[Prosthesis: indications, contraindications and follow-up].
The use of stents or endoprostheses to treat tracheobronchial obstruction is firmly established. The most important indication for stent placement are inoperable stenoses of the central airways, whose main component is extrinsic compression due to malignant, less frequently to benign disease. In experienced hands the short- and long-term results are excellent. When considering stent placement the functional benefit for the patient should be highly likely. With respect to this, the parameters to be assessed before and in regular intervals after stent placement include a physical examination, a chest roentgenogram or a CT scan, pulmonary function tests, bronchoscopy, and quality of life. Of all the various stents on the market the cylindrical silicone stent designed by Dumon is the one most widely used and represents the standard against which all other models have to compete. Expandable metal stents have advantages over most silicone stents through their thin walls and their excellent adaptability to greatly varying airway diameters. The current development of covered expandable stents should make it possible to combine the good biocompatibility known of silicone stents with the excellent flexibility and favorable wall to inner diameter ratio of the metal stents. This development will make expandable stents much more versatile for the treatment of malignant and benign obstructions of the central airways. Effective sealing of fistulas in airways without a concomitant obstructive component is another most welcome indication for this type of stents. The future might well belong to hybrid stents with metallic components and a smooth synthetic covering of silicone or polyurethane. The ongoing research in stents shows that the "ideal stent" for all purposes does not exist and probably never will. Quite often the specific stent type needed can only be determined during therapeutic endoscopy. Every specialist practicing in the area of stenting should therefore have an armamentarium of a few different types available and use the one best indicated in a specific situation.