Unilateral Pelvic Side-Wall Lymph Node Resection for Rectal Cancer: A Review of the Anatomy.

Background: The aim of this video is to highlight key safety and critical techniques employed during laparoscopic pelvic side-wall lymph node resection for rectal cancer. In addition, a review of the key pelvic side-wall anatomical structures will be included.

Methods: We report a case of a 50-year-old Chinese female who presented with per-rectal bleeding, with colonoscopy revealing a 1.5 cm moderately differentiated rectal adenocarcinoma 4 cm above the anorectal junction. Initial staging scans did not reveal any pelvic lymphadenopathy or distant metastasis and the patient underwent laparoscopic ultra-low anterior resection with concurrent total hysterectomy, bilateral salpingo-oophorectomy and natural orifice specimen extraction (NOTES) with defunctioning ileostomy. Final histology confirmed the diagnosis of moderately differentiated adenocarcinoma classified as pT1N0, resection R0. Subsequent follow-up detected a serial increase in carcinoembryonic antigen levels, and further investigations detected a 1.6 cm fluorodeoxyglucose (FDG)-avid right external iliac lymph node.

Results: Adhesiolysis was performed, and key structures in the right pelvic side-wall, such as the ureter, umbilical and gonadal vessels, external iliac vein, obturator artery, nerve and lymph nodes, and internal and external iliac artery, were identified. The right external iliac lymph node was dissected and extracted for histological examination.

Conclusions: Laparoscopic pelvic side-wall lymph node dissection for rectal cancer is a good technique to employ when investigating and obtaining FDG-avid lymph nodes. Key structures will need to be identified during dissection to prevent any injuries.