Different Tract Sizes of Miniaturized Percutaneous Nephrolithotomy Versus Retrograde Intrarenal Surgery: A Systematic Review and Meta-Analysis

Purpose: Miniaturized percutaneous nephrolithotomy (MPCNL), including minipercutaneous nephrolithotomy (PCNL), ultramini-PCNL, and micro-PCNL, have been developed recently. The aim of this meta-analysis was to compare the safety and efficacy of different tract sizes of MPCNL with retrograde intrarenal surgery (RIRS) in the management of kidney stones. Materials and Methods: We searched PubMed, Embase, and Web of Science to identify case-control trials and randomized controlled trials, which evaluated MPCNL vs RIRS before February 2017. Two reviewers independently evaluated the methodologic quality of the included studies, and the disagreements were solved by discussion. Meta-analysis was performed with Review Manager version 5.3 software. Results: Fourteen publications involving 1279 patients were included. Mini-PCNL provided a significantly higher stone-free rate (SFR; odds ratio [OR] OR 1.66; p=0.005), especially for lower pole renal stones (OR 2.65; p=0.003), but brought longer hospital stay (weighted mean difference [WMD] 1.23; p=0.0001) and larger hemoglobin drop (WMD 0.77; p<0.00001). There were no statistically significant differences between mini-PCNL and RIRS in the complications (OR 0.77; p=0.23) and operative time (WMD: -6.52; p=0.42). For ultramini-PCNL and micro-PCNL, the safety and efficacy were similar to RIRS. Conclusions: Mini-PCNL offers a significantly higher SFR than RIRS, for lower pole renal stones, the advantage of mini-PCNL is more obvious. However, RIRS is associated with shorter hospital stay and less hemoglobin drop. For ultramini-PCNL and micro-PCNL, tract size is smaller than mini-PCNL, and the SFR is similar to RIRS. In terms of the evidence at present, we recommend mini-PCNL for patients focusing more on the high SFR.