Role of poor urethral sphincter relaxation in men with voiding dysfunction refractory to α-blocker therapy: Clinical characteristics and predictive factors

This study evaluates the diagnostic value of poorly relaxed external sphincter (PRES) in men with voiding dysfunction. We analyzed clinical and video-urodynamic characteristics to identify predictive factors of PRES in patients with lower urinary tract symptoms (LUTS) refractory to α-1 adrenoceptor blocker (α-blocker) therapy.

This retrospective study included 3379 men with LUTS in whom the initial 1-month α-blocker therapy failed. Clinical parameters and video-urodynamic results were analyzed. Patients with bladder outlet disorders including bladder neck obstruction (BNO), benign prostatic obstruction (BPO), urethral stricture (US), or PRES were categorized according to video-urodynamic findings. Predictive factors for PRES were analyzed.

A total of 3379 men were included in this study. Among the patients with voiding dysfunction, 905 (43.6%) had BPO, 624 (30.0%) had BNO, 487 (23.4%) had PRES, and 62 (3.0%) had US. Patients with PRES were younger and had a higher maximum flow rate, larger bladder capacity, smaller total prostate volume (TPV) and transition zone index, and a lower rate of LUTS of urgency or urge urinary incontinence (UUI) than other groups. On multivariate analysis, only small TPV and lower urgency/UUI rate were predictive factors of PRES. A scale composed of voided volume, TPV, and urgency/UUI predicted PRES with high specificity.

PRES was the etiology of voiding dysfunction in 23.4% of the men with LUTS refractory to α-blocker therapy. A simple scale composed of voiding volume, TPV, and urgency/UUI was useful in predicting the presence of PRES before video-urodynamic studies.