Bladder Outlet Obstruction in the Female Overactive Bladder: Correct Diagnostic Criteria for Bladder Outlet Obstruction?

Abstract

Puropose: We analyzed retrospectively the result of urodynamic studies of the female patients with overactive bladder to reveal the incidence of accompanying bladder outlet obstruction and compared the urodynamic charateristics according to the diagnostic criteria for bladder outlet obstruction to help make the appropriate diagnosis. Material and methods: A total of 230 women who underwent urodynamic studies for evaluation of overactive bladder were retrospectively reviewed. The patients were classified as having obstruction based on two criteria, including one pressure flow cutoff point criteria (free Qmax < 12ml/ sec and pdetQmax ≧ 20cmH2O) (group I) and moderate or severe obstruction by the Blaivas- Groutz nomogram (group II). Urodynamic characteristics of the patients in Group 1 and 2 were compared with those of 42 patients having only overactive bladder without any voiding symptom (OAB group). Results: Of the patients 31 (13.5%) were in group I, 42 (18.3%) in group II. Qmax of group I was the lowest among 3 groups. Detrusor pressure at maximum measurable flow and maximum detrusor pressure during voiding in group 1 and II were significantly higher than in OAB group. Detrusor overactivity was more observed in group I and II, and there was no signigicant difference in the presence of voiding symptoms between group I and II. Only 9 patients (4%) had obstruction by both of criteria. Conclusions: Considering the high incidence of bladder outlet obstruction in the patients of overactive bladder and non-specificity of the symptoms by bladder outlet obstruction, thorough urodynamic study may be helpful in detection and treatment of bladder outlet obstruction of the overactive bladder patients. The further study for the criteria of female bladder outlet obstruction should be necessary to make its accurate diagnosis. (J Korean Continence Soc 2008;12:145-9)