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

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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.

Section snippets

Materials and Methods

All experimental procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals (18) and were approved by the committee of animal research at our institution. The trachea of mongrel dogs was chosen for the experimental model because tracheal cartilage rings are well developed in these animals. In addition, the tracheas of mongrel dogs have a similar anatomy and diameter to those of humans.

Results

A summary of survival data, degree of stenosis, and pathologic findings is presented in the Table.

Discussion

The present study was designed to develop a new method to induce tracheal stenosis in a canine model. This method consisted of concurrent bronchoscopic heat probe electrocautery and ethanol injection at the tracheal mucosa, and did not require intubation or tracheotomy. Histopathologic examination revealed that the resultant tracheal stenosis was caused by acute inflammation and edema with surrounding fibrosis, and corresponded with thickening of the mucosa and submucosa. The mucosa also showed

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    From the 2007 SIR Annual Meeting.

    This study was supported by a grant (2004-312) from the Asan Institute for Life Sciences, Seoul, Korea. None of the authors have identified a conflict of interest.

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    Copyright © 2008 SIR. Published by Elsevier Inc. All rights reserved.