Proceedings Article | 24 October 2012
KEYWORDS: Tissues, Scanning electron microscopy, Metals, Silicon, Endoscopy, Astatine, Esophagus, Diffusion, Coating, Polymers
Simple esophageal strictures, which are focal, straight, and large in diameter, usually require 1 - 3 dilation sessions to
relieve symptoms. However, complex strictures, which are long, tortuous, or associated with a severely compromised
luminal diameter, are usually more difficult to treat with conventional bougie or balloon dilation techniques, and often
have high recurrence rates.
Although the permanent placement of self-expandable metal stents (SEMS) has been used to manage refractory benign
esophageal strictures, this procedure is associated with additional problems, such as stricture from tissue hyperplasia,
stent migration, and fistula formation. Thus, several new types of stents have been developed, including temporary
SEMS, self-expandable plastic stents (SEPS), and biodegradable stents. The use of these new products has produced
varied results. Temporary SEMS that have been used to relieve benign esophageal conditions have caused granulation
tissue at both ends of the stent because of contact between the mucosa and the exposed metal components of the stent,
thus hindering stent removal. We examined the tissue response to two new types of SEMS, a flange-type and a straighttype,
each coated with a silicone membrane on the outside of the metal mesh. These two SEMS were evaluated
individually and compared with a conventional control stent in animal experiments. Although the newly designed stents
resulted in reduced tissue hyperplasia, and were thus more easily separated from the esophageal tissue, some degree of
tissue hyperplasia did occur.
We suggest that newly designed DES (drug-eluting stents) may provide an alternative tool to manage refractory benign
esophageal stricture.
