[Tracheal replacement with a swine prosthesis]

In 12 experimental operations the authors tested the biocompatibility of a xenologous trachea from a pig which was used to replace a 5 cm defect of the trachea in a dog. After special preparation eliminating the antigenicity of the pig trachea the thus prepared graft was sutured into the thoracic portion of the dog trachea. The experiment could not be evaluated in two instances because the dog died on the operating table. In the remaining ten cases it was found that all anastomoses healed perfectly. The fibrous tissues of the tunica propria of the graft was replaced by granulation tissue. Across the anastomoses newly formed capillaries penetrated into the trachea where they caused chondrolysis. This led to a breakdown of the central portion of the prosthesis and stenosis in the airways with terminal respiratory failure. The mucosa of the graft was at some sites covered by metaplastically altered epithelium. Even a reinforcing vascular prosthesis did not prevent the breakdown of the wall of the xenologous graft. An asset for future work is the finding of a well healed suture between the graft and the trachea and evidence that newly formed blood vessels penetrated into the prosthesis.