The usefulness and safety of natural stent in a canine model of tracheal stenosis

Background: In order to investigate the usefulness and safety of Natural Stent, we performed this study in a canine model of tracheal stenosis induced using Nd-YAG laser. Methods: After tracheal stenosis was induced in 12 Mongrel dogs using Nd-YAG laser, either Dumon (n=6) or Natural (n=6) stent was inserted into the trachea. To assess the degree of stent migration and mucostasis, bronchoscopy was performed every week for 4 weeks, after which all stents were removed. One week after stent removal, tracheal stenosis was evaluated by bronchoscopy. Results: The degree of stent migration was not different between the dogs with Dumon stent (3.0±0.8) and those with Natural (2.0±1.0), nor was the degree of mucostasis, at Dumon (1.7±0.5) and Natural Stent (1.5±0.6), respectively. One week after stent removal, the degree of tracheal stenosis was not different between the Dumon (1.5±0.5) and the Natural group (1.0±0.4). In addition, there was no death and the degree of tracheal stenosis remained always within the safe limit (less than 2.0) in all animals. Conclusion: In a canine model of tracheal stenosis induced using Nd-YAG laser, the usefulness and safety of Natural Stent were similar to those of Dumon Stent. A clinical trial is necessary to document the usefulness and safety of Natural Stent in patients with tracheal stenosis.