Pancreatoduodenectomy after neoadjuvant chemotherapy is the current treatment in patients with borderline pancreatic ductal adenocarcinoma in the head of the pancreas1,2,3. The total mesopancreas excision concept includes the resection of the lymphatic structures on the right side of the SMA and along the neuronal plexus of the pancreatic head. Complete clearance of this retroperitoneal area may increase the R0 resection rate in patients with adenocarcinoma in the head of the pancreas. This area is an important location of perineural infiltration of tumor cells in patients with pancreatic ductal adenocarcinoma4.
Hackert et al5 described the term “triangle operation” as a new surgical technique for patients with locally advanced pancreatic ductal adenocarcinoma and stable disease following neoadjuvant therapy. This area is defined by SMV/PV, celiac axis/common hepatic artery, and SMA, representing the typical view after completion of the resection. However, according to the definition of the authors, the procedure should be performed without arterial resection. Recently, Loss et al6 and Schneider et al7 observed that arterial resection is effective in patients with locally advanced pancreatic cancer after neoadjuvant chemotherapy, with better long-term survival than with palliative treatment. However, this procedure should be performed in experienced pancreatic centers. After neoadjuvant chemotherapy and centers with expertise in pancreatic resection, arterial resection is perfectly possible with acceptable morbidity and mortality.
Knowledge of the portal system and its anatomical variations aids to prevent surgical adverse events. The portal vein is usually made by the confluence of the superior mesenteric and splenic veins, together with their main tributaries, the inferior mesenteric, left gastric, and pancreaticoduodenal veins; however, anatomical variations are frequent.
This article presents a literature review regarding previously described anatomical variations of the portal venous system and their frequency.
A systematic review of primary studies was performed in the databases PubMed, SciELO, BIREME, LILACS, Embase, ScienceDirect, and Scopus. Databases were searched for the following key terms: Anatomy, Portal vein, Mesenteric vein, Formation, Variation, Variant anatomic, Splenomesenteric vein, Splenic vein tributaries, and Confluence.
We identified 12 variants of the portal venous bed, representing different unions of the splenic vein, superior mesenteric vein, and inferior mesenteric vein. Thomson classification of the end of 19th century refers to the three most frequent variants, with type I as predominant (M=47%), followed by type III (M=27.8%) and type II (M=18.6%).
Thomson classification of variants is the most well-known, accounting for over 90% of portal venous variant found in clinical practice, inasmuch as the sum of the three junctions are found in over 93% of the patients. Even though rarer and accounting for less than 7% of variants, the other nine reported variations will occasionally be found during many abdominal operations.
Desenvolvido por Surya MKT