such analysis to compare UNC and SIDHA cohorts at a single institution. METHODS: We retrospectively reviewed the records of 396 consecutive patients who underwent UNC or SIDHA for primary VUR from 1994–2008. Time to event multivariate analyses included demographic data, preoperative grade of VUR, presence of bladder or bowel dysfunction (BBD), and incidence of postoperative febrile UTI. RESULTS: We excluded patients with complete ureteral duplication or no postoperative voiding cystourethrogram. Of the remaining 316 patients, 210 underwent UNC (350 ureters, VUR grade distribution: I–19, II–65, III–120, IV–102, V–44) and 106 underwent SIDHA (167 ureters, VUR grade distribution: I–13, II–58, III–73, IV–20, V–3). Median age was 5.7 years (IQR 3.4–8.2) and median follow-up was 26 months (IQR 8–61). Ureteral success was significantly greater after UNC (91%, 318/350) than SIDHA (81%, 136/167) (p 0.05) and, when controlling for BBD and preoperative grade of VUR, the risk of persistent reflux was 2.6-times greater after SIDHA (OR 2.6, 95% CI 1.4, 4.4). The incidence of febrile UTI did not significantly differ after UNC (8%, 16/210) versus SIDHA (4%, 3/106) when controlling for preoperative grade of VUR (HR 1.3, 95% CI 0.4, 4.7, p 0.7), nor did it significantly differ in patients with persistent reflux versus correction of reflux (HR 1.3, 95% CI 0.4, 5.5, p 0.7). Significant predictors of postoperative febrile UTI were BBD (HR 3.7, 95% 1.3, 12.9) and preoperative grade of VUR (HR 2.1 per each increase in grade, 95% CI 1.3, 3.4). CONCLUSIONS: UNC was a superior method of correction of VUR in comparison with SIDHA. Nevertheless, the incidence of postoperative febrile UTI did not significantly differ between the treatment cohorts. Furthermore, our data suggest that the occurrence of postoperative febrile UTI is independent of procedural success.