Stress Distribution Patterns within Viscero- and Neurocranium during Nasoalveolar Molding: a Finite Element Analysis

• Main Authors: Lucas M. Ritschl, MD, DMD, Veronika Heinrich, MSc, Florian D. Grill, MD, Maximilian Roth, MD, Dennis M. Hedderich, MD, Andrea Rau, MD, DDS, PhD, Klaus-Dietrich Wolff, MD, DDS, PhD, Franz X. Bauer, MSc, Denys J. Loeffelbein, MD, DDS, PhD
• Format: Article
• Language: English
• Published: Wolters Kluwer 2018-07-01
• Series: Plastic and Reconstructive Surgery, Global Open
• Online Access: http://journals.lww.com/prsgo/fulltext/10.1097/GOX.0000000000001832

Background:. The purpose of this study was to evaluate the stress distribution patterns within the viscero- and neurocranium of neonates during nasoalveolar molding. Methods:. Finite element models of 3 different healthy neonates at different times of life (date of birth, 4 weeks, and 3.5 months) were generated on the basis of computed tomography scans. A validated workflow, including segmentation, meshing, setting of boundary conditions, and implementation of a bone density–dependent material model, was carried out for each model. A small and a large unilateral alveolar and hard palatal cleft were virtually cut in each model. The stress distribution pattern in each model was then analyzed by using Ansys APDL. Results:. Convergence analysis validated the results. The virtual experiments at the date of birth showed a stress pattern above a previously defined threshold value of 30,000 Pa in the ipsilateral naso-orbital-complex, frontal sinus, and the anterior fossa of the base of the skull, with von Mises values > 35,000 Pa. Stress patterns at the age of 4 weeks and 3.5 months showed reduced von Mises values at < 15,000 Pa. Conclusions:. Nasoalveolar molding therapy is a safe presurgical treatment modality without significant influence on the viscero- and neurocranium of neonates. Treatment, considering the stress distribution at the naso-orbital-complex and anterior fossa of the base of the skull, should begin in the second week of life, and treatment initiation of preterm infants should be adapted respectively.