SAGES Magazine

THE SOUTH AFRICAN GASTROENTEROLOGY REVIEW 2022 | VOLUME 20 | ISSUE 3 | 47 ERCP | A GUIDE FOR NURSES AND ASSISTANTS | Re-printed with permission PA R T 2 : C ANNU L A T I ON All parts of the ERCP are essential for it to succeed, but cannulation of the ampulla (ie getting a wire into the common bile duct) is the part where failure is most likely to occur. This part of the procedure can take literally seconds, or what seems like hours. Why is it so difficult? The ampulla is small - only a millimetre or two in diameter and can be inside a diverticulum, or pouch in the wall of the duodenum. In addition the opening may be elongated or ‘floppy’. Inside the ampulla are tiny hair like protrusions which are visible on the cartoon below. These are there to keep foreign bodies from the duodenum entering the bile ducts, and swell up if poked too often, particularly when the patient has been starved for a long time or has significant comorbidity. In addition there are usually two openings into the ampulla - one from the bile duct and one from the pancreatic duct. The pancreatic duct opening is directly opposite the scope and is theoretically easier to cannulate than the bile duct which curves upwards, then away from the duodenum as seen on the screen. To make matters worse, it may be hidden from view, at an unusual angle, or blocked. I have often maintained that watching ERCP is the worst spectator sport in the world. It can be massively frustrating, so on behalf of all operators and trainees out there, I beg you not to start chatting, discussing dinner or what is left on the list after this case if you see beads of sweat break out on the ERCPist when the cannulation has not been achieved after 15 minutes! (To be fair, pretty much all the assistants I have worked with are far more professional than I give them credit for!) Cannulation is achieved using a cannula or a sphincterotome, which is basically a cannula with a cutting wire attached to the side. Patients undergoing ERCP for a first time are termed to have a ‘virgin ampulla’. If an ERCP has been carried out before, subsequent cannulation is easier, and may be attempted with a balloon catheter. Cannulae have one or 21