New robotic arm can perform soft tissue surgery

Scientists have developed a robotic arm that can precisely stitch together soft tissues, an advance that may improve surgery outcomes for patients and make the best surgical techniques more widely available.
Researchers at the Johns Hopkins University in the US showed that a robot surgeon can adjust to the subtle movement and deformation of soft tissue to execute precise and consistent suturing.
Soft tissue can move and change shape in complex ways as stitching goes on, requiring a surgeon's skill to respond to these changes and keep suturing as tightly and evenly as possible.
The research involved suturing two structures. The procedure is called anastomosis, meaning joining two tubular structures such as blood vessels.

Complications such as leakage along the seams occur nearly 20 per cent of the time in colorectal surgery and 25 to 30 per cent of the time in abdominal surgery, researchers said.
Robotic soft tissue surgery promises substantial benefits through improved safety from reduction of human errors and increased efficiency due to procedure time reduction, they said.

However, the surgery can be tricky for a robot to adjust to the soft tissue's slips and squirms during suturing.
To perform the experiment, the researchers developed a robotic surgical system called the Smart Tissue Autonomous Robot, or STAR.
It features a 3D 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.

The STAR robotic sutures were compared with the work of five surgeons completing the same procedure using three methods: open, laparoscopic and robot-assisted surgery.
Researchers compared consistency of suture spacing, pressure at which the seam leaked, mistakes that required removing the needle from the tissue or restarting the robot, and completion time.
The robot's time was longer than open and robot-assisted surgery, but comparable to the laparoscopic procedure. The robotic procedure lasted 35 to 57 minutes, while the open surgery took eight minutes.
By all other measures, the robot's performance was comparable to or better than the surgeons'.
"No significant differences in erroneous needle placement were noted among all surgical techniques, suggesting that STAR was as dexterous as expert surgeons in needle placement," researchers said.

The intent is not to replace surgeons, but to "expand human capacity and capability," they said.
The study was published in the journal Science Translational Medicine.