Age-related changes of the larynx and trachea assessed by three-dimensional computed tomography in children: Application to endotracheal intubation and bronchoscopy

The purpose of this study was to establish normative data of laryngotracheal dimensions and shape and to evaluate differences associated with age and sex using three-dimensional (3D) imaging. A total of 120 patients (64 boys and 56 girls) were included. Subjects were divided into four groups: Group 1 (0-2 years), Group 2 (3-7 years), Group 3 (8-13 years), and Group 4 (14-20 years). Using 3D image processing software, the laryngeal volume (LV), tracheal volume (TV), anteroposterior diameter at the glottis, cross-sectional area (CSA) at the subglottis, and laryngeal angle (LA) of the thyroid laminae were measured. Parameters of laryngotracheal volume and size were positively correlated with age, whereas the LA was inversely correlated with age. The LV, TV, CSA-3 mm, and CSA-5 mm exhibited a growth spurt in Groups 2 and 3. The LA decreased at a faster rate in Group 1 (P = 0.012). In Groups 1 and 2, there were no differences between genders for each laryngotracheal segmentation or plane. However, gender differences in the TV of Group 3 were statistically significant (P = 0.030). In Group 4, gender differences of all airway parameters were evident. Volume and other dimensions of the laryngotracheal airway increase with age. There was a significant increase in the LV, TV, CSA-3 mm, and CSA-5 mm in Groups 2 and 3. The LA correlated negatively with age in the Group 1. Significant sex dimorphisms are evident in Group 4.