Bladder-neck opening

Second, the so-called wide bladder neck anomaly (WBNA) (Saxton et al. 1988 Hoebecke et al. 1999) is a permanent passive bladder-neck opening in the filling phase of the VCU independent of uninhibited detrusor contractions (Fig. 14.5). Wide bladder neck anomaly might be an acquired phenomenon and unstable bladder an important etiologic factor... 

Fig. 14.6a,b. Female, 8 years old urge incontinence, UTI, unstable bladder, bladder ultrasound, a Full bladder, minor bladder trabeculation, bladder neck closed, b Uninhibited detrusor contractions with bladder neck opening and filling the posterior urethra up to contracted external sphincter with urine (arrow)... 

In contractile bladders (hyperreflexive detrusor), uninhibited detrusor contractions lead to a sudden bladder-neck opening in a formerly normally configured bladder base, with bulging of the posterior urethra up to the contracted external sphincter. This VCU finding is the manifestation of sphincter detru-... 

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 so-called reflux nephropathy (RN) of the lower pole is commonly associated with VUR. It may be present already at birth with no pre-existing urinary tract infection (fetal RN). VUR may occur simultaneously in both moieties this implies that the ureteral openings within the bladder are very close or even common. VUR that flows into the upper pole usually only corresponds to an ectopic ureteral opening into the urethra close to the bladder neck (Bissett and Strife 1987). 

Bladder neck reconstruction is undertaken at the age of 4-5 years, where it can be expected that the child can cooperate actively with toilet training. A prerequisite for bladder neck repair is a bladder capacity of more than 60 ml (Ben-Chaim et al. 1996). Since nearly all patients suffer from VUR,new ureteral implantation must also be done. Afterwards muscle flaps are created from the mid-trigone to the prostatic urethra, and these flaps are closed over a catheter in order to produce a bladder neck. In cases where the bladder neck is wide open or continence is inadequate, submucosal injection of Teflon, collagen, or silicone microspheres can be an alternative treatment choice (Kelly 1998). 

VUR into an ectopic ureter that opens into the urethra or near the bladder neck may be difficult to visualize during a conventional VCU (Fig. 11.25). Cyclic filling of the bladder helps to demonstrate this condition, which is usually, but not always, associated with a duplex collecting system (Wyly 1984). A single-system ectopic ureter is usually associated with a small dysplastic kidney. 

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. 

Fig. 14.5. Female, 6 years old daytime and nighttime wetting, VCU. Wide bladder neck anomaly (arrow), vesicoureteric reflux grade 1 (open arrow)...

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-... 

Pediatric radiologists performing ultrasound studies in children with clinical symptoms of nonneurogenic bladder-sphincter dysfunction and in enurectic children should not only evaluate for structural abnormalities, but should search for signs of unstable bladder (open bladder neck) and should measure residual volume after voiding and bladder wall thickness according to published standards (bladder wall thickness varies minimally with age. 

In acontractile bladders (detrusor areflexia), no signs of radiologically detectable detrusor contractions can be found. The bladder neck is open during the entire filling phase in these cases. Sphincter-weakness incontinence is indicated by leakage around the catheter, usually during the rise in intraabdominal pressure or coughing. 

Fig.17.4a,b. Voiding cystourethrogram in an infant with prune belly syndrome, a High-grade reflux into the enlarged ureter b a wide bladder neck as a consequence of an open internal urethral sphincter... 

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