• bladder neck dysfunction;
  • bladder outlet obstruction;
  • dysfunctional voiding;
  • urethral stricture

Objective: To analyze the lower urinary tract symptoms (LUTS) and video-urodynamic characteristics of women with clinically unsuspected bladder outlet obstruction (BOO).

Methods: From 1997 to 2010, a total of 1605 women with bothersome LUTS received video-urodynamic study in our unit. We reviewed the charts of 212 women diagnosed with BOO based on video-urodynamic criteria and 264 women without abnormal findings. LUTS and urodynamic parameters were compared between obstructed and unobstructed cases and among the BOO subgroups.

Results: The mean ages of the BOO (58.2 years) and control groups (58.8 years) were similar. The mean values of detrusor pressure at maximum urinary flow rate (PdetQmax)/maximum flow rate (Qmax) of the BOO and control groups were 51.83 cm H2O/10.22 mL/s versus 18.81 cm H2O/20.52 mL/s. In the BOO group, cinefluoroscopy revealed dysfunctional voiding in 168 patients (79.2%), urethral stricture in 17 (8.0%), and bladder neck dysfunction in 27 (12.7%). Patients with dysfunctional voiding had significantly lower urethral resistance compared with the other two BOO subgroups. Combined lower urinary tract symptoms were present most often in all BOO patients (69.3%), followed by isolated storage symptoms (30.2%) and isolated voiding symptoms (0.5%). Seventy-seven patients (37.3%) had dysuria and 79 patients (36.3%) had frequency as their main symptom.

Conclusion: Women with BOO usually have nonspecific LUTS. Dysfunctional voiding was the most common form among women with clinically unsuspected BOO, but the degree of obstruction was less severe than with primary bladder neck obstruction and urethral stricture.