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World J Nephrol. Feb 6, 2015; 4(1): 111-117
Published online Feb 6, 2015. doi: 10.5527/wjn.v4.i1.111
Appropriate kidney stone size for ureteroscopic lithotripsy: When to switch to a percutaneous approach
Ryoji Takazawa, Sachi Kitayama, Toshihiko Tsujii
Ryoji Takazawa, Sachi Kitayama, Toshihiko Tsujii, Department of Urology, Tokyo Metropolitan Ohtsuka Hospital, Tokyo 170-8476, Japan
Author contributions: Takazawa R designed research, wrote the paper and generated the figures and tables; Takazawa R, Kitayama S and Tsujii T performed the research and data analysis. Tsujii T contributed to this work as a superviser.
Conflict-of-interest: The authors declare that they have no competing interests.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Ryoji Takazawa, MD, PhD, Chief, Department of Urology, Tokyo Metropolitan Ohtsuka Hospital, 2-8-1 Minami-Ohtsuka, Toshima-ku, Tokyo 170-8476, Japan. ryoji_takazawa@tmhp.jp
Telephone: +81-3-39413211 Fax: +81-3-39416347
Received: June 25, 2014
Peer-review started: June 26, 2014
First decision: September 3, 2014
Revised: September 29, 2014
Accepted: November 27, 2014
Article in press: December 1, 2014
Published online: February 6, 2015
Processing time: 226 Days and 15.1 Hours
Abstract

Flexible ureteroscopy (fURS) has become a more effective and safer treatment for whole upper urinary tract stones. Percutaneous nephrolithotomy (PNL) is currently the first-line recommended treatment for large kidney stones ≥ 20 mm and it has an excellent stone-free rate for large kidney stones. However, its invasiveness is not negligible considering its major complication rates. Staged fURS is a practical treatment for such large kidney stones because fURS has a minimal blood transfusion risk, short hospitalization and few restrictions on daily routines. However, as the stone size becomes larger, the stone-free rate decreases, and the number of operations required increases. Therefore, in our opinion, staged fURS is a practical option for kidney stones 20 to 40 mm. Miniaturized PNL combined with fURS should be considered to be a preferred option for stones larger than 40 mm. Moreover, URS is an effective treatment for multiple upper urinary tract stones. Especially for patients with a stone burden < 20 mm, URS is a favorable option that promises a high stone-free rate after a single session either unilaterally or bilaterally. However, for patients with a stone burden ≥ 20 mm, a staged operation should be considered to achieve stone-free status.

Keywords: Ureteroscopy; Lithotripsy; Laser; Kidney calculi; Nephrostomy; Percutaneous

Core tip: Flexible ureteroscopy (fURS) has become a more effective treatment for large and multiple kidney stones. However, as the stone size becomes larger, the stone-free rate decreases, and the number of operations required increases. We herein review the appropriate kidney stone size for ureteroscopic lithotripsy and for situations when it should be combined with percutaneous surgery. In our opinion, staged fURS is a practical option for stones 20 to 40 mm. Miniaturized percutaneous nephrolithotomy combined with fURS should be considered to be a preferred option for stones larger than 40 mm.