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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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Wang X, Jia L, Xu X, Guo J. The relationship between aerodynamic characteristics of the upper airway and severity of obstructive sleep apnea in adults. Cranio 2023:1-8. [PMID: 37980603 DOI: 10.1080/08869634.2023.2278958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
OBJECTIVE To investigate the relationship between aerodynamic characteristics of the upper airway and severity of obstructive sleep apnea (OSA) in adults. METHODS Ninety-seven adult OSA patients underwent polysomnography and cone beam computed tomography (CBCT). The anatomical and aerodynamic characteristics were measured based on CBCT images and computational fluid dynamics modelling of the upper airway. RESULTS After controlling for patients' gender, age, and body mass index (BMI), the maximum velocity during inspiration (In-Vmax) led to the largest increase in the explanatory power of apnea-hypopnea index (AHI) variation. The In-Vmax was closely correlated with the minimum axial area, and their relationship was represented by an inversely proportional fitted curve. CONCLUSIONS The In-Vmax was the most relevant to OSA severity, and it could be used to assist in recognizing severe OSA patients and as a primary variable to evaluate treatment outcomes of OSA. The In-Vmax was closely related to the most constricted area of the upper airway.
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Affiliation(s)
- Xiaoya Wang
- Department of Stomatology, Weihai Municipal Hospital, Cheeloo College of Medicine, Shandong University, Weihai, China
| | - Lu Jia
- Department of Orthodontics, Jinan Stomatological Hospital, Jinan, China
| | - Xin Xu
- Department of Implantology, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Jinan, China
| | - Jing Guo
- Engineering Laboratory for Biomaterials and Tissue Regeneration, Ningbo Stomatology Hospital, Zhejiang, China
- Savaid Stomatology School, Hangzhou Medical College, Hangzhou, Zhejiang, China
- Savaid medical institute for stomatology and ENT, Ningbo, China
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Jinan, China
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Mortezai O, Shalli Z, Tofangchiha M, Alizadeh A, Pagnoni F, Reda R, Testarelli L. Effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults: a retrospective cephalometric assessment. PeerJ 2023; 11:e15960. [PMID: 37901473 PMCID: PMC10601897 DOI: 10.7717/peerj.15960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/03/2023] [Indexed: 10/31/2023] Open
Abstract
Background This study aimed to assess the effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults by cephalometric assessment. Methods This retrospective study was conducted on 142 cephalograms of patients who underwent orthodontic treatment with premolar extraction in four groups of (I) 40 class I patients with bimaxillary protrusion and maximum anchorage, (II) 40 class I patients with moderate crowding and anchorage, (III) 40 class II patients with maximum anchorage, and (IV) 22 skeletal class III patients with maximum anchorage. The dimensions of the nasopharynx, velopharynx, oropharynx, and hypopharynx, and hyoid bone position were assessed on pre- and postoperative lateral cephalograms using AudaxCeph v6.1.4.3951 software. Data were analyzed by the Chi-square test, paired t-test, and Pearson's correlation test (alpha = 0.05). Results A significant reduction in oropharyngeal, velopharyngeal, and hypopharyngeal airway dimensions was noted in groups I, III, and IV (P < 0.001), which was correlated with the magnitude of retraction of upper and lower incisors (r = 0.6 - 0.8). In group II, a significant increase was observed in oropharyngeal and velopharyngeal dimensions (P < 0.001). A significant increase in nasopharyngeal dimensions occurred in all groups (P < 0.001). Also, in groups I and III, the position of hyoid bone changed downwards and backwards, which was correlated with reduction in airway dimensions (r = 0.4 - 0.6). Conclusion According to the present results, extraction orthodontic treatment affects upper airway dimensions and hyoid bone position. Maximum anchorage decreases airway dimensions while moderate anchorage increases airway dimensions.
