Finite element analysis animated simulation of velopharyngeal closure.

OBJECTIVE

To use finite element analysis animated simulations to investigate factors affecting velopharyngeal closure.

DESIGN

A coronal section multicomponent finite element analysis model of a human soft palate was created in Simulia Abaqus 6.5-1 from high resolution MRI images of a single adult female subject, interpreted by reference to published anatomic dissections. Tissues were assigned hyperelastic property coefficients for neo-Hookean behavior, with gravity at 9.8 ms(-2) in the y-axis. Vector forces based on estimations in previous publications were applied throughout levator veli palatini and palatopharyngeus muscles, using a nonlinear analysis algorithm, to produce animated simulations of velopharyngeal space closure. Variation of levator veli palatini angle from 60° to 49°, the contribution of palatopharyngeus muscle, and the effect of submucous cleft were investigated for their effects on velopharyngeal closure.

RESULTS

The animated simulations showed anthropomorphic behavior and supported the previously suggested effects of the levator veli palatini angle, with reduced effectiveness of velopharyngeal closure as levator veli palatini angle decreases. Palatopharyngeus action reduced the efficiency of closure for a levator veli palatini angle of 60°, and a submucous cleft reduced this for both our normal subject and for a levator veli palatini angle of 60°, but both palatopharyngeus action and a submucous cleft enhanced closure for a levator veli palatini angle of 49°.

CONCLUSIONS

This study advances soft palate finite element analysis to a real-subject-based multicomponent hyperelastic model that demonstrates anthropomorphic behavior. Animated simulations using the model demonstrate the possible effects of levator veli palatini angle, a submucous cleft, and the contribution of the palatopharyngeus.