Radiologic, Histologic and Functional Analysis after Transplantation of Autologous Cultured Chondrocytes into Trachea and Vocal Fold

Abstract

Reconstruction of tracheal defects is one of the most difficult procedures in head and neck surgery. To date, various reconstructing techniques have been used with no consensus on the best approach. This study investigated the feasibility of using a fibrin/hyaluronic acid (HA) composite gel with autologous chondrocytes for tracheal reconstruction. Chondrocytes from autologous rabbit auricular cartilages were expanded and seeded into a culture dish at high density to form stable tracheal cartilages mechanically using a fibrin/HA composite gel. A 1-cm long by 0.5-cm wide defect was created by a scalpel on the cervical tracheae of six rabbits. Tissue-engineered cartilages using fibrin/HA composite were trimmed and fixed to the defect boundaries with tissuecol��. Postoperatively, the site was evaluated endoscopically, histologically, radiologically, and functionally. None of the six rabbits showed signs of respiratory distress. Postoperatively, in all cases, rigid telescopic examination showed that the implanted scaffolds were completely covered with regenerated mucosa without granulation or stenosis. Histologically, the grafts showed no signs of inflammatory reaction and were covered with ciliated epithelium. Even when grafts were broken and migrated from their original insertion site, implanted cartilages were well preserved. However, the grafts did show signs of mechanical failure at the implantation site. The beat frequency of ciliated epithelium on implants was very similar to that of normal respiratory mucosa. In conclusions, implants with autologous chondrocytes cultured with fibrin/HA showed good tracheal luminal contour, functional epithelial regeneration, and preservation of neocartilage without inflammation, but lacked adequate mechanical stability.

Injection laryngoplasty is an option for treatment of glottic insufficiency following vocal fold paralysis, vocal fold atrophy or scarring. We intended to evaluate the plausibility of autologous chondrocytes cultured with fibrin/hyaluronic acid (HA) for permanent vocal fold augmentation. Chondrocytes from rabbit auricular cartilage were expanded and cultured with fibrin/HA composite gel. 0.1 ml dosages of fibrin/HA gel with autologous chondrocytes were injected into the left vocal folds of six rabbits. Four months postoperatively, the site was evaluated endoscopically, histologically, and radiologically. None of the six rabbits showed signs of respiratory distress. Computed tomography images and endoscopic evaluation revealed sufficient augmentation volume of the injected vocal fold. Histologic data showed that the injected material did not migrate from their original insertion site. Even though the number of chondrocyte that settled down and survived in the injected site was varying in rabbits, chondrocytes successfully formed neo-cartilage at four months postoperatively in all cases. Histologically, the grafts showed no signs of inflammatory reaction and were covered with ciliated epithelium. The chondrocytes cultured with fibrin/HA could be a plausible injection material for vocal fold augmentation.