Preservation of Genital Innervation in Women During Total Mesorectal Excision: Which Anterior Plane?

Background: Erectile dysfunction, principally related to injury of the autonomic nerve fibers in men, is a major cause of postoperative morbidity after anterolateral dissection during total mesorectal excision (TME) for rectal adenocarcinoma. However, the autonomic innervation of erectile bodies is less known in women, and the anterolateral plane of dissection during TME remains unclear. The existence of the rectovaginal septum(RVS) is controversial. The purpose of the present study was to identify the RVS in the human fetus and adult female by dissection, immunohistochemistry, and three-dimensional reconstruction, and to define its relationship with erectile nerve fibers so as to determine the anterolateral plane of dissection during TME, which could reduce postoperative sexual dysfunction in women.

Method: Macroscopic dissection, histologic studies, and immunohistochemistry examination with 3D reconstruction were performed in six fresh female adult cadavers and six female fetuses.

Results: The RVS was clearly definable in all adult specimens. It was composed of multiple connective tissue, with smooth muscle fibers originating from the uterus and the vagina. It is closely applied to the vagina and has a relationship with the neurovascular bundles (NVBs) that contain erectile fibers intended for the clitoris. The NVBs are situated anteriorly to the posterior extension of rectovaginal septum. This posterior extension protects the NVBs during the anterior and anterolateral dissection for removal of rectal cancer.

Conclusions: To reduce the risk of postoperative sexual dysfunction in women undergoing TME for rectal cancer, we recommend careful dissection to the anterior mesorectum to develop a plane of dissection behind the posterior extension of the RVS if oncologically reasonable.