Introduction: To investigate if potty training from infancy can affect bladder dysfunction in boys with posterior urethral valves (PUV). Subjects and Methods:The voiding pattern and emptying ability were followed using the 4-hour voiding observation method in 17 Vietnamese boys with PUV aged 3 months to 4 years who had been potty-trained from infancy. This group was compared with a group of healthy Vietnamese boys. Results: In the boys with PUV, the bladder volume increased according to age, and interrupted voiding was rare. However, when comparing boys with PUV with healthy boys, a significant difference was noted with more frequent voidings and lower voided volumes in the age group 0 -1 year (P < 0.001). Despite the minimum amount of residual urine, average 8 ml or less in the boys with PUV, the age groups 1 -2 and 2 -4 years had significantly higher residual volumes compared with those of the healthy boys (P < 0.001). Conclusion: The findings from the 4-hour voiding observation showed few signs of dysfunctional bladder in the Vietnamese boys with PUV, including residual urine, even if there were signs of dysfunction compared with the healthy Vietnamese boys. Potty training from infancy could favor early bladder rehabilitation in boys with PUV.

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