Abstract
Introduction: Flexible ureteroscopy (fURS) is widely recognized as an effective treatment for ureteral or renal stones. The used of flexible urinary endoscopy provides an effective treatment for ureteral stones, and the development of vacuum suction ureteral access sheaths has significantly improved the stone clearance rate. Our experimental aim is to prove the effectiveness of negative suction ureteral access sheath on decreasing intraluminal pressure in various settings, utilizing by stimulating an in vitroflexible ureteroscope model. Methods: An 8.6Fr disposable flexible ureteroscope was used to measure intraluminal pressure through a manufactured silicone urinary model using 3D printing technology. We conducted on three settings use of ureteral access sheaths (UAS), which are (1) conventional UAS, (2) negative pressure suction sheath with an open vent, and (3) negative pressure suction sheath with a fully closed vent. Intrarenal pressure and irrigation flow rate were recorded on various sizes of UAS under irrigation pressures ranging from 10 to 240 mmHg. Results: Under different infusion pressure conditions, the negative pressure sheath with an opened vent demonstrated marginally lower intraluminal ureteral pressure than the traditional sheath, but this difference was not statistically significant (P = 0.56). In contrast, when employing the closed vent method, the negative pressure aspiration sheath shwed a notably significantly distinct intraluminal pressure change from the traditional sheath and its opened vent mode (P < 0.01). Additionally, The choice of ureteral sheath size profoundly impacted intraluminal pressure; larger sheath sizes were associated with more reduced pressure levels under the same infusion pressure (P < 0.01). Conclusions: In ureteroscopy procedures, the intraluminal pressure in the ureter increases with the rise in irrigation pressure. However, applying negative pressure with a closed vent can effectively reduce the intraluminal pressure.