Topographic anatomy and laparoscopic technique for dissection of no. 6 infrapyloric lymph nodes in gastric cancer surgery.

We focused on the embryology and topographic anatomy of the infrapyloric lymph region, which is frequently involved in node metastases but technically complicated for dissection in gastric cancer surgery. Gastrointestinal organs possess their own mesenteries composed of double layers of peritoneum that enclose the intermediate adipose layer providing pathways for vessels, nerves, and lymphatic channels. The frontal layer of the mesoduodenum, in which no. 6 infrapyloric nodes lie, directly faces the pancreas and during gestation is overlain by the greater omentum and transverse mesocolon through the membranous connective tissue called the fusion fascia. Therefore, we performed no. 6 node dissection using the following process: (1) we traced out the mesoduodenum by detachment of the greater omentum and transverse mesocolon; (2) we transected the fusion fascia and (3) removed the adipose layer on the anterior face of the pancreas with its included lymph nodes together with the right gastroepiploic and infrapyloric vessels. The described technique is feasible and in keeping with the anatomical logic for oncologically reliable dissection of no. 6 infrapyloric nodes.