Bile is a thick and viscous fluid, with important digestive functions, which is produced by the liver, collected in the bile ducts and accumulated in the gallbladder. The gallbladder therefore has the function of depositing bile: it empties with each meal, pouring bile into the intestine, and then fills up again during the fast.
If the bile ducts are blocked, bile also begins to flow into the blood (hyperbilirubinemia), pathologically accumulating in the whole body. This determines the onset of jaundice, yellowish discoloration of the skin and ocular sclerae, and widespread itching, typical of the accumulation of bile.
If not drained, the buildup of bile can lead to liver failure or infection (cholangitis), or both, with serious and potentially life-threatening consequences.
Draining the bile out of the body restores intrahepatic pressure, allowing the liver to function normally and reducing the risk of infection and liver failure.
Biliary stenting provides long-term benefits in case of biliary occlusion allowing the bile to flow into the intestine according to regular anatomy, without external drainages. Biliary drainage may also be needed in preparation for surgery or other biliary tract procedures, such as to protect the biliary tract from potential surgical damage.
PERCUTANEOUS TRANSHEPATIC BILIARY DRAINAGE (PTBD)
In PTBD, a plastic drainage is placed through the skin and the liver directly into the biliary tree, allowing bile to both flow in an external bag and into the intestine, bypassing the obstruction.
INDICATIONS
Itching (due to increased bilirubinemia)
Cholangitis / Sepsis
Chemotherapy
Diversion (in case of lesions of the biliary tract, with leakage of bile and bilirubinemia values, therefore, within the norm)
Access for other procedures: stone removal, stenosis dilatation, srachytherapy, biopsies with brushing
CONTRAINDICATIONS
Absolute
Uncorrectable coagulopathy
Relative
Voluminous ascites
Hemodynamic instability
MAJOR COMPLICATIONS
Sepsis – 2.5%
Local infections/inflammations (abscesses, peritonitis, cholangitis, pancreatitis) – 1.2%
Death – 1.7%
PRE-PROCEDURAL PREPARATION
Imaging review
Laboratory tests: complete blood count, coagulation, liver function
Informed consent
Peripheral venous access
Fasting >6hh
Antibiotic prophylaxis
HOW PTBD IS PERFORMED
The PTBD is performed in the angiographic suite, under local anesthesia, with the guidance of ultrasound and X-ray images. The first step is the puncture, with a thin needle, of the peripheral biliary tree, using ultrasound images to guide the needle, or directly with X-rays, following the anatomical landmarks. The best approach is on the right, with intercostal access along the mid-axillary line, below the pleural recess.
Entering a bile duct, contrast medium is injected to perform cholangiography, i.e. the study of the biliary tree. Then, a metal guide wire is inserted through the needle and is conducted, with the guidance of X-rays, up to the duodenum.
When the guidewire is in place, small plastic tubes of increasing diameter (dilators) will be slid over the wire to allow easy placement of the drainage catheter.
The drainage catheter is placed so as to drain as much bile as possible and then it's fixed to the skin with plasters or stitches. A sterile dressing is applied.
BILIARY STENTING
Biliary stents are flexible tubes, made of plastic or metal material, which are placed across the obstruction of the biliary tract to keep them open and ensure the normal passage of bile.
The placement technique is similar to that of biliary drainage. Once the metal guidewire is placed in the duodenum, the stent is inserted over the wire and released across the obstruction. If the bile is not infected, the stent can be placed at the same time as the bile drainage. Otherwise, if indicated, it is placed once the infection has been resolved.
Indications
Malignant unresectable strictures
Benign strictures: primary sclerosing cholangitis; biliary leak from iatrogenic lesions or trauma; post-inflammatory strictures (e.g. pancreatitis) or post-radiotherapy; gallstones
Absolute contraindications
Hemobilia (blood in the bile)
Colangitis
Relative contraindications
Coagulopathy
Worsening liver function despite drainage
Life expectancy <30 days
Skin/subcutaneous infection at the access site
Biliary lithiasis
There are several kinds of stents, each one with its own characteristics and indications.
BARE METAL STENTS
Bare metal stents are like tubes made from wire mesh. They have great radial force and large internal diameter but are difficult to remove (sometimes it is impossible). As they are not covered, they can be obstructed by neoplastic tissue that grows between the meshes and occupies the lumen, in which case they can no longer be removed.
Indications
Unresectable malignant lesions
Life expectancy > 4 months
Advantages
Great radial force
Large luminal diameter
Long duration
Disadvantages
More difficult to remove than other types of stents; sometimes impossible
Could be obstructed by pathological tissue growing into the meshes
PLASTIC STENTS
Plastic stents have a smaller diameter than metallic stents, have less radial force, and last less before occluding, but have the great advantage of being able to be removed/replaced relatively easily.
Indications
Life expectancy < 4 months
Benign or dubious lesions
Uncertain resectability of the lesion
Advantages
Removable and replaceable
Disadvantages
Smaller diameter
Less duration
COVERED STENTS
Covered stents consist of a metal mesh, the scaffold, surrounded by a plastic cover. They have the advantage of preventing the growth of pathological tissue through the mesh. They can be more easily removed than uncoated metal stents, but are more prone to unwanted movement and can occlude lateral bile ducts, covering the outlet. They are also very expensive.
Advantages
They prevent ingrowth through the metal mesh
Percutaneous or endoscopic removal
No preclusions to surgery
Disadvantages
Greater risk of migration
Occlusion of lateral ducts or cystic duct
Poor cost-effectiveness
BILIARY STENTING COMPLICATIONS
EARLY COMPLICATIONS
Cholangitis 5 - 6.5%
Hemorrhage - 2%
Biliary fistulas
Bilomas
LATE COMPLICATIONS
Migration (5% of plastic stents vs 1% of uncoated metal stents)
Stent occlusion: blockage by biliary sludge or stones; ingrowth/overgrowth