title: Bare naked baskets: ureteroscope deflection and flow characteristics with intact and disassembled ureteroscopic nitinol stone baskets.
abstract: OBJECTIVE
  Lower pole renal access during flexible ureterorenoscopy is often limited by the active deflection capabilities of the ureteroscope. Deterioration in the deflection and flow capabilities of ureteroscopes occurs with the passage of instrumentation through the working channel. We performed in vitro evaluation of a novel technique using unsheathed nitinol baskets to minimize the deterioration in deflection and maximize the irrigant flow associated with instrument passage through the working channel during flexible ureterorenoscopy.
  
  
  METHODS
  Alterations in the irrigant flow and active deflection of 4 ureteroscopes from different manufacturers were evaluated. Each ureteroscope was evaluated with an empty working channel, and then with sheathed and unsheathed 2.2, 3 and 3.2Fr (Cook Urological, Inc., Indianapolis, Indiana), 2.4 and 3Fr (Microvasive Urology, Natick, Massachusetts) nitinol baskets in the working channel.
  
  
  RESULTS
  With all baskets tested and in all ureteroscopes the deterioration in active deflection and irrigant flow was improved with the unsheathed baskets. The disassembled basket within the working channel allowed an additional 15 to 20 degrees of active deflection. In addition, the disassembled basket allowed for a 2 to 30-fold increase in irrigant flow compared with an intact basket.
  
  
  CONCLUSIONS
  The combination of improved deflection and irrigant flow with this technique may improve ureteroscopic access to lower pole renal calculi.
authors: Division of Urology, Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA.
authors: Jaime
authors: J
authors: Landman
authors: Manoj
authors: M
authors: Monga
authors: Ehab A
authors: EA
authors: El-Gabry
authors: Jamil
authors: J
authors: Rehman
authors: David I
authors: DI
authors: Lee
authors: Sam
authors: S
authors: Bhayani
authors: Chandru P
authors: CP
authors: Sundaram
authors: Ralph V
authors: RV
authors: Clayman
mesh_terms: D000497:Alloys; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D007669:Kidney Calculi / Q000628:therapy*; D012212:Rheology; D007507:Therapeutic Irrigation; D020709:Ureteroscopes; D018666:Ureteroscopy
chemical_list: D000497:Alloys; C013616:nitinol