Step-by-Step Pancreaticoduodenectomy in Complete Situs Inversus: Technical Strategy to Preserve Oncologic Principles in a Rare Anatomical Setting

BACKGROUND: This video aims to illustrate the surgical strategy and key technical adaptations required to safely perform oncologic pancreaticoduodenectomy in this uncommon setting. METHODS: We present the case of a 68-year-old woman with a history of BRCA1-mutated breast cancer and complete situs inversus who presented with general deterioration and symptoms of high intestinal obstruction. Diagnostic work-up, including cross-sectional imaging and upper endoscopy with biopsy, confirmed a resectable pancreatic head adenocarcinoma with duodenal invasion in the setting of a complete common mesentery. The case was discussed in a multidisciplinary tumor board, and upfront surgical resection was recommended. A standard open pancreaticoduodenectomy was performed via midline laparotomy. Preoperative imaging was carefully analyzed to map vascular variations. The procedure included hepatoduodenal ligament dissection, lymphadenectomy of the celiac axis and hepatic artery stations, Kocher maneuver, and dissection of the mesenterico-portal axis. Particular attention was given to the identification and management of both venous and arterial jejunal trunks involved with the tumor. Reconstruction was achieved with pancreaticojejunostomy using a stented technique, hepaticojejunostomy with ductal enlargement, and precolic gastrojejunostomy, along with placement of a nasojejunal feeding tube. RESULTS: Complete oncologic resection (R0) was achieved. The postoperative course was complicated by Clavien-Dindo grade II events, including chylous ascites and grade A delayed gastric emptying, with a total hospital stay of 16 days. Final pathology demonstrated a poorly differentiated pancreatic adenocarcinoma staged as pT3N2, with 30 positive lymph nodes of 33 examined. CONCLUSIONS: Pancreaticoduodenectomy in patients with complete situs inversus and complete common mesentery is feasible and can be performed safely with meticulous preoperative planning and intraoperative adaptation to mirrored anatomy. A detailed understanding of vascular variations and a standardized stepwise approach are essential to ensure oncologic adequacy. This case highlights that, even in rare anatomical conditions, radical resection can be achieved without compromising surgical or oncological principles.