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Jimmy Yan Hu, Anurag Shrivastava, Roy S Chuck, Joann Kang; A novel experimental model for the comparison of tensile suture strength of various ophthalmic sutures and knots. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4339.
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© ARVO (1962-2015); The Authors (2016-present)
Data comparing the tensile suture strength and the effect of knot tying techniques in ophthalmic surgery has been scarce. To our knowledge, there is no previously described or established method to quantitatively measure the strength of sutures used in ophthalmic surgery (sutures smaller than 7-0) in the literature. Here we describe a novel experimental model to investigate and compare the tension-at-failure of several common knot types for several common ophthalmic sutures.
In this in vitro experiment, a selection of commonly used ophthalmic sutures of varying materials (Vicryl, Nylon, Prolene, Silk) and of varying sizes (from 10-0 to 6-0) were tied using surgeon’s knots, square knots, and 3-1-1 knots. A digital force gauge was used to measure the tension (measured in Newtons, N) at failure of the knots being investigated for each type of suture. For each measurement, a 4cm length of suture wire was tied in loop around a jig and subsequently soaked in warmed 0.9% sodium chloride solution for 60 seconds to mimic in vivo conditions. The tied suture was then immediately transferred to the measurement apparatus (see Figure 1), connecting the digital force gauge oriented above a secured hook. The digital force gauge was then raised upwards lengthening the suture while continuously measuring load until failure occurred. Failure was defined as breakage of the suture or any tail slippage. Tension at failure was defined as the tensile force (N) measured at failure. Measurements were made in triplicate. Standard error was measured by two-tailed t-test.
Expectedly, we found that the overall smaller diameter sutures were weaker regardless of the type of knot used. Furthermore, the suture material had a marked difference in the tension of failure. All sutures had a tension at failure of less than 5N.
Here we report a novel experimental model to perform the first quantitative comparison of suture strength of different suture types in an ophthalmic setting. Expectedly, suture material has a notable effect on overall tensile strength. More notably, the increased friction on the suture may affect the overall tensile strength of the suture, and should be taken into consideration by surgeons when placing sutures in varied and myriad applications.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Figure 1: A tied suture was connected to the digital force gauge oriented above a secured hook.
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