[Experimental study of patch reconstruction of tracheal defects with Marlex mesh]

Animal experiments of the patch reconstruction of tracheal defects using Marlex mesh were performed on 41 mongrel and beagle dogs. They were consisted of four groups. In group I, cervical tracheal defects were reconstructed with simple Marlex mesh patches. In group II, cervical tracheal defects were reconstructed with Marlex mesh patches which were reinforced by three polyacetal-resin half rings. In group III, thoracic tracheal defects were reconstructed with Marlex mesh patches which were reinforced by half rings, and were covered with omental pedicle flaps. In group IV, a pedicled rectus abdominis muscle flap was prepared, and the inner side of Marlex mesh was covered by anterior sheath of the rectus abdominis and the external surface of the mesh was reinforced by rings and rectus muscle. Accordingly, in this group, thoracic tracheal defects were reconstructed by this combined Marlex mesh and pedicled muscle flap. In group I, Marlex mesh patches protruded into the tracheal lumen a large number of cases. On the contrary, in group II, in which meshes were reinforced by half rings, no protrusion of Marlex mesh patches was recognized. But granulation and abscess formation was observed in a large number of this group. In group III (omentopexy group), in spite of few granulation and abscess formation, complete epithelialization were obtained in only three of twelve dogs. In group IV (muscle flap group), few granulation and abscess formation was observed, and complete epithelialization were obtained in seven of twelve dogs. In conclusion, 1: Reinforcement of Marlex mesh by polyacetal-resin half rings was effective to maintain the tracheal lumen. 2: Using of omental pedicle flap or rectus abdominis muscle flap was effective to prevent the abscess and granulation formation. 3: Use of rectus abdominis muscle flap resulted in good epithelialization. 4: The inner surface of patches was covered with the flattened epithelium 2-3 months after surgery, and then covered with ciliated cells almost completely except central area of patches 6-12 months after surgery. The reconstruction of tracheal defect with combined Marlex mesh and rectus abdominis muscle flap may be ready for clinical use, however further investigation is necessary to develop tubular reconstruction of trachea in future.