[Total mesorectal excision and preservation of autonomic nerves]

Abstract

The procedure of total mesorectal excision (TME) becomes a gold standard for the treatment of rectal cancer. The reason is the marvelously low incidence of local recurrence after TME even without other adjuvant treatment, which has been reported by several independent groups. Although controversy still exists about the role of TME in upper rectal cancer, it is now widely accepted for cancers of the middle and lower third. There are number of histopathological evidences that cancer cells can spread distally several centimeters from the lower margin of cancer, and cancer bearing lymph nodes are found in the distal portion of the mesorectal tissues far from the cancer. Therefore, the distal clearance of mesorectum should be performed downwardly to the level of pelvic diaphragm (puborectalis) and the rectum is divided within a few centimeters from the pelvic floor musculature. TME defines an en-bloc procedure, along the plane between parietal and visceral pelvic fasciae. If the dissection plane is breached, the chance of visceral pelvic fascia tearing is raised and mesorectal tissue might reside in the pelvis. There are problems in auditing the procedure. As many surgeons agree, this procedure requires a learning curve. Theoretically, the autonomic nerves run between the visceral and parietal pelvic fasciae since the nerves must be preserved to make visceral fascial envelop. Any patient who become incontinent or impotent after the surgery should have received decorticating surgery other than TME. Thus, the high quality of TME should fulfill two clinical measurements: absence of impotence or incontinence and at least single digit, 5-year, cumulative recurrence rate regardless of adjuvant therapy.