title: Efficacy of percutaneous nephrostomy during flexible ureteroscopy for renal stone management.
abstract: OBJECTIVE
  Preoperative percutaneous nephrostomy (PCN) can be applied to urinary stone patients with pyelonephritis as well as obstructive uropathy; thus, some patients undergo flexible ureteroscopy (fURS) in the presence of a PCN tube. We evaluated the effectiveness of PCN during fURS for the management of renal stones.
  
  
  METHODS
  We retrospectively analyzed 130 consecutive patients who underwent fURS for renal stones between January 2009 and December 2011. All fURS procedures were performed by a single experienced surgeon. The patients were divided into two groups depending on the presence of PCN during the surgery: patients with PCN (group 1, n=41) and patients without PCN (group 2, n=89). To evaluate operative outcomes, we compared success rates, operative times, and complication rates. We defined success as the absence of any residual stones in the kidney or stone fragments less than 2 mm that were too small to be extracted during follow-up.
  
  
  RESULTS
  There were no significant differences in age, sex, body mass index, stone laterality, burden, or location between the two groups. The mean operative times of groups 1 and 2 were 50.1 and 58.3 minutes, respectively (p=0.102). The success rates of groups 1 and 2 were 95.1% and 82.0%, respectively (p=0.044). There was no statistically significant difference in the complication rate between groups 1 and 2 (p=0.888).
  
  
  CONCLUSIONS
  Flexible ureteroscopy in the presence of PCN produced a superior outcome in terms of the success rate without increasing the operative time or complication rate. PCN may be helpful to induce better outcomes of fURS.
authors.affiliation: Department of Urology, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Se Yun
authors.initials: SY
authors.lastname: Kwon
authors.forename: Bum Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Hyun Tae
authors.initials: HT
authors.lastname: Kim
authors.forename: Yoon Kyu
authors.initials: YK
authors.lastname: Park
keywords: Kidney calculi; Percutaneous nephrostomy; Ureteroscopy