Diagnostic Value of Pressure-Flow Study Parameters in Women With Anatomical Bladder Outlet Obstruction

Purpose: This study aimed to evaluate the diagnostic value of pressure-flow study parameters in female patients with anatomical bladder outlet obstruction (BOO) and to investigate the association between obstruction location and urodynamic findings.Methods: A total of 72 women with anatomical BOO who underwent urodynamic examination between January 2007 and October 2023 were retrospectively analyzed. Based on obstruction location, patients were categorized into 3 groups: external urethral meatus stenosis (n=18), urethral stricture (n=49), and bladder neck obstruction (n=5). Urodynamic assessments included free-flow maximum flow rate (Qmax), postvoid residual urine volume, filling cystometry, and a pressure-flow study.Results: Statistically significant differences were observed between groups in free-flow Qmax, urethral caliber, and pressure-flow parameters. Bladder Outlet Obstruction Index - Female, Dybowski index, urethral resistance factor, obstruction coefficient (OCO), and Woman Obstruction Index values were significantly higher in the urethral stricture group than in the other groups (P=0.022, P=0.025, P=0.031, P=0.031, and P=0.031, respectively). The Blaivas-Groutz nomogram classified all patients as obstructed, regardless of obstruction location. Diagnostic accuracy exceeded 90% when using the Barco-Castillo, Dybowski, and OCO indices; however, the accuracy varied by obstruction location.Conclusions: In women with anatomical BOO, the diagnostic performance of pressure-flow studies varies by the anatomical location of the obstruction. While urethral strictures yield high diagnostic rates, external urethral meatus stenosis may be underdiagnosed by urodynamic assessment alone. This variability remains a challenge in standardizing BOO diagnosis in women.