Abstract:Background and Aims When pancreatic tumors invade the portal vein-superior mesenteric vein, especially with involvement exceeding 5 cm, end-to-end anastomosis is often not feasible, limiting the achievement of R0 resection. This study aimed to evaluate the feasibility and safety of using allogeneic common iliac vein and its branches for Y-shaped vascular reconstruction.Methods A retrospective analysis was conducted on two patients with pancreatic tumors involving long-segment portal vein-superior mesenteric vein treated between May 2022 and April 2024. Both patients underwent en bloc tumor and venous resection. Allogeneic common iliac vein with its branches was trimmed into a Y-shaped graft to reconstruct the portal vein-superior mesenteric vein and portal vein-splenic vein pathways.Results Both surgeries were successfully completed without major perioperative complications or venous thrombosis. The postoperative hospital stays were 27 and 23 days, respectively. Pathology revealed a solid pseudopapillary tumor in case 1 and poorly differentiated pancreatic adenocarcinoma in case 2. Case 1 remained recurrence-free at 12-month follow-up, whereas case 2 developed liver metastasis and died 4 months postoperatively. Postoperative imaging demonstrated good graft patency and effective restoration of splanchnic venous return.Conclusion For pancreatic tumors with portal vein-superior mesenteric vein involvement exceeding 5 cm, Y-shaped reconstruction using allogeneic common iliac vein and its branches is feasible and safe in the short term, enabling R0 resection while restoring both mesenteric and splenic venous return. Larger studies are needed for further validation.