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  • Review Article
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What is the stone-free rate following flexible ureteroscopy for kidney stones?

Nature Reviews Urology volume 12, pages 281–288 (2015)Cite this article

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An Erratum to this article was published on 02 June 2015

This article has been updated

Key Points

  • Use of flexible ureteroscopy (URS) for treating patients with kidney stones has increased compared with shockwave lithotripsy and percutaneous nephrolithotomy

  • Wide variations in use, and timing of postoperative imaging as well as definitions of stone-free rate (SFR) make accurate assessments of stone clearance after flexible URS challenging

  • CT provides the most accurate way to assess the presence of residual fragments; however, even when retrieval of fragments is employed, the complete SFR might only approach 55–60%

  • At the minimum, SFRs should report the zero-fragment rate; residual fragment size >2 mm is associated with significantly increased risk of a stone-related event and greater need for retreatment

  • Treatment of patients with lower-pole stones using a basket displacement technique can result in higher SFRs

  • Patients with larger stones receiving treatment with flexible URS might require staged procedures, especially if the cumulative stone size exceeds 1.5–2 cm

Abstract

Flexible ureteroscopy (URS) is increasingly being used as the first-line treatment for patients with renal stones. Despite this increase in use, substantial variations exist in the reported stone-free rates (SFR) following flexible URS. These variations are a result of inconsistencies in the definition of 'stone-free', which reflect variations in the type of imaging used to assess the presence of stones postoperatively and the timing of the assessment. Other possible factors such as the importance of residual fragments following stone surgery, and the size and position of the stones might also account for variations in stone-free rates. In order to obtain an accurate estimate of the SFR, especially within subgroups defined by stone characteristics and exact technique, we compare reported SFRs from studies that use imaging other than CT for follow-up and those that use only CT. We also review the evidence on the importance of active retrieval of fragments during flexible URS and whether this technique improves the outcomes of patients with kidney stones.

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Change history

  • 15 February 2016

    In the author line of the originally published article, the full initials of J. Stuart Wolf Jr were not included. Also, in the footnote of Table 2, "*Pre-operative stents present in all patients" should read "*Post-operative stents present in all patients". These errors have been corrected for the HTML and PDF versions of the article.

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Authors and Affiliations

  1. Division of Endourology and Stone Disease, Department of Urology, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, 48109, MI, USA

    Khurshid R. Ghani & J. Stuart Wolf Jr

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  1. Khurshid R. Ghani
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Contributions

K.R.G. researched data for the article, K.R.G. and J.S.W. made a substantial contribution to discussion of content, K.R.G. wrote the article, K.R.G. and J.S.W. reviewed and edited the manuscript before subsmission.

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Correspondence to Khurshid R. Ghani.

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Competing interests

K.R.G. declares that he has acted as a consultant for Boston Scientific and Lumenis. J.S.W. declares no competing interests.

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Ghani, K., Wolf, J. What is the stone-free rate following flexible ureteroscopy for kidney stones?. Nat Rev Urol 12, 281–288 (2015). https://doi.org/10.1038/nrurol.2015.74

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