VOIDING CYSTOURETHROGRAPHY IN BOYS - DOES THE PRESENCE OF THE CATHETER OBSCURE THE DIAGNOSIS OF POSTERIOR URETHRAL VALVES

OBJECTIVE. In voiding cystourethrography, the urethral catheter may or may not be left in place during voiding, The main argument for removi ng the catheter is that the diagnosis of posterior urethral valves may be missed because the catheter can hold open the valve, efface it, an d render it invisible, However, if the catheter does not prevent the d iagnosis of urethral disease, it is preferable to leave it in place, T he catheter makes it possible to repeat the procedure easily if necess ary, and using it to drain the bladder provides information about uret eric obstruction in the presence of vesicoureteric reflux, Accordingly , the purpose of this study was to determine whether leaving the ureth ral catheter in place throughout voiding cystourethrography affects th e efficacy of the procedure for the diagnosis of posterior urethral va lves. MATERIALS AND METHODS. Three radiologists reviewed the preoperat ive voiding cystourethrograms obtained in 48 boys who ranged in age fr om 1 day to 10 years old (mean, 1.5 years), All patients had a diagnos is of posterior urethral valves made at cystoscopy, which was used as the gold standard, The voiding cystourethrogram was obtained with a ca theter in place during voiding in 28 (58%) of the 48 boys, without a c atheter in 17(35%), and with and then without a urethral catheter duri ng the voiding phase of the study in three (6%). RESULTS. Posterior ur ethral valves were detected on 25 (89%) of the 28 voiding cystourethro grams obtained with a urethral catheter in place and in 15 (88%) of th e 17 voiding cystourethrograms done without a urethral catheter, The f ive children in whom posterior urethral valves had been diagnosed by c ystoscopy but were not detected on voiding cystourethrography had no d ilatation of the posterior urethra nor any other evidence of obstructi on; these were possibly false-positive cystoscopic diagnoses. CONCLUSI ON. Our results show that a urethral catheter does not obscure posteri or urethral valves in boys and need not be removed routinely during th e voiding phase of voiding cystourethrography.