title: Towards a better knot: Using mechanics methods to evaluate three knot-tying techniques in laparo-endoscopic single-site surgery.
abstract: BACKGROUND
  Knot tying is difficult but important for laparo-endoscopic single-site surgery (LESS). There are several techniques for LESS knot-tying. However, objective assessment of these skills has not yet been established. The aim of this study was to assess three different knot-tying techniques in LESS using mechanical methods.
  
  
  METHODS
  The subject tied 24 knots, eight knots with each of the three techniques in an inanimate box laparoscopic trainer while the movements of their instruments were evaluated using a LESS mechanical evaluation platform. The operations were assessed on the basis of the time, average load of the dominant hand. Then, forces caused the knots to rupture were measured using a material testing system and used to compare the knots's strength.
  
  
  RESULTS
  The intracorporeal one-hand knot-tying technique presented significantly better time and average load scores than the extracorporeal knot-tying technique (P < 0.01), and the intracorporeal side winding technique was more time and average load consuming in comparison to other techniques during the performance of knot-tying (P < 0.01). The intracorporeal one-handed knot-tying knots can tolerate better distraction forces compared with the intracorporeal side winding knot-tying knots and the extracorporeal knot-tying knots (P < 0.05).
  
  
  CONCLUSIONS
  The intracorporeal one-hand knot-tying technique and knots showed better results than the intracorporeal "side winding" technique and the extracorporeal knot-tying technique in terms of the time, average load taken and the force caused the knot to rupture.
authors.affiliation: Department of Minimally Invasive Surgery, East Hospital, Tongji University, School of Medicine, Shanghai 200120, China.
authors.forename: An An
authors.initials: AA
authors.lastname: Xu
authors.affiliation: Department of Minimally Invasive Surgery, East Hospital, Tongji University, School of Medicine, Shanghai 200120, China.
authors.forename: Jiang Fan
authors.initials: JF
authors.lastname: Zhu
authors.affiliation: Department of Minimally Invasive Surgery, East Hospital, Tongji University, School of Medicine, Shanghai 200120, China.
authors.forename: Yuantao
authors.initials: Y
authors.lastname: Su
keywords: Knot-tying techniques; laparo-endoscopic single-site surgery; objective assessment