In Vitro Comparison of a Disposable Flexible Ureteroscope and Conventional Flexible Ureteroscopes

Purpose: We compared and evaluated the objective characteristics (deflection characteristics, field of view and flow rate) of a disposable flexible ureteroscope and 6 established, commercially available flexible ureteroscopes. Material and Methods: Six commonly used ureteroscopes, including Olympus™ URF-P3, Storz® 11278AU and 11274AAU, ACMI™ DUR™-8 Elite and DUR-8, and Wolf 7331.001 (Richard Wolf Medical Instruments, Vernon Hills, Illinois), were compared with the recently introduced SemiFlex Scope™ disposable flexible ureteroscope. Specifications and purchase costs were acquired from each manufacturer. The disposable ureteroscope consisted of a reusable eyepiece and a semiflexible shaft with a 3.3Fr working channel. Active tip deflection was measured with and without the 3Fr basket, the 365 μm laser fiber and the 3Fr forceps. The flow rate and field of view of each scope were evaluated. Results: Active tip deflection (down/up) was highest in the disposable ureteroscope at 300/265 degrees. Although deflection was decreased by inserting the different endoscopic tools in all ureteroscopes, the disposable ureteroscope had the highest loss in flexion characteristics (35.7% down and 39.3% up). The flow rate, measured at 25 ml per minute in the disposable ureteroscope, was significantly lower than that of other ureteroscopes. The disposable ureteroscope had a 72-degree field of view, comparable to the optical characteristics of the other scopes. Compared to the other 6 flexible ureteroscopes the purchase price of the disposable scope was significantly lower and no further maintenance/repair expenses were required. Conclusions: The disposable flexible ureteroscope has acceptable active tip deflection, field of view and flow rate compared to those of other flexible ureteroscopes on the market. Further evaluation of surgical outcomes will help delineate the definitive usefulness of the disposable flexible ureteroscope.