title: First digital flexible ureterorenoscope: initial experience.
abstract: BACKGROUND
  Flexible ureterorenoscopy is a minimally invasive procedure that is rapidly gaining popularity as a treatment for patients with upper urinary tract lithiasis. One of the main drawbacks is the limited visualization imposed by fiberoptic technology in an endoscope, often only 7 to 8F and the fragility of fiber-based optics in a flexible endoscope.
  
  
  METHODS
  We report our initial experience with digital flexible URS and holmium laser lithotripsy using digital image capture in three patients. Two patients had upper tract calculi (1 cm lower pole calculus and 8 mm caliceal diverticular stone, respectively), and one patient underwent diagnostic URS.
  
  
  RESULTS
  After basket capture and intrarenal relocation of the lower pole stone, complete stone destruction was achieved. Similarly, the caliceal diverticular stone was destroyed after holmium laser incision of the caliceal diverticulum. Remarkable improvement in image quality was observed throughout the procedures in comparison with current fiberoptic image acquisition. Minor image interference was noted during fluoroscopic screening, which increased slightly during laser activation.
  
  
  CONCLUSIONS
  The first digital flexible ureterorenoscope provided excellent image quality and zoom capability, with a substantial improvement compared with fiberoptic technology. It does not require a separate light source and is an important step for the continued evolution of flexible URS as a therapeutic modality for upper urinary tract pathology.
authors.affiliation: St. Mary's Hospital, St. Mary's Campus, Praed Street, London, U.K. anup.patel@imperial.ac.uk
authors.forename: Stephen
authors.initials: S
authors.lastname: Mitchell
authors.forename: Erik
authors.initials: E
authors.lastname: Havranek
authors.forename: Anup
authors.initials: A
authors.lastname: Patel
mesh_terms: D000368:Aged; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007669:Kidney Calculi / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D020709:Ureteroscopes; D018666:Ureteroscopy