Artificial Trachea Covered by Epithelium

Kim, Kwang Taik; Lee, Yoon Shin; Sun, Kyung; Lee, In Sung; Kim, Hyoung Mook

Abstract

A variety of experiments concerning the development of ideal prosthetic grafts for correcting circumferential tracheal defects have been performed. The requirements for an ideal tracheal prosthesis are impermeability to air, consistency to prevent collapse, and acceptance by the host tissue causing a minimum inflammatory reaction, allowing fibroblastic infiltration and epithelialization. The synthetic material, polyurethane(PU), is known as a biocompatible polymer with an inert component. In this study, the tracheal prosthesis was made from microporous PU(30 micrometer in diameter) coated with gelatin and reinforced with isoplastic rings. This procedure provides the prosthesis with a compression strength. The out side diameter of the prosthesis was 20 mm with a length of 30 mm. The gelatin used in the study was obtained from pig skin and immobilized and cross-linked by irradiation(60 Co gamma ray) to promote host tissue incorporation and render the prosthesis epithelization after implantation. Animal experiments using 10 mongrel dogs were performed to compare three kinds of prosthesis; gelatin coated polyurethane graft, uncoated polyurethane graft, and prosthesis/ pericadium complex graft. After 6 weeks of implantation, the epithelialization of implants was seen on the gelatin-coated and prosthesis/pericadium complex grafts. Implanted prosthesis were complicated by airway obstruction due to anastomosis granuloma. Early tracheal stenosis was found in the uncoated graft group. Two kind of anastomosis techniques were tested on the gelatin-coated prosthesis. Everted anastomosis resulted severe granuloma than the inverted anastomosis. In the prosthesis/pericadium complex graft, bacteria and inflammation at an anastomotic site was found. Based on these results, gelatin coated porous polyurethane trachea prosthesis is biocompatible and may be useful in clinical application with further investigation.