Posterior Urethral Valves: Search for a Diagnostic Reference Standard

Objectives To test the agreement among pediatric urologists regarding endoscopic findings concerning posterior urethral valves. Methods A total of 25 experienced pediatric urologic surgeons observed 11 video fragments of cystourethroscopy in boys. For most of these boys, a strong suspicion of urethral obstruction had been present; however, some were controls. The video fragments stopped when an incision seemed about to be made using the endoscopic hook on, or behind, 17 folds/valves. The pediatric urologic surgeons were then asked whether they would have incised these folds/valves. The only additional clinical information given was that a suspicion of obstruction was present for most cases and that a few control cases had been included. They could only answer “yes” or “no.” Results Agreement of ≥80% was observed for 12 of the 17 questions. Of the 17 cases, 5 yielded agreement of 50%-75%. Only in 1 case, was 100% agreement reached. Most surgeons did not regard a flap valve at the 12-o'clock position as an obstruction. The voiding cystourethrograms of several cases with good positive agreement regarding posterior urethral valve obstruction displayed no radiologic suspicion of posterior urethral valves. Conclusions When judging cystoscopy results, we found fair to good agreement among pediatric urologists regarding whether a urethral obstruction is present. If a urethra appears normal on voiding cystourethrography, this does not exclude the possibility of a urethral obstruction. A true reference standard for urethral obstruction in boys does not seem to exist, and clinical data and additional diagnostic procedures are needed for diagnosis in most cases.