NATURAL FILLING CYSTOMETRY IN SMALL BOYS WITH POSTERIOR URETHRAL VALVES - UNSTABLE VALVE BLADDERS BECOME STABLE DURING SLEEP

Purpose: Our aim was to demonstrate the voiding pattern in small boys with posterior urethral valves during the day and night. Materials and Methods: Long-term natural filling and standard cystometry was perfor med in 16 boys 1.4 to 6 years old (mean age 3.4) in whom posterior ure thral valves were diagnosed in infancy. The boys were divided into 2 g roups according to whether they had day incontinence. Results: All boy s had instability in the daytime but at night bladders were mainly sta ble. Voiding frequency during the day was high at a mean of 1.7 and 0. 5 voidings per hour in the day incontinent and day continent groups, r espectively, compared to 0.1 voiding per hour at night in both groups. Voiding detrusor pressure was higher and functional bladder capacity was lower during the day than at night in both groups. Conclusions: Na tural filling cystometry revealed pronounced instability during the da y and stable bladders at night. This difference between day and night is an important factor contributing to frequent small voidings during the day, dry nights and high bladder volume in the morning.