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Affiliation(s)
- Omid Mortezai
- Department of Orthodontics, Dental faculty, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Zeynab Shalli
- Department of Orthodontics, Dental faculty, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Maryam Tofangchiha
- Dental Caries Prevention Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Ahad Alizadeh
- Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Francesco Pagnoni
- Department of Oral and Maxillo Facial Sciences, Sapienza University of Rome, Rome, Italy
| | - Rodolfo Reda
- Department of Oral and Maxillo Facial Sciences, Sapienza University of Rome, Rome, Italy
| | - Luca Testarelli
- Department of Oral and Maxillo Facial Sciences, Sapienza University of Rome, Rome, Italy
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Hudson TJ, Oubahou RA, Mongeau L, Kost K. Airway Resistance and Respiratory Distress in Laryngeal Cancer: A Computational Fluid Dynamics Study. Laryngoscope 2023; 133:2734-2741. [PMID: 36951521 PMCID: PMC10517074 DOI: 10.1002/lary.30649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/25/2023] [Accepted: 02/27/2023] [Indexed: 03/24/2023]
Abstract
BACKGROUND Obstructive upper airway pathologies are a great clinical challenge for the airway surgeon. Protection against acute obstruction is critical, but avoidance of unnecessary tracheostomy must also be considered. Decision-making regarding airway, although supported by some objective findings, is largely guided by subjective experience and training. This investigation aims to study the relationship between clinical respiratory distress and objective measures of airway resistance in laryngeal cancer as determined by computational fluid dynamic (CFD) and morphometric analysis. METHODS Retrospective CT and clinical data were obtained for series of 20 cases, defined as newly diagnosed laryngeal cancer patients who required admission or urgent airway surgery, and 20 controls. Cases and controls were matched based on T-staging. Image segmentation and morphometric analysis were first performed. Computational models based on the lattice Boltzmann method were then created and used to quantify the continuous mass flow, rigid wall, and constant static pressure inlet boundary conditions. RESULTS The analysis demonstrated a significant relationship between airway resistance and acute obstruction (OR 1.018, 95% CI 1.001-1.045). Morphometric analysis similarly demonstrated a significant relationship when relating measurements based on the minimum cross-section, but not on length of stenosis. Morphometric measurements also showed significance in predicting CFD results, and their relationship demonstrated that airway pressures increase exponentially below 2.5 mm. Tumor subsite did not show a significant difference, although the glottic subgroup tended to have higher resistances. CONCLUSION Airway resistance analysis from CFD computation correlated with presence of acute distress requiring emergent management. Morphometric analysis showed a similar correlation, demonstrating a radiologic airway assessment technique on which future risk estimation could be performed. LEVEL OF EVIDENCE 4 (case-control study) Laryngoscope, 133:2734-2741, 2023.
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Affiliation(s)
- Thomas J. Hudson
- Department of Otolaryngology – Head and Neck Surgery, McGill University Health Centre, Montreal, QC, Canada
| | - Rayane Ait Oubahou
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada
| | - Luc Mongeau
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada
| | - Karen Kost
- Department of Otolaryngology – Head and Neck Surgery, McGill University Health Centre, Montreal, QC, Canada
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Analysis of Upper Airway Flow Dynamics in Robin Sequence Infants Using 4-D Computed Tomography and Computational Fluid Dynamics. Ann Biomed Eng 2023; 51:363-376. [PMID: 35951208 DOI: 10.1007/s10439-022-03036-6] [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: 04/01/2022] [Accepted: 07/20/2022] [Indexed: 01/25/2023]
Abstract
Robin Sequence (RS) is a potentially fatal craniofacial condition characterized by undersized jaw, posteriorly displaced tongue, and resultant upper airway obstruction (UAO). Accurate assessment of UAO severity is crucial for management and diagnosis of RS, yet current evaluation modalities have significant limitations and no quantitative measures of airway resistance exist. In this study, we combine 4-dimensional computed tomography and computational fluid dynamics (CFD) to assess, for the first time, UAO severity using fluid dynamic metrics in RS patients. Dramatic intrapopulation differences are found, with the ratio between most and least severe patients in breathing resistance, energy loss, and peak velocity equal to 40:1, 20:1, and 6:1, respectively. Analysis of local airflow dynamics characterized patients as presenting with primary obstructions either at the location of the tongue base, or at the larynx, with tongue base obstructions resulting in a more energetic stenotic jet and greater breathing resistance. Finally, CFD-derived flow metrics are found to correlate with the level of clinical respiratory support. Our results highlight the large intrapopulation variability, both in quantitative metrics of UAO severity (resistance, energy loss, velocity) and in the location and intensity of stenotic jets for RS patients. These results suggest that computed airflow metrics may significantly improve our understanding of UAO and its management in RS.
