Endoscopic Step-up Approach for Walled-off Necrosis After Acute Pancreatitis.

This review outlines current interventional strategies for treating symptomatic walled-off necrosis (WON) after necrotizing pancreatitis. Mortality from acute pancreatitis has improved, but late mortality, particularly from infected necrosis, remains a challenge. WON requires invasive treatment in cases of infection or symptoms. A step-up approach is recommended, in which minimally invasive drainage is performed first, followed by more invasive treatments if the effect is insufficient. Among these, an endoscopic step-up approach mainly consisting of transmural treatment using endoscopic ultrasound-guided drainage and endoscopic necrosectomy (EN) has been reported with favorable outcomes. The use of lumen-apposing metal stents (LAMSs) has enhanced drainage efficiency and facilitated EN, although bleeding and stent-related adverse events remain concerns. Recent techniques such as multiple transluminal gateways and transcystic drainage have improved outcomes for complex, multilocular WON. With the introduction of the LAMS and additional endoscopic drainage techniques, most cases can be successfully treated with endoscopic therapy alone. However, endoscopic treatment alone has limitations for lesions spreading to the pelvic cavity, and a combination of percutaneous treatment or surgical treatment should be considered.