(016) ONE CLICK OR THREE: THE IMPACT OF CLAMPING FORCE ON UROLOGIC PROSTHESIS TUBING

Abstract Introduction It is a well-established guideline that urologic prosthesis tubing (UPT) should be clamped with a rubber-shod hemostat (RSH) using a single click to minimize potential damage. This recommendation is specifically emphasized in the instructional materials provided by implant manufacturers. However, in practice, tubing is sometimes clamped with multiple clicks. Additionally, there is considerable variability in hemostat brands, models, and the pressures they exert. This variability has led our group to investigate the impact of clamp pressure on UPT integrity, particularly when heavier hemostats, multiple clicks, or unshodded clamps are inadvertently used. Objective To evaluate the effect of RSH technique and pressure variability between surgical instruments on UPT integrity, we conducted in-vitro UPT stress tests under various conditions. Methods Boston Scientific kink-resistant tubing was trimmed to a standard length of 23 cm before being randomly sorted into one of four groups: control, RSH one-click, RSH three-click, or bare hemostat one-click. UPT segments were filled with dyed water to improve leak detection. Both ends of the UPT were secured into 10 cm loops with a wire rope clip to allow for the application of linear force. A 3 cm experimental section was left between each loop. All experimental groups were clamped for 60 seconds in the center of the experimental section at the point of intervention (POI). Linear tension was applied to the tubing, beginning at 0 newtons (N), and increased at a rate of 19.8 +/- 1.4 N/min (2 kg/min of downward force) until the UPT separated into 2 pieces. Force at the time of failure (FF), location of the tear, and incidence of leakage before tearing were recorded. Analysis of variance and Chi-squared test were used for analysis of FF and location of separation between groups, respectively. Scanning electron microscope (SEM) images were captured to subjectively evaluate for UPT damage from each intervention. Results The protocol was completed 10 times per group (40 total). Median FF was 99.4 N (range: 79.9-106.5), 104.8 N (range: 78.1-111.0), 97.2 N (range: 74.6-106.5), and 98.1 N (range: 87.9-107.4) for control, RSH one-click, RSH three-click, and bare hemostat one-click, respectively (P = 0.34). Tear location appeared random for all groups other than the bare hemostat one-click group, which tore at the POI in 6 of 10 (60%) experiments (p = 0.000082, Fig. 1). Only the bare hemostat one-click intervention caused leaking before a complete tear in 2 of 10 (20%) experiments. On SEM imaging, the bare hemostat damages the surface of the UPT while there is no appreciable difference between the remaining groups (Fig. 2). Conclusions The durability of UPT is not significantly compromised by RSH clamp pressures; however, bare hemostats cause surface damage, resulting in a loss of material integrity. Although minimal clamp pressures are advised, applying 2-3 clicks with an RSH may not constitute a significant surgical error. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Coloplast Corporation; Boston Scientific Corporation.