Abdelhalim A, et al. - Via a retrospective chart review conducted for 35 patients with ureteral duplication (UD) treated with ureteroureterostomy (UU) at the study institution, the researchers determined the predictors of adverse outcomes associated with UU. The majority of patients had distal anastomosis. Nine patients underwent a concomitant re-implantation of the recipient ureter. Adverse outcomes occurred in 9 patients associated with female gender, hydronephrosis of both upper and lower moieties, with ectopic ureteroceles and in patients with a concomitant re-implant performed, after a median follow-up of 36.7 months. In the absence of mechanical obstruction, most of the patients with ectopic ureteroceles who were treated with UU and concomitant ureteral reimplantation exhibited worsened hydronephrosis of both moieties and recurrent febrile urinary tract infection. Post-excision of the upper pole, the progression of hydronephrosis was observed in the same patients. Therefore, for UD, ureteroureterostomy was noticed as a successful option with a lesser risk of adverse events in ectopic ureters or intravesical ureteroceles patients. But, in patients with hydronephrosis of both moieties with ectopic ureteroceles or when a concomitant re-implant would be required, it should be carefully acknowledged.