In Vitro Comparison of the Mechanical and Optical Characteristics of the Storz Flex-X^C1 Single-use Ureteroscope and the Storz Flex-X^C Reusable Flexible Ureteroscope

Objective: This study compared the mechanical and optical characteristics of the Storz Flex-X^C1 single-use ureteroscope and the Storz Flex-X^C reusable flexible ureteroscope. The mechanical parameters comprised the upward/downward deflection, loop diameter, and irrigation flow rate. The optical parameters were image resolution and color representation. Materials and Methods: We conducted an in vitro evaluation of two Karl Storz flexible ureteroscopes. Specifically, we examined the Storz Flex-X^C1 single-use and Storz Flex-X^C reusable scopes for upward/downward deflection angles, loop diameter, irrigation flow rates, image resolution, and color representation. The Storz Professional Image Enhancement System was also applied. Results: The Storz Flex-X^C reusable ureteroscope achieved greater upward/downward deflection angles than did the Storz Flex-X^C1 single-use ureteroscope when a 200 µm laser or a 1.9 Fr tipless basket was used, with mean differences of 1.9°‒2.2° and 2.3°‒5.6°, respectively. No clinically significant difference in loop diameter was found. The Storz Flex reusable scope achieved a higher irrigation flow rate with an empty working channel (mean difference of 2.25 ml/min). Both scopes demonstrated identical image resolutions in air and in a normal saline solution, but the Storz Flex single-use device showed superior color representation. Conclusion: The Storz Flex-X^C reusable flexible ureteroscope displayed slight advantages in terms of the deflection angle and irrigation flow rate. The Storz Flex-X^C1 single-use flexible ureteroscope offered improved color representation and marginally better resolution in saline.