Spinning top urethra

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). 

Urodynamic studies coupled to a VCU are mandatory for the proper management of severely affected patients (Potter et al. 1986 Sillen 1999a Pfister 1999). On VCU, the bladder wall appears trabecu-lated and thickened, diverticula maybe present, the urethra is large (spinning top urethra), and the bladder neck appears tightened (Baunin 1993). 

Fig. 14.2a-c. Male, 2 months old moderate bilateral fetal hydronephrosis, VCU. Reduced bladder filling volume (20 ml) residual urine early uninhibited detrusor contractions transformed into premature micturition, a Minor bladder trabecu-lation, short phase of normal micturition. b,c Dyscoordinated voiding, contraction of external urethral sphincter dilated posterior urethra, male spinning top urethra... 

Fig. 14.4. Female, 6 years old daytime wetting, VCU. High-grade spinning top urethra, marked widening of the muscular segment of the urethra during voiding...

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. 

Risdon RA, Yeung CK, Ransley PG (1993) Reflux nephropathy in children submitted to unilateral nephrectomy a clinicopathological study. Clin Nephrol 6 308-314 Savage JP (1973) The deleterious effect of constipation upon the reimplanted ureter. J Urol 109 501-503 Saxton HM, Borzyskowski M, Mundy AR et al (1988) Spinning top urethra not a normal variant. Radiology 168 147-150... 

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