RT Journal Article
SR Electronic
T1 How to tie dangerous surgical knots: easily. Can we avoid this?
JF BMJ Surgery, Interventions, & Health Technologies
FD BMJ Publishing Group Ltd
SP e000091
DO 10.1136/bmjsit-2021-000091
VO 3
IS 1
A1 Eric Drabble
A1 Sofia Spanopoulou
A1 Eleni Sioka
A1 Ellie Politaki
A1 Ismini Paraskeva
A1 Effrosyni Palla
A1 Lauren Stockley
A1 Dimitris Zacharoulis
YR 2021
UL http://sit.bmj.com/content/3/1/e000091.abstract
AB Objective Secure knots are essential in all areas of surgical, medical and veterinary practice. Our hypothesis was that technique of formation of each layer of a surgical knot was important to its security.Design Equal numbers of knots were tied, by each of three groups, using three techniques, for each of four suture materials; a standard flat reef knot (FRK), knots tied under tension (TK) and knots laid without appropriate hand crossing (NHCK). Each knot technique was performed reproducibly, and tested by distraction with increasing force, till each material broke or the knot separated completely.Setting Temporary knot tying laboratory.Materials The suture materials were, 2/0 polyglactin 910 (Vicryl), 3/0 polydioxanone, 4/0 poliglecaprone 25 (Monocryl) and 1 nylon (Ethilon).Participants Three groups comprised, a senior surgeon, a resident surgeon and three medical students.Outcome measures Proportion of each knot type that slipped, degree of slippage and length of suture held in loop secured by each knot type.Results 20% of FRK tied with all suture materials slipped; all knots tied with the other two techniques, with all materials, slipped, TK (100%) and NHCK (100%). The quantitative degree of slip was significantly less for FRK (mean 6.3%–, 95% CI 2.2% to 10.4%) than for TK (mean 312%, 95% CI 280.0% to 344.0%) and NHCK (mean 113.0%, –95% CI 94.3% to 131.0%).The mean length of suture in loops held within (FRK mean 25.1 mm 95% CI 24.2 to 26.0 mm) was significantly greater than mean lengths held by the other techniques (TK mean 17.0 mm, 95% CI 16.3 to 17.7 mm), (NHCK mean 16.3 mm, 95% CI 15.9 to 16.7 mm). The latter two types of knot may have tightened more than anticipated, in comparison to FRK, with potential undue tissue tension.Conclusion Meticulous technique of knot tying is essential for secure knots, appropriate tissue tension and the security of anastomoses and haemostasis effected.Data are available on reasonable request. We would be delighted to share and publish our raw data.