The role of prostatic apex shape in voiding symptoms and urine flow: an exploratory and confirmatory study

Purpose Lower urinary tract symptoms in men have previously been attributed to obstruction from an enlarged prostate. However, several factors in addition to prostate volume have been identified as impacting urine flow. Prostatic apex shape is one factor that has not been evaluated. This study evaluates the relationship between prostatic apex shape and voiding symptoms and urine flow. Methods A retrospective, exploratory data review was conducted for 806 healthy men who underwent routine transrectal ultrasonography at our hospital, and data for 329 patients with uroflowmetric measurements were reviewed for the confirmatory study. Patients were categorized into four groups according to the prostatic apex shape on midsagittal ultrasonography. The association between prostatic apex shape and voiding symptoms was investigated. International Prostate Symptom Score (IPSS) and uroflowmetry were measured, and the associations between IPSS, uroflowmetry, and prostatic apex shape were analyzed. Results Patients in group 4 (356/806, 44.2%), whose prostatic apex did not overlap the membranous urethra anteriorly or posteriorly, had a significantly lower incidence of moderate and severe lower urinary tract symptoms compared to other groups. There was a significant relationship between prostatic apex shape and total International Prostate Symptom Score. Patients in group 3, whose prostatic apex overlapped posteriorly with the membranous urethra, had lower maximum flow rates on uroflowmetry. There were significant correlations between the maximum flow rate and independent factors including age, intravesicle prostatic protrusion, and prostatic apex shape. Conclusions Prostatic apex shape is an independent risk factor for voiding symptom severity and low maximum flow rate.