Association of high bladder neck elevation with urodynamic bladder outlet obstruction in patients with lower urinary tract symptoms and benign prostatic hyperplasia

Objective To ascertain the association of cystourethroscopic findings of bladder neck elevation with urodynamic bladder outlet obstruction (BOO) in patients with lower urinary tract symptoms and benign prostatic hyperplasia (LUTS-BPH). Materials and Methods Study subjects were 646 consecutive men aged >40 years diagnosed with LUTS-BPH at Seoul National University Hospital from December 2005 through January 2012. We collected the International Prostatic Symptom Score, serum prostate-specific antigen levels, prostate volume measured by transrectal ultrasonography, uroflowmetry with postvoid residual volume, and urodynamics with a pressure flow study. We examined the degree of lateral lobe protrusion of prostate, bladder neck elevation degree (BNE-D), and bladder neck elevation angle (BNE-A) under a cystourethroscopic examination. Results When we examined BNE by cystourethroscope, the mean BNE-A was 26.1°. Higher BNE-D was strongly positively correlated with BNE-A, but neither was associated with the degree of lateral lobe protrusion of prostate. Patients with higher BNE-A (≥35°) had higher BOO index and more obstructed voiding patterns than those with lower BNE-A (<35°). BNE-A was positively correlated with BOO index (r = 0.186). However, we identified only total prostate volume (odds ratio [OR], 1.036), maximal flow rate (Qmax; OR, 0.843), and detrusor pressure at Qmax (PdetQmax; OR, 1.278) as significant predictors of BOO in the multivariate analysis. Conclusion In sum, patients with higher BNE-A (≥35°) by cystourethroscope had higher BOO index and more obstructed voiding patterns than those with lower BNE-A (<35°). Moreover, both BNE-D and BNE-A were positively correlated with BOO index. Thus, cystourethroscopic findings of BNE status can be helpful to predict urodynamic BOO in the patients with LUTS-BPH.