The presacral fascia (Waldeyer fascia) is a condensed layer of endopelvic connective tissue spanning from the sacrum and coccyx to the posterior rectal wall at the level of S4-S5, forming the posterior boundary of the mesorectal envelope. It lies anterior to the sacral venous plexus and the pelvic nerves. It must be identified and divided to complete the posterior plane of total mesorectal excision.
Anchors the rectum to the anterior sacrum and forms the posterior mesorectal fascial boundary. Contains the presacral venous plexus (Batson plexus) and the pelvic autonomic nerves anterior to it.
Division of the presacral fascia at the correct level during TME is the key to entering the sacred plane of Holy Plane anterior to the sacral venous plexus, avoiding catastrophic presacral venous bleeding. If the dissection strays too posteriorly through Waldeyer fascia, the presacral venous plexus is entered, producing difficult-to-control venous haemorrhage from the valveless presacral veins. Thumbtacks (gauze pledgets with metal tacks) or sterile pushpins are the last resort for presacral vein haemorrhage when sutures and cautery fail.
Inadvertent posterior dissection through Waldeyer fascia into the presacral venous plexus during rectal cancer excision produces massive haemorrhage from the valveless presacral veins that is extremely difficult to control by suturing or cautery, occasionally requiring direct pressure with gauze thumbtacks or surgical gauze packing as a last resort.
