Urodynamics.

UDS = urodynamic study. N/A = not available. Poor bladder compliance = detrusor pressure >10 cm H2O at expected bladder capacity (BC) for age. Bladder hypocontractility = maximal detrusor pressure (Pdetmax)<20 cmH2O. Decreased BC = BC>20% smaller than expected BC for age. Increased BC = BC>20% larger than expected BC for age. PVR = post void residual: >20% of expected BC for age. aMedian. bDefinition PVR: >10% of expected BC for age. c8 boys with anterior urethral valves. d<90% of calculated capacity. epoor compliance defined as <15 mL/cm H2O. fUndergoing 86 UDS (mean 2.8 each) with an interval of at least 3 years between first and last examination.