During total mesorectal excision (TME) for mid-rectal carcinoma, which anatomical landmark defines the posterior dissection plane that minimizes autonomic nerve injury?
- A The presacral (Waldeyer's) fascia — the correct avascular embryological plane between mesorectal fascia and parietal pelvic fascia (presacral fascia) ✓
- B Waldeyer's fascia (rectosacral fascia)
- C Denonvilliers' fascia
- D The lateral ligaments (lateral stalks) of the rectum
Explanation
TME dissection proceeds in the embryological avascular plane between the mesorectal fascia (visceral fascia) and the parietal pelvic (presacral) fascia, keeping the hypogastric nerves and pelvic plexuses on the parietal side and the intact mesorectum on the visceral side. Waldeyer's fascia is the condensation at the S4 level that must be divided sharply to enter the proper plane. Denonvilliers' fascia is the anterior plane between rectum and prostate/vagina; dividing anterior to it in males may risk urethral injury. Preserving the avascular plane preserves the pelvic autonomic nerves responsible for continence and sexual function.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.