ICS
1999, Denver
Informally discussed
posters
Urodynamics
Pressure-flow
study for bladder outlet obstruction in female: a prospective study
H.S. Kim, S.J. Oh, C.S.
Kang, M.S. Choo
Department of Urology, Asan medical Center, University of Ulsan College of Medicine,
Seoul, Korea
Aims of Study: There is some controversy in the literature as to standardized definition of bladder outlet obstruction (BOO) in female (1,2). Also there is no accepted urodynamic criteria of BOO in women. We attempted to find out useful urodynamic parameters for the diagnosis of BOO in women.
Methods: Two groups, control and clinically BOO patients were studied prospectively from September 1998 tot January 1999. All had a complete history, physical examination, normal neurologic evaluation, uroflowmetry, and urodynamics (pressure-flow study with 6 Fr. Triple lumen catheter). The control group consisted of women with stress urinary incontinence who had no previous history of pelvic surgery or urethral pathology. The obstructed group was defined by their obstructive symptoms, peak flow < 12 ml/s in uroflowmetry (2), significant residual urine (> 50 ml), and good detrusor contraction. To predict obstruction, comparisons were made between two groups; receiver operator characteristic (ROC) curve analysis was used to determine the optimum cutoff values for peak flow rate (Qmax), detrusor pressure at maximum flow (PdetQmax), free flow residual urine (FFRU), CMG flow residual urine (CFRU) and maximal urethral closing pressure (MUCP).
Results:
One hundred and three patients were available for the analysis, of which 17 were obstructed by clinical definition and 87 served as a control. Three women who were not met aforementioned criteria were excluded. Obstructed group was consisted of the patients with previous anti-incontinence surgery (7pts.), urethral stricture (3 pts.) and idiopathic or functional obstruction (7pts.). Qmax in pressure-flow study for the control group was 17.6 ± 0.9 ml/s (mean ± SD) and for the obstructed group, 7.9 ± 0.8 ml/s (student t-test, P<0.05). PdetQmax for the control group was 31.1 ± 1.7 cmH2O and for the obstructed group, 55.3 ± 5.4 cmH2O (P<0.05). FFRU and CFRU for control group were 27.6 ± 8.2 ml, 38.5 ± 8.4 ml and for obstructed group, 39.5 ± 9.1 ml and 174.6 ± 36.0 ml, respectively. During pressure-flow study, residual urine was much more exaggerated in obstructed group than in control group (P<0.05). MUCP for the control group was 57.5 ± 2.0 cmH2O and for the obstructed group, 97.3 ± 2.9 cmH2O (P<0.05). On the basis of ROC curves, using cutoff values of Qmax< 12 ml/s and < 10 ml/s, sensitivity were 93.8% and 75.0%, and specificity 78.0% and 89.0%, respectively. Using PdetQmax > 40 and > 30 cmH2O, sensitivity were 75.0% and 100%, and specificity 77.1% and 54.2%. Using MUCP > 80 cmH2O, sensitivity was 94.1% and specificity 84.0%. Because the ranges of FFRU and CFRU were too wide in both groups, these parameters were not valid. Using a combined cutoff value of Qmax< 12 ml/s and PdetQmax > 30 cmH2O, sensitivity was 93.8% and specificity, 91.5%. Using a combined cutoff value of Qmax< 12 ml/s and PdetQmax > 30 cmH2O, and MUCP > 80 cmH2O, sensitivity was 85.4% and specificity, 95.2%. Although the sensitivity of cutoff value by three parameters (Qmax , PdetQmax and MUCP) was lower than that by two parameters (Qmax , and PdetQmax ), the specificity of the former was higher than that of the latter.
Conclusions: Although the exact diagnosis of BOO in female on the basis of pressure-flow parameters is difficult, our results show that BOO might be diagnosed by the criteria of Qmax<12 ml/s, PdetQmax > 30 cmH2O, and MUCP > 80 cmH2O. Residual urine volume does not seem to be of valid predictive value in our study. MUCP, however, could be an additional parameter for the diagnosis of BOO if combined with pressure-flow plot.
References