Hanyao Huang1, Xu Cheng1, Yang Wang2, Dantong Huang3, Yuhao Wei1, Heng Yin1, Bing Shi1, Jingtao Li1. 1. 1 State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Oral Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China. 2. 2 State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University, Chengdu, China. 3. 3 Department of Biomedical Engineering, Columbia University, New York, USA.
Abstract
OBJECTIVES: Competent velopharyngeal (VP) function is the basis for normal speech. Understanding how VP structure influences the airflow during speech details is essential to the surgical improvement of pharyngoplasty. In this study, we aimed to illuminate the airflow features corresponding to various VP closure states using computed dynamic simulations. METHODS: Three-dimensional models of the upper airways were established based on computed tomography of 8 volunteers. The velopharyngeal port was simulated by a cylinder. Computational fluid dynamics simulations were applied to illustrate the correlation between the VP port size and the airflow parameters, including the flow velocity, pressure in the velopharyngeal port, as well as the pressure in oral and nasal cavity. RESULTS: The airflow dynamics at the velopharynx were maintained in the same velopharyngeal pattern as the area of the velopharyngeal port increased from 0 to 25 mm2. A total of 5 airflow patterns with distinct features were captured, corresponding to adequate closure, adequate/borderline closure (Class I and II), borderline/inadequate closure, and inadequate closure. The maximal orifice area that could be tolerated for adequate VP closure was determined to be 2.01 mm2. CONCLUSION: Different VP functions are of characteristic airflow dynamic features. Computational fluid dynamic simulation is of application potential in individualized VP surgery planning.
OBJECTIVES: Competent velopharyngeal (VP) function is the basis for normal speech. Understanding how VP structure influences the airflow during speech details is essential to the surgical improvement of pharyngoplasty. In this study, we aimed to illuminate the airflow features corresponding to various VP closure states using computed dynamic simulations. METHODS: Three-dimensional models of the upper airways were established based on computed tomography of 8 volunteers. The velopharyngeal port was simulated by a cylinder. Computational fluid dynamics simulations were applied to illustrate the correlation between the VP port size and the airflow parameters, including the flow velocity, pressure in the velopharyngeal port, as well as the pressure in oral and nasal cavity. RESULTS: The airflow dynamics at the velopharynx were maintained in the same velopharyngeal pattern as the area of the velopharyngeal port increased from 0 to 25 mm2. A total of 5 airflow patterns with distinct features were captured, corresponding to adequate closure, adequate/borderline closure (Class I and II), borderline/inadequate closure, and inadequate closure. The maximal orifice area that could be tolerated for adequate VP closure was determined to be 2.01 mm2. CONCLUSION: Different VP functions are of characteristic airflow dynamic features. Computational fluid dynamic simulation is of application potential in individualized VP surgery planning.