title: Techniques to maximize flexible ureteroscope longevity.
abstract: OBJECTIVE
  To assess methods to improve the longevity and durability of flexible ureteroscopes by using the ureteral access sheath, 200-microm holmium laser fiber, and nitinol baskets or graspers during routine ureteroscopic procedures. Despite adequate advances in fiberoptics and endoscope design, the decreased size of currently available flexible ureteroscopes makes damage inevitable after repeated use. However, new auxiliary tools may be able to enhance ureteroscope durability.
  
  
  METHODS
  The indications for performing flexible ureteroscopy were proximal ureteral stones (n = 32), renal calculi (n = 59), treatment of upper tract transitional cell carcinoma (n = 3), evaluation of hematuria or filling defect (n = 7), and treatment of ureteral strictures or ureteropelvic junction obstruction (n = 8). Using four new 7.5F flexible ureteroscopes, we prospectively evaluated the number of passes of each ureteroscope until more than 20 optical fibers were broken, more than a 25 degrees loss of deflection in either direction had occurred, or the instrument sustained injury requiring repair by the manufacturer.
  
  
  RESULTS
  One hundred nine flexible ureteroscopic procedures (average 27.5 procedures per instrument; range 19 to 34) were performed with the four new flexible ureteroscopes before being sent for repair. Adjuncts to reduce scope damage during these procedures were the use of the ureteral access sheath (n = 109), nitinol devices allowing lower pole stone retrieval (n = 27), and the 200-microm holmium laser fiber for stone fragmentation, tumor ablation, and incision of ureteropelvic junction/ureteral stenoses (n = 91). The average number of passes until more than 20 optical fibers were broken was 15.3 (range 12 to 20), until more than a 25 degrees loss of deflection occurred was 50.3 (range 42 to 66), or until the scope required repair was 66.7 (range 46 to 82).
  
  
  CONCLUSIONS
  Flexible ureteroscopy will be used increasingly to manage upper urinary tract pathologic findings. Historically, the number of procedures performed before a flexible ureteroscope requires repair averaged 6 to 15. By incorporating the new ureteroscopic accessories, such as nitinol devices, a ureteral access sheath, and the 200-microm holmium laser fiber into common practice, one can reduce the strain on these fragile 7.5F endoscopes, thereby maximizing their longevity.
authors.affiliation: Comprehensive Kidney Stone Center, Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Pietrow
authors.forename: Brian K
authors.initials: BK
authors.lastname: Auge
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Delvecchio
authors.forename: Ari D
authors.initials: AD
authors.lastname: Silverstein
authors.forename: Alon Z
authors.initials: AZ
authors.lastname: Weizer
authors.forename: David M
authors.initials: DM
authors.lastname: Albala
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Preminger
mesh_terms: D004868:Equipment Failure; D017743:Equipment Reuse / Q000706:statistics & numerical data; D005336:Fiber Optic Technology; D020702:Hysteroscopes / Q000592:standards / Q000706:statistics & numerical data*; D055100:Optical Fibers; D011446:Prospective Studies; D013997:Time Factors