How Reliable is Intracorporeal Laparoscopic Knot Tying?

Background: Are knots tied laparoscopically as reliable as those tied in open surgery? The aim of our study was to try to answer this question.

Materials And Methods: Using a standardized technique, one senior laparoscopic surgeon tied 3 suture materials using 3 methods of knotting: hand, instrument, and laparoscopic (in a simulator). The tension in the knots was measured using a tension gauge at the time of knotting and 5 minutes later. The surgeon was blinded to the value. The experiment was repeated 4 times. The 36 sutures were then analyzed using a materials-testing machine. The force achieved prior to breakage, the extension, and the breaking points were recorded. The scientist performing the analysis was blinded as to the method of tying and tensions produced.

Results: There were no significant differences in tension at 5 minutes between suture materials or method of knot tying. The mean extension achieved prior to breakage for 33 sutures was 29.71 mm with a force of 16.09 N. In 3 sutures the knot slipped completely while tension was being increased, thus no measure of breakage force could be obtained. These 3 sutures were monofilament and tied laparoscopically.

Conclusion: There were no significant changes in suture tension after 5 minutes regardless of material or method of knot tying. Three of the 12 knots tied laparoscopically came undone under strain testing. All 3 knots were monofilament suture. This may have important implications when choosing suture material. Further studies are planned to expand the analysis of different knotting techniques with different suture materials.