Pathophysiological mechanisms of benign prostatic obstruction in men with small prostate volume and the emerging role of ultra-minimally invasive prostatic urethral dilation: a narrative review.

Background: Lower urinary tract symptoms (LUTS) in men have traditionally been interpreted within a volume-based paradigm, in which benign prostatic enlargement is considered the principal driver of bladder outlet obstruction. However, a subset of patients with an operationally defined small prostate volume (≤30 mL) present with disproportionate symptom severity, indicating that prostate size alone is an insufficient determinant of disease burden. Objectives: To review the pathophysiological basis of benign prostatic obstruction in men with small prostate volume and to evaluate the emerging role of prostatic urethral dilation (PUD) within a pathophysiology-informed therapeutic framework. Evidence Synthesis: Small-volume BPO is increasingly recognized as a functionally driven condition involving multiple interacting processes. Enhanced α Conclusion: Small-volume BPO should be considered a distinct clinical phenotype in which functional mechanisms play a prominent role, although anatomical contributors may still coexist in selected patients. PUD may represent an emerging dilation-based strategy that is potentially relevant in this setting. High-quality randomized trials with long-term follow-up are required to define its durability, safety, and position in contemporary management algorithms.