Opening of the bladder neck

Fig. 19.4a-c. Voiding cystourethrosonography in a patient with vesical neck obstructive syndrome. The transrectal study shows absence of bladder neck tunneling (a), incomplete opening of the bladder neck with a posterior ledge-like protrusion (b,c), which does not disappear even in advanced phases of urination (c)... 

The combination of a transient opening of the bladder neck with a flow of contrast material into the posterior urethra up to the voluntarily contracted striated urethral sphincter (Potter et al. 1986 Passerini-Glazel et al. 1992) together with cessation and/or back-up of contrast material drip flow suggests the presence of an uninhibited detrusor contraction (Fig. 14.3). These findings are valid they can stand alone without urodynamic results. Modified VCU allows detection of the majority of these dysfunctions in neonates, infants and small children with the same reliability and in the same way as in older age groups. 

For the evaluation of children with symptoms of nonneurogenic bladder-sphincter dysfunction by ultrasound, a careful examination of the urinary bladder has to be performed in particular. Not only structural abnormalities have to be searched for bladder wall thickness, bladder volume and residual urine volume after voiding have to be assessed. Similar as described before for the modified VCU technique, the bladder base and bladder neck respectively have to be observed carefully by ultrasound as well. A transient opening of the bladder neck together with uninhibitetd detrusor contractions with filling of the posterior urethra up to the con-... 

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