Effect of suprapubic operation on urethral closure. Evaluation by single cough urethrocystometry.

To evaluate urodynamic effects of modified Burch colposuspension, 24 patients with stress urinary incontinence were investigated before and 6 to 9 months after the operation. A new method of urodynamic evaluation was performed using a multitransducer-catheter, 5 microtransducers inside the urethra and 1 in the bladder, connected to a computer and graphic plotter. Single coughs were analysed with the catheter in a fixed position and the patient in the standing position. The operation, which was successful, in all but 1 patient, did not alter urethral pressure at rest, but urethral closure pressure at stress after the operation (mean 45.0 cm H2O (SD 21.6) was significantly higher (P less than 0.005) than the -3.6 cm H2O (SD 10.2) recorded before the operation. The pressure transmission ratio was less than 100% in 22 patients before the operation and more than 100% in 18 patients afterwards, the pre- and post-operative mean values being 78.9% (SD 11.9) and 109.5% (SD 17.2) respectively (P less than 0.0005). Burch colposuspension markedly improves urethral closure function as evaluated by this method, which analyses the pressure data at different points of the urethra and bladder during one single cough.