Ito K, Takahashi T, Somiya S, et al. - In this single-center, retrospective cohort study, researchers sought to assess the risk of repeat surgery and stone-related events after flexible ureteroscopy (fURS) for renal stones and to identify their predictive factors. Participants in the study were 664 patients who underwent fURS for renal stones with or without concomitant ureteral stones between January 2012 and December 2019. One hundred three (15.5%) and 135 (20.3%) patients experienced surgical intervention and any stone-related event, respectively, during a median follow-up of 31.1 months. Data reported that the estimated 2-year intervention-free survival and stone-event-free survival was 86.9% and 81.6%, respectively, and the estimated 2-year intervention-free survival rates in low-, intermediate-, and high-risk groups were 96.2%, 86.4%, and 71.3%, respectively. Findings suggested that people undergoing fURS are at risk of future ipsilateral surgical intervention and stone-related events. Simple predictive tools can facilitate treatment decision-making by identifying patients at high risk of recurrence.