A Computational Model of Velopharyngeal Closure for Simulating Cleft Palate Repair

The levator veli palatini (LVP) muscle has long been recognized as the muscle that contributes most to velopharyngeal (VP) closure and is therefore of principal importance for restoring normal speech in patients with a cleft palate. Different surgical reconstructive procedures can utilize varying degrees of LVP overlap, and this study developed a new finite-element model of VP closure designed to understand the biomechanical effects of LVP overlap. A three-dimensional finite-element model was created from adult anatomical dimensions and parameters taken from the literature. Velopharyngeal function was simulated and compared with experimental measurements of VP closure force from a previous study. Varying degrees of overlap and separation of the LVP were simulated, and the corresponding closure force was calculated. The computational model compares favorably with the experimental measurements of closure force from the literature. Furthermore, the model predicts that there is an optimal level of overlap that maximizes the potential for the LVP to generate closure force. The model predicts that achieving optimal overlap can increase closure force up to roughly 100% when compared with too little or too much overlap. The results of using this new model of VP closure suggest that optimizing LVP overlap may produce improved surgical outcomes due to the intrinsic properties of muscle. Future work will compare these model predictions with clinical observations and provide further insights into optimal cleft palate repair and other craniofacial surgeries.