Submucosal injection to facilitate needle-knife sphincterotomy: a novel technique

Needle-knife sphincterotomy (NKS) is a valuable rescue technique for biliary access but carries an increased risk of bleeding and perforation, particularly in flat (type 1) ampullae. Such adverse events typically result from poor visualization or differentiation of the various tissue planes during NKS. We describe a novel technique using submucosal dye injection to better visualize anatomical planes during dissection.

A 59-year-old woman with a pancreatic head mass and obstructive jaundice was referred for ERCP. EUS-guided biopsy confirmed pancreatic adenocarcinoma. She was found to have a flat ampulla during ERCP. Despite multiple attempts using a standard sphincterotome, deep cannulation of the common bile duct was not achieved. We subsequently decided to proceed with advanced cannulation using a NKS with submucosal lift. Three mL of hetastarch with methylene blue was injected 2 mm above the ampullary os, resulting in an adequate submucosal lift. A mucosal incision was made, starting at the ampullary os and extending cranially to the 12-o'clock position.

Layer-by-layer dissection was performed, and deep cannulation of the bile duct was obtained without adverse events.

In our patient, submucosal injection enhanced tissue-plane visualization during NKS, allowing for controlled and anatomically guided dissection.