Intraoperative positioning strategies to improve stone-free outcomes during retrograde intrarenal surgery: a systematic review and meta-analysis.

Abstract

Purpose: To evaluate whether intraoperative patient positioning strategies improve stone-free outcomes and safety compared with standard lithotomy during retrograde intrarenal surgery (RIRS) for renal calculi.

Methods: PubMed, Embase, Cochrane Library, Web of Science, CNKI, Wanfang, and SinoMed were searched from inception to December 2025. Comparative studies of intraoperative positioning strategies versus standard lithotomy during RIRS were included. Risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated using random-effects models where quantitative synthesis was appropriate. Subgroup analysis by stone location and exploratory sensitivity analyses according to dominant gravitational axis and CT-based outcome assessment were performed.

Results: Eight studies involving 998 patients were included. Positioning strategies significantly increased the stone-free rate compared with standard lithotomy (RR 1.20, 95% CI 1.12-1.28; P < 0.001). Benefits were consistent in mixed intrarenal calculi and lower pole stones, and CT-based sensitivity analyses yielded comparable estimates. Postoperative fever did not differ significantly between groups (RR 1.15, 95% CI 0.53-2.53; P = 0.720). Operative-time and hospital-stay outcomes showed extreme heterogeneity or single-study dependency, and reintervention data were too limited for definitive conclusions.

Conclusion: Intraoperative positioning strategies during RIRS may improve stone-free outcomes. However, endpoint variability, exploratory subgroup classification, limited reintervention data, and the absence of direct intrarenal pressure monitoring warrant cautious interpretation. Standardized trials with CT-based endpoints, clearly defined positioning protocols, and intrarenal pressure monitoring are needed.