Purpose: To systematically assess the effectiveness and safety of retrograde flexible ureteroscopy (FURS) versus percutaneous nephrolithotomy (PCNL) in treating intermediate-size renal stones (2-3cm).

Materials and methods: PubMed, Ovid MEDLINE, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL) and EMBASE were researched to identify relevant studies up to May 2018. Article selection was performed through the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. The Newcastle-Ottawa Scale was applied to assess the methodological quality of case-control studies.

Results: Six retrospective case-controlled trials were included for meta-analysis. The pooled results showed that PCNL was associated with a higher initial stone-free rate (SFR). After more complementary treatments, FURS provided a final SFR (OR: 1.69; 95% CI, 0.93-3.05; P = 0.08) comparable to that achieved by PCNL. PCNL was associated with a higher rate of overall intraoperative complications (OR: 1.48; 95% CI, 1.01-2.17; P = 0.04) and longer hospital stay (MD: 2.21 days; 95% CI, 1.11 to 3.30; P < 0.001). Subgroup analysis by Clavien-graded complication showed PCNL had significantly higher rates of minor complications (OR: 1.58; 95% CI, 1.04-2.41; P = 0.03). No significant difference was noted in major complications (OR: 1.14; 95% CI, 0.53-2.45; P = 0.73) or operative times (MD: -9.71 min; 95% CI, -22.02 to 2.60; P = 0.12).

Conclusions: Multisession FURS is an effective and safe alternative to PCNL for the management of intermediate-size renal stones (2-3cm). It is advisable to balance the benefits and risks according to the individual characteristics of patients and to decide with patients by discussing the advantages and disadvantages of each procedure.