A Novel Technique of Overtube‐assisted Ultrathin Endoscopic Biliary Drainage Using Multi‐Hole Self‐Expandable Metal Stents: A Case Report

Endoscopic retrograde cholangiopancreatography (ERCP) is the standard procedure for biliary drainage; however, access can be challenging in patients with altered anatomy or tumor-related distortion. Endoscopic ultrasound-guided biliary drainage (EUS-BD) is a common alternative, yet it is not always feasible, particularly in patients with prior hepatic resection or severe gastrointestinal deformation. A 67-year-old woman developed obstructive jaundice due to hilar biliary stricture secondary to peritoneal dissemination following colorectal cancer surgery. Initial ERCP achieved side-by-side placement of multi-hole self-expandable metal stents (MHSEMSs), resulting in effective drainage. At recurrence of cholangitis, repeat ERCP failed because of anatomical distortion, and EUS-BD was not feasible due to the patient's prior left hepatectomy. We therefore employed a novel technique: a double-balloon enteroscope overtube was advanced to the duodenum, and a side hole was created 10 cm distal to the insertion port. An ultrathin endoscope was inserted through this side hole, retroflexed in the duodenum, and successfully accessed the papilla. The previously placed MHSEMSs were removed, and new MHSEMSs were deployed using a stent-in-stent method. The patient's cholangitis and associated liver abscesses improved, allowing continuation of systemic chemotherapy. This case demonstrates a novel overtube-assisted ultrathin endoscope technique. The combination of thin delivery systems and an overtube modification may provide a valuable alternative when both conventional ERCP and EUS-BD are not feasible.