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Saha SC, Huang X, Francis I, Saha G. Airway stability in sleep apnea: Assessing continuous positive airway pressure efficiency. Respir Physiol Neurobiol 2024; 325:104265. [PMID: 38653435 DOI: 10.1016/j.resp.2024.104265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/11/2024] [Accepted: 04/19/2024] [Indexed: 04/25/2024]
Abstract
Obstructive Sleep Apnea Syndrome (OSAS) disrupts millions of lives with its burden of airway obstruction during sleep. Continuous Positive Airway Pressure (CPAP) therapy has been scrutinized for its biomechanical impact on the respiratory tract. This study leverages computational fluid dynamics to investigate CPAP's effects at 9 cm H2O (882.6 Pa) on the computed-tomography-based nasal-to-14-generation full respiratory tract model compared to ambient conditions, focusing on static pressure, airflow velocity, and shear stress. Our findings reveal that CPAP significantly increases static pressure, enhancing airway patency without adverse changes in airflow velocity or harmful shear stress on lung tissue, challenging prior concerns about its safety. Notably, the larynx experiences the highest shear stress due to its narrow anatomy, yet CPAP therapy overall supports airway walls against collapse. This investigation highlights CPAP's critical role in OSAS treatment, offering reassurance about its safety and efficacy. By clarifying CPAP therapy's physiological impacts, our study contributes vital insights for optimizing OSAS management strategies, affirming CPAP's benefit in maintaining open airways with minimal tissue strain.
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Affiliation(s)
- Suvash C Saha
- School of Mechanical and Mechatronic Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia.
| | - Xinlei Huang
- School of Mechanical and Mechatronic Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia
| | - Isabella Francis
- School of Mechanical and Mechatronic Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia
| | - Goutam Saha
- School of Mechanical and Mechatronic Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia
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Chen Y, Cai W, Shi XQ, Li B, Feng X. Impact of palatopharyngeal sizes changing on pharyngeal airflow fluctuation and airway vibration in a pediatric airway. J Biomech 2024; 168:112111. [PMID: 38657433 DOI: 10.1016/j.jbiomech.2024.112111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 03/08/2024] [Accepted: 04/16/2024] [Indexed: 04/26/2024]
Abstract
Snoring is common in children and is associated with many adverse consequences. One must study the relationships between pharyngeal morphology and snoring physics to understand snoring progression. Although some model studies have provided fluid-structure interaction dynamic descriptions for the correlation between airway size and snoring physics, the descriptions still need to be further investigated in patient-specific airway models. Fluid-structure interaction studies using patient-specific airway structures complement the above model studies. Based on reported cephalometric measurement methods, this study quantified and preset the size of the palatopharynx airway in a patient-specific airway and investigated how the palatopharynx size affects the pharyngeal airflow fluctuation, soft palate vibration, and glossopharynx vibration with the help of a verified FSI method. The results showed that the stenosis anterior airway of the soft palate increased airway resistance and airway resistance fluctuations, which can lead to increased sleep effort and frequent snoring. Widening of the anterior airway can reduce airflow resistance and avoid obstructing the anterior airway by the soft palate vibration. The pharyngeal airflow resistance, mouth inflow proportion, and soft palate apex displacement have components at the same frequencies in all airway models, and the glossopharynx vibration and instantaneous inflow rate have components at the same frequencies, too. The mechanism of this same frequency fluctuation phenomenon can be explained by the fluid-structure interaction dynamics of an ideal coupled model consisting of a flexible plate model and a collapsible tube model. The results of this study demonstrate the potential of FSI in studying snoring physics and clarify to some degree the mechanism of airway morphology affecting airway vibration physics.
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Affiliation(s)
- Yicheng Chen
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin, China; School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China
| | - Weihua Cai
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin, China; School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China.
| | - Xie-Qi Shi
- Department of Clinical Dentistry, Section for Oral and Maxillofacial Radiology, University of Bergen, Norway; Department of Oral Maxillofacial Radiology, Faculty of Odontology, Malmö University, Sweden
| | - Biao Li
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China
| | - Xin Feng
- Division of Ear, Nose and Throat Surgery, Akerhus University Hospital, Lørenskog, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
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Koca CGE, Bilgir E, Çolakoğlu G, Bakkal FK, Yildirim B, Güngör MA, Erdil A. Comparative study of anatomical features of primary and accessory maxillary ostia between patients with obstructive sleep apnea and healthy controls. Sleep Breath 2024; 28:541-554. [PMID: 37452886 DOI: 10.1007/s11325-023-02874-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 05/26/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023]
Abstract
PURPOSE The purpose of this study was to examine how the size and shape of the maxillary sinus and its ostia (the primary maxillary ostium and accessory maxillary ostium) relate to each other in patients with OSA using computed tomography (CT) scans. Additionally, the study aimed to explore whether or not obstructive sleep apnea (OSA) had an effect on these structures. METHODS CT images of patients diagnosed with OSAS and healthy participants were evaluated to compare the patency, location, dimension, and presence of PMOs and AMOs using the Mann-Whitney U, Student t, and chi-square tests. Also, intragroup correlations were analyzed by Spearman's correlation test. RESULTS Among 139 patients with OSA and healthy controls, there were significant variations in the average length (p = 0.001) and width (p = 0.008) of PMOs among the study groups. The mean maxillary sinus volume was significantly decreased in the OSA group (p = 0.001). A significant decrease in the maxillary sinus volume was observed in the OSA group (p = 0.001). In the OSA group, a significant correlation was observed between PMO obstruction and the presence of AMO (p = 0.004). The healthy group had significant correlations (r = 0.755, p = 0.000) between the vertical height and the distance between PMO and the maxillary sinus floor. Correlation analyses revealed positive, strong correlations between study variables such as the mean length and width of AMO and the vertical height of the maxillary sinus (r = 0.566, p = 0.000) in the OSA group. CONCLUSIONS The current study indicated significant differences in sinus volume, PMO occlusion, and AMO-related dimensions between patients with OSA and healthy controls.
