The nature of detrusor bladder neck dyssynergia in non-neurogenic bladder dysfunction

There have been two major opinions on the pathology or nature of the bladder neck contracture. One is an organic fibrosis, and the other is an accentuated sympathetic nervous function, or detrusor bladder neck dyssynergia. The existence of active detrusor bladder neck dyssynergia in neurogenic bladder was reported in a urodynamical manner using microtip transducer catheters. However, it has not been confirmed whether or not detrusor bladder neck dyssynergia is responsible for bladder neck contracture in patient without neurogenic bladder. The present study was designed to determine by means of video urodynamic study whether or not bladder neck contracture would be of the same nature as detrusor bladder neck dyssynergia in non-neurogenic bladder subjects. The study included 32 male subjects of 16-84 years old (average 52.3): 17 bladder neck contracture subjects including 7 subjects associated with minimum complications (4 with trapped benign prostatic hyperplasia and 3 with incomplete neurological lesion) and 15 non-bladder neck contracture subjects (10 healthy volunteers, 2 chronic prostatitis, 3 prostatodynia). A 5-microtip transducer catheter was used to measure the pressure in the bladder and at the bladder neck, the external urethral sphincter and the bulbous urethra during voiding. Proper localization of the transducers was done with an image intensifier. Bladder outlet obstruction localized at the bladder neck (diameters smaller than 0.75 cm) on voiding cystourethrogram was defined as bladder neck contracture. Detrusor bladder neck dyssynergia was defined where pressures were higher at the level of bladder neck than in the bladder during detrusor contraction. An alpha-blocker, terazosin hydrochloride (0.5 mg, b.i.d., two weeks), was orally administered to subjects judged to have detrusor bladder neck dyssynergia by the above methods for the purpose of confirming whether detrusor bladder neck dyssynergia was really due to accentuated sympathetic nervous function. Detrusor bladder neck dyssynergia was found in seven cases with bladder neck contracture: 6 cases with bladder neck contracture with minimum complications and only 1 case with bladder neck contracture without complications (p < 0.01). Detrusor bladder neck dyssynergia was found at the beginning and ending of micturition, but not at maximum flow. In six cases with detrusor bladder neck dyssynergia, the condition disappeared after terazosin. In conclusion, detrusor bladder neck dyssynergia was not thought to be a major factor of voiding dysfunction in bladder neck contracture in non-neurogenic bladder. In the presence of sympathetic hyperactivity or in cases with increased number of alphareceptors, detrusor bladder neck dyssynergia occurs, being predominantly noted in trapped benign prostatic hyperplasia and neurological disorder patients.