Thermoplastic Stents: A New Concept for Endoluminal Prosthesis

Background and Study Aims: Intraluminal stenting of organs with stenoses or fistulae in anatomically difficult locations (for instance cardia, pylorus, large bowel), with a tendency to kinking or increased motility, still carries a high risk of stent dislocation. In the search for a solution, we report on the use of a new thermoplastic stent in animal experiments.

Material and Methods: The new stent consists of a plastic-coated wire mesh which can be heated electrically. Once it is warmed up to 55 °C, its size and shape can be changed. After being expanded by a dilatation balloon across the stenosed area, the stent can be fitted onto the inner organ surface. This guarantees a low dislocation risk and high stability. In an animal experiment, stents were endoscopically placed in the trachea and the surgically stenosed esophagus of two dogs. The animals were observed for 3 months.

Results: The thermostents were implanted easily and without complications. It was possible to mold the thermostent evenly onto the intraluminal wall. No stent dislocation, bleeding or perforation was observed. Upon histologic evaluation, granulation tissue was found to be growing through the wire mesh of the stent.

Conclusion: It was shown that the stent described here can be implanted without major problems. The greater effort of the implantation procedure, in comparison with self-expanding stents, is compensated by the special mechanical characteristics of the stent. These characteristics may permit implantation in anatomically difficult locations where up to now stenting has been impossible or inadequate.

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