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Affiliation(s)
- Cansu Gül Efeoğlu Koca
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Uşak University, Cumhuriyet Mh. Kolej Sk. No:3 64200, Merkez, Uşak, Turkey
| | - Elif Bilgir
- Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Eskişehir Osmangazi University, Eskişehir, Turkey
| | - Gizem Çolakoğlu
- Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, İstanbul Aydın University, Istanbul, Turkey
| | - Faruk Kadri Bakkal
- Department of Otorhinolaryngology, Uşak Education and Research Hospital, Uşak, Turkey
| | - Bengisu Yildirim
- Department of Prosthodontics, Faculty of Dentistry, Uşak University, Uşak, Turkey
| | - Mehmet Ali Güngör
- Department of Prosthodontics, Faculty of Dentistry, Uşak University, Uşak, Turkey
| | - Aras Erdil
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Uşak University, Cumhuriyet Mh. Kolej Sk. No:3 64200, Merkez, Uşak, Turkey.
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Impact of sleep posture and breathing pattern on soft palate flutter and pharynx vibration in a pediatric airway using fluid-structure interaction. J Biomech 2023; 152:111550. [PMID: 36996600 DOI: 10.1016/j.jbiomech.2023.111550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/01/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023]
Abstract
Snoring is a common condition in the general population, and the management of snoring requires a better understanding of its mechanism through a fluid-structure interaction (FSI) perspective. Despite the recent popularity of numerical FSI techniques, outstanding challenges are accurately predicting airway deformation and its vibration during snoring due to complex airway morphology. In addition, there still needs to be more understanding of snoring inhibition when lying on the side, and the possible effect of airflow rates, as well as nose or mouth-nose breathing, on snoring remains to be investigated. In this study, an FSI method verified against in vitro models was introduced to predict upper airway deformation and vibration. The technique was applied to predict airway aerodynamics, soft palate flutter, and airway vibration in four sleep postures (supine, left/right lying, and sitting positions) and four breathing patterns (mouth-nose, nose, mouth, and unilateral nose breathing). It was found that, at given elastic properties of soft tissues, the evaluated flutter frequency of 19.8 Hz in inspiration was in good agreement with the reported frequency of snoring sound in literature. Reduction in flutter and vibrations due to the mouth-nose airflow proportion changes were also noticed when having side-lying and sitting positions. Breathing through the mouth results in larger airway deformation than breathing through the nose or mouth-nose. These results collectively demonstrate the potential of FSI for studying the physics of airway vibration and clarify to some degree the reason for snoring inhibition during sleep postures and breathing patterns.
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Chen Y, Feng X, Shi XQ, Cai W, Li B, Zhao Y. Computational fluid-structure interaction analysis of flapping uvula on aerodynamics and pharyngeal vibration in a pediatric airway. Sci Rep 2023; 13:2013. [PMID: 36737491 PMCID: PMC9898500 DOI: 10.1038/s41598-023-28994-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 01/27/2023] [Indexed: 02/05/2023] Open
Abstract
The uvula flapping is one of the most distinctive features of snoring and is critical in affecting airway aerodynamics and vibrations. This study aimed to elucidate the mechanism of pharyngeal vibration and pressure fluctuation due to uvula flapping employing fluid-structure interaction simulations. The followings are the methodology part: we constructed an anatomically accurate pediatric pharynx model and put attention on the oropharynx region where the greatest level of upper airway compliance was reported to occur. The uvula was assumed to be a rigid body with specific flapping frequencies to guarantee proper boundary conditions with as little complexity as possible. The airway tissue was considered to have a uniform thickness. It was found that the flapping frequency had a more significant effect on the airway vibration than the flapping amplitude, as the flapping uvula influenced the pharyngeal aerodynamics by altering the jet flow from the mouth. Breathing only through the mouth could amplify the effect of flapping uvula on aerodynamic changes and result in more significant oropharynx vibration.
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Affiliation(s)
- Yicheng Chen
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China
| | - Xin Feng
- Division of Ear, Nose and Throat Surgery, Akerhus University Hospital, Lørenskog, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Xie-Qi Shi
- Department of Clinical Dentistry, Section for Oral and Maxillofacial Radiology, University of Bergen, Bergen, Norway.,Department of Oral Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Weihua Cai
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China. .,School of Energy and Power Engineering, Northeast Electric Power University, Jilin, China.
| | - Biao Li
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China.
