INJURY-LINKED AND AGE-LINKED DIFFERENCES IN WOUND-HEALING AND STENOSIS FORMATION IN THE SUBGLOTTIS

We studied the effects of superficial and deep endolaryngeal trauma of the subglottic airway in young and adult rabbits. In both age groups a soft stenosis was formed as long as the cartilaginous cricoid ring i s not involved. This stenosis comprised a thickened subepithelial zone of scar tissue, separated from the cricoid cartilage by a layer of fa tty tissue. Injury of the internal side of the cricoid cartilage induc ed a compact mass of scar tissue with local differentiation into fibro cartilage. In young animals only, injury of the cartilage led to remod elling of the cricoid ring (indentation or collapse of the traumatized sectors). On the basis of the differentiating effects of age and dept h of the lesion, three histopathological types of subglottic stenosis were distinguished. The experimental results provide an explanation fo r the variability in the histopathological features of the wall of the stenotic subglottic airway, as observed in biopsies and postmortem sp ecimens.