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Hu B, Yin G, Fu S, Zhang B, Shang Y, Zhang Y, Ye J. The influence of mouth opening on pharyngeal pressure loss and its underlying mechanism: A computational fluid dynamic analysis. Front Bioeng Biotechnol 2023; 10:1081465. [PMID: 36698641 PMCID: PMC9868155 DOI: 10.3389/fbioe.2022.1081465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/20/2022] [Indexed: 01/11/2023] Open
Abstract
Objective: During inspiration, mechanical energy generated from respiratory muscle produces a negative pressure gradient to fulfill enough pulmonary ventilation. The pressure loss, a surrogate for energy loss, is considered as the portion of negative pressure without converting into the kinetic energy of airflow. Mouth opening (MO) during sleep is a common symptom in patients with obstructive sleep apnoea-hypopnea syndrome (OSAHS). This study aimed to evaluate the effects of mouth opening on pharyngeal pressure loss using computational fluid dynamics (CFD) simulation. Methods: A total of four subjects who were morphologically distinct in the pharyngeal characteristics based on Friedman tongue position (FTP) grades were selected. Upper airway computed tomography (CT) scan was performed under two conditions: Mouth closing (MC) and mouth opening, in order to reconstruct the upper airway models. computational fluid dynamics was used to simulate the flow on the two different occasions: Mouth closing and mouth opening. Results: The pharyngeal jet was the typical aerodynamic feature and its formation and development were different from mouth closing to mouth opening in subjects with different Friedman tongue position grades. For FTP I with mouth closing, a pharyngeal jet gradually formed with proximity to the velopharyngeal minimum area plane (planeAmin). Downstream the planeAmin, the jet impingement on the pharyngeal wall resulted in the frictional loss associated with wall shear stress (WSS). A rapid luminal expansion led to flow separation and large recirculation region, corresponding to the interior flow loss. They all contributed to the pharyngeal total pressure loss. While for FTP I with mouth opening, the improved velopharyngeal constriction led to smoother flow and a lower total pressure loss. For FTP IV, the narrower the planeAmin after mouth opening, the stronger the jet formation and its impingement on the pharyngeal wall, predicting a higher frictional loss resulted from higher WSS. Besides, a longer length of the mouth opening-associated constant constrictive segment was another important morphological factor promoting frictional loss. Conclusion: For certain OSAHS patients with higher Friedman tongue position grade, mouth opening-related stronger jet formation, more jet breakdown and stronger jet flow separation might contribute to the increased pharyngeal pressure loss. It might require compensation from more inspiratory negative static pressure that would potentially increase the severity of OSAHS.
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Affiliation(s)
- Bin Hu
- Department of Otolaryngology-Head Neck Surgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Guoping Yin
- Department of Otolaryngology-Head Neck Surgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China,Sleep Medicine Center, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Song Fu
- School of Aeronautics and Astronautics, Tsinghua University, Beijing, China
| | - Baoshou Zhang
- School of Aeronautics and Astronautics, Tsinghua University, Beijing, China
| | - Yan Shang
- School of Aeronautics and Astronautics, Tsinghua University, Beijing, China
| | - Yuhuan Zhang
- Sleep Medicine Center, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Jingying Ye
- Department of Otolaryngology-Head Neck Surgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China,Sleep Medicine Center, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China,*Correspondence: Jingying Ye,
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Nomura T, Horikoshi T, Kitano Y, Yamada M, Kondo K, Kikuchi S. Postoperative functional evaluation of obstructive sleep apnea syndrome by computational fluid dynamics. Indian J Otolaryngol Head Neck Surg 2022; 74:5044-5051. [PMID: 36742941 PMCID: PMC9895218 DOI: 10.1007/s12070-021-02681-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/07/2021] [Indexed: 02/07/2023] Open
Abstract
The aim of this study is to evaluate the efficacy of uvulopalatopharyngoplasty and the corresponding postoperative airflow. Eleven patients diagnosed with obstructive sleep apnea syndrome who complained of snoring and apnea were enrolled in this study. Computational fluid dynamics (CFD) was implemented. CFD could be accomplished in nine cases. Airflow analysis was not possible in cases with a high respiratory event index (REI) score. Before surgery, stenosis was identified in the oropharynx and epiglottic area. And the airflow velocity and pressure were found to have significantly decreased in the oropharynx postoperatively, while in the epiglottic area, those data had increased postoperatively in some cases. The velocity and pressure of the oropharynx are related to REI score. From the CFD analysis, airflow analysis is important for evaluating the apnea state. It is suggested that the postoperative function can now be predicted preoperatively.
