A Case of Acute Pancreatitis after Pancreatectomy in Grade C Leading to Walled-Off Necrosis Successfully Treated with Necrosectomy by Retroperitoneal Approach.

Introduction: Grade B or C post-pancreatectomy acute pancreatitis (PPAP) is associated with a higher incidence of postoperative complications and mortality. The reason for this is the activation of proteolytic processes that can lead to pancreatic destruction and the activation of systemic reactions that can have adverse consequences such as systemic inflammatory response syndrome, sepsis, and death. We report a case of a patient with Grade C PPAP with walled-off necrosis (WON) who was successfully treated with necrosectomy using a step-up approach.

Case presentation: A 73-year-old man was referred to our hospital with elevated biliary enzymes. Results of blood tests, computed tomography (CT), and magnetic resonance imaging led to the diagnosis of distal bile duct cancer. He underwent a pyloric ring-sparing pancreaticoduodenectomy with lymph node dissection. Postoperative P-AMY (pancreatic amylase) was high at 1766 U/L, and contrast-enhanced CT showed increased density of peripancreatic fatty tissue and fluid accumulation on the pancreatic resection surface, leading to the diagnosis of postoperative pancreatitis and pancreatic fistula. On postoperative day (POD) 9, continuous washing with saline solution was started through the drain at the pancreatic anastomosis. Contrast-enhanced CT showed increased fluid retention in the pancreatic body tail. On POD 43, endoscopic ultrasonography drainage was performed for pancreatic necrosis encapsulated in the retroperitoneum; however, the patient self-extracted the drainage tube. On POD 50, CT-guided drainage was performed for a retroperitoneal subcapsular abscess. On POD 69, the patient underwent necrotomy with guided retroperitoneal drainage, a drain was inserted, and continuous flushing was performed. On POD 76, fecal discharge was observed from the drain, and drainage and enterography were performed; a fistula with the colon was confirmed, and an ileal bifurcation colostomy was performed on the same day. On PODs 83, 85, and 100, endoscopic necrotomy was performed through a retroperitoneal incision wound because a contrast-enhanced CT showed a residual abscess on the gastric dorsum. The patient's general condition improved, and his inflammatory response also improved. On POD 139, the patient was transferred for rehabilitation.

Conclusion: We describe a case of successful postoperative nutritional management and necrosectomy for Grade C PPAP leading to WON.