Translation. Region: Russian Federation –
Source: People's Republic of China in Russian – People's Republic of China in Russian –
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Source: People's Republic of China – State Council News
HANGZHOU, November 30 (Xinhua) — "Why not tie a slip knot?" a professor at the Center for Cross Mechanics suggested to surgeons at a laboratory at Zhejiang University (Zhejiang Province, east China).
This innovation, which recently seemed too simple, has now turned into a cover story in Nature called “The Precision Knot,” offering a potential solution to a persistent problem in robotic surgery: how to close a wound with precisely the right amount of force.
In robotic surgeries, surgeons typically lose the tactile feedback, or "feel," they rely on in traditional open surgery to determine how tightly to tighten a suture knot. A loose knot can lead to leaks, while an overly tight knot can block the blood supply, leading to tissue damage.
Instead of developing complex electronic sensors, an interdisciplinary team from Zhejiang University drew inspiration from fundamental mechanics. Their solution, dubbed "Sliputure," is a special suture with a pre-tied slip knot.
The technology operates on a very simple principle. The sliding knot is designed to release at a specific force. When the surgical robot tightens the suture, the sliding knot is held until the precise optimal force is reached, after which it is released.
According to the study, this same action transfers a certain force to a surgical permanent knot that is tied nearby, so the robot stops only when the correct tension is applied.
"If a slipknot is connected to a deadknot on the same seam, they can share the tensile load," said Li Tefeng, one of the study's authors.
The team fabricated 500 slip knots, collected data from surgeons of all skill levels, using a variety of materials and styles, and then modeled and braided hundreds of sutures, each with its own unique knot that opened under a specific load. The slip knot mechanism demonstrated remarkable stability, with a 95.4% accuracy rate out of 100 trials.
In surgery, surgeons are allowed to choose the knot that best suits their needs. A study showed that the invention allowed novice surgeons to improve knot tying accuracy by 121 percent and tie knots indistinguishable from those of experienced surgeons.
During intestinal surgery on mice, the device clamped each knot with a force of 1.3 newtons, half that of an uncontrolled robot with its 2-3 newtons, eliminating leaks without blocking blood flow and accelerating healing.
In a rat colon injury model, the group receiving the "smart" suture achieved normal healing two days earlier than the control group and demonstrated a more abundant blood supply. For the surgical robotics, the team added a vision-based recognition feature: when the camera detected loosening of the sliding knot, the robotic arm automatically stopped, without any additional equipment.
The innovation is valuable for its simplicity and reliability. Unlike sensor systems, it requires no electricity, complex electronics, or computer algorithms, making it potentially cheaper, easier to sterilize, and suitable for use in challenging environments, such as remote areas and even deep-sea or space missions.
The team also built a fully automated patch knot production line that produces identical, shelf-ready stitches at scale. -0-
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