- Primary bladder neck obstruction (PBNO) is a functional obstruction of the bladder caused by abnormal opening of the bladder neck during the voiding phase. A variety of symptoms may be present, including voiding symptoms such as hesitancy, poor stream, inttermitent stream, incomplete emptying and urinary retention; storage symptoms such as frequency, urgency, urgency incontinence and nocturia; suprapubic discomfort and urinary tract infection.
- The true prevalence of PBNO in women is not know. It is estimated that 4.6% to 16% of women presenting with obstructive voiding have PBNO (1,2).
- There are multiple theories as to the etiology of PBNO, including fibrous narrowing, hyperplasia, abnormal quantities of non-muscular connective tissue, abnormal morphologic arrangement of the detrusor/trigonal musculature and also increased sympathetic nervous system activity exerting an effect at the level of the bladder neck.
- The diagnosis can be made by videourodynamic which demonstrates high-pressure with low-flow voiding.  Fluoroscopic image demonstrates obstruction at the bladder neck.
- Treatment options include conservative and pharmacologic management, and surgical intervention.

Case report:

Female, 60-year-old
Long-standing voiding symptoms (hesitancy, poor stream and intermittent flow)
UTI in the last 10 years
Two episodes of urinary retention

Previous history:
Two vaginal labours
No cesarian, nor abortions
No pelvic surgery

Urologic evaluation:
Ultrasound: bilateral hydronephrosis
Videourodynamic (attached in the video presentation): high-pressure, low-flow voiding dynamics with obstruction at the bladder neck and vesicoureteral reflux (Fig 1). 
Qmax: 3ml/s
Pdet max: 148cmH2O
VV: 152 mL
PVR: 480 mL

Patient was submitted to bilateral transurethral incision of the bladder neck (attached in the video presentation).
Transurethral 5 and 7 o'clock incisions of the bladder.
The results were reviewed with follow-up of three months. 
There was marked symptomatic improvement after transurethral incision of the bladder outlet. 
The peak urine flow rate increased from 3.0 ml/s to 46 ml/s (Fig 2) and no signal of urinary incontinence.

Videourodynamic is a valuable tool that shows a relative high-pressure, low-flow voiding with radiographic evidence of obstruction at the bladder neck and allow to make the differential diagnosis with dysfunctional voiding.
In properly diagnosed cases, 5 and 7 o’clock transurethral incision of the bladder neck is an effective procedure for relief of bladder outlet obstruction in woman.

Kuo HC. Videourodynamic characteristics and lower urinary tract symptoms of female bladder outlet obstruction. Urology. 2005;66:1005-1009.
Brucker BM, Fong E, Shah S, et al. Urodynamic differences between dysfunctional voiding and primary bladder neck obstruction in women. Urology. 2012;80:55-60.