fluorescent liquid. If you shine on that liquid glue with a special light, it will emit light in a range that we cannot see, but infrared cameras can see that light very well. It comes up as a very bright spot in the camera.  We are able to track the formations of the intestine,” said Leonard.

The markers can be used to track the formations of just about every organ of soft tissue, Leonard said, helping researchers plan where the robot needs to do stitching. “We can send the robot and put the needle at this place and the robot will make the stitch,” Leonard said.

Here’s a video news segment discussing STAR and the study:

Photo: Children’s National Health System