Total mesorectal excision for cancer of the rectum.

The concept of total mesorectal excision (TME) was first described by R. J. Heald in 1982 as a radical cancer operation based on the anatomy of fascial planes and fibrous spaces of the pelvis. The ampulla recti is invested by a fascia propria which is a part of the visceral pelvic fascia. The fascia propria is separated from the parietal pelvic fascia by the pelvirectal fibrous space, which is a compartment of the subperitoneal space of the pelvis. The lateral ligaments of the rectum divides the pelvirectal space into a prerectal and a retrorectal part. TME is defined as the resection of the rectum with its surrounding fatty and lymphatic tissue contained within the visceral sheet of the pelvic fascia. The dissection proceeds in the nearly avascular cleavage plane between the visceral and the parietal fascial sheets, allowing maximal protection of the hypogastric nerves and the inferior hypogastric plexus. Continuity of the prerectal and retrorectal parts of the field of dissection is established by dividing the lateral ligaments of the rectum slightly inside the point where they swing away from the parietal fascia of the pelvic side wall. By following this plane of dissection it is possible to achieve en bloc excision of the total mass of perirectal lymphatic and fatty tissue down to the pelvic floor.