Prenatal and early postnatal morphogenesis and growth of human laryngotracheal structures

Abstract

Advances in neonatal medicine have resulted in increased care of fetal and neonatal airways. These advances have required an exhaustive knowledge of fetal airway anatomy and development. The aim of this study was to determine the anatomical development of laryngotracheal structures during the fetal and immediate postnatal period and to correlate these observations with other fetal biometric parameters to estimate developmental particularities of the fetal airway. An anatomical prospective study was based on examination of larynx and trachea from 300 routine autopsies of fetuses and infants, free of malformation and never intubated. Anatomical measurements of cricoid cartilage, thyroid cartilage, glottis, arytenoid cartilage and trachea were performed using a precision calliper and precision divider. Statistical analysis was performed to represent the growth of anatomical structures and to evaluate the correlation with biometric data. Raw data and 10th and 90th percentile curves were fitted satisfactorily with a linear model for gestational age. A linear relationship between laryngotracheal measurement and body weight and height was observed except for glottis length, interarytenoid distance and anterior cricoid height. The diameter of the cricoid lumen was significantly less than that of the trachea and glottis lumen. A sexual dysmorphism was noted for thyroid cartilage measurements and interarytenoid distance, with measurements significantly smaller in females. This study reports the anatomical development of normal laryngotracheal structures during the fetal period. Despite the fact that this study was performed during postmortem examination, these observations can be useful to develop criteria, materials and surgical procedures adapted to fetal and neonatal airways as well as for the purposes of early diagnosis and management of laryngotracheal malformations.

In vivo and in vitro morphometry of the human trachea

“…Two further pieces of evidence show that differences in stature are not the sole explanation for the observed sexual dimorphism of the trachea. First, male and female infants and prepubertal boys and girls have similar tracheal dimensions (Fayoux et al, 2008;Griscom and Wohl, 1986), despite boys being taller. Second, tracheal diameters continue to increase after tracheal length has plateaued in teenage boys (Griscom and Wohl, 1986).…”

New quantitative patterns of the growing trachea in human fetuses

“…After reviewing the professional literature on tracheal measurements in fetuses [6,8,12,13,23,24], we found little information about length and diameter of the growing trachea. In keeping with other reports [12,23–25], a lack of statistically significant sex differences for the parameters of the fetal trachea was found in this study.…”

“…To date, the relationship between tracheal variables (length, external and internal diameters) and gestational age has been expressed only by linear functions [10–13]. Of note, few studies have focused on internal cross-sectional area [14–16] and contained volume [15,16] of the trachea, assessed on chest CT scans in children, adolescents and adults, but with no detailed growth curves.…”

Technical aspects of fetal endoscopic tracheal occlusion for congenital diaphragmatic hernia

“…The dimensions of the balloon were chosen such that it slightly oversizes the anticipated tracheal diameter at the anticipated time of release ( Table 2). The biometry of the trachea has been well studied [46]. Experimental work has documented the local pressure it can generate, as well as the local side effects on the fetal trachea [47,48].…”