Operating Behind Denonvilliers' Fascia for Reliable Preservation of Urogenital Autonomic Nerves in Total Mesorectal Excision: A Histologic Study Using Cadaveric Specimens, Including a Surgical Experiment Using Fresh Cadaveric Models

TLDR

The study aimed to determine which urogenital nerves are at risk of injury when operating in front of or behind Denonvilliers' fascia during total mesorectal excision. Semiserial histology of five fixed male pelves and fresh cadaveric dissections of five unfixed male pelves were used to map the pelvic plexus and its relationship to Denonvilliers' fascia. The study found that the pelvic plexus branches lie immediately anterior to Denonvilliers' fascia, that the fascia’s lateral extension separates the neurovascular bundle from the mesorectum, that the mesorectum contains few ganglion cells, and that incisions in front of the fascia risk damaging the superior pelvic plexus and neurovascular bundle, so dissection behind the fascia is required to preserve autonomic nerves.

Abstract

Little is known about which urogenital nerves are liable to be injured along surgical planes in front of or behind Denonvilliers' fascia.Using semiserial histology for five fixed male pelves, we demonstrated that: 1) left/right communicating branches of bilateral pelvic plexuses run immediately in front of Denonvilliers' fascia; and 2) a lateral continuation of Denonvilliers' fascia separates the urogenital neurovascular bundle from the mesorectum. Notably, the mesorectum contains no or few extramural ganglion cells. At the level of the seminal vesicles, incision in front of Denonvilliers' fascia seems likely to injure superior parts of the pelvic plexus and the left/right communication. Moreover, at the prostate level, this incision misleads the surgical plane into the neurovascular bundle. Fresh cadaveric dissections of five unfixed male pelves confirmed that the surgical plane in front of Denonvilliers' fascia continues to a fascial space for the pelvic plexus containing ganglion cell clusters lateral and/or inferior to the seminal vesicles.To preserve all autonomic nerves for urogenital function, optimal total mesorectal excision for rectal cancer requires dissection behind Denonvilliers' fascia.