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.

Prognostic value of lymph node metastases detected during surgical exploration for pancreatic or periampullary cancer: A systematic review and meta-analysis

“…Previous studies have demonstrated that the paraaortic lymph node station is important in pancreatic lymphatic drainage. 45,46 Indeed, occurrence of para-aortic LNM has been associated with LNM in more proximal nodes such as stations 13, 14 and other peripancreatic lymph nodes. 26,29,47 The method to estimate mean survival times using reported medians, ranges and sample sizes has been widely used and validated.…”

The lymphatic system and pancreatic cancer

“…Today, a broad range of similar pancreatic resection procedures are in use in modern surgical practices around the world. Differences in primary tumor placement within the pancreas—head/neck vs. body/tail—and tumor invasion into surrounding tissues and organs often necessitate customization of resection [44–55] beyond the traditional PD to such procedures as distal pancreatectomy with or without splenectomy [41,56], pancreaticogastrostomy [35], pylorus-preserving PD [37,38,40], pylorus-resecting PD [40], subtotal stomach-preserving PD, pancreatojejunostomy, duodenum-preserving head resection, wedge resection of inferior vena cava, and total [39] or regional [57] pancreatectomy [58,59]. …”

“…Conservative surgical views support the standard PD with loco-regional lymphadenectomy [27,31,34,36,38,42,56,59,64–74], while others, most notably numerous Japanese groups, advocate that a more radical PD with extensive removal of retroperitoneal soft tissue and extended lymphadenectomy [27,34,39,42,75–84] results in better patient outcomes. Collected studies in Table 1 [8,27,31,34,36,37,39,40,42,59,64–75,77–99] demonstrate the broad range of study designs and conclusions that have fueled this debate. A recent set of randomized, controlled clinical trials from several centers around the world and a mathematical model of outcomes prediction have concluded that extended lymphadenectomy does not improve survival over traditional, more conservative resection and that quality-of-life may be decreased with more radical surgery [67–70,72,74,81,83,87,88,95].…”

“…Other groups have focused efforts on imaging routes of pancreatic drainage in attempts to identify sentinel lymph nodes for pancreatic tumors arising in various locations within the pancreas. Injection of indocyanine green fluorescent dye into the pancreatic surface during PD surgery allowed visualization of pancreatic lymphatic vessels intraoperatively and resulted in identification of seven routes of lymphatic drainage highlighting the complexity of the pancreatic lymphatic vascular network [40]. In a similar study methylene blue dye was injected peri- and intratumorally during pancreatic cancer resection, but the authors concluded that detection of patterns of pancreatic lymphatic drainage and sentinel lymph node identification were not feasible with this protocol [39].…”

Pancreatic Cancer

“…PanNETs are less aggressive than invasive ductal adenocarcinomas, with a 10-year survival rate of 45%. 56 whereas venous drainage of the pancreas to the liver proceeds through the PV. 53 Adenosquamous carcinoma is a rare histological variant with squamous differentiation in addition to ductal differentiation.…”