Is the mode of occurrence of vesicoureteral reflux correlated to bladder function and spontaneous resolution

Abstract Purpose To investigate whether mode of occurrence of vesicoureteral reflux (VUR), during micturition (M), during filling without increase in pressure (passive, P) or in response to an overactive contraction (OA), can be explained by differences in bladder function. Also, to study if the mode of occurrence of VUR can predict spontaneous resolution. Materials and methods There were 93 infants (68 boys and 25 girls) with VUR (grade III–V) included. Videocystometry was performed at median ages 5, 22 and 32 months registering grade and mode of reflux and bladder function characteristics. Results Mode of occurrence of reflux changed with age. During infancy P, OA and M reflux comprised almost equal parts. At follow up, P reflux had increased and both OA and M reflux had decreased. This was partly due to a significantly higher probability of spontaneous resolution for M than P reflux, at 40 months (42 vs 18%). P and M reflux were significantly correlated to bladder function characteristics. P reflux was seen in children with high bladder capacity and occurred early in filling. Other predictors were higher age within the respective group and female sex. M reflux was correlated to lack of residual urine, low bladder capacity and absence of overactivity. Other indicators were male sex and low-grade reflux. Conclusions P and M reflux correlate to different bladder patterns: P with high bladder capacity and M with low bladder capacity and without signs of bladder dysfunction. M seems to be benign with a higher resolution rate.