Urine flow rates and residual urine volumes in urogynecology patients

Two hundred and fifty consecutive women referred because of symptoms of lower urinary tract dysfunction underwent a full clinical and urodynamic assessment. Their urine flow rates and residual urine volumes were analyzed. The urine flow rates of the urogynecology patients were found to be significantly less than those of an asymptomatic population. There were significant declines in urine flow rates in the presence of a previous hysterectomy and with increasing grades of prolapse, particularly uterine prolapse, cystocele and enterocele. Unlike the normal female population, there was also deterioration with increasing parity and age, the latter largely due to the increasing incidence of hysterectomy and prolapse with age. The 10th centile of the Liverpool Nomogram for the maximum urine flow rate was found to be the most useful discriminant for a final urodynamic diagnosis of voiding difficulties. Most urogynecology patients have no or small residual urine volumes, 74% < 10 ml and 81% < 30 ml (vs 95% < 30 ml in asymptomatic women). In urogynecology patients residuals were larger where there had been a prior hysterectomy or with grade 2 or higher uterine prolapse, cystocele and enterocele. Mean residual was 14.8 ml (vs 4.8 ml in asymptomatic women). These data indicate a higher incidence of voiding difficulties (abnormally slow urine flow (under 10th centile) and/or abnormally high residual urine volume (over 30 ml) in urogynecology patients, particularly those with higher grades of prolapse and with prior hysterectomy.