Identification of the Lymphatic Drainage Pathways from the Pancreatic Head Guided by Indocyanine Green Fluorescence Imaging during Pancreaticoduodenectomy

Abstract

Aims: We identified the lymphatic drainage pathways from the pancreatic head guided by indocyanine green (ICG) fluorescence imaging to analyze optimal lymphadectomy for pancreatic cancer. Methods: The lymphatic pathways in 20 patients undergoing pancreaticoduodenectomy were analyzed. We injected ICG into the parenchyma in the anterior (n = 10) or posterior surface (n = 10) of the pancreas head and observed the intraoperative lymphatic flows by ICG fluorescence imaging. Results: The seven main lymphatic drainage pathways were identified: (1) along the anterior or posterior pancreaticoduodenal arcade, (2) running obliquely down behind the superior mesenteric vein (SMV), (3) reaching the left side of the superior mesenteric artery (SMA), (4) running longitudinally upward between the SMV and SMA, (5) along the middle colic artery toward the transverse colon, (6) reaching the paraaortic (PA) region, and (7) reaching the hepatoduodenal ligament. The lymphatic pathway reaching the left side of the SMA was observed in 4 patients (20%), while that reaching the PA region in 17 patients (85%). The mean time to reach around the SMA was longer than that to reach the PA region. Conclusions: We found that several lymphatic drainage routes were observed from the pancreatic head, suggesting that a lymphadectomy around the SMA might have a similar oncological impact as that of the PA region.