Endoscopic implantation of a biodegradable tracheal stent: Toward pediatric applications in airway surgery — A preclinical study

Background

Obstructions of the tracheobronchial tree can result from various etiologies. Most cases of tracheal stenosis or tracheomalacia are associated with patient-specific anatomical and functional abnormalities, making treatment challenging. Despite progress in the development of tracheal support devices, the optimal or near-optimal stent design remains elusive.

Methods

A multidisciplinary team developed a novel endoscopically implantable tracheal stent using three-dimensional (3D)-printed bioabsorbable polymer caprolactone. The stents were implanted into the trachea of 6 healthy adult male Texel sheep and after 8 weeks the animals were euthanized. Clinical, endoscopic, and histopathological findings were analyzed.

Results

All animals exhibited normal feeding habits, no significant weight loss (P = 0.82), and no significant clinical manifestations (P = 0.48) over the 8-week follow-up period. At the time of euthanasia, the stents were fully covered by respiratory epithelium in 2 animals (33 %) and partially covered in 3 (50 %). Complete regenerative epithelialization of the inner stent surface was observed in all animals. Cartilage reaction, squamous metaplasia/atrophy, and polyp formation did not differ significantly between the stented and unstented regions.

Conclusion

The 3D-printed caprolactone stent was well tolerated, demonstrating remarkable biocompatibility and rapid degradation with little residual inflammation. Its open design allowed tracheal secretion clearance, facilitated re-epithelialization along the inner stent surface, and should permit dynamic customization. Clinical studies of this novel tracheal support device in adult and pediatric patients are warranted.