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Affiliation(s)
- Tsutomu Nomura
- Division of Otolaryngology, Department of Comprehensive Medical Sciences, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama, 350–0283 Japan
| | - Tomomi Horikoshi
- Department of Otolaryngology, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Yuka Kitano
- Department of Otolaryngology, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Masato Yamada
- Department of Otolaryngology, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Kenji Kondo
- Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shigeru Kikuchi
- Department of Otolaryngology, Saitama Medical Center, Saitama Medical University, Saitama, Japan
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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] [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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Chen H, Elham E, Li Y, Ge S, Schmittbuhl M, Lavigne G, van der Stelt PF, Huynh N. Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults. J Clin Sleep Med 2022; 18:759-768. [PMID: 34636319 PMCID: PMC8883080 DOI: 10.5664/jcsm.9716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES First, to compare the upper airway's anatomic and aerodynamic characteristics of the edentulous older adults who experience mild, moderate, and severe obstructive sleep apnea (OSA). Second, to examine the correlation between the severity of OSA and the anatomic and aerodynamic characteristic(s) of the upper airway in these edentulous individuals. METHODS NewTom5G cone beam computed tomography scans of 58 edentulous individuals with mild, moderate, and severe OSA were included in this analysis. 1) Computational models of the upper airway were reconstructed based on cone beam computed tomography images and the anatomical and aerodynamic characteristics of the upper airway were examined by an observer blind to OSA severity. 2) Pearson correlation analysis was used to determine the correlation between apnea-hypopnea index and the anatomic and aerodynamic characteristics of the upper airway. RESULTS Compared with edentulous patients with mild and moderate OSA, those with severe OSA have a more hourglass-shaped upper airway. The severity of OSA, namely, apnea-hypopnea index, was significantly correlated with the length, shape, and minimum cross-sectional area of the upper airway. During inspiration, the mean velocity of the airflow within the upper airway of the edentulous patients with severe OSA was higher than that of patients with mild and moderate OSA. During both inspiration and expiration, apnea-hypopnea index was found to be significantly correlated with maximum velocity (P = .05) and airway resistance (P = .024, 0.038). CONCLUSIONS The edentulous patients with severe OSA have a more hourglass-shaped upper airway. The findings also suggest that, during inspiration, the airflow travels faster in edentulous patients with severe OSA than in those with mild or moderate OSA. CLINICAL TRIAL REGISTRATION Registry: ClinicalTrials.gov; Name: The Effect of Nocturnal Wear of Dentures on Sleep and Oral Health Related Quality of Life; URL: https://clinicaltrials.gov/ct2/show/NCT01868295; Identifier: NCT01868295. CITATION Chen H, Elham E, Li Y, et al. Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults. J Clin Sleep Med. 2022;18(3):759-768.
