Urodynamic evaluation of dysfunctional bladder neck obstruction in men.

Dysfunctional bladder neck obstruction in young men has received increasing interest in recent years. The urodynamic characteristics of this disorder include elevated voiding pressure, normal reflex relaxation of the urethral rhabdosphincter, increased pressure gradient between the membranous urethra and the bladder, and inadequate radiographic bladder neck opening during detrusor activity. The functional changes occurring at the internal sphincter in 3 patients with dysfunctional bladder neck obstruction are described herein. It is demonstrated that the obstruction may result from either an active dyssynergic bladder neck contraction or failure of bladder neck relaxation. While the pathophysiology of dysfunctional bladder neck obstruction is uncertain possible mechanisms are discussed.