Primary bladder neck obstruction (PBNO) is a functional disorder of the bladder neck characterized by incomplete or inadequate opening, resulting in impaired voiding, in the absence of anatomical obstruction such as urethral stricture, benign prostatic enlargement or sphincteric dyssynergia. While the exact etiology is incompletely understood, early theories suggest possible increased detrusor muscle hyperplasia at the bladder neck [1]. This condition tends to be more common in young and middle-aged men between the ages of 21 and 50 years [2].

We report a case of a 31-year-old male who presented acutely following referral for hypertensive crisis and found incidentally to have an elevated post void residual (PVR) of > 800 mL without symptoms. He endorsed a long-standing history of difficulty voiding including storage symptoms and a weak stream for which he has to perform Crede to empty. He has no history of radical pelvic surgery or neurologic injury. Cystoscopy was negative for urethral stricture or stenosis, no prostatic enlargement, but a tight bladder neck was demonstrated (fig 1. A and B) along with a large left-sided bladder wall diverticulum and significant bladder trabeculation. Prostate volume of 21g. Videourodynamics demonstrated a maximum cystometric capacity of 300 mL, severely impaired compliance (3.96 mL/cmH2O), synergistic electromyography and very low flow on pressure-flow studies. Fluoroscopic images captured the patient performing Crede maneuver to void, without vesicoureteral reflux, bladder diverticulum, and failure of the bladder neck to open (fig. 2).

The patient underwent laser incision of the bladder neck using the GreenLightTM MoXy fiber with incisions performed at the 5 and 7 o’clock locations proximally at the bladder neck moving distally towards the verumontanum and down to the prostatic capsule, resulting in a widely patent aperture (fig 1. C and D, video). On postoperative day one, the patient underwent a successful voiding trial without Crede maneuver and PVR of 101 mL. At three months follow up, his PVR remains < 100 mL with improvement of Qmax to 16 ml/s.

PBNO can be a challenging diagnosis to make, given the myriad of alternative disorders causing lower urinary tract obstruction and dysfunction. A high clinical index of suspicion is critical to initiating early diagnosis with appropriate investigations, namely fluoroscopic urodynamics which demonstrates high pressure voiding with low urinary flow and a closed bladder neck. Treatment may be conservative, pharmacologic or surgical. When surgical treatment is employed, the bladder neck incision technique using laser technology is both safe and effective with immediate and sustained results.

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Padmanabhan P and Nitti VW: Primary bladder neck obstruction in men, women, and children. Curr Urol Rep 2007; 8: 379.