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Affiliation(s)
- Hui Chen
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University and Shandong Key Laboratory of Oral Tissue Regeneration and Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Shandong, China,Faculty of Dental Medicine, University of Montreal, Montreal, Quebec, Canada,Address correspondence to: Hui Chen, PhD, No. 44-1 Wenhua Road West, 250012, Jinan, Shandong, China; ; and Shaohua Ge, PhD, No. 44-1 Wenhua Road West, 250012, Jinan, Shandong, China;
| | - Emami Elham
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Yingguang Li
- Kunshan Industrial Technology Research Institute Co., Ltd., Kunshan, China
| | - Shaohua Ge
- Department of Periodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University and Shandong Key Laboratory of Oral Tissue Regeneration and Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Shandong, China,Address correspondence to: Hui Chen, PhD, No. 44-1 Wenhua Road West, 250012, Jinan, Shandong, China; ; and Shaohua Ge, PhD, No. 44-1 Wenhua Road West, 250012, Jinan, Shandong, China;
| | | | - Gilles Lavigne
- Faculty of Dental Medicine, University of Montreal, Montreal, Quebec, Canada
| | | | - Nelly Huynh
- Faculty of Dental Medicine, University of Montreal, Montreal, Quebec, Canada
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Chen YF, Sheen MH, Chang HP, Tseng YC. Pediatric obstructive sleep apnea: Computational fluid dynamics analysis of upper airway. J Dent Sci 2022; 17:589-591. [PMID: 35028092 PMCID: PMC8739249 DOI: 10.1016/j.jds.2021.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/15/2021] [Indexed: 11/26/2022] Open
Affiliation(s)
- Yu-Feng Chen
- Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Ming-Hsuan Sheen
- Department of Pediatric Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Hong-Po Chang
- School of Dentistry and Graduate Program of Dental Science, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Dentistry, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung, Taiwan
| | - Yu-Chuan Tseng
- School of Dentistry and Graduate Program of Dental Science, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Orthodontics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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11
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Choy KR, Sin S, Tong Y, Udupa JK, Luchtenburg DM, Wagshul ME, Arens R, Wootton DM. Upper airway effective compliance during wakefulness and sleep in obese adolescents studied via two-dimensional dynamic MRI and semiautomated image segmentation. J Appl Physiol (1985) 2021; 131:532-543. [PMID: 34080921 DOI: 10.1152/japplphysiol.00839.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Novel biomarkers of upper airway biomechanics may improve diagnosis of obstructive sleep apnea syndrome (OSAS). Upper airway effective compliance (EC), the slope of cross-sectional area versus pressure estimated using computational fluid dynamics (CFD), correlates with apnea-hypopnea index (AHI) and critical closing pressure (Pcrit). The study objectives are to develop a fast, simplified method for estimating EC using dynamic MRI and physiological measurements and to explore the hypothesis that OSAS severity correlates with mechanical compliance during wakefulness and sleep. Five obese children with OSAS and five control subjects with obesity aged 12-17 yr underwent anterior rhinomanometry, polysomnography, and dynamic MRI with synchronized airflow measurement during wakefulness and sleep. Airway cross section in retropalatal and retroglossal section images was segmented using a novel semiautomated method that uses optimized singular value decomposition (SVD) image filtering and k-means clustering combined with morphological operations. Pressure was estimated using rhinomanometry Rohrer's coefficients and flow rate, and EC was calculated from the area-pressure slope during five normal breaths. Correlations between apnea-hypopnea index (AHI), EC, and cross-sectional area (CSA) change were calculated using Spearman's rank correlation. The semiautomated method efficiently segmented the airway with average Dice Coefficient above 89% compared with expert manual segmentation. AHI correlated positively with EC at the retroglossal site during sleep (rs = 0.74, P = 0.014) and with change of EC from wake to sleep at the retroglossal site (rs = 0.77, P = 0.01). CSA change alone did not correlate significantly with AHI. EC, a mechanical biomarker which includes both CSA change and pressure variation, is a potential diagnostic biomarker for studying and managing OSAS.NEW & NOTEWORTHY This study investigated the dynamics of the upper airway at retropalatal and retroglossal sites during wakefulness and sleep by evaluating the effective compliance (EC) of each site and its correlation with apnea-hypopnea index (AHI) using novel semiautomated image processing. AHI correlated significantly with retroglossal EC during sleep and change of retroglossal EC from wake to sleep. The results suggest EC as a promising noninvasive diagnostic marker for estimating the mechanical properties of various upper airway regions in patients with OSAS.
