title: Percutaneous nephrolithotomy in horseshoe kidneys: factors affecting stone-free rate.
abstract: OBJECTIVE
  We report a 2-center study of factors affecting the stone-free rate after percutaneous nephrolithotomy in horseshoe kidneys.
  
  
  METHODS
  The postoperative stone-free rate after percutaneous nephrolithotomy was evaluated in 47 male and 11 female patients with horseshoe kidneys. All data were collected prospectively. Patient and procedure related factors predicting the stone-free rate were analyzed by univariate and multivariate tests.
  
  
  RESULTS
  The mean ± SD stone burden was 7.62 ± 7.18 cm(2) (range 1 to 45) and the stone was larger than 10 cm(2) in 14 patients (24.1%). Complex stones and staghorn stones were present in 21 (36.2%) and 19 patients (32.7%), respectively. The overall stone-free rate was 65.5%. Complex stones (p = 0.01), stone burden greater than 5 cm(2) (p = 0.013), stone burden greater than 10 cm(2) (p = 0.012), multiple stones (p = 0.006) and staghorn stones (p <0.001) were related to adverse outcomes on univariate analysis. Logistic regression analysis revealed that staghorn calculi was the only factor that significantly predicted the stone-free rate (p = 0.002). A patient with staghorn calculi in the horseshoe kidney was 45 times more likely to have a lower stone-free rate after percutaneous nephrolithotomy than a patient without staghorn calculi in the horseshoe kidney.
  
  
  CONCLUSIONS
  Stone parameters are important when treating calculi in horseshoe kidneys. Staghorn calculi are associated with a lower stone-free rate after percutaneous nephrolithotomy.
authors.affiliation: Second Department of Urology, Athens Medical School, Sismanoglio Hospital, Athens, Greece. andskol@yahoo.com
authors.forename: Andreas
authors.initials: A
authors.lastname: Skolarikos
authors.forename: Murat
authors.initials: M
authors.lastname: Binbay
authors.forename: Apostolos
authors.initials: A
authors.lastname: Bisas
authors.forename: Erhan
authors.initials: E
authors.lastname: Sari
authors.forename: Andrew
authors.initials: A
authors.lastname: Bourdoumis
authors.forename: Ahmet
authors.initials: A
authors.lastname: Tefekli
authors.forename: Ahmet Yaser
authors.initials: AY
authors.lastname: Muslumanoglu
authors.forename: Charalambos
authors.initials: C
authors.lastname: Deliveliotis
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007668:Kidney / Q000002:abnormalities*; D008096:Lithotripsy; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous; D012189:Retrospective Studies