title: Percutaneous nephrolithotomy: critical analysis of unfavorable results.
abstract: OBJECTIVE
  To identify the risk factors of unfavorable results of percutaneous nephrolithotomy (PCNL).
  
  
  METHODS
  A total of 602 patients were subjected to 616 PCNL procedures. Patients were divided into two groups according to the results of treatment. Group 1 with favorable results includes patients who became stone free after a single PCNL procedure without major complications. Group 2 with unfavorable results includes three subgroups: a) Patients who developed major complications, b) Those who required second major intervention to complete stone removal, and c) Patients with residual stones > 4 mm at 3 month. Risk factors for unfavorable outcome were studied by univariate and multivariate analyses.
  
  
  RESULTS
  Unfavorable results were documented in 176 patients (28.6%) due to major complications in 40 (6.5%), need for second intervention in 124 (20%), and presence of residual stones > 4 mm at 3 month in 12 (1.9%). The remaining 440 patients (71.4%) were considered of favorable outcome. Independent risk factors of unfavorable results on multivariate analysis were staghorn stones, multiple stones and stone largest diameter > 50 mm.
  
  
  CONCLUSIONS
  To optimize the results of PCNL, urologists should consider careful patient selection. Patients with staghorn stones, multiple stones or large stone burden are more susceptible to unfavorable outcome.
authors.affiliation: Department of Urology, Hamad General Hospital, Doha, Qatar.
authors.forename: Abdulkader
authors.initials: A
authors.lastname: Alobaidy
authors.forename: Abdulla
authors.initials: A
authors.lastname: Al-Naimi
authors.forename: Khalid
authors.initials: K
authors.lastname: Assadiq
authors.forename: Haidar
authors.initials: H
authors.lastname: Alkhafaji
authors.forename: Abdulla
authors.initials: A
authors.lastname: Al-Ansari
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Shokeir
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053040:Nephrolithiasis / Q000601:surgery*; D009403:Nephrostomy, Percutaneous / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome