Tying modified clinch knots during single-incision laparoscopic surgery

Recent advances in single-incision laparoscopic surgery (SILS) have caused increased difficulties when tying knots because of the limited working space. Although extracorporeal knot-tying techniques may be a practical alternative choice in SILS, it is not always appropriate. For example, sliding resistance may be encountered when tying knots for a Z-shaped suture, and it could damage the sutured tissue.

The clinch knot is a kind of slipknot that has been historically used by fishermen. We modified it for SILS so that it has a locking mechanism caused by knot deformation. We apply pre-tied modified clinch (MC) knots in the peritoneal cavity with a needle driver. After the suture, the needle is pulled through the knot and exits out the trocar. After the MC knot has been tightened, locking is achieved by pulling the other end of the axial thread and folding the thread in an acute angle. Because both ends of the suture thread leave the trocar together, every step can be carried out quickly through a single trocar. The MC knot can also be used to tie knots for Z-shaped sutures because of its short sliding distance. Twelve simple interrupted sutures and 55 Z-shaped sutures were tied by MC knot in SILS. All knots were successfully tied, and the mean required time to tie a knot was 27 s.

The MC knot is feasible knot-tying procedure especially for a Z-shaped suture during SILS.