Benchtop comparison of seven ureteroscopes: evaluating physical properties and deflection with flexible and navigable...

To evaluate the physical properties of seven ureteroscopes (URSs) and compare the maximal angle of deflection (MAD) when used with flexible and navigable suction access sheaths (FANSs) of varying sizes.

Seven commercial URSs (ranging from 6.3 to 9.5 F in size) were evaluated for outer diameter, irrigation flow rate, image resolution, colour reproduction and MAD. MAD was measured under three conditions: standalone URS deflection without the FANS; standard deflection of the FANS while positioned at the URS tip; and advanced FANS deflection, with the URS fully deflected beyond the FANS, and the FANS advanced. For each URS type, standalone deflection was repeated five times, and FANS deflections were repeated four times to calculate an average. FANS sizes of 10/12 F, 11/13 F and 12/14 F (ClearPetra) were tested.

The HugeMed URS had the smallest scope diameter (6.3 F) and the lowest flow (20 mL/min), while the Endoso URS had the highest flow (32 mL/min). All the URSs had similar resolutions except the MacroLux, Seegen and Endoso URSs, which were noticeably superior in this respect. Colour reproduction was best with the MacroLux and Endoso URSs. Without a FANS, the standalone mean MAD across all URS types was 293°. Standard deflection with FANS significantly decreased the MAD (up to a 49% reduction), whereas advanced deflection maintained the MAD (up to 269°). Larger FANS, especially the 12/14-F size, tended to reduce deflection. The MacroLux URS maintained the highest MAD across all FANS sizes, followed by the Seegen and Urotech devices.

Ureteroscope deflection significantly varied by model. Use of a FANS reduced deflection angles, especially with larger sheaths. However, advancing the FANS over a deflected scope preserved deflection angles. Overall, the MacroLux URS showed the best deflection with FANS, whereas the Seegen, Endoso and Urotech URSs showed a balance between flow rate, optics and deflection. These findings could inform clinicians in their selection of a URS for endourology procedures.