Functional bladder neck obstruction. Voiding cysto-urethrography and pressure-flow measurements.

The results of voiding cysto-urethrography with simultaneous pressure-flow measurements in 24 patients with functional bladder neck obstruction are reported and compared with the findings in 10 healthy younger males. The bladder neck diameter was statistically significantly smaller in the patients (p less than 0.01). Absence of or slight funnelling of the bladder neck during voiding occurred in 79 per cent of the patients. The pressure-flow recording documented infravesical obstruction in the patients. Voiding cystourethrography appears to be mandatory in the diagnosis of functional bladder neck obstruction.