Placing a stent in the bile duct in the dog is an uncommon surgical procedure, usually performed by a specialist. 

The liver produces bile and stores it in the gallbladder. The latter empties into the duodenum (the first part of the small intestine) via the bile duct. If the bile duct becomes blocked then the gall bladder cannot empty out, becomes too full, and may rupture, and in addition bile acids build up in the liver with toxic consequences. 

The clinician will attempt to treat the underlying condition that is causing the bile duct obstruction, but in rare cases, the bile duct may be damaged or scarred and stent placement may be necessary. 

The patient has a full workup including blood tests, radiography, and an ultrasound scan. If liver disease is suspected then an ultrasound guided liver biopsy might also be useful. The aim is to identify and  treat any underlying problem, such as pancreatitis or liver disease, and identify physical blockages in the bile duct. 

The treatment of choice is to address the underlying health issue. Once pressure on the bile duct is relieved, this allows bile to flow freely once more, thus making a stent redundant. 

However, in rare cases scar tissue has formed or the bile duct ruptured, meaning the best option is a stent. 

The specialist surgeon will stabilize the patient prior to surgery, with intravenous fluids, pain relief, and possibly intravenous antibiotics. The surgeon performs a laparotomy (opens into the abdomen) to directly visualize the liver, gallbladder, and bile duct. 

The surgeon makes a clinical decision about which is the best procedure for that individual patient. Choices include removing the gallbladder, surgically opening the bile duct to remove a stone, or placing a stent. 

The stent is a fine tube which may be fed into the bile duct via an incision in the gallbladder or in the bile duct itself. 

The surgeon will take the opportunity to harvest any biopsy material, and then close the abdomen in three layers: muscle, fat, and skin. 

Stents may be permanent or temporary, and have an important role to play in promoting the free flow of bile, which in turn reduces the risk of complications and scar tissue formation in the liver or bile duct. 

However, surgery of the biliary tree (gall bladder and its ducts) is considered high risk surgery with a mortality rate of between 28 and 60%. This is in large part due to toxaemia (a release of toxins) or septicaemia (bacterial infection in the blood stream) associated with a buildup of toxins in the gallbladder and liver, when bile duct blockage has been present for a length of time. 

Other risks associated with this particular surgery include kidney failure, low blood pressure, and micro-blood clots in the circulation. With this in mind, if the specialist surgeon is presented with a case early, they may suggest surgery sooner rather than later because complications are more likely the sicker the patient is. 

After surgery, the patient needs careful monitoring for complications and may be placed in the canine equivalent of intensive care. Their blood pressure, blood gases, and kidney function may be monitored so as to address complications early and take corrective action. 

Their body temperature and white cell count may also be monitored in order to detect the earliest signs of septicemia, so that appropriate antibiosis can be started. Repeated ultrasound scans may be necessary in order to check the stent is in place and allowing free drainage of the gallbladder. 

Bile duct stent placement is a costly procedure, likely to be counted in thousands of dollars, rather than hundreds. In addition, the patient is liable to incur considerable costs prior to referral to a specialist. This involves workup fees for screening blood tests (estimated around $150), ultrasound scans ($50 to $200 depending on the operator's experience), vet consults, and therapy.

Bile duct stent placement is not a procedure to be taken on lightly. The surgeon will be certain of the benefits to the patient, and have balanced the risks of taking no action against those involved with surgery.

For example, it might be inevitable if a dog has certain types of long term liver disease that the bile duct will eventually become obstructed and the dog deteriorate dramatically. If this is inevitable then there is a discussion to be had about a high risk procedure which could extend life if successful, versus certain death in the short to medium term if nothing is done. 

Whilst in some cases placement of a bile duct stent may be curative (such as for ruptured bile ducts), in other cases it supports a patient with long term disease, but is unlikely to be curative. All of which means a full and frank discussion with the surgeon is best before electing to go ahead. 

Preventing the need for a bile duct stent is mainly a matter of promoting a healthy lifestyle, and particularly healthy liver function, which includes vaccination against leptospirosis in high risk regions. 

Some breeds, such as miniature Schnauzers, have a natural tendency to high blood cholesterol levels which the predisposes them to pancreatitis. The latter is an inflammatory condition which could compress the bile duct. To a certain degree, a low fat diet may be helpful  to reduce the risk of pancreatitis episodes.