Histological identification of fascial structures posterolateral to the rectum

Background: A comprehensive understanding of fascial structures around the rectum is important for surgeons. Multilaminar fascial structures have provided different interpretations of reliable surgical planes in rectal surgery. Methods: Pelvic visceral materials for histological assessment were obtained from 12 male cadavers. Large specimens covering wide areas around the mesorectum were embedded in paraffin, followed by preparation of semiserial horizontal sections and sagittal sections for histological examination. Results: Histological examination demonstrated a prehypogastric nerve fascia and parietal presacral fascia in the retrorectal multilaminar structure. The parietal presacral fascia seemed to divide into several lateral continuations. The prehypogastric nerve fascia appeared to join the most medial continuation of the parietal presacral fascia, which continued ventrally and communicated with Denonvilliers' fascia. Any fascial structure connecting directly between the fascia propria of the rectum and the parietal presacral fascia (that is, the rectosacral fascia) was not found in sagittal sections. Conclusion: In the retrorectal multilaminar structure, prehypogastric nerve fascia is evident between the fascia propria of the rectum and the parietal presacral fascia. Sharp dissection in front of the prehypogastric nerve fascia according to the histological configuration of the posterolateral fasciae seems reliable.