Intravesical prostatic protrusion volume: effect on lower urinary tract symptoms and urinary flow in patients with benign prostatic enlargement.

Purpose: We aimed to evaluate the effect of intravesical prostatic protrusion (IPP) in patients with benign prostatic enlargement (BPE), using three-dimensional assessment.

Methods: Men presenting with lower urinary tract symptoms (LUTS) to the urology clinic of a state hospital between March 2023 and July 2025 were evaluated. Treatment-naïve 369 BPE patients aged 50-80 years were included in the study. Prostate volume (PV), IPP length, IPP transverse diameter, IPP antero-posterior diameter, and IPP volume were measured using transabdominal ultrasonography by a single radiologist. IPP volume was calculated using the following formula: length × transverse diameter × antero-posterior diameter × 0.52.

Results: The International Prostate Symptom Score (p = 0.014) and IPP volume (p = 0.018) were identified as two independent predictors of low Qmax in patients with BPE. Subsequently, receiver operating characteristic curve analysis was performed for IPP volume. The optimal cut-off value was 3.65 mL, with an area under the curve of 0.823. At this cut-off value, sensitivity was 80% and specificity was 79%. In the multivariate correlation analysis, only IPP volume demonstrated an independent correlation with post-void residual volume (B = 0.211, p = 0.030). In the same analysis, parameters independently correlated with the International Prostate Symptom Score included IPP length (B = 0.219, p = 0.002), IPP antero-posterior diameter (B = 0.391, p = 0.009), and IPP volume (B = 0.188, p = 0.001).

Conclusion: In addition to IPP length, a three-dimensional assessment of the intravesical prostate-incorporating its transverse and antero-posterior diameters-may be a more objective parameter for LUTS.