Successful redrainage after failure of lumen-apposing metal stents by addressing flange-induced ostial occlusion: A case report

BACKGROUND Endoscopic ultrasound-guided drainage is the standard treatment for symptomatic walled-off necrosis (WON). Lumen-apposing metal stents (LAMSs) revolutionize this approach using large lumens and stable flanges, enabling efficient drainage and direct necrosectomy. While established complications (intraluminal occlusion, and migration) are well-documented, LAMS flange-complex WON anatomy interaction remains unclear. Up to date, no cases of the distal flange causing mechanical occlusion of branch cavity ostia have been reported. This case addresses this complication and its successful endoscopic management. CASE SUMMARY We report a 34-year-old man with recurrent WON caused by LAMS edge-induced branch cavity ostium obstruction, managed via endoscopic LAMS removal and salvage plastic stent drainage. Admitted for biliary pancreatitis complicated by cholangitis, he underwent endoscopic stone extraction and biliary stenting. Postoperative fever prompted abdominal computed tomography (CT), which revealed peripancreatic collections consistent with WON; endoscopic ultrasound-guided transgastric LAMS placement achieved immediate purulent drainage. Endoscopic necrosectomy resolved fever, and follow-up CT/endoscopy confirmed near-complete cavity collapse before discharge. Five days later, recurrent high fever led to repeat CT, showing pancreatic body reaccumulation. Endoscopy indicated branch ostium obstruction by the LAMS distal flange. LAMS removal identified a purulent fistula, and fluoroscopy-guided stenting with a double-pigtail stent and nasobiliary tube achieved prompt resolution. The nasobiliary tube was removed prior to discharge, with the pigtail stent retained for spontaneous passage. CONCLUSION LAMS edge obstruction of branch ostia can cause recurrent WON. Endoscopic removal plus cavity inspection and drainage is effective.