| | - Yijun Zhao
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China
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Chen Y, Feng X, Shi X, Cai W, Li B, Zhao Y. Evaluation of computational fluid dynamics models for predicting pediatric upper airway airflow characteristics. Med Biol Eng Comput 2023; 61:259-270. [PMID: 36369608 DOI: 10.1007/s11517-022-02715-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/03/2022] [Indexed: 11/13/2022]
Abstract
Computational fluid dynamics (CFD) has the potential for use as a clinical tool to predict the aerodynamics and respiratory function in the upper airway (UA) of children; however, careful selection of validated computational models is necessary. This study constructed a 3D model of the pediatric UA based on cone beam computed tomography (CBCT) imaging. The pediatric UA was 3D printed for pressure and velocity experiments, which were used as reference standards to validate the CFD simulation models. Static wall pressure and velocity distribution inside of the UA under inhale airflow rates from 0 to 266.67 mL/s were studied by CFD simulations based on the large eddy simulation (LES) model and four Reynolds-averaged Navier-Stokes (RANS) models. Our results showed that the LES performed best for pressure prediction; however, it was much more time-consuming than the four RANS models. Among the RANS models, the Low Reynolds number (LRN) SST k-ω model had the best overall performance at a series of airflow rates. Central flow velocity determined by particle image velocimetry was 3.617 m/s, while velocities predicted by the LES, LRN SST k-ω, and k-ω models were 3.681, 3.532, and 3.439 m/s, respectively. All models predicted jet flow in the oropharynx. These results suggest that the above CFD models have acceptable accuracy for predicting pediatric UA aerodynamics and that the LRN SST k-ω model has the most potential for clinical application in pediatric respiratory studies.
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Affiliation(s)
- Yicheng Chen
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China
| | - Xin Feng
- Department of Clinical Dentistry, Section for Oral and Maxillofacial Radiology, University of Bergen, Bergen, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Xieqi Shi
- Department of Clinical Dentistry, Section for Oral and Maxillofacial Radiology, University of Bergen, Bergen, Norway.,Department of Oral Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Weihua Cai
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China. .,School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, China.
| | - Biao Li
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China.
| | - Yijun Zhao
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China
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Lin S, Premaraj TS, Gamage PT, Dong P, Premaraj S, Gu L. Upper Airway Flow Dynamics in Obstructive Sleep Apnea Patients with Various Apnea-Hypopnea Index. Life (Basel) 2022; 12:1080. [PMID: 35888168 PMCID: PMC9318930 DOI: 10.3390/life12071080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/03/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND AND AIM This study evaluates the upper airway flow characteristics, anatomical features and analyzes their correlations with AHI in patients with varied degrees of OSA severity seeking for discernments of the underlying pathophysiological profile. MATERIALS AND METHODS Patient-specific computational fluid dynamics models were reconstructed from high-resolution cone-beam computed tomography images for 4 OSA patients classified as minimal, mild, moderate, and severe according to AHI. RESULTS The parameters, minimal cross-sectional area (MCA), and the pharyngeal airway volume did not show clear correlations with the OSA severity defined according to AHI. No correlations were found between the classically defined resistance of the airway in terms of pressure drop and AHI. The flow analysis further showed that the fluid mechanisms likely to cause airway collapse are associated with the degree of narrowing in the pharyngeal airway rather than AHI. Results also suggested that some patients classified as severe OSA according to the AHI can show less susceptibility to airway collapse than patients with relatively lower AHI values and vice versa. CONCLUSIONS The relative contribution of anatomical and non-anatomical causes to the OSA severity can significantly vary between patients. AHI alone is inadequate to be used as a marker of the pathophysiological profile of OSA. Combining airflow analysis with AHI in diagnosing OSA severity may provide additional details about the underlying pathophysiology, subsequently improving the individualized clinical outcomes.
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Affiliation(s)
- Shengmao Lin
- School of Civil Engineering and Architecture, Xiamen University of Technology, Xiamen 361024, China;
| | | | - Peshala T. Gamage
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA;
| | - Pengfei Dong
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA;
| | - Sundaralingam Premaraj
- College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, FL 33328, USA; (T.S.P.); (S.P.)
| | - Linxia Gu
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA;
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Ashraf W, Jacobson N, Popplewell N, Moussavi Z. Fluid–structure interaction modelling of the upper airway with and without obstructive sleep apnea: a review. Med Biol Eng Comput 2022; 60:1827-1849. [DOI: 10.1007/s11517-022-02592-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/28/2022] [Indexed: 10/18/2022]
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A Novel Portable Real-Time Low-Cost Sleep Apnea Monitoring System based on the Global System for Mobile Communications (GSM) Network. Med Biol Eng Comput 2022; 60:619-632. [PMID: 35029814 PMCID: PMC8759063 DOI: 10.1007/s11517-021-02492-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022]
Abstract
Background and objective Continuous monitoring of breathing activity plays a vital role in the detection of respiratory-based diseases (SA, COPD, etc.). Sleep Apnea (SA) is characterized by recurrent upper airway obstruction during sleep associated with arterial blood desaturation, sympathetic nervous system activation, and cardiovascular impairment. Untreated patients with SA have increased mortality rates compared to the general population. This study aims to design a remote monitoring system for sleep apnea to ensure patient safety and ease the workload of doctors in the Covid-19 era. Methods This study aims to design a remote monitoring system for sleep apnea to ensure patient safety and ease the workload of doctors. Our study focuses on a novel portable real-time low-cost sleep apnea monitoring system utilizing the GSM network (GSM Shield Sim900a). Proposed system is a remote monitoring and patient tracking system to detect the apnea event in real time, and to provide information of the sleep position, pulse, and respiratory and oxygen saturation to the medical specialists (SpO2) by establishing a direct contact. As soon as an abnormal condition is detected in the light of these parameters, the condition