Suturing under tension in minimally invasive surgery: A comparison of three intracorporeal knot types

Abstract Purpose Intracorporeal knot tying (ICKT) and suturing under tension are essential skills for performing advanced minimally invasive surgery (MIS) procedures. Over recent years, various intracorporeal knot types with specific properties have been developed. The classical surgical square knot (CSK) continues to be used as the standard knot in MIS. Previously published studies suggested that the security of the surgical square knot improves when the knot throw combination is adjusted from four wraps (2W1W1W) to five wraps (3W1W1W). Additionally, the intracorporeal slipping knot (SLK) has been found to be superior to the CSK in sutures under tension. This study aimed to compare ICKT of the CSK, a modified square knot (MSK) and the SLK during simulated suture placement under tension. Methods A laparoscopic box trainer and a standardized silicone suture pad was utilized for ICKT. The participants consisted of medical students, surgical residents and senior physicians. A standardized video demonstrating the ICKT variants was shown to all participants before evaluation. The procedural implementation, knot quality, total task time and accuracy were evaluated. Results A total of 267 knots were included in the study. Compared to the CSK, the MSK showed significantly better results across the entire group in terms of time, knot quality, and procedural implementation score.  Conclusion In the evaluation of all participants’ knots, the MSK showed significantly better results for all variables except accuracy compared to the CSK. The MSK showed similarly good results to the SLK. Both the MSK and SLK appear particularly well-suited for tension sutures.