In Vitro Evaluation of Single-Use Digital Flexible Ureteroscopes: A Practical Comparison for a Patient-Centered Approach

Objective: To compare the manufacturing and in vitro performance characteristics of two single-use flexible ureteroscopes with a permanent optical flexible ureteroscope.

Materials And Methods: Two single-use flexible ureteroscopes, LithoVue (Boston Scientific) and Pusen (1rs. generation; Zhuhai Pusen Medical Technology Company Limited, China), were tested and compared with a permanent Flex-X ureteroscope (Karl Storz, Germany) in terms of technical characteristics, optics, deflection mechanism, and additional parameters which could potentially affect surgical technique.

Results: Pusen was the lightest ureteroscope while the LithoVue had the longest working length. LithoVue had a higher resolution power than the other two ureteroscopes at all distances tested (p < 0.001). Pusen showed higher resolution than Flex-X (p < 0.01). Field of view was wider for LithoVue (87°), followed by Flex-X (85°) and Pusen (75°). Color representation was superior for Flex-X than LithoVue and then Pusen. LithoVue outperformed Pusen and Flex-X for all settings with instruments in terms of deflection loss (p < 0.01). Pusen had the highest irrigation flow (52 mL/min) with an empty working channel (p < 0.01). LithoVue and Pusen showed similar flow rates with a 200 μm (21 mL/min) and 365 μm laser fiber (7 mL/min) and 1.3F basket (18 mL/min), being superior to Flex-X (p < 0.01). With the 1.9F basket, LithoVue had superior flow rate (7 mL/min) than Pusen (3.5 mL/min) and Flex-X (4 mL/min; p = 0.01).

Conclusion: LithoVue outperformed the other ureteroscopes in terms of optical resolution, field of view, deflection capacity, and irrigation flow with larger instruments. Pusen is the lighter scope and showed better results in terms of irrigation when no instruments are in place. Flex-X was superior in terms of color representation.