Objectifying Micrognathia Using Three-Dimensional Photogrammetric Analysis

Abstract

Background: Micrognathia occurs isolated and as part of entities like Robin sequence (RS). An objective measurement of mandible size and growth is needed to determine the degree of micrognathia and enable a comparison of treatment outcomes. We undertook a pilot study to investigate the usability of 3D facial photogrammetry, a fast, non-invasive method, to estimate mandible size and growth in a small cohort of newborns and infants. Methods: We estimated exterior mandibular volume using a tetrahedron defined by four facial landmarks. We selected 12 patients with RS with different etiologies and obtained photogrammetric images prospectively in three patients with RS in whom mandibular growth in the first year of life was determined. We used three tetrahedra defined by six landmarks on mandibular CT scans to estimate an interior mandibular volume, which we compared to the exterior mandibular volume in 10 patients. Results: The exterior mandibular volume using 3D photography could be determined in all patients. Signature heat maps allowed visualization of facial dysmorphism in three dimensions; signature graphs demonstrated similarities of facial dysmorphism in patients with the same etiology and differences from those with other diagnoses and from controls. The correlation between interior (3D photogrammetry) and exterior mandibular volumes (CT imaging) was 0.8789. Conclusion: 3D facial photogrammetry delineates the general facial characteristics in patients with different syndromes involving micrognathia, and can objectively estimate mandibular volume and growth, with excellent correlation with bony measurement. We conclude that 3D facial photogrammetry could be a clinically effective instrument for delineating and quantifying micrognathia.

Mutations in the Bone Morphogenetic Protein signaling pathway sensitize zebrafish and humans to ethanol-induced jaw malformations

“…From a study of children recruited with and without PAE, we show here that several SNPs in BMPR1B are significantly associated with ethanol- associated jaw malformations. Jaw hypoplasia is commonly observed in FASD (6,7,69) but studying FASD in humans is incredibly challenging due to the complex interplay between genetic background and ethanol timing and dosage. Our results show that zebrafish analyses can model gene-ethanol associations in humans, strongly phenocopying both the malformation and the variation inherent in human data (7,11,70).…”

“…DSMs allow us to compute facial signatures, which represent normalized differences between groups, and visualize using a heatmap representation group or individual differences (85). To evaluate micrognathia, we computed mandible volume, which was outlined and validated against CT images in (69). This technique estimated the volume of a trapezoid formed by four specific points on the size- normalized face: the left and right lower otobasion inferius (lowest points of the ears), gnathion (tip of the mandible), and lower lip vermillion center (Supplement Fig.…”

European Guideline Robin Sequence An Initiative From the European Reference Network for Rare Craniofacial Anomalies and Ear, Nose and Throat Disorders (ERN-CRANIO)

“…After further assessment 7 articles were included to answer the second research question of this chapter. Of these, 4 studies addressed micrognathia: a retrospective cohort study by Gao et al (2019), a pilot study by Basart et al (2018) and 2 prospective cohort studies by Mermans et al (2020) and Mimouni et al (2020). [15][16][17][18] Glossoptosis was discussed in 3 studies: a retrospective study by Lee et al (2018) and 2 prospective cohort studies by 2018).…”

“…The use of 3 dimensional (3D) photogrammetric analysis is studied by Basart et al (2018). 16 4 isolated RS patients and 8 nonisolated RS patients were included.…”

Modelling growth curves of the normal infant’s mandible: 3D measurements using computed tomography

“…3D facial measurements of the normal and micrognathic infant are available using 3D surface scanners [9,10]. A recent study showed good correlation between surface measurements and interior mandibular volume [11].…”