Small intestinal submucosa covered expandable Z stents for treatment of tracheal injury: An experimental pilot study in swine

PURPOSE: To evaluate efficacy of small intestinal submucosa (SIS) as a sten t covering in healing experimentally created tracheal defects and to explor e the trachea's reaction to placement of SIS-covered stents, MATERIAL AND METHODS: A tracheal defect with a diameter of approximately 10 mm was created in six swine with use of a blade or electrocauterization. A double-body, self-expandable SIS-covered Gianturco Rosch Z stent was place d into the trachea to cover the defect, The animals were observed, and were killed when they developed respiratory problems, Autopsy and histologic st udies were performed, RESULTS: The SIS-covered stents were accurately placed without immediate co mplications related to placement, All animals developed respiratory problem s on follow-up, One animal died 9 days after procedure because of pneumonia , the others five were killed at 12, 17, 18, 28, and 56 days because of str ider, wheezing, and cough, At autopsy and histology, the tracheal defects w ere found to be completely healed, with epithelial lining and regeneration of submucosal glands, Animals whose defects were created with a blade demon strated cartilage remodeling between 9 and 18 days, and apparent deposition of new cartilage at 28 days after SIS placement, The defects made by elect rocauterization showed only fibrous tissue with no cartilage regeneration, The tracheal lumen was narrowed by overgrowth of granulation tissue, partic ularly at the end wires of the stents, In three animals, polypoid masses ca used 60%, 70%, and 80% tracheal obstruction, respectively, CONCLUSION: Placement of SIS-covered stents contributed to rapid and effect ive healing of large tracheal defects, Rigidity and oversizing of Gianturco Rosch Z stents led to secondary changes of the tracheal wall, causing sign ificant airway obstructions, Smaller size and flexible stents should be sel ected for future work.