THE DISTRIBUTIONS OF AIRFLOW WITHIN THE UPPER AIRWAY AND POSTURE CHANGES OF SOFT PALATE IN PATIENTS WITH OSAHS AFTER NASAL STRUCTURAL CORRECTION
Nasal obstruction frequently has been associated with obstructive sleep apnea-hypopnea syndrome (OSAHS). Based on the CT data before and after the operation of the three Chinese patients, 3D numerical models involving the upper airway and the soft palate are established. Computational modeling for inspiration and expiration was performed by using fluid–structure interaction (FSI) method. The airflow characteristics such as velocity and pressure drop, and displacement distribution of soft palate are selected for comparison. The distribution of airflow in the upper airway and the motion changes of the soft palate are analyzed quantitively before and after the surgery. From the results, that the inner connection between the both upper and lower part of the upper airway is very complex due to the individual difference of own unique feature of upper airway. Whether can it treat OSAHS only through nasal surgery, which depends primarily on the improvement of ventilation in upper part of upper airway giving a beneficial effect on the lower part (especially in the velopharyngeal region). The simulation results correspond with the monitoring results of polysomnography (PSG) and the patient's presenting complaint. Moreover, the mechanical parameters obtained by numerical simulation can support the improvement of OSAHS symptoms after surgery, which provides quantitative and referential evidence for further study the role of nasal structure in OSAHS and the treatment effect of nasal surgery on OSAHS.