Hepatobiliary-pancreatic surgery for patients with a prepancreatic postduodenal portal vein: a case report and literature review

Abstract

Background Prepancreatic portal vein (PPV) is a congenital anatomical variant of the portal vein (PV). PPVs are extremely rare and generally classified into two categories, prepancreatic preduodenal portal vein and prepancreatic postduodenal portal vein (PPPV). Prepancreatic preduodenal portal veins are rare, with approximately 100 reported cases globally; PPPVs are even more atypical, with less than 20 documented cases globally. Despite the extremely low occurrence, PPPV knowledge and recognition are important, especially for hepatobiliary-pancreatic (HBP) surgeries, such as pancreaticoduodenectomy (PD) for patients of a PPPV. Here, we report a case of PPPV and a literature review. Case presentation A 73-year-old-male with ampullary carcinoma underwent PD at our hospital. Preoperative enhanced CT revealed an abnormal L-shaped PV, identified as a PPPV. Both the PPPV and the postpancreatic “normal” superior mesenteric vein (SMV) divaricated from the SMV at the caudal side of the pancreas. A splenic vein and inferior mesenchymal vein flowed into the postpancreatic “normal” PV, which encircled the common bile duct and potentially flowed into the liver, forming a cavernous transformation at the hilar plate. During surgery, we attempted to isolate the PV from the pancreas and common bile duct. However, it was difficult to isolate from the pancreas. The PPPV was so fragile that bleeding from the PPPV became uncontrollable. To remove the tumor, we resected the PPPV and reconstructed a “normal” PV as an autogenous graft. To maintain intraoperative hepatic blood flow and avoid small bowel congestion, an antithrombogenic bypass catheter was placed between the SMV and umbilical vein during reconstruction. After surgery, several complications occurred, such as PV thrombosis and hyperammonemia. The patient was discharged on postoperative day 45. Conclusions PPPV is a rare vascular variant but is easily diagnosed preoperatively due to its distinct shape on CT imaging. However, isolating the PPPV from the pancreas and bile duct is incredibly difficult and potentially associated with increased operative risks and postoperative complications. PV resection rather than isolation is a potential solution to reduce the risk of hemorrhage, even in the absence of invasion.

Prepancreatic postduodenal portal vein: a case report and literature review

“…6 C). We summarized 15 PPPV cases reported so far [ 6 – 18 ], including the present case (Table 1 ). Twelve of these 15 cases have been reported in Japan.…”

“…Moreover, of the 13 PPPV cases for which information on portal vein morphology was provided, seven (53.8%) had irregularly dilated or winding portal vein in the hepatic hilum, and there were five cases with a fragile and thin portal vein wall and firm adhesion with the surrounding tissue. Five of these patients underwent pancreaticoduodenectomy and three underwent combined resection of the portal vein because of difficulty in dissecting the portal vein [ 9 , 16 , 18 ], and two of them had intraoperatively massive bleeding while isolating the portal vein, and thrombosis in the reconstructed portal vein [ 16 , 18 ]. Shimizu et al reported the difficulty of portal vein reconstruction due to the thinness of the portal vein wall and the difficulty of postoperative management due to complications of portal vein thrombosis [ 16 ].…”

Pancreaticoduodenectomy performed for a patient with prepancreatic postduodenal portal vein: a case report and literature review

“…PPPV was first reported by Brook and Gardner ( 6 ), and a total of 17 cases have been reported to date, including the present case. We have summarized all cases to date and our cases in Table 1 ( 1 , 2 , 5 – 17 ). Among them, 11 were reported as L-shaped PPPV, while only three were normal-shaped PPPV.…”

“…All four cases of L-shaped PPPV had a much thinner venous wall, with close adhesion to pancreas and difficult to isolate. Therefore, three of them underwent PPPV resection and reconstruction after attempting to isolate the PPPV due to intraoperative massive hemorrhage ( 1 , 8 , 15 ), and one case underwent R2 resection with PPPV preserved ( 5 ). In the present case and Tanaka’s report ( 2 ), the normal-shaped PPPV had normal thickness of venous wall and there was a loose tissue area posterior to PPPV and anterior to the pancreatic head which could be isolated safely.…”

“…Prepancreatic postduodenal portal vein (PPPV) is a rare congenital variant of portal vein system, with only 16 cases reported in the literature and five of them undergoing pancreaticoduodenectomy (PD) ( 1 ). Of these, four were L-shaped PPPV with a thin wall that was difficult to isolate, while only one normal-shaped PPPV was reported previously ( 2 ).…”