title: Factors affecting outcomes of percutaneous nephrolithotomy in horseshoe kidneys.
abstract: OBJECTIVE
  To analyze the patient- and procedure-related factors affecting the outcomes of percutaneous nephrolithotomy (PNL) in horseshoe kidneys (HSKs).
  
  
  METHODS
  A retrospective analysis was done of patients with stones in HSKs treated with PNL in 3 referral centers between 1998 and 2013. Demographics, along with perioperative characteristics, were evaluated in detail as to whether or not they had an effect on the success and complication rates.
  
  
  RESULTS
  A total of 54 HSKs with calculi in 53 patients were treated with PNL. Mean stone size was 28.4 ± 19.6 mm (range, 10-120 mm). Fifty-three patients were treated through a single tract, and 1 patient required additional access. Access was directed to the upper calyx (n = 27), middle calyx (n = 17), and lower calyx (n = 10) through the intercostal (n = 23) and subcostal (n = 31) areas. Flexible nephroscopy was used in 18.5% of the procedures. Postoperative complications were observed in 9 (16.7%) of the procedures. Success rate was 66.7% after a single session of PNL and increased to 90.7% with additional treatments. Although patient demographics, preoperative imaging, and other operative measures did not have significant effect on the complication rate, stone complexity and multiplicity, in combination with flexible nephroscopy, were found to significantly affect the success rate (P = .026, P = .043, and P = .021, respectively). However, in multivariate analysis stone multiplicity was the only factor that affected success rate (P = .004).
  
  
  CONCLUSIONS
  Stone parameters play an important role in achieving stone-free status in HSKs. Use of flexible nephroscopy positively affects the success rate by allowing reaching the peripherally located calices.
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI. Electronic address: tepeler@urology.wisc.edu.
authors.forename: Abdulkadir
authors.initials: A
authors.lastname: Tepeler
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Priyanka D
authors.initials: PD
authors.lastname: Sehgal
authors.affiliation: Department of Urology, Faculty of Medicine, Bezmialem Vakif University, Istanbul Turkey.
authors.forename: Tolga
authors.initials: T
authors.lastname: Akman
authors.affiliation: Department of Urology, Kecioren Teaching and Research Hospital, Ankara, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Unsal
authors.affiliation: Department of Urology, Kecioren Teaching and Research Hospital, Ankara, Turkey.
authors.forename: Ekrem
authors.initials: E
authors.lastname: Ozyuvali
authors.affiliation: Department of Urology, Faculty of Medicine, Bezmialem Vakif University, Istanbul Turkey.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Armagan
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Stephen Y
authors.initials: SY
authors.lastname: Nakada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007668:Kidney / Q000002:abnormalities* / Q000601:surgery; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D053040:Nephrolithiasis / Q000000981:diagnostic imaging / Q000601:surgery*; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D061214:Patient Safety; D011183:Postoperative Complications / Q000453:epidemiology / Q000503:physiopathology; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D014564:Urogenital Abnormalities / Q000000981:diagnostic imaging / Q000601:surgery*; D055815:Young Adult