title: Alteration in irrigant flow and deflection of flexible ureteroscopes with nitinol baskets.
abstract: OBJECTIVE
  Introduction of an instrument into the working channel of ureteroscopes adversely affects flow and deflection. We evaluated the alterations in ureteroscope channel flow and deflection caused by available Nitinol(R) baskets.
  
  
  METHODS
  We compared the effects of 11 Nitinol baskets on irrigation flow and deflection of three flexible ureteroscopes (Olympus P3, ACMI DUR8, and ACMI DUR8 Elite). ANOVA was used to compare the loss of flow and deflection for each basket, with P values adjusted for multiple comparisons by the Tukey method.
  
  
  RESULTS
  Ureteroscope flow and deflection were progressively adversely affected by all baskets as their diameter increased. The average baseline irrigant flow (46.6 mL/min) was decreased significantly: by 78.5% (to 9.9 mL/min), with the smaller baskets (Microvasive 1.9F and Cook 2.2F) and by 99.1% (to 0.4 mL/min) with the larger baskets (ACMI 3.0F and Microvasive 3.0F). Similarly, the mean baseline upward deflection (162 degrees) decreased by 2 degrees (1.2%) for the Cook 2.4F N-Compass and by 20 degrees (12.3%) for the ACMI 3.0F. Loss of downward deflection from baseline (170 degrees) ranged from 6 degrees (3.5%) for the Microvasive 1.9F to 17 degrees (10%) for the Microvasive 2.6F grasping forceps. The least deterioration in flow and deflection occurred with the two smallest baskets (Microvasive 1.9F and Cook 2.2F).
  
  
  CONCLUSIONS
  Ureteroscope irrigation flow and deflection deteriorate progressively with larger-caliber Nitinol baskets. The Microvasive 1.9F and Cook 2.2F baskets resulted in the least deterioration of irrigation and deflection metrics. However, basket size is not the only factor responsible for changes in flow and ureteroscope deflection.
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, Saint Louis, Missouri 63110, USA.
authors.forename: Caroline D
authors.initials: CD
authors.lastname: Ames
authors.forename: Juan M
authors.initials: JM
authors.lastname: Perrone
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Weld
authors.forename: Kelley V
authors.initials: KV
authors.lastname: Foyil
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Ramakrishna
authors.initials: R
authors.lastname: Venkatesh
authors.forename: Jaime
authors.initials: J
authors.lastname: Landman
mesh_terms: D000497:Alloys; D004867:Equipment Design; D006801:Humans; D018583:Pliability; D007507:Therapeutic Irrigation / Q000295:instrumentation; D020709:Ureteroscopes
chemical_list: D000497:Alloys; C013616:nitinol