Abstract
Purpose :
Despite the frequency and importance of corneal suturing by ophthalmologists, there is a paucity of data comparing the tensile strength of these knots. This study aims to compare the tensile strength of the slipknot versus surgeon’s (3-1-1) knot using 10-0 nylon sutures.
Methods :
Initial testing of cadaveric phakic eyes was performed by closing a 5mm linear full-thickness corneal wound with either a slipknot or surgeon’s knot using 10-0 nylon suture material. Burst pressure was measured using a cardiac transducer inserted into the vitreous cavity and defined as the intraocular pressure (IOP) at suture failure after constant infusion of saline solution via a 25-gauge needle into the anterior chamber (Fig 1). Follow-up testing of tensile suture strength was performed using a digital force tensiometer. A loop of suture was tied around a tuberculin syringe and the loop was gently removed and mounted on a stand with the tensiometer. Tensile testing was performed at a rate of 0.25mm/s on each type of knot and ultimate tensile strength was measured as the maximum load just prior to knot failure (Fig 2). Light microscopy was used to analyze the site of suture failure. All suture knots were tied by an experienced corneal surgeon and outcome assessors were blinded to each knot type.
Results :
6 cadaveric eyes (3 slipknot, 3 surgeon’s knot) were obtained to assess burst pressure. Minor aqueous leakage through the wound was observed in all cadaveric eyes however both suture knots did not fail despite measured IOP over 300mmHg. A total number of 50 knots (25 surgeon’s knot, 25 slipknot) were tied for tensile testing. The ultimate tensile force upon breakage was higher in the surgeon’s knots compared with that in slipknots (0.75 vs. 0.59 N, p = 0.02). After tensile testing, light microscopy revealed that within the collected slipknot sutures (n=8), 3 unraveled and 5 experienced breakage. Of collected surgeon’s knot sutures (n=11), 2 had unraveled and 9 experienced breakage.
Conclusions :
Surgeon’s knots provide higher tensile strength compared to slipknots in an experimental model. However, when properly tied, both types of knots provide excellent strength, but it is unclear if this difference is clinically relevant with in vivo conditions.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.