Bladder Neck Angle Associated with Lower Urinary Tract Symptoms and Urinary Flow Rate in Patients with Benign Prostatic Hyperplasia

To evaluate the effect of the funnel-shaped structure of the bladder neck in patients with benign prostatic hyperplasia (BPH), we investigated the correlation of the bladder neck angle (BNA) with the urinary flow rate and lower urinary tract symptoms (LUTS).The cohort comprised 281 first-visit patients. The anatomical prostatic parameters, including BNA, total prostate volume, prostate urethral angle, intravesical prostatic protrusion, and prostate urethral length, were measured by transrectal ultrasonography. The International Prostate Symptom Score (IPSS), postvoid residual urine volume, and uroflowmetric measurements were evaluated.As revealed by multivariable linear regression analysis, BNA was independently associated with the peak flow rate (Qmax) and IPSS. The mean BNA significantly differed according to the severity of prostate symptoms and Qmax, and the mean BNA was 85.5°±17.4° and 89.84°±16.31° in patients with severe prostate symptoms and a Qmax<10 ml/s (P <0.001 and <0.001, respectively). The linear regression analysis showed that BNA was positively associated with the total IPSS (R = 0.718, P <0.001) and inversely associated with Qmax (R = 0.569, P <0.001). In addition, the mean BNA in patients with acute urine residual (AUR) was higher than that in patients without AUR (86.04°±16.36° vs 63.75°±15.14°, P <0.05).BNA is significantly correlated with LUTS and urinary flow rate in patients with BPH. Our findings suggest that BNA could play an important role in the pathogenic mechanism of BPH and AUR.