is reported (instant or in the form of short reports after sleep) to the patient relatives, the doctor’s mobile telephone or to the emergency medical centers (EMCs) through a GSM network to handle the case depending on the patient’s emergency condition. Results A study group was formed of six patients for monitoring apnea events (three males and three females) between the ages of 20 and 60. The patients in the study group have sleep apnea (SA) in different grades. All the apnea events were detected, and all the patients were successfully alerted. Also, the patient parameters were successfully sent to all patient relatives. Patients who could not get out of apnea were called through the CALL feature, and they were informed about their ongoing apnea event and told that intervention was necessary. The proposed system is tested on six patients. The beginning moment of apnea was successfully detected and the SMS/CALL feature was successfully activated without delay. During the testing, it has been observed that while some of the patients start breathing after the first SMS, some others needed the second or the third SMS. According to the measurement result, the maximum breathless time is 46 s among the patients, and a SMS is sent every 15 s. In addition, in cases where the patient was breathless for a long time, the CALL feature was actively sought from the relatives of the patient and enabled him to intervene. The proposed monitoring system could be used in both clinical and home settings. Conclusions The monitoring of a patient in real time allows to intervene in any unexpected circumstances about the patient. The proposed work uses an acceleration sensor as a reliable method of the sleep apnea for monitoring and prevention. The developed device is more economical, comfortable, and convenient than existing systems not only for the patients but also for the doctors. The patients can easily use this device in their home environment, so which could yield a more comfortable, easy to use, cost-effective, and long-term breathing monitoring system for healthcare applications. Graphical abstract ![]()
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The effect of rapid maxillary expansion on the upper airway's aerodynamic characteristics. BMC Oral Health 2021; 21:123. [PMID: 33731068 PMCID: PMC7968163 DOI: 10.1186/s12903-021-01488-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/04/2021] [Indexed: 12/20/2022] Open
Abstract
Background The effect of rapid maxillary expansion (RME) on the upper airway (UA) has been studied earlier but without a consistent conclusion. This study aims to evaluate the outcome of RME on the UA function in terms of aerodynamic characteristics by applying a computational fluid dynamics (CFD) simulation. Methods This retrospective cohort study consists of seventeen cases with two consecutive CBCT scans obtained before (T0) and after (T1) RME. Patients were divided into two groups with respect to patency of the nasopharyngeal airway as expressed in the adenoidal nasopharyngeal ratio (AN): group 1 was comprised of patients with an AN ratio < 0.6 and group 2 encompassing those with an AN ratio ≥ 0.6. CFD simulation at inspiration and expiration were performed based on the three-dimensional (3D) models of the UA segmented from the CBCT images. The aerodynamic characteristics in terms of pressure drop (ΔP), maximum midsagittal velocity (Vms), and maximum wall shear stress (Pws) were compared by paired t-test and Wilcoxon test according to the normality test at T0 and T1. Results The aerodynamic characteristics in UA revealed no statistically significant difference after RME. The maximum Vms (m/s) decreased from 2.79 to 2.28 at expiration after RME (P = 0.057). Conclusion The aerodynamic characteristics were not significantly changed after RME. Further CFD studies with more cases are warranted.
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Kim YJ, Shin HK, Lee DY, Ryu JJ, Kim TH. Decreased maxillary sinus volume is a potential predictor of obstructive sleep apnea. Angle Orthod 2021; 90:556-563. [PMID: 33378503 DOI: 10.2319/080819-520.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/01/2020] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES To investigate the associations between nasal airway volume and the presence and severity of obstructive sleep apnea (OSA) in adults. MATERIALS AND METHODS The medical records of adult patients who visited the sleep clinic at University Hospital between June 2013 and April 2017 and underwent overnight polysomnography for the diagnosis of obstructive sleep apnea were reviewed retrospectively. Using computed tomography, the volumes of the nasal airways and maxillary sinuses were measured, and associations with the presence and severity of OSA were analyzed while controlling for the effects of possible confounders such as lateral cephalometric variables, maxillary widths, tongue/hyoid position, and soft palate dimensions. RESULTS Comparison between normal subjects and patients with OSA revealed that the latter had decreased ratios of maxillary sinus volume to whole nasal airway volume (P = .029) than normal subjects. OSA severity was greater in those with inferior positions of the hyoid (P = .010), in older patients (P = .011), and in those with high body mass index (P = .001). The volume of the total nasal airway or maxillary sinuses were not associated with OSA severity. CONCLUSIONS A decreased ratio of maxillary sinus volume to whole nasal airway volume is associated with adult OSA. However, OSA severity is not associated with either maxillary sinus volume or whole nasal airway volume.
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Effect of inhalation on oropharynx collapse via flow visualisation. J Biomech 2020; 118:110200. [PMID: 33548657 DOI: 10.1016/j.jbiomech.2020.110200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 11/28/2020] [Accepted: 12/11/2020] [Indexed: 11/21/2022]
Abstract
Computational fluid dynamics (CFD) modelling has made significant contributions to the analysis and treatment of obstructive sleep apnoea (OSA). While several investigations have considered the flow field within the airway and its effect on airway collapse, the effect of breathing on the pharynx region is still poorly understood. We address this gap via a combined experimental and numerical study of the flow field within the pharynx and its impacts upon airway collapse. Two 3D experimental models of the upper airway were constructed based upon computerised tomography scans of a specific patient diagnosed with severe OSA; (i) a transparent, rigid model for flow visualisation, and (ii) a semi-flexible model for understanding the effect of flow on pharynx collapse. Validated simulation results for this geometry indicate that during inhalation, negative pressure (with respect to atmospheric pressure) caused by vortices drives significant narrowing of the pharynx. This narrowing is strongly dependent upon whether inhalation occurs through the nostrils. Thus, the methodology presented here can be used to improve OSA treatment by improving the design methodology for personalised, mandibular advancement splints (MAS) that minimise OSA during sleep.
