Effect of Conventional Versus Flexible and Navigable Suction Ureteral Access Sheaths on Ureteral Temperature Modulation During High-power Ho:YAG Laser Lithotripsy: An In Vitro Evaluation

Background and objective: Ureteral thermal injury during high-power laser lithotripsy with holmium:yttrium-aluminum-garnet (Ho:YAG) laser has become a clinical concern. We evaluated the influence of irrigation flow rates on ureteral temperature profiles during high-power Ho:YAG lithotripsy in an in vitro model. Methods: A customized silicone model of the urinary tract was used to simulate retrograde intrarenal surgery. A 6-mm stone was fixed 3 cm below the model ureteropelvic junction and treated with Ho:YAG laser at 6 W (0.6 J/10 Hz), 12 W (0.6 J/20 Hz), or 24 W (0.6 J/30 Hz) for 40 s. Steady irrigation at 30-60 ml/min was maintained via an automated irrigation system. We evaluated conventional ureteral access sheath (C-UAS) and flexible and navigable suction UAS (FANS) options in four sizes (10/12 Fr, 11/13 Fr, 12/14 Fr, 13/15 Fr). Temperature data were captured via four thermometer probes. Statistical analyses were performed using two-way analysis of variance (device × flow interaction test), with multiplicity controlled using Tukey's honestly significant difference test. Key findings and limitations: A higher flow rate and use of suction via FANS significantly reduced the elevation in ureteral temperature during laser application. At