Urodynamic analysis of successful and failed incontinence surgery.

Seventy-nine patients were investigated by simultaneous urethrocystometry before and, on average, 15 months after vaginal and/or suprapubic operations for stress urinary incontinence. Subjective and objective success rates were 78% and 60%, respectively, with no significant differences between operation types. Patients with a low (less than 0.6) index of urethral relaxation at stress preoperatively indicating excessive loss of basal urethral pressure at stress, had objective success rates of 39% whereas a higher index was associated with a success rate of 70%. Maximal urethral closure pressure and functional urethral length did not correlate with the operative result and were virtually unchanged postoperatively. Successful operations increased the index of urethral relaxation at stress and urethral pressure peaks at stress especially in the distal functional urethra. No significant quantitative differences except for sling operations producing higher urethral closure pressure at stress in the proximal and lower in the distal functional urethra compared to the other operations were found. The results indicate, that successful operations eliminate the failure to maintain adequate basal urethral pressure at stress and emphasizes the importance of reflex activity of pelvic floor musculature at stress for continence.