Subglottic Cryotherapy: A Pilot Study in New Zealand White Rabbits

To describe proof of concept and pilot data for a cryotherapy application in the subglottis in a rabbit airway model. Four New Zealand white rabbits (3 experimental, 1 control) underwent general anesthesia and laryngoscopy and bronchoscopy. Experimental animals had cryotherapy applied with a direct contact 1.9-mm cryoprobe. Animals were euthanized at days 0, 2, and 6 posttreatment. Histologic changes were assessed in the treated subglottic tissues. This preliminary work has demonstrated that, with early cryogenic injury in the subglottis, there is mild mucosal epithelial injury associated with submucosal edema, acute inflammatory infiltrate, and degeneration of venule endothelial cells. Mucosal epithelial repair and resolution of the inflammatory response appear to be relatively rapid. We hope that this may provide a foundation to further explore cryotherapy as a primary or adjuvant treatment option for pediatric subglottis stenosis.