Study on Tracheal Prosthesis using promotive materials for tissue regeneration

(1)用自制的人工气管替代了犬的胸腔内气管。气管假体由连续的聚丙烯螺旋增强的Marlex网(聚丙烯网)组成，它被嫁接并涂上猪真皮胶原。术中人工气管和吻合口漏气最少。所有假体均与宿主组织完全结合。然而，在颈段气管置换术中，网片暴露于气管管腔的情况比以往的实验更为显著。(2)为了克服这一问题，我们在胸腔内气管置换术中增加了网眼固定术。结果表明，新粘膜层的再生速度更快、更完整，比以往未植入大网膜的替代物更完整。此外，在组织学检查中，上皮再生更快、更完整。但是，由于仍有部分犬存在气管狭窄，需要进一步改善管腔狭窄以促进上皮再生。(3)因此，我们研制了一种新的气管假体，以促进新生粘膜的再生。该假体与实验(1)中使用的假体相同，由猪真皮胶原蛋白制成的胶原胶原海绵层压在其上。这种新的气管可以部分克服管腔狭窄和网片外露两大问题。然而，由于胶原海绵很容易从网眼的圆柱体中脱落，因此吻合口的并发症被认为是容易发生的。由于在一些胸腔内置换术中，气管漏气是致命的，胶原海绵的使用似乎没有预期的那么有效。

(1) We replaced the intrathoracic trachea of dogs'using our tracheal prosthesis. The tracheal prosthesis consists of Marlex mesh (polypropylene mesh) reinforced with a continuous polypropylene spiral, which is grafted and coated with porcine dermal collagen. At the operation the air leakage from the tracheal prosthesis and anastomotic site were minimal. All the prosthesis were completely incorporated with the host tissue. However, the exposure of mesh to tracheal lumen were more remarkably observed than in the previous experiment of replacement at the cervical trachea.(2) In order to overcome this problem, we added omentpexy to the intrathoracic tracheal replacement prosedure. As the result, the regeneration of neomucosa was faster and more complete than in the previous replacements without omentopexy. Moreover, in histological study, the epithelial regeneration were faster and more complete. But, since there were still remain in some dogs, stenoses of tracheal lumen furter improvement is requiered to promote the epithelial regeneration.(3) Therefore, we manufactured a new tracheal prosthesis to promote the regeneration of neomucosa. This prosthesis consists of tthe same as the prosthesis used in the experiment (1) as a bulk on which collagen sponge made from porcine dermal collagen was laminated.We replaced dog's cervical tracheae using this prosthesis. This new trachea could partially overcome the 2 major problems such as stenosis of the lumen and exposure of the mesh. However, since collagen sponge easily came off from the cylinder of mesh, the complications at the anastomotic sites is consider to be ready to occure. As the air leakage from this trachea were lethal in some intrathoracic replacements, the use of collagen sponge appeared not so effective than expected.