手動彎曲吸引式輸尿管導入鞘對軟式輸尿管鏡彎曲性能的影響：跨品牌比較研究

范子宣¹、林承家

基隆長庚紀念醫院 泌尿部

Effect of Manual Pre-bending of Flexible And Navigable Suction ureteral access sheath on Deflection Angle of Flexible Ureteroscopes: A Comparative Study Across Different Brands

 Tzu-Hsuan Fan¹, Cheng-Chia Lin

 Keelung Chang Gung Memorial Hospital, Department of Urology

Abstract

Purpose:

Flexible ureteroscopy commonly employs a flexible and navigable suction ureteral access sheath (FANS-UAS), which is typically used without modification after unpacking. We hypothesized that standardized manual pre-bending of the FANS-UAS may enhance the maximal deflection angle of a flexible ureteroscope, potentially improving access to difficult calyceal stones. This study aimed to evaluate the impact of manual pre-bending on ureteroscope deflection across different commercially available FANS-UAS brands and sizes

Methods

This experimental study evaluated the maximal deflection angle of a Pusen flexible ureteroscope using four commercially available FANS-UAS brands (OTU, ZSR, Clear Petra, and Innovex) in 10/12 Fr and 11/13 Fr sizes. Each sheath was tested under two conditions: direct use after unpacking and after standardized manual pre-bending. The pre-bending maneuver consisted of rotating the sheath approximately 1.25 turns (450°) in any direction and maintaining the twist for 30 seconds. Maximal deflection angles were measured under standardized conditions, and comparisons were made between pre-bending and control groups across brands and sizes.

Results:

    Across the eight flexible and navigable suction ureteral access sheath (FANS-UAS) configurations tested (four brands, two calibers), manual pre-bending consistently increased the mean maximal deflection angle (average of upward and downward deflection) when using a standardized Pusen flexible ureteroscope. Overall, the mean deflection angle increased from 162.9° without pre-bending to 194.6° after pre-bending, corresponding to a mean absolute gain of 31.7° and a mean percentage improvement of 24.2%. Innovex 10/12 Fr showed the greatest deflection both at baseline (245.0°) and after pre-bending (267.5°). The largest absolute and relative improvements were observed in OTU 11/13 Fr (+62.5°, 55.31%), whereas ClearPetra 11/13 Fr demonstrated the smallest change (+11.0°, 6.65%).

Conclusion:

    Notably, this is the first benchtop testing to propose and demonstrate that intentional pre-bending of a flexible and navigable suction ureteral access sheath can enhance maximal deflection without device redesign or additional equipment. This low-cost, reproducible technique may improve access to challenging intra-renal anatomy and warrants prospective clinical validation to determine its impact on procedural efficiency and stone-free outcomes.