Urinary flow patterns in infants with distal hypospadias.

OBJECTIVE

To investigate preoperative urinary flow patterns in hypospadic infants and compare them to those from normal infant boys.

PATIENTS AND METHODS

Twenty-one boys (median age 14.0, range 12.8-21.6 months) referred for distal hypospadias surgery were compared to 19 healthy boys (median age 12.0, 9.2-19.8 months). In both groups a 14-mm transit-time ultrasound flow probe mounted around the base of the penis continuously registered uroflow.

RESULTS

Median maximum flow rate (Q(max)) was significantly lower in hypospadics (2.4 vs 4.4 ml/s, P < 0.01) while there was no difference in the voided volume per micturition (19.0 vs 21.0 ml, P 0.33). Flow curve pattern analysis revealed plateau-shaped curves in 31% of hypospadics compared to none in normal infant boys. Interestingly, dyscoordinated flow curves (interrupted, staccato, spike-dome) were less common in the hypospadics (36% vs 64%, P < 0.01). Meatal size did not correlate to Q(max) (rho = 0.26, P = 0.26).

CONCLUSIONS

Infants with hypospadias void with a lower Q(max) and a lesser degree of dyscoordination as compared to normal infant boys. It can be speculated that decreased urethral compliance may contribute to the lower Q(max) and may act as a silencer for dyscoordination.