title: A Novel method of ensuring safe and accurate dilatation during percutaneous nephrolithotomy.
abstract: OBJECTIVE
  To report our technique that helps locate the guidewire into the ureter enabling safe dilatation during PCNL.
  
  
  METHODS
  Cases in which the guidewire failed to pass into the ureter following successful puncture of the desired calyx were subjected to this technique. A second guidewire was passed through the outer sheath of a 9 Fr. metallic dilator cannula, passed over the first guidewire. The cannula and outer sheath were removed, followed by percutaneous passage of a 6/7.5 Fr ureteroscope between the two guidewires, monitoring its progress through both the endoscopic and fluoroscopic monitors. Once the stone was visualized in the calyx a guidewire was passed through the working channel and maneuvered past the stone into the pelvis and ureter under direct endoscopic vision. This was followed by routine tract dilatation.
  
  
  RESULTS
  This technique was employed in 85 out of 675 cases of PCNL carried out at our institute between Jan 2010 to June 2014. The mean time required for our technique, calculated from the point of introduction of the ureteroscope untill the successful passage of the guidewire down into the ureter was 95 seconds. There were no intraoperative or postoperative complications as a result of this technique. Guidewire could be successfully passed into the ureter in 82 out of 85 cases.
  
  
  CONCLUSIONS
  Use of the ureteroscope introduced percutaneously through the puncture site in PCNL, is a safe and effective technique that helps in maneuvering the guidewire down into the ureter, which subsequently enables safe dilatation.
authors.affiliation: M.S. Ramaiah Hospital, Bangalore, India.
authors.forename: Tarun
authors.initials: T
authors.lastname: Javali
authors.affiliation: M.S. Ramaiah Hospital, Bangalore, India.
authors.forename: Amey
authors.initials: A
authors.lastname: Pathade
authors.affiliation: M.S. Ramaiah Hospital, Bangalore, India.
authors.forename: H K
authors.initials: HK
authors.lastname: Nagaraj
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004106:Dilatation / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000601:surgery; D007670:Kidney Calices / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000295:instrumentation / Q000379:methods*; D011677:Punctures / Q000295:instrumentation / Q000379:methods; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome; D014513:Ureter / Q000601:surgery*; D020709:Ureteroscopes; D055815:Young Adult