Degree of female stress urinary incontinence: an objective classification by simultaneous urethrocystometry

Urodynamic examinations carried out on 45 patients with stress urinary incontinence (SUI) and 17 women without a history of incontinence using simultaneous microtransducer urethrocystometry were examined in order to develop an objective indicator of the severity of the condition. Five urethral pressure profiles (UPP) with stress were recorded, maintaining a constant coughing strength as seen in the bladder pressure rises. The coughing strength was increased stepwise for successive profiles. Zero urethral closure pressure, indicating genuine SUI, appeared with bladder pressure rises of less than 50, 75 and 100 mm Hg and of 100 mm Hg or more in 7, 27, 45 and 67% of the 45 symptomatic patients, respectively. 33% had a positive closure pressure in every UPP. 2 women without symptomatic incontinence had negative urethral closure pressures. The lowest bladder pressure rise needed for zero urethral closure pressure showed a significant negative correlation with the clinical grade of SUI and the degrees of social restriction experienced. We suggest that SUI can be classified urodynamically into minimal (lowest bladder pressure rise producing zero urethral closure pressure 100 mm Hg or more), mild (75-99 mm Hg), moderate (50-74 mm Hg) and severe forms (less than 50 mm Hg).