A New Model of Tracheal Stenosis in Dogs Using Combined Bronchoscopic Electrocautery and Ethanol Injection

Purpose: To establish a new animal model of tracheal stenosis in dogs that involves combined bronchoscopic electrocautery and ethanol injection. Materials and Methods: Ten mongrel dogs were included in the study. With flexible bronchoscopic and fluoroscopic guidance, a combination of electrocautery (30 W) and ethanol injection (total volume 2 mL) was circumferentially applied to the trachea at the third thoracic vertebra level. Dogs were euthanized 4 weeks later and the stenosis diameter and histologic findings were evaluated. Results: All procedures were successful. Eight of the 10 dogs survived to 4 weeks, whereas two died from respiratory failure before the planned endpoint. For the eight full-term dogs, the mean percentage diameter stenosis (±SD) was 70.8% ± 9.3%, with a range of 56%-81%. Microscopic analysis showed that the maximum tracheal wall thickness was 2.48 mm ± 0.77. The degree of inflammatory cell infiltration varied, but cartilage destruction and mucosal ulceration were evident in all cases. Conclusions: A new tracheal stenosis model was developed in dogs with use of combined bronchoscopic electrocautery and ethanol injection. This animal model is a technically simple, reliable, and tracheotomy-free model for the creation of tracheal stenosis.