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Impact of sleeping position, gravitational force & effective tissue stiffness on obstructive sleep apnoea. J Biomech 2020; 104:109715. [DOI: 10.1016/j.jbiomech.2020.109715] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/28/2020] [Accepted: 02/21/2020] [Indexed: 12/26/2022]
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Taherian S, Rahai H, Lopez S, Shin J, Jafari B. Evaluation of human obstructive sleep apnea using computational fluid dynamics. Commun Biol 2019; 2:423. [PMID: 31799426 PMCID: PMC6872714 DOI: 10.1038/s42003-019-0668-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 10/28/2019] [Indexed: 11/21/2022] Open
Abstract
Obstructive sleep apnea (OSA) severity might be correlated to the flow characteristics of the upper airways. We aimed to investigate the severity of OSA based on 3D models constructed from CT scans coupled with computational fluid dynamics (CFD) simulations. The CT scans of seven adult patients diagnosed with OSA were used to reconstruct the 3D models of the upper airways and CFD modeling and analyses were performed. Results from the fluid simulations were compared with the apnea-hypopnea index. Here we show a correlation between a CFD-based parameter, the adjusted pressure coefficient (Cp*), and the respective apnea-hypopnea index (Pearson's r = 0.91, p = 0.004), which suggests that the anatomical-based model coupled with CFD could provide functional and localized information for different regions of the upper airways.
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Affiliation(s)
- Shahab Taherian
- Center for Energy and Environmental Research and Services, California State University Long Beach, Long Beach, CA USA
- Department of Internal Medicine, University of California Irvine School of Medicine, Irvine, CA USA
| | - Hamid Rahai
- Center for Energy and Environmental Research and Services, California State University Long Beach, Long Beach, CA USA
| | - Samuel Lopez
- Center for Energy and Environmental Research and Services, California State University Long Beach, Long Beach, CA USA
| | - Jamie Shin
- Center for Energy and Environmental Research and Services, California State University Long Beach, Long Beach, CA USA
| | - Behrouz Jafari
- Department of Internal Medicine, University of California Irvine School of Medicine, Irvine, CA USA
- Section of Pulmonary, Critical Care, and Sleep Medicine, Veterans Affairs Long Beach Healthcare System, Long Beach, CA USA
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Yeom SH, Na JS, Jung HD, Cho HJ, Choi YJ, Lee JS. Computational analysis of airflow dynamics for predicting collapsible sites in the upper airways: machine learning approach. J Appl Physiol (1985) 2019; 127:959-973. [PMID: 31318618 DOI: 10.1152/japplphysiol.01033.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Obstructive sleep apnea (OSA) is a common sleep breathing disorder. With the use of computational fluid dynamics (CFD), this study provides a quantitative standard for accurate diagnosis and effective surgery based on the investigation of the relationship between airway geometry and aerodynamic characteristics. Based on computed tomography data from patients having normal geometry, 4 major geometric parameters were selected and a total of 160 idealized cases were modeled and simulated. We created a predictive model using Gaussian process regression (GPR) through a data set obtained through numerical method. The results demonstrated that the mean accuracy of the overall GPR model was ~72% with respect to the CFD results for the realistic upper airway model. A support vector machine model was also used to identify the degree of OSA symptoms in patients as normal-mild and moderate and severe. We achieved an accuracy of 82.5% with the training data set and an accuracy of 80% with the test data set.NEW & NOTEWORTHY There have been many studies on the analysis of obstructive sleep apnea (OSA) through computational fluid dynamics and finite element analysis. However, these methods are not useful for practical medical applications because they have limited information for OSA symptom. This study employs the machine learning algorithm to predict flow characteristics quickly and to determine the symptoms of the patient's OSA. The overall Gaussian process regression model's mean accuracy was ~72%, and the accuracy for the classification of OSA was >80%.
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Affiliation(s)
- Seung Ho Yeom
- Department of Mechanical Engineering, College of Engineering, Yonsei University, Seoul, Korea
| | - Ji Sung Na
- Unit of Ice Sheet and Sea Level Changes, Korea Polar Research Institute, Incheon, Korea
| | - Hwi-Dong Jung
- Department of Oral and Maxillofacial Surgery, Yonsei University College of Dentistry, Seoul, Korea
| | - Hyung-Ju Cho
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Yoon Jeong Choi
- Department of Mechanical Engineering, College of Engineering, Yonsei University, Seoul, Korea.,Department of Orthodontics, The Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea
| | - Joon Sang Lee
- Department of Mechanical Engineering, College of Engineering, Yonsei University, Seoul, Korea.,Department of Orthodontics, The Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea
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16
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Le TB, Moghaddam MG, Woodson BT, Garcia GJM. Airflow limitation in a collapsible model of the human pharynx: physical mechanisms studied with fluid-structure interaction simulations and experiments. Physiol Rep 2019; 7:e14099. [PMID: 31116516 PMCID: PMC6530458 DOI: 10.14814/phy2.14099] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 04/30/2019] [Indexed: 12/15/2022] Open
Abstract
The classical Starling Resistor model has been the paradigm of airway collapse in obstructive sleep apnea (OSA) for the last 30 years. Its theoretical framework is grounded on the wave-speed flow limitation (WSFL) theory. Recent observations of negative effort dependence in OSA patients violate the predictions of the WSFL theory. Fluid-structure interaction (FSI) simulations are emerging as a technique to quantify how the biomechanical properties of the upper airway determine the shape of the pressure-flow curve. This study aimed to test two predictions of the WSFL theory, namely (1) the pressure profile upstream from the choke point becomes independent of downstream pressure during flow limitation and (2) the maximum flowrate in a collapsible tube is V I max = A 3 / 2 ( ρ d A / d P ) - 1 / 2 , where ρ is air density and A and P are the cross-sectional area and pressure at the choke point respectively. FSI simulations were performed in a model of the human upper airway with a collapsible pharynx whose wall thickness varied from 2 to 8 mm and modulus of elasticity ranged from 2 to 30 kPa. Experimental measurements in an airway replica with a silicone pharynx validated the numerical methods. Good agreement was found between our FSI simulations and the WSFL theory. Other key findings include: (1) the pressure-flow curve is independent of breathing effort (downstream pressure vs. time profile); (2) the shape of the pressure-flow curve reflects the airway biomechanical properties, so that V I max is a surrogate measure of pharyngeal compliance.
