Microvascular architecture of the prostatic urethra: anatomical basis for extended urethral preservation in robot-assisted radical prostatectomy.

PURPOSE: To characterize the microvascular architecture of the prostatic urethra (PU) and assess its potential anatomical relevance to extended prostatic urethral preservation (EPUP) during robot-assisted radical prostatectomy.

METHODS

This pilot morphological study included three non-distorted prostate specimens obtained from cystoprostatectomy. Specimens were entirely submitted for histological examination and evaluated using hematoxylin and eosin and modified Verhoeff-Masson staining. Periurethral vascular structures were morphologically characterized, and their distance from the urothelial basement membrane was measured on digital whole-slide images.

RESULTS

Two morphologically distinct periurethral vascular compartments were identified. The Inner Periurethral Capillary Network (IPCN) consisted of small-caliber vascular structures within the subepithelial connective tissue (SCT/chorion), whereas the Outer Vascular Network (OVN) comprised predominantly larger vessels with more conspicuous muscular walls. The distance between the urothelial basement membrane and the IPCN ranged from 0.10 to 0.94 mm. However, the present study does not demonstrate arterial connectivity, independent perfusion, or a causal relationship between IPCN preservation and functional outcomes.

CONCLUSION

A distinct inner periurethral vascular compartment was identified within the SCT of the PU. Its anatomical location may provide a potential substrate for preservation of the local vascular environment during EPUP. Larger anatomical studies incorporating immunohistochemical and intraoperative perfusion assessment of the preserved urethra in cases of EPUP are warranted.