The predictive value of a repeat micturating cystourethrogram for remnant leaflets after primary endoscopic ablation of posterior urethral valves

ObjectiveWe routinely perform a cystourethroscopy 3 months after initial ablation of posterior urethral valves. The aim of this study was to determine the predictive value of the urethral appearance on preoperative micturating cystourethrogram (MCUG) for further valve resection at check cystoscopy.Patients and methodsWe retrospectively reviewed 31 consecutive boys (aged 4–18 months) who underwent check cystoscopy and repeat MCUG between 2006 and 2008.ResultsRepeat MCUG suggested remnant valves in 10, but no residual leaflets were identified cystoscopically in 4. In 20 boys, the valves appeared completely ablated on MCUG but valve leaflets received further resection in 10. One study was undiagnostic. Residual valves were resected in 83% (5/6) where valves and urethral dilatation were noted on MCUG. Where MCUG suggested either valves or persistent dilatation alone, further resection occurred in 40% (4/10). Remnant leaflets were also present in half of those (7/14) in whom the repeat MCUG had shown complete ablation and resolved/reduced posterior urethral dilatation.ConclusionsThe positive predictive value of valve leaflets and/or posterior urethral dilatation on repeat MCUG for subsequent resection of valve remnants was 56%; the negative predictive value was 50%. We found repeat MCUG alone imprecise in excluding residual valve tissue and recommend check cystoscopy in all.