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Affiliation(s)
- Trung B. Le
- Department of Biomedical EngineeringMarquette University & The Medical College of WisconsinMilwaukeeWisconsin
- Present address:
Department of Civil and Environmental EngineeringNorth Dakota State UniversityFargoNorth Dakota
| | - Masoud G. Moghaddam
- Department of Biomedical EngineeringMarquette University & The Medical College of WisconsinMilwaukeeWisconsin
| | - B. Tucker Woodson
- Department of Otolaryngology and Communication SciencesMedical College of WisconsinMilwaukeeWisconsin
| | - Guilherme J. M. Garcia
- Department of Biomedical EngineeringMarquette University & The Medical College of WisconsinMilwaukeeWisconsin
- Department of Otolaryngology and Communication SciencesMedical College of WisconsinMilwaukeeWisconsin
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17
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Shang Y, Dong J, Tian L, Inthavong K, Tu J. Detailed computational analysis of flow dynamics in an extended respiratory airway model. Clin Biomech (Bristol, Avon) 2019; 61:105-111. [PMID: 30544055 DOI: 10.1016/j.clinbiomech.2018.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/27/2018] [Accepted: 12/06/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Understanding respiratory physiology can aid clinicians in diagnosing the cause of respiratory symptoms or shed light on drug delivery inhaler device optimisation. However, the sheer complexity of the human lung prohibits a full-scale study. METHODS In this study, a realistic respiratory airway model including large-to-small conducting airways was built. This airway model consists of subject-specific upper and lower airways, extending from nasal and oral openings to terminal bronchioles (up to the 15th generation). Based on the subject-specific airway model, topological information was extracted and a digital reference model that exhibits strong asymmetry and multi-fractal properties was provided. Inhalation flow rates 18 L/min and 50 L/min were adopted to understand inspiratory conditions subjecting to resting and light exercise inhalation modes. Regional airflow in terms of axial velocity and secondary flow vortices along the lung airway model was extracted. FINDINGS Obvious secondary flow currents were seen in the larynx-trachea segment and left main bronchus, while for the terminal conducting airway in the right lower lobe, the airflow tends to be much smoother with no secondary flow currents. INTERPRETATION This paper provides insights on respiratory physiology, especially in the lower lung airways, and will be potentially useful for diagnosis of lower airway diseases.
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Affiliation(s)
- Yidan Shang
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
| | - Jingliang Dong
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
| | - Lin Tian
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia.
| | - Kiao Inthavong
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
| | - Jiyuan Tu
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia; Key Laboratory of Ministry of Education for Advanced Reactor Engineering and Safety, Institute of Nuclear and New Energy Technology, Tsinghua University, PO Box 1021, Beijing 100086, China.
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18
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Lambeth C, Wang Z, Kairaitis K, Moshfegh A, Jabbarzadeh A, Amis TC. Modelling mucosal surface roughness in the human velopharynx: a computational fluid dynamics study of healthy and obstructive sleep apnea airways. J Appl Physiol (1985) 2018; 125:1821-1831. [PMID: 30284517 DOI: 10.1152/japplphysiol.00233.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously published a unique methodology for quantifying human velopharyngeal mucosal surface topography and found increased mucosal surface roughness in obstructive sleep apnea (OSA) patients. In fluid mechanics, surface roughness is associated with increased frictional pressure losses and resistance. This study used computational fluid dynamics (CFD) to analyse the mechanistic effect of different levels of mucosal surface roughness on velopharyngeal airflow. METHODS Reconstructed velopharyngeal models from OSA and Control subjects were modified, giving each model three levels of roughness, quantified by the curvature based surface roughness index (CBSRI0.6; range 24.8-68.6mm-1). CFD using the k-ω shear stress transport (SST) turbulence model was performed (unidirectional, inspiratory, steady state, 15l/min volumetric flow rate), and the effects of roughness on flow velocity, intraluminal pressure, wall shear stress and velopharyngeal resistance (Rv) were examined. RESULTS Across all models, increasing roughness increased maximum flow velocity, wall shear stress and flow disruption, while decreasing intraluminal pressures. Linear mixed effects modelling demonstrated a log-linear relationship between CBSRI0.6 and Rv, with a common slope (log(Rv)/CBSRI0.6) of 0.0079 (95%CI 0.0015-0.0143; p=0.019) for all subjects, equating to a 1.9-fold increase in Rv when roughness increased from Control to OSA levels. At any fixed CBSRI0.6, the estimated difference in log(Rv) between OSA and Control models was 0.9382 (95%CI 0.0032-1.8732; p=0.049), equating to an 8.7-fold increase in Rv. CONCLUSION This study supports the hypothesis that increasing mucosal surface roughness increases velopharyngeal airway resistance, particularly for anatomically narrower OSA airways, and may thus contribute to increased vulnerability to upper airway collapse in OSA patients.
