The characteristics of the urogenital fascia in the retrorectal space based on male cadaveric dissection and its clinical application.

BACKGROUND: The architecture of retrorectal fasciae is complex, as determined by different anatomical concepts. The aim of this study was to examine the anatomical characteristics of the inferomedial extension of the urogenital fascia (UGF) involving the pelvis to explore its relationship with the adjacent fasciae. Furthermore, we have expounded on the clinical application of UGF. METHOD: For our study, we examined 20 adult male pelvic specimens fixed in formalin, including 2 entire pelvic specimens and 18 semipelvic specimens. Our department has performed 466 laparoscopic rectal cancer procedures since January 2020. We reviewed the surgical videos involving UGF preservation and analyzed the anatomy of the UGF. RESULTS: The bilateral hypogastric nerves ran between the visceral and parietal layers of the UGF. The visceral fascia migrated ventrally at the fourth sacral vertebra, which formed the rectosacral fascia together with the fascia propria of the rectum; the parietal layer continually extended to the pelvic diaphragm, terminating at the levator ani muscle. At the third to fourth sacral vertebra level, the two layers constituted the lateral ligaments. CONCLUSION: The double layers of the UGF are vital structures for comprehending the posterior fascia relationship of the rectum. The upper segment between the fascia propria of the rectum and the visceral layer has no evident nerves or blood vessels and is regarded as the " holy plane" for the operation.