Morphological Study of the Human Hyoid Bone in Cleft Lip and Palate Patients

Abstract

Qualitative assessment of 3-D reconstructions derived from MRI and CT imaging technologies is critical for the diagnosis and treatment of patients with cleft lip and palate (CLP). However, rapid and reliable quantitative assessment remains elusive. This is particularly true for the analysis of regional deficiencies in morphology of CLP patients. Recent interest has focused on the morphology of the hyoid region of CLP patients since this area is derived from pharyngeal arch 2 and may be indirectly affected by the deficiency in the primary palate derived from pharyngeal arch 1. The objective of this study is to develop and apply novel morphometric methodology to quantitatively assess hyoidal morphology in CLP patients. The hypothesis to be tested is that CLP patients display hyoidal regions that differ quantitatively from patients lacking CLP. Five geometric models with known parameters were designed to simulate size and shape descriptors and used to test the precision and accuracy of ER3D. Cone beam computed tomography (CBCT) images derived from CLP patients as well as patients lacking CLP and these were utilized to generate 3D reconstructions of the hyoidal region in corresponding individuals and compared utilizing affine and non-affine methodologies.. Anatomical landmarks were determined and digitized on the model. Results showed significant accuracy of ER3D morphometric analysis with respect to volumetric and linear measurements and proved the ability of the software to quantitatively record changes in size and shape. For the hyoid models, CLP individuals mostly displayed affine hyoidal changes relative to controls since the defect likely causes size reductions in affected individuals. Non-affine changes were consistent among CLP subjects and were characterized as changes in position with respect to controls rather than shape change. Interestingly, female controls revealed a high degree of diversity compared to both male controls and all CLP groups. These data suggest that the hyoidal region is affected as a result of CLP, but the difference is dominated by size rather than shape change.