What is Biliary Stenting?
Obstructive jaundice is a common condition where the flow of bile is blocked, which can be caused by harmful or harmless diseases. Bile, a fluid produced by the liver, helps us digest fats. But when a blockage happens, it can result in jaundice, a yellowing of the skin and the whites of the eyes.
Before the early 1980s, surgery was predominantly used to treat instances of this blockage. Surgical treatments for obstructive jaundice included various procedures, such as a Whipple procedure with a hepatocojejunostomy (a surgical procedure connecting the liver to the small intestine), cholecystojejunostomy (connecting gallbladder to small intestine), choledochojejunostomy (connecting bile duct to small intestine), or other procedures tailored for the specific condition causing the obstruction.
However, a technique called endoscopic biliary stenting was introduced in the early 1980s, which changed the treatment approach. Biliary stents are small tubes made of plastic or metal placed in the bile duct to help clear the blockage or to fix any leaks in the biliary system.
What Causes Biliary Stenting?
Malignant obstructive jaundice, which is a yellowing of the skin and eyes caused by cancer, can be due to diseases like pancreatic cancer, cholangiocarcinoma (a cancer that forms in the bile ducts), and diseases that have spread from other parts of the body.
On the other hand, benign obstructive jaundice, which is not cancerous, can be due to both acute and chronic pancreatitis (inflammation of the pancreas), choledocholithiasis (stones in the bile duct), primary sclerosing cholangitis (a disease that damages the bile ducts), AIDS cholangiopathy (a condition affecting the bile ducts in people with AIDS), scarring following invasive procedures, and certain parasitic infections. The parasites that can cause this include Ascaris lumbricoides, Clonorchis sinensis or Chinese liver fluke, Fasciola hepatica, and other liver flukes (parasites that target the liver).
Risk Factors and Frequency for Biliary Stenting
Pancreatic cancer is the 11th most commonly diagnosed cancer, making up around 3% of all cancer cases in the United States. Cholangiocarcinoma, which is a type of bile duct cancer, does not occur as frequently, but it still contributes to a noticeable number of cancer cases each year.
Signs and Symptoms of Biliary Stenting
Patients with certain conditions may show various symptoms. These symptoms or signs include:
- Jaundice (a yellowing of the skin and eyes)
- Abdominal pain
- Pruritus (itching)
- Dark urine
- Clay-colored stools
- Signs of infection, like in cholangitis(a bile duct infection)
There may also be conditions that are discovered through routine blood tests, such as hyperbilirubinemia, a condition where there is too much bilirubin in the blood.
Testing for Biliary Stenting
Your doctor might ask for a blood test to check levels of two things: bilirubin and alkaline phosphatase. When these are higher than normal, it could suggest a problem with your liver or gallbladder.
Additionally, scans like a CT scan or an MRI can help determine what’s causing the problem and where exactly it’s located. These scans create detailed images of your abdomen, giving doctors a closer look at what’s going on.
There’s also a special kind of MRI called Magnetic Resonance Cholangiopancreatography (MRCP). This is a noninvasive (not involving any cuts or special procedures) technique often used to examine the ducts (small tubes) that bile (a fluid that helps with digestion) and pancreatic juice (a fluid that helps break down food) pass through. Reliable and hassle-free, MRCP can help spot problems in these ducts.
Treatment Options for Biliary Stenting
Biliary drainage is a medical process that can take two different routes: percutaneous transhepatic biliary drainage (PTBD), which involves inserting a tube through the skin into the liver to drain bile, or endoscopic biliary drainage (EBD), which involves draining bile through a tube inserted down the throat and into the bile duct. EBD can be done externally, in a process known as endoscopic nasobiliary drainage (ENBD), or internally, through a process called stent placement. Most doctors prefer endoscopic drainage because it seems to have fewer complications compared to percutaneous drainage.
PTBD is often performed by doctors specialized in interventional radiology. These procedures could be helpful for future treatments of the bile duct like, removing gallstones, placing biliary stents, or treating biliary strictures (narrowed areas). Both PTBD and ENBD procedures have some risks, including the tube getting dislodged, twisted, or collapsed. Additionally, patients may experience discomfort and loss of essential electrolytes due to bile loss. Extra complications of PTBD could be bile leakages and chest infection. Bile cultures or examination of the bile for disease, can be carried out, if it’s needed, using both these methods. An advantage with endoscopic biliary drainage is that patients don’t get exposed to discomfort or loss of electrolytes.
Biliary stents are one method of ensuring that bile flows freely from the liver to the intestines and may be crafted out of either plastic or metal. Inserting these stents often doesn’t require cutting into the bile duct. These stents come in several sizes, measured in a unit called the ‘French,’ where one ‘French’ unit equals one third of a millimeter.
In the case of bile duct blockage due to cancer, endoscopic biliary stenting is a safer solution than surgery. When choosing the type of stent to use, self-expanding metal stents (SEMS) typically tend to stay open longer than plastic stents. If a patient’s life expectancy is less than four months, plastic stents tend to be the more cost-effective choice. But if the life expectancy is more than four months, SEMS is usually recommended. However, if it’s possible to remove the cancerous blockage, surgery is often seen as the best option.
Stents can also be helpful in cases of bile leaks, sometimes seen after gallbladder removal, or in treating acute cholangitis (inflammation of the bile duct), or severe gallstone conditions.
Insertion of a biliary stent requires specialized tools including a wire guide for navigation, a stent insertion system, and dilators for stretching the duct. The doctor chooses the shortest stent length that would still allow adequate drainage. The stent should extend 1-2 cm beyond the area of blockage on the upstream side, and 1 cm into the duodenum, the first part of the small intestine, downstream. If the portion of the stent in the duodenum is too long, it could cause perforation or bleeding ulcer. After insertion, an X-ray is usually done to ensure proper stent placement and flow of bile.
Potential complications after stent insertion include infection, bleeding, and pancreatitis. The stent may also become blocked by bile sludge or tissue overgrowth in case of metal stents and may sometimes get dislodged.
There are new types of stents being investigated, including anti-reflux stents, medication-releasing stents, bioabsorbable stents (those that dissolve over time), and magnetic stents, which can be removed using a magnet, avoiding the need for another invasive procedure to take out the stent.
What else can Biliary Stenting be?
Some of the medical conditions that could be involved are:
- Alcoholic hepatitis (Liver inflammation due to alcohol)
- Ampullary carcinoma (A type of cancer in the bile duct)
- Ascariasis (A type of parasitic worm infection)
- Bile duct strictures (Narrowing of the bile duct)
- Bile dust tumors
- Biliary disease (Disease involving the bile ducts)
- Biliary trauma (Injury to the bile ducts)
- Cholangiocarcinoma (Cancer of bile duct cells)
- Cholangitis (Inflammation of the bile ducts)
- Cholecystitis (Inflammation of the gallbladder)