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Affiliation(s)
- Kok Ren Choy
- The Cooper Union for the Advancement of Science and Art, New York, New York
| | - Sanghun Sin
- Division of Respiratory and Sleep Medicine, Children's Hospital at Montefiore, Bronx, New York
| | - Yubing Tong
- Medical Image Processing Group, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jayaram K Udupa
- Medical Image Processing Group, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dirk M Luchtenburg
- The Cooper Union for the Advancement of Science and Art, New York, New York
| | - Mark E Wagshul
- Department of Radiology, Gruss MRRC, Albert Einstein College of Medicine, Bronx, New York
| | - Raanan Arens
- Division of Respiratory and Sleep Medicine, Children's Hospital at Montefiore, Bronx, New York.,Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York
| | - David M Wootton
- The Cooper Union for the Advancement of Science and Art, New York, New York
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12
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Bitners AC, Sin S, Agrawal S, Lee S, Udupa JK, Tong Y, Wootton DM, Choy KR, Wagshul ME, Arens R. Effect of sleep on upper airway dynamics in obese adolescents with obstructive sleep apnea syndrome. Sleep 2021; 43:5819384. [PMID: 32280981 DOI: 10.1093/sleep/zsaa071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Indexed: 02/06/2023] Open
Abstract
STUDY OBJECTIVES The biomechanical basis of obstructive sleep apnea syndrome (OSAS) may influence upper airway dynamics. In this study, we investigate dynamic changes during respiration in wakefulness and sleep in obese adolescents with and without OSAS. METHODS Respiratory-gated dynamic magnetic resonance imaging (MRI) at the retropalatal and retroglossal regions was performed with simultaneous measurement of SpO2 and nasal-oral mask airflow and pressure. Airway cross-sectional area (CSA) was determined using AMIRA. Percent change in CSA was calculated from five continuous tidal breaths in states of wakefulness and sleep. Mixed effects models were used to evaluate interactions between group (OSAS/control), site (retropalatal/retroglossal), and stage (wake/sleep). RESULTS We studied 24 children with OSAS (mean age 15.49 ± 2.00 years, mean apnea-hypopnea index [AHI] 16.53 ± 8.72 events/h) and 19 controls (mean age 14.86 ± 1.75 years, mean AHI 2.12 ± 1.69 events/h). Groups were similar in age, sex, height, weight, and BMI Z-score. Participants with OSAS had a 48.17% greater increase in percent change of airway CSA during sleep than controls (p < 0.0001), while there was no difference between groups during wakefulness (p = 0.6589). Additionally, participants with OSAS had a 48.80% increase in percent change of airway CSA during sleep as compared with wakefulness (p < 0.0001), whereas no such relationship was observed in controls (p = 0.5513). CONCLUSIONS This study demonstrates significant effects of sleep on upper airway dynamics in obese children with OSAS. Dynamic MRI with physiological data can potentially provide further insight into the biomechanical basis of OSAS and assist in more effective management.
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Affiliation(s)
| | - Sanghun Sin
- Department of Pediatrics, Division of Respiratory and Sleep Medicine, Children's Hospital at Montefiore, Bronx, NY
| | - Sabhyata Agrawal
- Department of Pediatrics, Division of Respiratory and Sleep Medicine, Children's Hospital at Montefiore, Bronx, NY
| | - Seonjoo Lee
- Department of Biostatistics and Psychiatry, Columbia University and New York State Psychiatric Institute, New York, NY
| | - Jayaram K Udupa
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
| | - Yubing Tong
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
| | - David M Wootton
- Department of Mechanical Engineering, Cooper Union, New York, NY
| | - Kok Ren Choy
- Department of Mechanical Engineering, Cooper Union, New York, NY
| | - Mark E Wagshul
- Albert Einstein College of Medicine, Bronx, NY.,Department of Radiology, Montefiore Medical Center, Bronx, NY
| | - Raanan Arens
- Albert Einstein College of Medicine, Bronx, NY.,Department of Pediatrics, Division of Respiratory and Sleep Medicine, Children's Hospital at Montefiore, Bronx, NY
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13
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Chen S, Wang J, Liu D, Lei L, Wu W, Liu Z, Lee C. Open oral cavity has little effects on upper airway aerodynamics in children with obstructive sleep apnea syndrome: A computational fluid dynamics study based on patient-specific models. J Biomech 2021; 121:110383. [PMID: 33848827 DOI: 10.1016/j.jbiomech.2021.110383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 02/10/2021] [Accepted: 03/10/2021] [Indexed: 11/15/2022]
