title: Ureteroscopy-assisted retrograde nephrostomy (UARN) without ureteral access sheath (UAS).
abstract: BACKGROUND
  We previously described ureteroscopy assisted retrograde nephrostomy (UARN). In UARN, it is possible to continuously visualize the dilation of the ureter from puncture to insertion of the nephroaccess sheath with minimal complication. But in the course of making nephrostomy, UARN requires ureteral access sheath (UAS). UAS has a potential risk of ureteral stricture. Herein, we report the first case of UARN without the use of UAS.
  
  
  METHODS
  A 53-year-old female was referred to our hospital for treatment of her right renal stone. Because her stone burden was 27mm, we planned to perform percutaneous nephrolithotomy (PCNL) using UARN without UAS.
  
  
  CONCLUSIONS
  UAS facilitates a decrease in the intrarenal pressure due to irrigation, and it makes controlling the URS easier. However, in terms of the risk of ureteral stricture, unnecessary insertion of a UAS should be avoided.
  
  
  CONCLUSIONS
  We describe the first case of a renal stone successfully treated by PCNL using the UARN method without the use of a UAS.
authors: Department of Urology, Ohguchi Higashi General Hospital, Japan; Department of Urology, Yokohama City University, Graduate School of Medicine, Japan. Electronic address: takashi_tk2001@yahoo.co.jp.
authors: Takashi
authors: T
authors: Kawahara
authors: Department of Urology, Ohguchi Higashi General Hospital, Japan; Department of Urology, Yokohama City University, Graduate School of Medicine, Japan.
authors: Hiroki
authors: H
authors: Ito
authors: Department of Urology, Ohguchi Higashi General Hospital, Japan.
authors: Hideyuki
authors: H
authors: Terao
authors: Department of Urology, Yokohama City University, Graduate School of Medicine, Japan.
authors: Hiroji
authors: H
authors: Uemura
authors: Department of Urology, Yokohama City University, Graduate School of Medicine, Japan.
authors: Masahiro
authors: M
authors: Yao
authors: Department of Urology, Ohguchi Higashi General Hospital, Japan.
authors: Junichi
authors: J
authors: Matsuzaki
keywords: PCNL; UARN; Ureteral access sheath; Ureteroscopy