When obstruction of the bile duct occur your veterinarian may choose to perform a choledochtomy, which is a procedure to surgically open the bile duct and remove the blockage. The bile duct transports bile produced in the liver into the gallbladder where it is stored and then released to digest fats in the intestine. When obstruction of the bile duct occurs from gallstones or a buildup of thick bile (mucocele), a dangerous condition develops characterized by inflammation of the bile duct and sometimes the gallbladder and if not treated rupture and death can result. Choledochotomy is rarely performed in cats due to their small size and the complexity of the procedure. As a result, removal of the organ is usually performed. However, if blockage occurs in an area of the bile duct of your cat large enough to permit surgical intervention, a choledochotomy may be performed under general anesthetic by a veterinary surgeon.

Choledochotomy may be performed during exploratory surgery to determine the source of gastrointestinal problems. However often bile duct blockage is revealed by radiographs or haematology results indicating raised enzymes such as AST and ASP and/or increased bilirubin levels. Surgery to remove bile duct blockages may be performed laproscopically or by traditional open surgery procedures, which is more common in veterinary medicine.

The night prior to surgery you will need to fast your cat from food in order to reduce the danger of aspiration during anesthesia.

When you arrive at the veterinarian a physical examination will be performed to ensure infection is not present. 

Your cat will be given a sedative to calm them followed by intravenous anesthetic, a breathing tube will be inserted, and anesthesia maintained by gas for the duration of the procedure.

The abdominal area will be shaved and cleaned antiseptically. During the procedure your cat's vital signs will be monitored closely. An incision will be made in your cat’s abdomen and tissues moved to expose the liver, bile duct and gallbladder. The bile duct will be isolated and an incision made adjacent to the apparent blockage. Radiographs will be used to guide your surgeon in determining the location of the blockage and most effective site to effect removal. 

Gallstones or mucocele will be removed and the bile duct repaired. Use of a stent is possible to allow drainage of the bile duct if stricture of the duct has occurred. If a tumor is removed, surrounding organ tissue may also be biopsied and the biopsied tissue sent for laboratory examination to determine if cancerous cells are present.

Your cat will require hospitalization post surgery to provide care such as intravenous hydration and ensure no complication arise from surgery.

Cats that require surgical removal of bile duct blockages are often in serious medical condition upon presentation at a veterinarian and the effectiveness and prognosis of treatment depends on how far disease has progressed. Surgical removal of obstruction in the bile duct is often not possible due to the small size of these tissues in cats, however it may be possible if blockage occurs in a wider area of the bile duct. Choledochotomy is usually successful at resolving the condition, providing extensive damage to duct and organs have not occurred. Obstruction can reoccur, making repeat surgical intervention necessary and if chronic, removal of the gallbladder may be indicated.

Surgery to remove bile duct blockage is invasive and may require hospitalization for a few days. Once released home your cat will be given pain medication and possibly antibiotics or anti-inflammatories if required. Your cat should rest and be restricted from exercise or outdoor activity for two weeks. An Elizabethan collar to prevent interference with abdominal incisions is usually required. A special diet, low in fat, subsequent to surgery of the bile duct should be fed to reduce stress on the biliary system.

Cost of surgery to remove bile duct obstruction varies depending on the cost of living in your region and the medical intervention required to stabilize your cat prior to and during surgery. Choledochotomy surgery in cats usually ranges from $1,000-$2,000 including pre-surgical tests, anesthesia, procedure, and postoperative care and medication.

Due to the risk of inflammation and rupture of a blocked bile duct prior to and during surgery, a surgeon experienced in this procedure should conduct surgery to unblock and repair your cats bile duct. Due to the difficulty of performing this procedure in small animals and especially cats, increased risks are associated with the procedure and it is not common in cats. Alternative surgical procedures to remove the gallbladder are more commonly performed. Your cat’s medical condition prior to surgery should be considered and chances of recovery assessed as complications from inflammation, rupture, infection, hemorrhaging and anesthetic exist with surgical intervention to the bile ducts.

Monitoring of your pet's health for signs of gastrointestinal disorder and prompt intervention will increase their chance of recovery if obstruction of the bile duct occurs. Ensuring that your cat maintains an appropriate weight by providing a healthy balanced diet and ensuring your cat gets adequate exercise will reduce the chances of bile duct obstructions from occurring.