Urodynamic parameters for the diagnosis of bladder outlet obstruction in women

Introduction: Bladder outlet obstruction ( BOO) is often overlooked in the diagnosis of women with lower urinary tract symptoms. Although the incidence of BOO is not high in the female population with lower urinary tract symptoms, a correct diagnosis for BOO is important. This study was designed to compare the urodynamic parameters in women with bladder outlet obstruction ( BOO), stress urinary incontinence ( SUI) and asymptomatic volunteers. Materials and Methods: Videourodynamic study was performed in 76 patients who were clinically diagnosed as BOO, 265 with stress urinary incontinence ( SUI). In addition, 30 asymptomatic female volunteers were recruited and served as controls. Voiding pressure (P-det.Qmax), maximum flow rate (Qmax), and urodynamic parameters were compared among the BOO, SUI and control groups and the criteria values for BOO in women were estimated. Results: BOO was identified in 30 women with bladder outlet stricture, 40 women with dysfunctional voiding, and 6 women with high-grade cystocele. The mean P-det.Qmax was significantly higher and the mean Qmax was significantly lower in the obstructed groups. When a P-det.Qmax greater than or equal to35 cm H2O was set as the criteria for BOO, the sensitivity was 96.1% and specificity was 89.0%, whereas a P-det.Qmax of greater than or equal to30 cm H2O had a sensitivity of 100% but the specificity was only 65.5%. If the criteria of BOO was set as P-det. Qmax greater than or equal to35 cm H2O combined with Qmax less than or equal to 15 ml/s, the sensitivity for BOO was 81.6% and specificity was 93.9%. Conclusions: Our results demonstrate a P-det. Qmax of greater than or equal to30 cm H2O is a good index value for screening of female BOO. When a P-det. Qmax of greater than or equal to35 cm H2O combined with a Qmax less than or equal to 15 ml/ s was found, a high suspicion of BOO should be raised, for which a specificity of 93.9% and sensitivity of 81.6% for BOO was obtained. Copyright (C) 2004 S. Karger AG, Basel.