Velopharyngeal Muscle Morphology in Children with Congenital Palatal Microforms

Children born with palatal microforms are often clinically mismanaged due to difficulties in diagnosis and treatment. These difficulties are exacerbated by anatomical and physiological differences in clinical presentation. Although a variety of physical and functional findings related to palatal microforms have been documented, there is no consensus on what features or combination of features lead to velopharyngeal dysfunction (VPD) in this population. This study was designed to evaluate and compare the velopharyngeal musculature and related structures in children with palatal microforms and VPD with age and sex-matched noncleft controls with normal velopharyngeal anatomy. Nineteen subjects, four with palatal microforms and VPD, and 15 noncleft controls with normal velopharyngeal anatomy and normal speech and resonance participated in this study. Subjects were scanned at rest using magnetic resonance imaging (MRI) protocols specially designed to assess the velopharyngeal musculature. Measures of the levator veli palatini muscle (levator), musculus uvulae, and related velopharyngeal and craniometric structures were obtained. After controlling for the effect of vocal tract size, children with palatal microforms demonstrated quantitative and qualitative differences in the velopharyngeal musculature compared to noncleft controls. These differences included levator diastasis, abnormal attachment to the hard palate, and irregular dispersal of the levator muscle in the velar midline. Absence of the musculus uvulae was observed in three of four subjects with palatal microforms. Children with palatal microforms demonstrated decreased acuity of the velar genu angle and decreased alpha angle compared to noncleft controls, and these differences were statistically significant. Findings from this study demonstrate that children with palatal microforms and VPD present with velopharyngeal anatomy that is quantitatively and qualitatively different compared to noncleft controls with normal speech and resonance. Results from the present study are the first to demonstrate quantitative and qualitative differences in the velopharyngeal musculature in children with palatal microforms and VPD using MRI. This study adds valuable information to the body of literature documenting velopharyngeal differences in children with palatal microforms and VPD, and may help improve clinical diagnostic and treatment approaches