PLASTIC OR EXPANDABLE BILIARY ENDOPROSTHESES

Endoscopic biliary drainage with a PVC stent provides excellent palliation for the patient with malignant biliary obstruction. The main disadvantage of this technique is occlusion of the stent after 3-4 months by biliary sludge. This complication is reduced with larger diameter stents, which have led to the development of expandable metal stents. These stents are less susceptible to obstruction by biliary sludge and remain patent longer than the PVC endoprostheses. Their main disadvantage is that tumor ingrowth through the open meshwork eventually leads to stent obstruction. Other relative disadvantages include the high cost of the metal stents and the inability to retrieve them endoscopically or surgically once deployed. Studies have shown that patients with a short life expectancy do not benefit from metal stents over the use of the standard PVC stent. Patients with a longer life expectancy, however, who are not considered surgical candidates, are better palliated with an expandable metal stent. Further development in metal stent technology may lead to improved function and will broaden the indication for its use.