Tissue compatibility and biodegradation of new absorbable stents for tracheal stabilization: an experimental study

Newly designed absorbable stents for temporary tracheal stabilization were implanted into the trachea of 35 Wistar rats. The stents consisted of Vicryl filaments in a homogeneous PDS melt. Compatibility and biodegradation were investigated over a study period of up to 24 weeks. After the animals were killed, the trachea was examined with an optic and scanning electron microscope. During the first 2 weeks erosive mucosal defects appeared in the trachea, as well as distinct polyps of granulation tissue, focal metaplasia of the epithelium, and inflammatory infiltrates of the lamina propria. During the period leading to the sixth week, the granulations flattened and mild fibrotic alterations evolved. After the eighth week no stent residues could be detected, whereas only slight signs of chronic fibrotic inflammation persisted. No evidence for aspiration of foreign bodies or progressive inflammatory changes of the mediastinum was found.