[A new balloon-expandable plastic endoprosthesis. Initial report of experience with the malleable thermostent]

A new system of balloon-expandable stents for different purposes is presented. A special plastic material that can be shaped by a hot balloon technique or other internal or external heating modalities has been developed. The plastic material - a distant derivative of polyurethane - is caprolactone, which is soft from 52 degrees C to 70 degrees C. Using balloon techniques, the "thermo-stent" can be modeled to suit the form of the vessels, the bile ducts or the bronchial tree, as required. The balloon can be heated simply by means of a warm NaCl solution, electric matter in the balloon itself or microwaves. The plastic material can even be heated directly, which is especially beneficial if the stent needs to be thicker, e.g. in the bronchial tree, by an electric network within the plastic material, which heats the material to the necessary temperature by electric current. When the balloon is cooled after the dilatation the new form, the plastic has been modeled to is maintained exactly. The advantages of this thermo-stent will be the perfect adaptation to every individual situation in the intraluminal vessels, the bile ducts, and even the bronchi. The problems encountered hitherto with conventional metallic stents, e.g. high thrombogenicity, risk of metal intoxication or metallic rupture of filaments, have not be seen so far in animal experiments.