Walled-off necrosis (WON) is defined as an encapsulated collection of solid and liquid necrotic material that is usually formed 4 weeks after an episode of acute necrotizing pancreatitis. As the advances in endoscopic techniques and accessories, Endoscopic ultrasound (EUS)-guided transluminal drainage has evolved to become the treatment of choice for symptomatic pancreatic walled-off necrosis (WON). This article aims to compare the efficacy and safety of a double mushroom head metal stent and a double pigtail plastic stent in the treatment of encapsulated necrosis of the pancreas.

According to the revised Atlanta classification, pancreatic fluid collections (PFCs) include acute peripancreatic fluid collections(APFCs) and acute necrotic collections(ANCs), which, over time, turn into pancreatic pseudocysts (PPs) and walled-off pancreatic necrosis (WON). Drainage of these PP and WON is required when they increase in size and become infected or become symptomatic.

Traditionally, WON has been managed surgically, however, surgical necrosectomy is associated with substantial morbidity and mortality, particularly when pursued early. In recent years, with the development of minimally invasive techniques, Endoscopic ultrasound (EUS)-guided transluminal drainage has evolved to become the treatment of choice for symptomatic pancreatic walled-off necrosis (WON).

Double-pigtail plastic stents(DPPS) is the earliest stent used for WON drainage in ultrasound endoscopy, however, These stents are limited by their small diameter leading to increased risk of stent obstruction. Recently, lumen-apposing metal stents (LAMS) have been increasingly used because of the advantage of better lumen apposition and wider diameter, improving access for endoscopic debridement. However, more adverse events(AEs) such as bleeding have been reported.

This article aims to compare the efficacy and safety of DPPS and LAMS in the treatment of Walled-off necrosis

Inclusion Criteria:

• Obtention of a written informed consent
• According to Revised Atlanta Classification, abdominal CT/MRI and EUS were diagnosed as WON
• The diameter of WON ≥6cm
• Patient capable of fill in the quality of life questionnaire
• The distance between the EUS-probe and WON was < 1 cm.

Exclusion Criteria:

• No written informed consent
• pancreatic cystic tumor, pancreatic cancer and other benign and malignant tumors
• pancreatic pseudocyst
• WON too far from the stomach and duodenum to perform endoscopic drainage
• Serious abnormalities in liver and kidney function and coagulation function
• Pregnant, parturient or breastfeeding women