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Affiliation(s)
- Christopher Lambeth
- Ludwig Engel Centre for Respiratory Research, The Westmead Institute for Medical Research, Australia
| | | | - Kristina Kairaitis
- Westmead Hospital, Ludwig Engel Centre for Respiratory Research,Westmead Millennium Institute and the University of Sydney, Australia
| | | | | | - Terence Charles Amis
- Westmead Hospital, Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute and the University of Sydney
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19
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Kimbell JS, Basu S, Garcia GJM, Frank-Ito DO, Lazarow F, Su E, Protsenko D, Chen Z, Rhee JS, Wong BJ. Upper airway reconstruction using long-range optical coherence tomography: Effects of airway curvature on airflow resistance. Lasers Surg Med 2018; 51:150-160. [PMID: 30051633 DOI: 10.1002/lsm.23005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Adenotonsillectomy (AT) is commonly used to treat upper airway obstruction in children, but selection of patients who will benefit most from AT is challenging. The need for diagnostic evaluation tools without sedation, radiation, or high costs has motivated the development of long-range optical coherence tomography (LR-OCT), providing real-time cross-sectional airway imaging during endoscopy. Since the endoscope channel location is not tracked in conventional LR-OCT, airway curvature must be estimated and may affect predicted airway resistance. The study objective was to assess effects of three realistic airway curvatures on predicted airway resistance using computational fluid dynamics (CFD) in LR-OCT reconstructions of the upper airways of pediatric patients, before and after AT. METHODS Eight subjects (five males, three females, aged 4-9 years) were imaged using LR-OCT before and after AT during sedated endoscopy. Three-dimensional (3D) airway reconstructions included three airway curvatures. Steady-state, inspiratory airflow simulations were conducted under laminar conditions, along with turbulent simulations for one subject using the k-ω turbulence model. Airway resistance (pressure drop/flow) was compared using two-tailed Wilcoxon signed rank tests. RESULTS Regardless of the airway curvatures, CFD findings corroborate a surgical end-goal with computed post-operative airway resistance significantly less than pre-operative (P < 0.01). The individual resistances did not vary significantly for different airway curvatures (P > 0.25). Resistances computed using turbulent simulations differed from laminar results by less than ∼5%. CONCLUSIONS The results suggest that reconstruction of the upper airways from LR-OCT imaging data may not need to account for airway curvature to be predictive of surgical effects on airway resistance. Lasers Surg. Med. 51:150-160, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Julia S Kimbell
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Saikat Basu
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Guilherme J M Garcia
- Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin.,Medical College of Wisconsin, Biotechnology and Bioengineering Center, Milwaukee, Wisconsin
| | - Dennis O Frank-Ito
- Otolaryngology-Head and Neck Surgery, Duke University Medical Center, Durham, North Carolina
| | - Frances Lazarow
- Beckman Laser Institute, University of California, Irvine, California
| | - Erica Su
- Beckman Laser Institute, University of California, Irvine, California
| | - Dimitry Protsenko
- Beckman Laser Institute, University of California, Irvine, California
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, California
| | - John S Rhee
- Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Brian J Wong
- Beckman Laser Institute, University of California, Irvine, California.,Otolaryngology-Head and Neck Surgery, University of California, Irvine, California
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20
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Chang KK, Kim KB, McQuilling MW, Movahed R. Fluid structure interaction simulations of the upper airway in obstructive sleep apnea patients before and after maxillomandibular advancement surgery. Am J Orthod Dentofacial Orthop 2018; 153:895-904. [PMID: 29853247 DOI: 10.1016/j.ajodo.2017.08.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 07/01/2017] [Accepted: 08/01/2017] [Indexed: 11/24/2022]
Abstract
INTRODUCTION The purpose of this study was to analyze pharyngeal airflow using both computational fluid dynamics (CFD) and fluid structure interactions (FSI) in obstructive sleep apnea patients before and after maxillomandibular advancement (MMA) surgery. The airflow characteristics before and after surgery were compared with both CFD and FSI. In addition, the presurgery and postsurgery deformations of the airway were evaluated using FSI. METHODS Digitized pharyngeal airway models of 2 obstructive sleep apnea patients were generated from cone-beam computed tomography scans before and after MMA surgery. CFD and FSI were used to evaluate the pharyngeal airflow at a maximum inspiration rate of 166 ml per second. Standard steady-state numeric formulations were used for airflow simulations. RESULTS Airway volume increased, pressure drop decreased, maximum airflow velocity decreased, and airway resistance dropped for both patients after the MMA surgery. These findings occurred in both the CFD and FSI simulations. The FSI simulations showed an area of marked airway deformation in both patients before surgery, but this deformation was negligible after surgery for both patients. CONCLUSIONS Both CFD and FSI simulations produced airflow results that indicated less effort was needed to breathe after MMA surgery. The FSI simulations demonstrated a substantial decrease in airway deformation after surgery. These beneficial changes positively correlated with the large improvements in polysomnography outcomes after MMA surgery.
