Risk Factors for Primary Retrograde Ureteral Access Failure During Ureteroscopy—A Systematic Review and Meta-Analysis by the YAU and EAU Section of Endourology

OBJECTIVES: Primary ureteroscopic access failure necessitates ureteral stenting and staged procedures, increasing patient and healthcare burden. This systematic review aims to identify risk factors for primary failure to enhance clinical decision-making and identify patients who may benefit from prestenting or medical pretreatment to mitigate failure risks. METHODS: A systematic search of MEDLINE (PubMed), Embase, and Web of Science was performed through May 2025 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered in PROSPERO. Studies reporting primary retrograde access failure during ureteroscopy in unstented, unprepared ureters were included. Failure was defined as inability to advance the ureteroscope or ureteral access sheath to the stone, with or without intraoperative adjunctive measures. Risk of bias was assessed using Cochrane Collaboration guidance. Pooled failure rates and associations with clinical risk factors were analyzed using random-effects meta-analysis. Heterogeneity and publication bias were formally assessed. RESULTS: 93%). Younger age (mean difference 3.29 years), male sex (odds ratio [OR] 1.36), and proximal ureteral stone location (OR 2.31) were associated with increased failure risk. Thin ureteroscopes (OR 0.10) and prior ipsilateral stone surgery (OR 0.40) were protective. Funnel plot asymmetry suggested publication bias. Evidence quality was limited by retrospective designs and heterogeneity. CONCLUSIONS: This review, despite the low quality of evidence, identifies possible risk factors for primary ureteroscopy access failure. These findings may assist in clinical decision-making and patient counseling.