Development of an artificial tracheal prosthesis: A semicircular shape polyurethane scaffold

The purpose of this study is to develop an artificial prosthesis for reconstruction of a partial tracheal defect. Experimental animal study. A semicircular shape bi-layered (inner: porous, outer: dense) scaffold was made from polyurethane (PU). Polyethylene glycol was grafted onto the inner surface of the PU scaffold to act as a surfactant. Variable sized scaffolds (2×1, 2×2, 3×1, 3×2 and 3×3 cm²) were transplanted into ten beagles. Endoscopic and histological examinations were performed monthly (From 1 month to 6 month after transplantation). Scanning electron microscopy was performed to evaluate the ultrastructure. The measurement of trachea cilia beat frequency was carried out. The tensile strength was measured for evaluation the biomechanical property of the prosthesis. Seven out of the ten beagles survived to the expected date. The endoscopic examination showed granulation tissue on the scaffold transplanted site until one week after transplantation. The mucosa was completely covered after four weeks. The histological examination showed that a large amount of fibrous tissue had grown through pores of the porous scaffold. Ciliated respiratory mucosa was restored onto the surface of the PU scaffold, as visualized by scanning electron microscopy. About 16 -20 Hz cilia beat frequency was noted on the functional exam. The tensile stress (the stress strain curve) of the scaffold transplanted site was very similar with that of the normal cartilage. The semicircular shape PU scaffold could be used as a ready-made type prosthesis for tracheal reconstruction.