Primary bladder neck obstruction (PBNO) is a functional disorder characterized by inadequate bladder neck opening during voiding, leading to bladder outlet obstruction (BOO). It predominantly affects younger men but accounts for 4.6%–8% of female BOO cases. Diagnosis typically relies on videourodynamic studies (VUDS). Although α-blockers, botulinum toxin A (BoNT-A) injections, and transurethral incision of the bladder neck (TUI-BN) are available treatments, optimal strategies, especially for women, remain uncertain. This study aimed to evaluate PBNO treatment outcomes.

This retrospective study included patients aged ≥18 years diagnosed with PBNO by VUDS between January 2019 and January 2024. Exclusion criteria included neurological disorders, prior urological surgeries, other BOO etiologies, or incomplete follow-up within one year. Treatments comprised α-blockers, bladder neck BoNT-A injection, and TUI-BN. Outcomes were changes in uroflowmetry parameters, post-void residual (PVR) volume, and subjective symptom improvement. Statistical analysis was performed using SPSS, with significance set at P < 0.05.

Fifty-two patients (29 females, 23 males; mean age 55.1 years) were included, treated with α-blockers (n=32), TUI-BN (n=16), or BoNT-A injection (n=4). 
Among 34 patients with follow-up uroflowmetry data within three months, the TUI-BN group showed the greatest improvements in voided volume (+95.49%), Qmax (+199.07%), and mean flow rate (+197.45%), but no significant differences among groups were found (voided volume p=0.516; Qmax p=0.264; mean flow rate p=0.1).  
Among 37 patients with follow-up PVR data, graded on a six-point scale, the TUI-BN group achieved the greatest PVR grade reduction (mean −0.55), followed by the α-blocker group (−0.5), while BoNT-A patients had worsened PVR (+0.75). Differences were not statistically significant (p=0.277).  
Subjective symptom improvement within three months was assessed in 48 patients using a simplified Global Response Assessment (GRA) 7-point scale (−3 to +3). The mean GRA score was 1.45, with the highest score in the TUI-BN group (1.8) and the lowest in the α-blocker group (1.21), with no significant intergroup difference (p=0.086).

Although no statistically significant differences were observed among the three treatment groups, trends favored TUI-BN in both objective and subjective outcome measures. Patients undergoing TUI-BN exhibited the greatest improvements in uroflowmetry parameters, including nearly a twofold increase in Qmax and mean flow rate, suggesting enhanced bladder emptying efficiency compared to α-blockers and BoNT-A injections. Similarly, the TUI-BN group demonstrated the most substantial reduction in PVR grades, indicating better post-void bladder evacuation.

Regarding subjective symptom improvement, the highest Global Response Assessment (GRA) scores were observed in the TUI-BN group (mean 1.8), while the α-blocker group showed the lowest improvement (mean 1.21). Interestingly, the BoNT-A injection group achieved a relatively high mean GRA score of 1.75 despite minimal objective improvements. This discrepancy may reflect a stronger placebo effect associated with undergoing procedural interventions.

Although statistical significance was not reached, TUI-BN showed trends toward better voiding efficiency and PVR reduction compared with other treatments. These findings emphasize the need for greater awareness of PBNO in women and highlight the necessity for larger prospective studies to optimize treatment strategies.

Markic, D., Maricic, A., Oguic, R., Spanjol, J., Rahelic, D., Rubinic, N., & Valencic, M. (2014). Transurethral bladder neck incision in women with primary bladder neck obstruction. Wiener klinische Wochenschrift, 126(7–8), 217–222. https://doi.org/10.1007/s00508-014-0502-z