title: Comparison of optics and performance of single channel and a novel dual-channel fiberoptic ureteroscope.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Achim
authors.initials: A
authors.lastname: Lusch
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Zhamshid
authors.initials: Z
authors.lastname: Okhunov
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Michael
authors.initials: M
authors.lastname: del Junco
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Renai
authors.initials: R
authors.lastname: Yoon
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Ramtin
authors.initials: R
authors.lastname: Khanipour
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA.
authors.forename: Ashleigh
authors.initials: A
authors.lastname: Menhadji
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA. Electronic address: landmanj@uci.edu.
authors.forename: Jaime
authors.initials: J
authors.lastname: Landman
mesh_terms: D000818:Animals; D004867:Equipment Design; D005336:Fiber Optic Technology; D013552:Swine; D020709:Ureteroscopes