Primary bladder neck obstruction in men—new perspectives in physiopathology

Primary bladder neck obstruction (PBNO) is a dysfunction of the bladder neck (BN) in which the collum vesicae is narrow or fails to open adequately during voiding, resulting in bladder outlet obstruction 1 . The precise cause of PBNO isn’t fully understood, even if, historically, several etiologies have been hypothesized 2 . The clinical presentation of PBNO varies from voiding and storage symptoms, but also pelvic pain and discomfort, with or without ejaculation disorders 2 , 3 , 4 . Its incidence is underestimated but has been reported in 28–54% of young men (age 18–50) with lower urinary tract symptoms (LUTS) 2 . The common young patient with symptomatic PBNO has a low body mass index, limited comorbidity scores, lower PSA levels, and severe IPSS scores but with a small prostate volume 4 , 5 , 6 . A video urodynamic assessment with voiding cystourethrogram could show several degrees of urinary obstruction with adequate detrusor function without an adequate bladder neck opening 1 , 2 . Endoscopically, the features considered suggestive of PBNO are lack of elasticity and hypercontraction of bladder neck (high bladder neck) in the absence of urethral strictures, posterior urethral valves, inflammatory lesions, or foreign bodies 3 , 7 . Only very few studies specifically focus on the risk of developing long-term complications of PBNO (e.g., renal function, detrusor under activity). A better comprehension of the overall pathogenesis, the pathophysiological changes within the bladder neck over time and a broader awareness of PBNO as a differential diagnosis in younger men or men with a lifelong history of voiding disorder is needed. This also provides a basis to establish tailored therapies.