Comparison of optics and performance of single channel and a novel dual-channel fiberoptic ureteroscope

Objective: To evaluate performance characteristics and optics of a novel dual-working channel fiberoptic ureteroscope (Wolf Cobra) with 2 single-channel fiberoptic ureteroscopes and to a single-channel distal sensor standard definition digital ureteroscope URF-V (SD-DS).

Methods: Four new ureteroscopes (Cobra, Viper, X(2), and SD-DS) were compared for active deflection, irrigation flow, and optical characteristics. We performed a porcine ureteroscopy and measured the time for cleaning the middle calyx after injection of 10 cc of a standardized bloody solution.

Results: The SD-DS showed a higher resolution (7.42 lines/mm; P = .0001) compared with the fiberoptic ureteroscopes; among the fiberoptic ureteroscopes, the Cobra had the highest resolution than the Viper and X(2) (P = .0001). Grayscale distribution and color representation were identical for the fiberoptic ureteroscopes, whereas the SD-DS provided a superior color representation and a significant higher depth of field. The Cobra provided superior flow with empty working channel (86 cc/min vs 68 cc/min [Viper] vs 62.5 cc/min [X(2)] vs 62 cc/min [SD-DS]; P = .0001) and with various accessories (P <.0001). With regard to deflection, the Storz X(2) and the Cobra provided superior deflection up and down (P <.0001). When evacuating a standardized bloody field, the Cobra provided significant shorter evacuation times compared with those of the Viper, X(2), and SD-DS (36.6 vs 72 vs 65.6 vs 72.6 seconds, respectively; P = .0001).

Conclusion: The additional working channel of the Wolf Cobra may improve vision and performance during challenging ureteroscopic cases by providing an increased flow. The enhanced irrigation capabilities of the Cobra have to be balanced with a larger diameter of this ureteroscope.