title: Percutaneous nephrolithotomy in patients with urinary tract abnormalities.
abstract: OBJECTIVE
  Patients with urinary tract abnormalities are at an increased risk of stone formation. Percutaneous nephrolithotomy (PCNL) plays an important role in the treatment of this patient population; however, outcomes are less well defined compared with patients with normal urinary tract anatomy. Our objective was to evaluate the influence of urinary tract abnormalities on intraoperative and postoperative outcomes with PCNL.
  
  
  METHODS
  We report on a single-center prospective database of 2284 consecutive PCNLs in 1935 patients from 1990 to 2012. For the purposes of this analysis, patients were categorized by the presence or absence of a urinary tract abnormality. Multivariable analyses were used to identify independent predictors of the length of hospital stay, operative time, complications, and residual stones at discharge and 3 months.
  
  
  RESULTS
  A urinary tract abnormality was present in 14.4% (n=330) of the cohort. On univariable analysis, patients with urinary tract abnormalities were more likely to present with urinary tract infection (28% vs 19%, P<0.001) and less likely to present with hematuria (13% vs 19%, P<0.02). On multivariable regression, a urinary tract abnormality was predictive of residual stone at discharge, need for a secondary procedure, but did not increase the risk of residual stone at 3 months or the development of complications. Operative time and hospital stay were only moderately prolonged.
  
  
  CONCLUSIONS
  Patients with urinary tract abnormalities who undergo PCNL have a higher risk of residual stones at discharge and need for secondary procedures, but comparable complication rates, operative time, and hospital stay.
authors.affiliation: Department of Surgery, Division of Urology, Schulich School of Medicine & Dentistry, Western University , London, Ontario, Canada .
authors.forename: Philippe D
authors.initials: PD
authors.lastname: Violette
authors.forename: Marie
authors.initials: M
authors.lastname: Dion
authors.forename: Thomas
authors.initials: T
authors.lastname: Tailly
authors.forename: John D
authors.initials: JD
authors.lastname: Denstedt
authors.forename: Hassan
authors.initials: H
authors.lastname: Razvi
mesh_terms: D000328:Adult; D000368:Aged; D016208:Databases, Factual; D005260:Female; D006417:Hematuria / Q000209:etiology; D006801:Humans; D007669:Kidney Calculi / Q000150:complications / Q000601:surgery*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D061646:Operative Time; D010351:Patient Discharge; D011183:Postoperative Complications / Q000453:epidemiology*; D011446:Prospective Studies; D012086:Reoperation; D016896:Treatment Outcome; D014547:Urinary Diversion; D014551:Urinary Tract / Q000002:abnormalities*; D014552:Urinary Tract Infections / Q000209:etiology; D014564:Urogenital Abnormalities / Q000150:complications*