ERCP

Endoscopic retrograde cholangiopancreatography (ERCP) combines endoscopy with fluoroscopy to image and intervene on the biliary and pancreatic ducts. Once predominantly diagnostic, modern ERCP is almost exclusively therapeutic — for choledocholithiasis, malignant and benign biliary strictures, post-surgical bile leaks, primary sclerosing cholangitis, chronic pancreatitis, and pancreatic fluid collections.

The procedure is performed with a side-viewing duodenoscope. Selective biliary cannulation is achieved with a sphincterotome and guidewire; difficult cannulation may require precut needle-knife sphincterotomy or transpancreatic septotomy. Sphincterotomy, balloon dilation of the papilla, stone extraction with balloons or baskets, mechanical or laser lithotripsy for large stones, and stent placement are the workhorse interventions.

ERCP carries the highest complication rate of routine GI endoscopy. Post-ERCP pancreatitis (3–10%) is the most common; risk factors include young female sex, sphincter of Oddi dysfunction, difficult cannulation, and pancreatic duct injection. Rectal indomethacin and prophylactic pancreatic stents reduce risk in high-risk patients. Other complications include post-sphincterotomy bleeding, perforation, and cholangitis. Complication risk is meaningfully lower in high-volume centers and with experienced operators.