Prone versus supine percutaneous nephrolithotomy: a systematic review and meta-analysis of current literature.

Introduction: Percutaneous nephrolithotomy (PNL) can be performed either in prone or supine position. This study aimed at gathering together randomized controlled trials (RCTs) comparing efficacy and safety between prone and supine PNL.

Evidence Acquisition: Systematic review of literature was conducted using the Scopus, Medline and Web of Science databases. Study selection, data extraction and quality assessment were independently assessed by two authors. Meta-analysis was performed with Review Manager 5.3. Sensitivity analyses were performed to exclude studies with high risk of bias.

Evidence Synthesis: Pooled data from 12 studies including 1290 patients were available for analysis. Only one study was found to have overall low risk of bias. Significantly shorter operative time was found in favor of supine PNL (mean difference 13 minutes, 95% confidence interval [CI]: 3.4-22.7; P<0.01). Stone-free rate (SFR)≥14 days after surgery was significantly higher in prone PNL (odds ratio [OR]=2.15, 95% CI: 1.07-4.34; P=0.03). Significantly higher fever rate was found in prone PNL (OR=1.60, 95% CI: 1.03-2.47; P=0.04). Overall SFR, hospital stay length, complications rate, transfusions rate and blood loss, as well as non-lower calyx puncture rate, puncture attempts and tubeless intervention rate did not differ between prone and supine PNL (P>0.05).

Conclusions: Efficacy of PNL seems balanced between prone and supine position, with comparable overall SFR and shorter operative time in favor of supine PNL. Safety of PNL appears in favor of supine PNL, with lower fever rate. Because of study heterogeneity and possible risks of outcome bias, results from this study should be interpreted with caution. Altogether, both prone and supine PNL account for appropriate therapy options.