THE EFFECT OF KNOT GEOMETRY ON THE STRENGTH OF LAPAROSCOPIC SLIP KNOTS

Objective: To evaluate and compare the strength of six different knot geometries used in laparoscopic slip knots. Methods: The strength of s ix extracorporeal slip knots used in laparoscopic surgery was measured using a tensiometer. Two multiple-throw laparoscopic square knots (th e intracorporeal two-turn flat square knot and the extracorporeal slid ing square knot) were used as controls. Each knot type was tied five t imes, and each type was tied in random order by the same primary and a ssisting surgeons using a laparoscopic pelvic surgery training model. One-way analysis of variance was performed to detect significant diffe rences in knot strengths, and the variability in knot strength for eac h knot type was determined by Tukey's multiple comparison. test. Resul ts: A statistically significant effect for knot geometry was identifie d. The mean knot strengths +/- standard deviation (SD), measured in ne wtons, from strongest to weakest, were: 4S knot (28.01 +/- 11.45), fis herman's knot (22.45 +/- 6.89), modified Roeder knot (19.86 +/- 9.30), Roeder knot (15.77 +/- 7.02), Weston knot (7.28 +/- 7.96), and Duncan knot (6.55 +/- 0.95). The mean knot strengths for the multiple-throw control square knots were as follows: intracorporeal two-turn flat squ are knot (41.21 +/- 2.69) and extracorporeal sliding square knot (27.8 1 +/- 16.27). The intracorporeal two-turn flat square knot (control) w as significantly stronger (P < .05) than all slip knots except the 45 and fisherman's knot. Conclusion: The 4S and fisherman's knots are the strongest laparoscopic slip knots and are the only slip knots similar in strength to multiple-throw square knots.