New quantitative patterns of the growing trachea in human fetuses

Abstract

SummaryBackgroundRapid progress in perinatal medicine has resulted in numerous tracheo-bronchial interventions on fetal and neonatal airways. The present study was performed to compile normative data for tracheal dimensions at varying gestational ages.Material/MethodsUsing anatomical dissection, digital image analysis (NIS-Elements BR 3.0) and statistical analysis (Wilcoxon signed-rank test, Student’s t test, one-way ANOVA, post-hoc Bonferroni test, linear and nonlinear regression analysis) a range of the 4 variables (length in mm, middle external transverse diameter in mm, proximal internal cross-sectional area in mm2, internal volume in mm3) for the trachea in 73 spontaneously aborted human fetuses (39 male, 34 female) aged 14–25 weeks was examined.ResultsNo significant male-female differences were found (P>0.05). The length ranged from 10.37±2.15 to 26.54±0.26 mm as y=−65.098 + 28.796 × ln (Age) ±1.794 (R2=0.82). The middle external transverse diameter varied from 2.53±0.09 to 5.09±0.42 mm with the model y=−11.020 + 5.049 × ln (Age) ±0.330 (R2=0.81). The trachea indicated a proportional evolution because the middle external transverse diameter-to-length ratio was stable (0.23±0.03). The proximal internal cross-sectional area rose from 1.46±0.04 to 5.76±1.04 mm2 as y=−3.562 + 0.352 × Age ±0.519 (R2=0.76). The internal volumetric growth from 11.89±2.49 to 119.63±4.95 mm3 generated the function y=−135.248 + 9.919 × Age ±10.478 (R2=0.86).ConclusionsThe growth in both length and middle external transverse diameter of the trachea follows logarithmic functions, whereas growth of both its proximal internal cross-sectional area and internal volume follow linear functions. The length and middle external transverse diameter of the trachea develop proportionally to each other. The tracheal dimensions may be helpful in the prenatal diagnosis and monitoring of tracheal malformations and obstructive anomalies of the upper respiratory tract.

Quantitative anatomy of the growing abdominal aorta in human fetuses: An anatomical, digital and statistical study

“…The present study constitutes the continuation of our previous morphometric studies on the normal evolution of the ascending aorta [22], aortic arch [23], and thoracic aorta [24], which provided both detailed normative ranges and growth patterns for these aortic segments during gestation. Because the existing data on the abdominal aorta have been precisely focused on its length and diameters only [18], the present study provides reference values and growth patterns for length, external diameters and volume of the abdominal aorta in human fetuses.…”

Airway dimensions from fetal life to adolescence—A literature overview

“…Twenty‐five studies were identified that represent airway dimensions in fetuses or premature infants, between 1923 and 2013 . The measured structures range from the thyroid to the two main bronchi and are summarized in Supplementary Appendix SI‐SIV under references superscripted as following numbers: 99 (MRI studies table), (anatomical studies table), 42 (X‐ray studies table), 101, 103, 106 (USG studies table). The scientific work by means of ultrasound only includes measurements of the diameter of the airways .…”

“…The first measurements go back almost 100 years, whilst the measuring scientific instruments have evolved steadily in recent years. In some scientific works, the measurement is performed directly on the freshpreparations, while in other studies, frozen, or epoxy resin or formalin fixations were embedded. Eight studies do not discuss fixation.…”

“…An important exception to this, is the work by Griscom and colleagues, which was useful for comparisons in many subsequent studies . Furthermore, all these studies have a natural variation in ethnic and racial groups of patient selection, which ranges from American as in Griscom, to European as in Fayoux, Szpinda, and Weiss50, group, to Australian as in Masters group, to Middle East as in Wani group, to Asian as in Dalal, Harjeet, and other groups and hence the results cannot be generalized for the entire pediatric population. One recent multicentre study tried to overcome this problem and represented lower airway dimensions in a large pediatric population representing different racial and ethnic groups.…”

“…63 An important exception to this, is the work by Griscom and colleagues, 58,59,[63][64][65] which was useful for comparisons in many subsequent studies. 68,[72][73][74][75]78,79,83,85 Furthermore, all these studies have a natural variation in ethnic and racial groups of patient selection, which ranges from American as in Griscom,58,59,[63][64][65] to European as in Fayoux, [34][35][36] Szpinda,9,[39][40] and Weiss50, 51,78,83,8551,78,83,85 group, to Australian as in Masters 86,87 group, to Middle East as in Wani 60,[72][73][74][75][76] group, to Asian as in Dalal,89,90 Harjeet, 12,13,17…”