ERCP is a study of the ducts that drain the liver and pancreas. Ducts are drainage routes into the bowel. The ones that drain the liver and gallbladder are called bile or biliary ducts. The one that drains the pancreas is called the pancreatic duct. The bile and pancreatic ducts join together just before they drain into the upper bowel, about 3 inches below the stomach. The drainage opening is called the papilla. It is surrounded by a circular muscle, called the sphincter of Oddi. A diagnostic ERCP is when x-ray contrast dye is injected into the bile duct, the pancreatic duct or both to obtain x-ray pictures of the ducts. Most ERCP’s are actually done to allow treatment and are called therapeutic endoscopies.
What are the indications for ERCP?
The most common reason for ERCP are abdominal pain suggestive of gallstones, jaundice, pancreatitis and evaluation of abnormal ducts as seen by radiological studies.
What treatments can be done through an ERCP scope?
Sphincterotomy is cutting the muscle that surrounds the opening of the ducts, or the papilla. This cut is made to enlarge the opening. A small wire on a special catheter uses electric current to cut the tissue. A sphincterotomy does not cause discomfort as there are no nerve endings. The actual cut is quite small, usually less than 1/2 inch. This small cut allows various treatments in the ducts. Cutting of the bile duct opening is called biliary sphincterotomy. Cutting of the pancreatic duct is called pancreatic sphincterotomy.
Stent placement Stents are placed into the bile or pancreatic ducts to bypass a stricture, or narrowed parts of the duct. These narrowed areas of the bile or pancreatic duct can be due to scar tissue or tumors that cause blockage of normal duct drainage. Discomfort may occur due the presence of stent(s), tiny plastic tubes placed within the opening of the duct. These stents also allow the pancreatic/biliary juices to drain from the ducts during the healing period and allows time for swelling to be minimized, thus reducing the risk of procedure-associated pancreatitis. These stents are usually removed within 2-5 days after the initial procedure; however, there are indications in which the stents may need to stay in for a prolonged period of time i.e., strictures of the ducts and/or blockage due to tumors. The stents are considered to be temporary stents and unless removed, will become clogged over time and need replacement (when indicated). Metal stents are considered permanent, however, they also can become clogged and may require replacement.
Stone Removal is another common treatment through an ERCP scope. This is the removal of bile duct or pancreatic duct stones. These stones may form in the gallbladder and travel into the bile duct or may form in the duct itself years after your gallbladder has been removed. Pancreatic stones may also form in the pancreas and travel into the pancreatic duct. After a sphincterotomy is performed to enlarge the opening of the bile duct, stones can be pulled from the duct into the bowel. A variety of balloons and baskets attached to specialized catheters can be passed through the ERCP scope into the ducts allowing stone removal. Very large stones can be crushed in the duct with a specialized basket and the fragments can be pulled out through the sphincterotomy.
Balloon Dilation ERCP catheters fitted with dilating balloons that can be placed across a narrowed area or stricture. The balloon is then inflated to stretch out the narrowing. Dilation with balloons is often performed when the cause of the narrowing is benign (not a cancer). After balloon dilation, a temporary stent may be placed for a few months to help maintain the dilation.
Tissue Sampling One procedure that is commonly performed through the ERCP scope is to take samples of tissue from the papilla or from the bile or pancreatic ducts. There are several different sampling techniques although the most common is to brush the area with subsequent examination of the cells obtained. Tissue samples can help decide if a stricture or narrowing is due to a cancer. If the sample is positive for cancer, it is very accurate. Unfortunately, a tissue sampling that does not show cancer may not be accurate.