ERCP and EUS Procedures

Episode one of the ERCP and EUS Procedures chapter starts from the single fact that reorganizes everything: ERCP is a therapy, not a test, so you earn the right to do it only when a non-invasive study cannot answer the question. From there the whole episode is risk management. Wire-guided cannulation replaces the hydraulic contrast push that floods the pancreatic duct, difficult-cannulation maneuvers each solve one anatomic problem, and the prophylaxis stack is held by mechanism because the mechanisms tell you who needs which. The organizing thread: find the duct by guidance, then stack indomethacin, a pancreatic duct stent, and lactated Ringer on the patient whose risk factors say the pancreas will react.

Episode two is about the decision that comes before cannulation and the restraint it takes to decline the procedure when objective evidence for benefit is absent. A landmark sham-controlled trial retired type three sphincter of Oddi dysfunction as a sphincterotomy indication, so pain with normal labs and a normal duct becomes a functional pain disorder, not an ERCP. Pregnancy raises the threshold highest because a second patient absorbs all the risk and none of the benefit. The back half turns on two failure mechanisms, the cut that bleeds and the elevator that harbors biofilm, and each names the patient to protect and the device choice that protects them.

Episode three centers on the stricture you cannot name: painless jaundice, a tight narrowing, and imaging that says cancer without proving it. Tissue acquisition is the whole game, and every step up the diagnostic cascade works by getting closer to the tumor, from a shallow brush that misses submucosal cholangiocarcinoma to intraductal biopsy and FISH to cholangioscopy to an EUS needle in the mass itself. The transplant candidate inverts that hierarchy, because a needle in the hilar primary can seed the peritoneum and disqualify the cure. Then durable drainage follows anatomy: covered metal distally to block ingrowth, uncovered metal at the hilum to preserve side branches, and always enough viable liver drained to clear the bilirubin.

Episode four picks up the moment standard ERCP fails, and it runs on a single habit: name the anatomic barrier and let it choose the technique. When you cannot cannulate the papilla, a dilated duct becomes an EUS target, and the finishing options rank by how much natural drainage they keep, rendezvous over choledochoduodenostomy over hepaticogastrostomy. When surgery has hidden the papilla, the question is how to restore the duodenoscope's en face view through the particular barrier, so EDGE tunnels into the bypassed stomach, balloon enteroscopy reaches a hepaticojejunostomy, and a reversed cautious approach handles Billroth two. Device design and technique are consequences of the anatomy, not lists to memorize.

Episode five holds EUS and ERCP to one standard in the pancreatitis spectrum: they earn their place only when there is structural disease or stone burden to act on, because every procedure carries a real pancreatitis risk weighed against a modest expected benefit. In the recurrent-attack workup, EUS for microlithiasis is the highest-yield study after MRCP, while sphincterotomy for divisum and idiopathic disease is the reflex sham-controlled data have humbled. In the chronic gland you decompress discrete obstructive lesions and read the true predictors of success, disease duration, cessation, and stone burden rather than head calcification. Standing over all of it, a randomized trial favors early surgical drainage for the painful dilated duct.

Episode six takes the pancreatitis spectrum to its end: the collections the gland leaves behind. Timing runs on wall-maturation logic, waiting about four weeks for a rind strong enough to hold a transmural anastomosis, and the contents decide everything downstream, since a pseudocyst and walled-off necrosis need different stents and different follow-through. Before any puncture you image for a pseudoaneurysm and embolize it first, because needling a shared wall can cause uncontrolled hemorrhage. Drainage is a step-up, transmural first and necrosectomy only when the cavity will not empty, and two failure modes both turn on sequence. Necrosectomy itself carries one non-negotiable safety rule: carbon dioxide insufflation, because air can embolize.

The final episode turns EUS from a guide for therapy into a diagnostician and a palliator, and it runs on one habit: reason from substrate to answer. The five alternating wall layers plus echotexture place a subepithelial lesion and narrow the differential before a needle moves, so a hypoechoic layer-four mass is a GIST until tissue proves otherwise. The needle choice then turns on a single distinction, cells versus architecture, because lymphoma, GIST, and autoimmune pancreatitis all live in structure a core preserves and cytology destroys. Finally the same probe that finds the tumor treats its pain: alcohol neurolysis for cancer, a reversible steroid block for benign disease, with complications that read straight off the interrupted sympathetic outflow.