[Detrusor instability--an important but underestimated factor in urinary incontinence in women]

157 consecutive female patients complaining of urinary incontinence were studied by history and urodynamics. 21 of them (13.4%) demonstrated urge-incontinence due to severe detrusor instability, 20 (12.7%) showed mixed (both urge and stress) incontinence, 14 (9%) only detrusor instability and 12 (7.6%)--stress incontinence accompanied by detrusor instability. Pure stress incontinence was diagnosed in 79 cases (50.3%) while 11 patients (7%) manifested no abnormality during the urodynamics. A total of 67 patients (42.7%) showed urodynamic evidence of detrusor overactivity. In 55 (35% of the studied subjects) it was the main urodynamic finding. The prevalence of detrusor instability was higher among those with recurrent incontinence and was the highest (60%) among the women with more than one previous operations. When urge incontinence was present it occurred at detrusor pressures lower than the maximum urethral closure pressure, which implies possible failure of the sphincteric mechanisms associated with detrusor instability. 14% of the women with detrusor instability did not report complaints typical for this disorder but had history of stress incontinence alone. The authors confirm the necessity of objective assessment of the lower urinary tract in all cases with history suspicious of detrusor instability as well as when surgical treatment for stress incontinence is planned.