Nasal cavity shape in unilateral choanal atresia and the role of fetal ventilation in facial growth

Objective: The respiratory movements of fetal amniotic fluid areconsidered by certains cleft surgery teams to contribute to the growth of the nasal cavities (NC). To assess this functional hypothesis, we considered a group of patients with unilateral choanal atresia (CA) as a model of unilateral absence of amniotic fluid flux in the NC, and compared their NCs shape to age-matched controls.

Material and methods: Three-dimensional reconstructions of NC were performed using Avizo 9.7 (Thermo Fisher Scientific, MA, USA), based on CT-scans of 32 patients with unilateral CA and 96 age- and gender-matched controls. Landmarks were placed on anatomical structures of NC. Procrustes superimpositions and principal component analysis were performed. Anatomically relevant Euclidean distances were computed using the coordinates of selected landmarks - maxillary length, piriform orifice width, choanal width - and tested using multivariate analysis. Growth rates between patients and controls for these distances were screened for correlations.

Results: The atretic NC was significantly deformed when compared to the control cases: Procrustes distance was 0.28 (P<0.0001). The maxillary length and width of the atretic choana were significantly decreased compared to controls (-2.95mm and -1.35mm respectively, P<0.001). There were no differences in growth rates between CA and controls, except for the choanal width on the atretic side.

Conclusion: NCs in CA were significantly different from controls. More precisely, the maxillary length was significantly reduced in the CA group. There was no other major shape difference between the NC in CA and controls. NC seems to develop despite abnormal fetal ventilation.