Use of Computational Modeling to Predict Responses to Upper Airway Surgery in Obstructive Sleep Apnea

Abstract

Objectives. Despite the well-recognized consequences of obstructive sleep apnea (OSA), its treatment remains unsatisfactory. Therapeutic strategies are complicated by often poor adherence in the case of continuous positive airway pressure or the highly variable efficacy in the case of many upper airway surgeries. Computational models of the upper airway using finite element analysis to simulate the effects of various anatomic and physiologic manipulations on pharyngeal mechanics could be helpful in predicting surgical success. Study Design: Computational and physiologic study. Methods: Using representative OSA magnetic resonance images and experimentally measured upper airway dilator muscle activities, we developed a working two-dimensional and a partial three-dimensional model of the upper airway. Results: As predicted from experimental measurements, the OSA model airway has a closing pressure of −2 cm H₂O. Manipulations such as palatal stiffening, palatal resection, and tongue stiffening all have demonstrable effects on pharyngeal mechanics. We have also developed a partial three-dimensional OSA model in which we simulate the mechanics of the pharyngeal airway in the mid-sagittal and parasagittal slices, spanning more than 1 inch in thickness. Using this model, we have observed important effects of tongue and palatal stiffening on anteroposterior collapse of the pharyngeal airway. Conclusions: Our data suggest that computational modeling is feasible and can be used to generate hypotheses for subsequent clinical trials regarding anatomic manipulations in OSA. We further believe that the goal of individualizing OSA therapy on the basis of underlying mechanisms could be facilitated by computational modeling.