Establishment and evaluation of an animal model of acquired tracheomalacia following tracheostomy in rabbits.

Purpose: Acquired tracheomalacia (TM) following tracheostomy can hinder decannulation and affect the quality of life of pediatric patients. Therefore, a reproducible animal model of type III TM is required for further research and therapeutic development.

Methods: We established a rabbit model of acquired TM by resecting the anterior walls of the 2nd to 4th tracheal cartilage rings, while preserving the mucosa. Bronchoscopic evaluations were conducted at three time points: before surgery (term 1), immediately after surgery (term 2), and 3-4 months post-surgery (term 3). The area of the tracheal lumen was measured under varying negative suction pressures using image analysis.

Results: Five of the six rabbits survived and successfully modeled TM. Progressive luminal narrowing was observed, particularly at term 3, where the area decreased to 15.0 ± 18.8% under 30 cmHg suction. Compared with term 1, the same suction pressures resulted in a greater collapse at terms 2 and 3, indicating gradual structural weakening. No respiratory symptoms were observed during the follow-up.

Conclusion: This rabbit model of acquired type III TM is reproducible and enables the quantitative evaluation of airway collapsibility. This may be useful for investigating TM pathophysiology and testing new treatment strategies.