scholarly journals Simulation of the Retroglossal Fluid-Structure Interaction During Obstructive Sleep Apnea

2006 ◽  
pp. 48-57 ◽  
Author(s):  
Franz Chouly ◽  
Annemie Van Hirtum ◽  
Pierre-Yves Lagrée ◽  
Jean-Roch Paoli ◽  
Xavier Pelorson ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Obstructive Sleep

Predicting the Treatment Response of Oral Appliances for Obstructive Sleep Apnea Using Computational Fluid Dynamics and Fluid-Structure Interaction Simulations

2013 ◽  
Author(s):  
Moyin Zhao ◽  
Tracie Barber ◽  
Peter Cistulli ◽  
Kate Sutherland ◽  
Gary Rosengarten
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Pressure Drop ◽  
Treatment Response ◽  
Fluid Structure Interaction ◽  
Maximum Pressure ◽  
Structure Interaction ◽  
Obstructive Sleep

In this study we used computational fluid dynamics (CFD) to analyze the therapeutic effect of an oral device (mandibular advancement splint – MAS, that protrudes the lower jaw during sleep) as a treatment for Obstructive Sleep Apnea (OSA). Anatomically-accurate upper airway (UA) computational models were reconstructed from magnetic resonance images (MRI) of 7 patients with and without a MAS device fitted. CFD simulations of UA airflow were performed at the maximum flow rate during inspiration. The CFD results indicated the lowest pressure often occurs close to the soft palate and the base of the tongue. The airway pressure gradient was estimated as the best indicator for treatment response since the change in the pressure drop forms a linear correlation with the change in patients’ Apnea-Hypopnea Index (AHI). This correlation has the potential to be developed into a model for predicting the outcome of the MAS treatment. However the rigid wall assumption of CFD models is the major uncertainty. To overcome this uncertainty we set up a full fluid-structure interaction model for a typical responder case with a compliant UA wall. The results demonstrated the different UA flow field associated with using MAS alleviated the airway collapse, which was successfully predicted for the untreated patient. We thus show for the first time that FSI is more accurate than CFD with rigid walls for the study of OSA, and can predict treatment response. Comparison of the FSI and CFD results for the UA flow and pressure profiles showed variation between the models. The structural deflection in oropharynx effectively reformed the flow pattern, however, the maximum pressure drops of both results were close. This supports the competence of the CFD method in clinical applications, where maximum pressure drop data can be used to develop a treatment-predicting model.

Using Two-Way Fluid-Structure Interaction to Study the Collapse of the Upper Airway of OSA Patients

2014 ◽  
Vol 553 ◽  
pp. 275-280 ◽  
Author(s):  
Mo Yin Zhao ◽  
Tracie J. Barber ◽  
Peter A. Cistulli ◽  
Kate Sutherland ◽  
Gary Rosengarten
Keyword(s):  
Computational Models ◽  
Treatment Success ◽  
Fluid Structure Interaction ◽  
Maximum Velocity ◽  
Upper Airway ◽  
Post Treatment ◽  
Mandibular Advancement ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Obstructive Sleep

Obstructive Sleep Apnea (OSA) is a common sleep disorder characterized by repetitive collapse of the upper airway (UA) during sleep. Treatment options for OSA include mandibular advancement splints (MAS), worn intra-orally to protrude the lower jaw to stabilize the airway. However not all patients will respond to MAS therapy and individual effects on the upper airway are not well understood. Simulations of airway behavior represent a non-invasive means to understand this disorder and treatment responses in individual patients. The aims of this study was to perform analysis of upper airway (UA) occlusion and flow dynamics in OSA using the fluid structure interaction (FSI) method, and secondly to observe changes associated with MAS usage. Magnetic resonance imaging (MRI) scans were obtained with and without mandibular advance splint (MAS) treatment in a patient known to be a treatment responder. Computational models of the anatomically correct UA geometry were reconstructed for both pre-and post-treatment (MAS) conditions. By comparing the simulation results, the treatment success of MAS was demonstrated by smaller UA structure deformation (maximum 2mm) post-treatment relative to the pre-treatment fully collapsed (maximum 6mm) counterpart. The UA collapse was located at the oropharynx and the low oropharyngeal pressure (-51 Pa to-39 Pa) was induced by the velopharyngeal jet flow (maximum 10 m/s). The results support previous OSA computational fluid dynamics (CFD) studies by indicating similar UA pressure drop and maximum velocity values. These findings lay a firm platform for the application of computational models for the study of the biomechanical properties of the upper airway in the pathogenesis and treatment of OSA.

Predicting critical closing pressure in children with obstructive sleep apnea using fluid structure interaction simulations

2021 ◽  
Author(s):  
Goutham Mylavarapu ◽  
Ephraim Gutmark ◽  
Sally Shott ◽  
Robert J. Fleck ◽  
Mohamed Mahmoud ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Upper Airway ◽  
Dynamic Mri ◽  
Patient Specific ◽  
Apnea Hypopnea Index ◽  
Structure Interaction ◽  
Obstructive Sleep ◽  
Mri Scans ◽  
Closing Pressure

Surgical treatment of obstructive sleep apnea (OSA) in children requires knowledge of upper airway dynamics, including the closing pressure (Pcrit), a measure of airway collapsibility. We applied a Flow-Structure Interaction (FSI) computational model to estimate Pcrit in patient-specific upper airway models obtained from magnetic resonance imaging (MRI) scans. We sought to examine the agreement between measured and estimated Pcrit from FSI models in children with Down syndrome. We hypothesized that the estimated Pcrit would accurately reflect measured Pcrit during sleep and therefore reflect the severity of OSA as measured by the obstructive apnea hypopnea index (AHI). All participants (n=41) underwent polysomnography and sedated sleep MRI scans. We used Bland Altman Plots to examine the agreement between measured and estimated Pcrit. We determined associations between estimated Pcrit and OSA severity, as measured by AHI, using regression models. The agreement between passive and estimated Pcrit showed a fixed bias of -1.31 (CI=-2.78, 0.15) and a non-significant proportional bias. A weaker agreement with active Pcrit was observed. A model including AHI, gender, an interaction term for AHI and gender and neck circumference explained the largest variation (R2 = 0.61) in the relationship between AHI and estimated Pcrit. (P <0.0001). Overlap between the areas of the airway with lowest stiffness, and areas of collapse on dynamic MRI, was 77.4%±30% for the nasopharyngeal region and 78.6%±33% for the retroglossal region. The agreement between measured and estimated Pcrit and the significant association with AHI supports the validity of Pcrit estimates from the FSI model.

Toward numerical simulations of fluid–structure interactions for investigation of obstructive sleep apnea

2015 ◽  
Vol 30 (1-2) ◽  
pp. 87-104 ◽  
Author(s):  
Chien-Jung Huang ◽  
Shao-Ching Huang ◽  
Susan M. White ◽  
Sanjay M. Mallya ◽  
Jeff D. Eldredge
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Numerical Simulations ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Obstructive Sleep
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