Biliary stents

Treatment, temporary or permanent management, for biliary obstruction resulting from benign or malignant disease.

Initially biliary drainage was achieved with percutaneous transhepatic drainage procedures: presently endoscopic placement of an internal biliary prosthesis at the time of endoscopic retrograde cholangiopancreatography (ERCP)is utilized.

Current percutaneous biliary interventions include percutaneous transhepatic cholangiography (PTC) and biliary drainage to manage benign and malignant obstruction and percutaneous cholecystostomy. 

Percutaneous treatment of biliary stone disease, with or without choledochoscopy, is still performed in selected cases. 

Among the principal indication for stent placement for benign bile duct strictures.

Other uses  include cholangioplasty for biliary strictures, biopsy of the biliary duct, and management of complications from laparoscopic cholecystectomy and liver transplantation.

The most common indication for biliary stenting is for treatment of obstructive jaundice from either benign or malignant causes. 

Endoscopic treatment of the benign biliary strictures is significantly less morbid than surgery and percutaneous approaches and has recently low recurrence rates when an aggressive strategy is implemented.

Benign biliary strictures require intervention to treat jaundice, cholestasis, and cholangitis, and to avoid the development of secondary biliary cillosis.

Biliary stenting can be done for the management of bile leaks. 

Biliary stents are plastic or metal, and they are placed to provide internal drainage, eliminating the need for an external catheter.

Metal stents most often used for providing palliation in patients with malignancy.

The major advantage plastic stents have over metallic stents is that they can be removed and replaced if necessary. 

Metallic stents are generally permanent, but they have the advantages of a larger lumen and longer patency. 

Self-expanding metallic stents placed in the biliary tree have a luminal diameter of 10 mm, which is significantly larger than plastic stents, which are typically 2-4 mm in luminal diameter. 

But, the patency of metallic stents is only 60-70% at 6 months, and nearly all are occluded by 1 year. 

The use of permanent metallic stents to treat benign biliary obstruction is not recommended, because of short patency duration in patients with long-term requirement needs.

In patients with malignant disease and a life expectancy less than 6-12 months, metallic stents are more cost-effective and are associated with shorter hospital stays and fewer reinterventions. 

The use of metallic stents for biliary obstruction is reserved for patients with inoperable malignant biliary obstruction and a life expectancy less than 6-12 months.

Complications may be early or late, with 30 days from placement as the break point.

Early complications include bleeding, pain, infection, and stent instability.

Late complications include obstruction, migration, tumor occlusion and rarely stent fracture.

Fractures can occur if in place for a longer time than expected, secondary to a malignant stricture and by retrieval procedures.

Fractures occur usually at level of the anchoring flap.

Fragments that occur with fracture usually remain within the biliary tree.

Most patients with fractures present with obstructive jaundice or cholangitis.

Radiographs can demonstrate a change in the size of a stent from the time of placement in the presence of a fracture.

Cholangiography or CT scanning may be warranted to demonstrate complications associated with a stent fracture.

In a randomized trial a comparison between preoperative biliary train each with surgery alone for patients with cancer of the head of the pancreas: the rates of serious complications were 39% in the surgery group and 74% in biliary drainage group, and surgery related complications occurred in 37% in the early surgery group and 47% biliary group, there was no difference in mortality linked of hospital stay between groups (van der Gaag NA).

In the van der Gaag study comparing surgical outcomes with preoperative ERCP for biliary drainage for 4-6 weeks, followed by surgery compared with surgery alone within one week of diagnosis of potentially resectable pancreatic cancer with biliary obstruction: the initial ERCP procedure failed in 25% of the cases, and after a second ERCP successful biliary drainage was achieved in 94% of the patients, and in the ERCP group 46% of patients experienced pancreatitis, perforation, bleeding and cholangitis.

In the above study plastic stents were used and not self expanding metal stents which have a longer patency and fewer stent related problems then plastic stents because they are larger.

Self-expanding metal stents that have a thin layer of material such as polytetrafluoroethylene (PTFE) on the exterior, which improves patency by preventing tumor ingrowth are available.

Contraindications for percutaneous biliary stenting: bleeding disorders, ascites.

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