title: Comparison of the mechanical, flow, and optical properties of contemporary flexible ureteroscopes.
abstract: OBJECTIVE
  New designs have improved the ability of flexible ureteroscopes to assess the upper urinary tract. However, limitations of tip deflection may interfere with diagnosis and treatment of lower pole renal pathologic features and smaller working channels may impair irrigant flow. Our purpose was to compare the new flexible ureteroscopes with prior models to determine whether engineering advances have overcome these problems.
  
  
  METHODS
  Two newly released flexible ureteroscopes, the ACMI DUR-8 Elite and the Storz 11278AU, were compared with four other ureteroscopes, the ACMI DUR-8, Storz 11274AAU, Olympus URF-P3, and Wolf 9F. Active tip deflection, irrigation flow rates, and intraluminal pressures with and without various endoscopic tools were assessed. The specifications, purchase prices, and repair costs were obtained from the individual manufacturers. Also, the field of view and screen image size of each scope were compared.
  
  
  RESULTS
  The ACMI DUR-8 Elite and Storz 11278AU had improved tip deflection of 79 degrees and 144 degrees, respectively, from previous ureteroscopes. Although the tip deflections of all ureteroscopes were compromised by the insertion of endoscopic tools, new ureteroscopes were less affected. With a 3F basket within the working channel, the ACMI DUR-8 Elite and the Storz 11278AU had a loss of downward deflection of only 0.7% and 2.8% compared with a loss of 9.6% and 5.0% for their older models, respectively. However, the flow rate of these new instruments was decreased.
  
  
  CONCLUSIONS
  The new flexible ureteroscopes have significantly better active tip deflection than previous models, both with and without endoscopic instrumentation inserted. However, improved flexibility comes at the expense of a decreased flow rate.
authors: Department of Urology, Long Island Jewish Medical Center, New Hyde Park, New York 11040, USA.
authors: Kun-Yuan
authors: KY
authors: Chiu
authors: Yi
authors: Y
authors: Cai
authors: Robert
authors: R
authors: Marcovich
authors: Assaad
authors: A
authors: El-Hakim
authors: Arthur D
authors: AD
authors: Smith
authors: Benjamin R
authors: BR
authors: Lee
mesh_terms: D004867:Equipment Design; D055095:Optics and Photonics; D018583:Pliability; D012212:Rheology; D007507:Therapeutic Irrigation; D020709:Ureteroscopes / Q000191:economics