Endoscopic insertion of plastic biliary endoprostheses is a well-established treatment for obstructive jaundice.
The major limitation of this technique is late stent occlusion.
Dr van Berkel and colleagues from the Netherlands compared events involved in biliary stent clogging.
The research team identified the distribution of bacteria in unblocked stents by using confocal laser scanning and scanning electron microscopy.
The team carried out these procedures on 2 different stent materials including polyethylene and hydrophilic polymer-coated polyurethane.
The researchers included in the study 10 consecutive patients with postoperative benign biliary strictures.
|The inner stent surface was covered with a uniform amorphous layer of bacteria|
The team inserted 2 different10-Fr stents 9 cm in length, where 1 was made of polyethylene and the other of hydrophilic polymer-coated polyurethane.
The stents were electively exchanged after 3 months and examined using confocal laser scanning and scanning electron microscopy.
The researchers noted no differences between the 2 types of stent, but found that the inner stent surface was covered with a uniform amorphous layer.
On top of this layer, a biofilm of living and dead bacteria was found, which in most cases was unstructured.
The researchers observed that the lumen was filled with free-floating colonies of bacteria and crystals, surrounded by mobile laminar structures of mucus.
An open network of large dietary fibers was seen in all of the stents.
Dr van Berkel's team concludes, “The same clogging events occurred in both polyethylene and hydrophilic polymer-coated polyurethane stents.”
“The most remarkable observation was the identification of networks of large dietary fibers, resulting from duodenal reflux, acting as a filter.”
“The build-up of this intraluminal framework of dietary fibers appears to be a major factor contributing to the multifactorial process of stent clogging.”