[Measurement of urinary flow velocity and peak flow rate in the detection of subvesical obstructions in boys].

Urinary flow velocity and urinary peak flow rate were measured in 41 boys. Using combined urodynamic and radiological methods 23 boys showed proximal and/or distal urethral obstruction, whilst 18 boys had no signs of subvesical obstructions. The peak flow rate alone does not discriminate reliably between the normal and abnormal population. Many boys with normal flow rates showed subvesical obstruction on measurement of the peak urinary velocity. In spite of the fact that flow velocity determination alone only partially discriminated between the different groups, in combination with uroflowmetry it proved to be a valuable secondary non-invasive parameter. The flow velocity vs. flow rate diagram is shown to be a good tool for the urodynamic classification of boys with subvesical obstruction.