(0809) Development of a Novel Open Surgical Animal Model for Subglottic and Tracheostomy-Related Stenosis

Introduction: Previously published small animal models of airway stenosis utilize endoscopic approaches. To date, these models have not been used to meaningfully study this disorder. Here we present a novel approach for reproducible and survivable stenosis in a rabbit model and compare it to our experience with a more traditional endoscopic approach.

Methods: New Zealand white rabbits (n = 8) underwent two trials for inducing airway stenosis. In trial 1, 4 anesthetized rabbits underwent bronchoscopy and a Fraizer suction needle was used to gently scrape the posterior tracheal mucosa. At week 3, bronchoscopy revealed absence of stenosis and rabbits were reinjured. At week 6, tracheas were harvested for analysis. In trial 2, 4 rabbits were sedated, and an open airway surgery was performed. A 1 cm vertical incision was made on the anterior tracheal wall, through which a nylon brush was inserted and used to injure the posterior mucosal wall. At 3 weeks, the tracheas were harvested for analysis.
The area of the cross-section slices from histology and CT were measured using ImageJ.

Results: In trial 1, 2 rabbits developed between 30-60% stenosis while 1 rabbit remained uninjured. A single rabbit did not survive after re-injury. Trial 2 resulted in 26-78% overall stenosis in all 4 rabbits. In each rabbit, maximal mucosal stenosis ranged from 26-67% and was present immediately inferior to the vocal cords (superior to the tracheotomy site). In comparison, structural stenosis (20-50%) was present near the tracheotomy.

Conclusions: Our open surgical approach to generating airway stenosis provides precise control and reliable injury when compared to our experience with the transoral approach. In the open approach, both structural and mucosal stenosis was achieved, producing a reproducible and survivable model of stenosis.