Baseline morphometry of the pterygoid hamulus in a neonatal South African population

Abstract

Objective: The purpose of this study was to establish a baseline database consisting of the morphometry of the South African neonatal pterygoid hamulus. Methods: Cone Beam Computed Tomography (CBCT) scans were conducted on 74 formalin-fixed neonatal cadavers and displayed on the Planmeca Romexis 4.6.0.R program for quantitative data measurement. The length, width and angle of inclination in the coronal and sagittal planes of the pterygoid hamulus and the inter-hamular distance were measured. Additionally, the distance from the pterygoid hamulus to the posterior nasal spine was measured. Statistical analysis was performed to compare sides, population groups and weight classes and to establish correlations between measurements. Results: Weight was found to be a determining factor in the morphometrics of the pterygoid hamulus, the exception being the inclination in the sagittal plane, results were therefore separated according to weight class. For neonates weighing less than or equal to 1 kg, the length of the pterygoid hamulus was 2.23 (SD 0.377) mm, the width of the pterygoid hamulus in the coronal plane was 0.938 (SD 0.162) mm and in the sagittal plane was 1.68 (SD 0.373) mm. For neonates weighing more than 1 kg, the length was 2.74 (SD 0.438) mm, the width in the coronal plane was 1.12 (SD 0.226) mm and in the sagittal plane was 1.87 (SD 0.446) mm. The regression formula between the inter-hamular distance and the distance between the pterygoid hamulus and posterior nasal spine was determined to be y=2.44+0.52x. No significant difference between right and left sides, sex or population group was found. Conclusion: Understanding how the neonatal pterygoid hamulus differs from the adult structure is important when surgery in the oropharyngeal area of infants is concerned. The correlations established in this study between biometrics and morphometrics allows for extrapolation of the morphometrics to be made in the absence of proper scanning equipment.