Video cystometry in newborn with no apparent voiding dysfunction

Objective To investigate the urodynamic pattern in infants with no apparent lower urinary tract symptoms. Methods Video cystometry with simultaneous perineal EMG recording was performed in 14 infants (10 male and 4 female,age 2 d to 2.5 months) with congenital renal pelvis dilatation who were screened for potential bladder dysfunction and VUR.No abnormal lower urinary tract was observed at examination. Results The post-voiding residual urine volume was (1.2±0.8)ml.The maximum bladder capacity was (33±24)ml,with voiding efficiency being 0.87±0.17.Detrusor instability occurred in 21%(3/14) of the subjects. The intermittent voiding pattern was observed in 64% (9/14) of the subjects and characterized by one or repeated increase in sphincter activity with simultaneous rise in voiding detrusor pressure curve. The maximum voiding detrusor pressure was (74±24)cmH 2O.The peak voiding detrusor pressure induced by dyssynergia could rise up to more than 100 cmH 2O. Conclusions In infants with no apparent lower urinary tract symptoms,bladder instability is uncommon,but the capacity is lower than the expected normal range.The high voiding pressure is induced by detrusor-sphincter dyssynergia.