Prefabrication of Composite Tissue for Improved Tracheal Reconstruction

Abstract

Tracheal repair tissues were evaluated experimentally to provide an evidence-based choice for decision-making in clinical tracheal reconstruction. Tracheal reconstructive tissue was characterized as providing for vascularization, support, and/or lining. A tissue equivalent was developed in the rabbit for each of the individual tissues. The individual tissues consisted of nonepithelialized soft tissue (vascularized fascia), epithelialized tissue (vascularized fascia grafted with buccal mucosa), and supportive tissue (ear cartilage). The 3 reconstructive tissues were evaluated in 30 rabbits after repair of an anterior laryngotracheal defect. Morphometric and histologic analysis was applied to the reconstructions. After a 1-month follow-up period, defects repaired with nonepithelialized soft tissue showed healing by secondary intention and a wound that was contracted to 44% of the initial surface area of the defect. Mucosa-lined soft tissue flaps and cartilage grafts showed a less than 10% wound contraction. Compared to cartilage grafts, mucosa-lined soft tissue (vascularized fascia grafted with buccal mucosa) seemed preferable for clinical use, because it showed healing by primary intention. A mucosa-lined radial forearm fascia flap was used successfully in cases of restenosis after tracheal resection. One deficiency of the mucosa-lined soft tissue was the absence of supportive tissue. In cases of extensive stenosis, it might be useful to obtain additional expansion of the airway lumen by creating a convexity at the site of reconstruction. In a second set of experiments, we attempted to improve the mucosa-lined soft tissue concept by adding elastic cartilage. A composite tissue consisting of vascularized fascia, buccal mucosa, and auricular cartilage was developed. Heterotopic prefabrication of the composite tissue was essential for survival of the cartilaginous component. Additional airway lumen expansion could be obtained after heterotopic flap prefabrication. After experimental evaluation, the concept of the prefabricated composite tissue was successfully applied in a clinical case of long-segment stenosis. Experimental and clinical evidence suggests that the combination of buccal mucosa and fascia form an optimized tissue combination for tracheal reconstruction. This combination can be improved by adding strips of autologous ear cartilage.