Computational fluid dynamic study of upper airway flow to predict the success of oral appliances in treating sleep apnea

In this study we used computational fluid dynamics (CFD) to analyse the therapeutic effect of an oral device (mandibular advancement splint – MAS) that protrudes the lower jaw during sleep on obstructive sleep apnea (OSA). Clinical data of 4 patients were used for CFD analysis, with patient selection being on the basis of their known different treatment responses. Anatomically accurate upper airway (UA) computational models were reconstructed from magnetic resonance images (MRI) with and without a MAS device fitted. CFD simulations of airflow were performed at the maximum flow rate during inspiration. Factors such as velocity, pressure, area in the restricted region is closely associated with the change in severity of OSA for patients using MAS. The CFD analysis clearly demonstrated the way MAS treatment affected the patients’ UA airflow patterns. The results show that there is a strong relationship between the calculated flow and physical properties and the treatment response. We plan to study more patients in order to develop a model to predict treatment response of MAS by patient-specific CFD results.