Retroperitoneal Nerve Plexus Dissection During Pancreatoduodenectomy

Abstract

The poor prognosis for pancreatic cancer after surgery has been attributed to a strong tendency of the cancer cells to spread along the peripancreatic neural plexuses and to infiltrate into the retropancreatic tissue. The concept of the nerve plexus around the pancreatic head was first reported by Yoshioka in 1958, and the Japan Pancreas Society has incorporated this concept and a corresponding diagram in the General Rules for the Study of Pancreatic Cancer. In this classification, the extrapancreatic nerve plexuses were categorized into seven groups: pancreatic head plexus I (PL ph I), pancreatic head plexus II (PL ph II), superior mesenteric arterial plexus (PL sma), common hepatic artery plexus (PL cha), plexus within the hepatoduodenal ligament (PL hdl), splenic plexus (PL sp), and celiac plexus (PL ce). After extrapancreatic nerve plexus invasion, particularly PL ph I and PL sma invasion, was found to have a correlation with patient prognosis and lymph node involvement along the superior mesenteric artery, it was adopted as a staging factor in the General Rules for the Study of Pancreatic Cancer. In 2007, Gockel et al. introduced the concept of the “mesopancreas.” The mesopancreas is a retropancreatic structure extending from the back of the pancreatic head to the superior mesenteric artery, including the lymphatic system, vessels, and nerves, which corresponds to PL ph I and PL ph II according to the General Rules for the Study of Pancreatic Cancer. The mesopancreas was reported to be the most frequent site of R1 resections; therefore, total excision of the mesopancreas and complete circumferential lymphadenectomy have recently been considered to be key points in curative surgery.