Renal Hematoma after Ureteroscopy and Retrograde Intrarenal Surgery: Incidence, Risk Factors, and Management Strategies—Application of the REVEAL Framework from EAU Endourology

Introduction: To determine the incidence, risk factors, and clinical predictors of subcapsular renal hematoma (SRH) and perirenal hematoma (PRH) after ureteroscopy (URS) and retrograde intrarenal surgery (RIRS) using a structured multilevel evidence synthesis (Rare Events Valuation through Evidence-based And Layered synthesis [REVEAL] framework). Methods: A systematic review and multilevel analysis were conducted according to PRISMA and a registered protocol (PROSPERO CRD420251085350). Literature searches (2000–2025) identified studies reporting SRH/PRH after URS/RIRS. A three-step framework was applied: meta-analysis (MA) of incidence using generalized linear mixed-effects models; MA of risk factors from comparative studies; and individual patient data (IPD) synthesis from case series and reports, followed by prognostic model development and nomogram construction. Results: Fifteen studies, including 23,258 patients and 74 hematomas, were included. The pooled incidence of SRH/PRH was 0.42% (95% confidence interval: 0.22–0.79%), with slightly higher rates after RIRS (0.8%) compared with URS (0.4%). Stone size, longer operative time, hydronephrosis, and elevated intrarenal pressure were associated with increased risk. IPD analysis of 54 patients identified fever as the strongest predictor of unsuccessful conservative management. A multivariable model incorporating age, fever, hematoma length, hemoglobin drop, and time to presentation achieved strong discrimination and was translated into a prognostic nomogram to estimate individualized risk. Conclusions: SRH and PRH are rare but clinically significant complications of URS and RIRS. Using the REVEAL framework, we integrated heterogeneous evidence, identified technical and clinical risk factors, and developed the first prognostic tool for individualized risk stratification. Validation in multicenter prospective studies is required before clinical implementation.