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Affiliation(s)
- Kwang K Chang
- Center for Advanced Dental Education, Saint Louis University, St. Louis, Mo.
| | - Ki Beom Kim
- Center for Advanced Dental Education, Saint Louis University, St. Louis, Mo
| | - Mark W McQuilling
- College of Engineering, Aviation and Technology, Saint Louis University, St. Louis, Mo
| | - Reza Movahed
- Center for Advanced Dental Education, Saint Louis University, St. Louis, Mo; private practice, St. Louis, Mo
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21
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Liu Y, Mitchell J, Chen Y, Yim W, Chu W, Wang RC. Study of the upper airway of obstructive sleep apnea patient using fluid structure interaction. Respir Physiol Neurobiol 2018; 249:54-61. [DOI: 10.1016/j.resp.2018.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/30/2017] [Accepted: 01/04/2018] [Indexed: 11/17/2022]
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22
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Hur JS, Kim HH, Choi JY, Suh SH, Baek SH. Investigation of the effects of miniscrew-assisted rapid palatal expansion on airflow in the upper airway of an adult patient with obstructive sleep apnea syndrome using computational fluid-structure interaction analysis. Korean J Orthod 2017; 47:353-364. [PMID: 29090123 PMCID: PMC5653684 DOI: 10.4041/kjod.2017.47.6.353] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/06/2017] [Accepted: 05/08/2017] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE The objective of this study was to investigate the effects of miniscrew-assisted rapid palatal expansion (MARPE) on changes in airflow in the upper airway (UA) of an adult patient with obstructive sleep apnea syndrome (OSAS) using computational fluid-structure interaction analysis. METHODS Three-dimensional UA models fabricated from cone beam computed tomography images obtained before (T0) and after (T1) MARPE in an adult patient with OSAS were used for computational fluid dynamics with fluid-structure interaction analysis. Seven and nine cross-sectional planes (interplane distance of 10 mm) in the nasal cavity (NC) and pharynx, respectively, were set along UA. Changes in the cross-sectional area and changes in airflow velocity and pressure, node displacement, and total resistance at maximum inspiration (MI), rest, and maximum expiration (ME) were investigated at each plane after MARPE. RESULTS The cross-sectional areas at most planes in NC and the upper half of the pharynx were significantly increased at T1. Moreover, airflow velocity decreased in the anterior NC at MI and ME and in the nasopharynx and oropharynx at MI. The decrease in velocity was greater in NC than in the pharynx. The airflow pressure in the anterior NC and entire pharynx exhibited a decrease at T1. The amount of node displacement in NC and the pharynx was insignificant at both T0 and T1. Absolute values for the total resistance at MI, rest, and ME were lower at T1 than at T0. CONCLUSIONS MARPE improves airflow and decreases resistance in UA; therefore, it may be an effective treatment modality for adult patients with moderate OSAS.
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Affiliation(s)
- Jae-Sik Hur
- Department of Orthodontics, School of Dentistry, Seoul National University, Seoul, Korea
| | - Hyoung-Ho Kim
- Department of Mechanical Engineering, Soongsil University, Seoul, Korea
| | - Jin-Young Choi
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul, Korea.,Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Sang-Ho Suh
- Department of Mechanical Engineering, Soongsil University, Seoul, Korea
| | - Seung-Hak Baek
- Department of Orthodontics, School of Dentistry, Seoul National University, Seoul, Korea.,Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
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23
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Kita S, Oshima M, Shimazaki K, Iwai T, Omura S, Ono T. Computational Fluid Dynamic Study of Nasal Respiratory Function Before and After Bimaxillary Orthognathic Surgery With Bone Trimming at the Inferior Edge of the Pyriform Aperture. J Oral Maxillofac Surg 2016; 74:2241-2251. [PMID: 27425883 DOI: 10.1016/j.joms.2016.06.171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 06/10/2016] [Accepted: 06/12/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE This study aimed to evaluate the influence of maxillary impaction orthognathic surgery on nasal respiratory function and the efficacy of bone trimming at the inferior edge of the pyriform aperture. MATERIALS AND METHODS The participants were 10 patients (3 male and 7 female patients) with mandibular prognathism who underwent bimaxillary orthognathic surgery with maxillary impaction. The surgical procedures performed were Le Fort I osteotomy with bone trimming at the inferior edge of the pyriform aperture and bilateral sagittal split osteotomy. Three-dimensional models of the nasal cavity were reconstructed from preoperative and postoperative computed tomography images. Furthermore, we remodeled the nasal valve region based on the postoperative models by adding a 1-mm and 2-mm stenosis to investigate the effects of bone trimming at the inferior edge of the pyriform aperture on the pressure effort. The 3-dimensional models were simulated with computational fluid dynamics, and the results of the pressure effort and the cross-sectional area (CSA) were compared for the anterior, middle, and posterior parts of the nasal cavity. The Wilcoxon signed rank test and Spearman rank correlation coefficients were used for statistical comparisons (P < .05). RESULTS In the preoperative and postoperative models, there were considerable correlations between the CSA and the pressure effort in each part of the nasal cavity. The postoperative pressure effort showed a tendency to decrease and the CSA showed a tendency to increase in each part of the nasal cavity. In four 2-mm stenosis models, the pressure effort in the anterior nasal cavity was larger than the preoperative pressure effort and the CSA of the anterior nasal cavity was smaller than the preoperative CSA. CONCLUSIONS Bone trimming at the inferior edge of the pyriform aperture appears to be useful for avoiding nasal respiratory complications with maxillary impaction.
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Affiliation(s)
- Soma Kita
- Postgraduate Student, Department of Orthodontic Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
| | - Marie Oshima
- Professor, Institute of Industrial Science, The University of Tokyo, Komaba, Meguro-ku, Tokyo, Japan
| | - Kazuo Shimazaki
- Assistant Professor, Department of Orthodontic Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Toshinori Iwai
- Assistant Professor, Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Fukuura, Kanazawa-ku, Yokohama, Kanagawa, Japan
| | - Susumu Omura
- Professor, Department of Oral and Maxillofacial Surgery, Yokohama City University Medical Center, Urafunecho, Minami-ku, Yokohama, Kanagawa, Japan
| | - Takashi Ono
- Professor, Department of Orthodontic Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan
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