Ellison JS, et al. - The predictors of repeat intervention for children with upper urinary tract calculi (UUTC) were evaluated using a nationwide administrative dataset. Adjusting for measured confounders, an association of shock wave lithotripsy (SWL) with a 2.6-fold higher risk of repeat stone-related interventions was seen. The likelihood of retreatment was noted to be increased by additional patient-related factors (SWL, stenting at the index operation without pre-index stenting, chronic comorbidities, renal calculi, and age <5 years). A strong predictor of retreatment was intra-operative stent placement, perhaps serving as a marker for complex cases or planned staged procedures.