Wide bladder neck anomaly

The bladder neck is the poorly delineated junction between the bladder and urethra at the level of the internal urethral sphincter. At the beginning of voiding the bladder floor descends and becomes funnel-shaped and in continuity with the proximal urethra. At the end of voiding, the bladder base ascends to its normal position. A wide bladder neck and a dilated proximal urethra during voiding (wide bladder neck anomaly and spinning top urethra, respectively) are variants that will be discussed in Chapter 14 on nonneurogenic bladder-sphincter dysfunction (functional disorders of the lower urinary tract). 

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... 

A slightly modified VCU technique allows the diagnosis of unstable detrusor contractions with similar accuracy to urodynamic techniques. Spinning top urethra and wide bladder neck anomaly, even in the absence of unstable bladder, should alert the attention to occult or healed dysfunction. 

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

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