An operative cholangiogram is a type of imaging study carried out during gall bladder surgery. The cholangiogram uses dye which is opaque to x-rays in order to reveal the outline of the bile duct, the tube which drains bile juices from the gall bladder. This is useful because it shows whether the bile duct is blocked by a gallstone, enabling the surgeon to remove the stone during the operation. An operative cholangiogram can also help reveal any injuries to the bile duct which might occur during surgery. Injury of the bile duct is a known complication of gall bladder surgery when keyhole, or laparoscopic, techniques are used.
Bile is a digestive juice which is produced in the liver and stored inside the gall bladder. When a person eats, bile is released from the gall bladder and passes though the bile duct into the gut where it helps to digest fatty foods. Sometimes bile inside the gall bladder crystallizes into stones, which may block the outlet. This can cause a condition known as cholecystitis, where the gall bladder becomes swollen and inflamed. Stones may pass out of the gall bladder and become lodged in the bile duct causing symptoms such as pain and jaundice, in which case surgery may be required to remove the gall bladder and stones.
The process by which an operative cholangiogram is carried out is called cholangiography. Laparoscopic instruments, which are inserted into the abdomen through small skin incisions, are used to carry out the gall bladder surgery and to perform the cholangiogram. Special dye, known as contrast medium, is injected into the bile duct, and x-ray images are taken which the surgeon is able to view on a monitor. As the contrast medium does not let x-rays pass through, the areas where it is present appear highlighted on the x-ray images. This means that the operative cholangiogram will show clearly whether the bile duct is obstructed by a stone or stones, and should also reveal any accidental damage caused by surgery.
In addition to an operative cholangiogram, there are other methods of cholangiography which may be used to examine the bile duct. What is known as percutaneous transhepatic cholangiography (PTC) involves injecting contrast medium through the skin into that area of the liver which drains into the bile duct. This procedure can be carried out while the patient is awake and may be used to decide what further treatment is necessary.