Abstract
Obstructive sleep apnea syndrome (OSAS) is a common disorder with recurrent pharyngeal airway collapse and sleep disruption. Recently, great progress has been made in investigating the physical mechanism of OSAS development and treatment using computational fluid dynamics (CFD). However, previous studies always neglected the oral cavity artificially in the patient's upper airway CFD model, but did not give any specific explanation. The oral cavity effect on the OSAS upper airway flow is still a matter of unclear. This paper reconstructed the patient-specific upper airway models based on the cone beam computed tomography images of ten children subjects (seven boys and three girls) and used CFD to simulate both the steady and unsteady expiration and inspiration states in the upper airway model with or without the oral cavity. A series of pressure measurement experiments based on the in vitro 1:1 scaled airway model were performed to validate the reliability of the present CFD methods. Finally, the CFD results indicate that the open oral cavity is almost a region of flow stasis with constant pressure, and both the upper airway aerodynamics with and without the oral cavity have the similar trends, with the maximum average relative difference less than 6%. The present study shows that the open oral cavity causes very little impacts on the upper airway flow of the children patients with OSAS using the nasal respiration only, and confirms the reasonability of ignoring the oral cavity for CFD simulation.
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Affiliation(s)
- Shuai Chen
- Department of Orthodontics, School and Hospital of Stomatology, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250012, China
| | - Jingying Wang
- School of Energy and Power Engineering, Shandong University, Jinan 250061, China.
| | - Dongxu Liu
- Department of Orthodontics, School and Hospital of Stomatology, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250012, China.
| | - Li Lei
- School of Energy and Power Engineering, Shandong University, Jinan 250061, China
| | - Wei Wu
- Department of Stomatology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China; Department of Stomatology, Weifang People's Hospital, Weifang 261041, China
| | - Zhenggang Liu
- School of Energy and Power Engineering, Shandong University, Jinan 250061, China
| | - Chunhian Lee
- School of Energy and Power Engineering, Shandong University, Jinan 250061, China
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14
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Computational Fluid Dynamic Analysis of the Pharyngeal Airway after Bimaxillary Orthognathic Surgery in Patients with Mandibular Prognathism. Processes (Basel) 2021. [DOI: 10.3390/pr9010152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This study aimed to analyze pharyngeal airflow characteristics and their relationship with the skeletal movement of the maxilla and mandible after bimaxillary orthognathic surgery in patients with skeletal class III (mandibular prognathism) malocclusion. Cone-beam computed tomography (CBCT) was conducted before surgery (T0), immediately after surgery (T1), and at least six months after surgery (T2). Digital imaging and communications in medicine files were transferred to InVivo (Anatomage) software to measure the skeletal changes after surgery. The changes in the maxillary and mandibular position, tongue position, and hyoid bone position were analyzed. Patient-specific models were reconstructed using 3D-Doctor software. The models after converting to the stereolithography (STL) file for Ansys integrated computer engineering and manufacturing code for computational fluid dynamics (ICEM CFD), commercial software were used for calculating the geometry, pressure drop and adjusted pressure coefficient value. The total volume of the upper airway including nasal cavity was reduced by 23% immediately after surgery and recovered to 92.2% of the initial volume six months after surgery. The airflow computation analysis showed a decrease in the pressure drop values immediately after surgery and six months after surgery. The adjusted pressure coefficients were slightly different but the change was statistically insignificant. The airflow characteristics computed using the computational fluid dynamics were correlated to the surgical changes. The surgical changes can affect the aerodynamics of the pharyngeal airway. In clinical practice, this knowledge is useful for developing a suitable orthognathic surgery treatment plan.
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15
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Takahashi T, Sakai N, Iwasaki T, Doyle TC, Mobley WC, Nishino S. Detailed evaluation of the upper airway in the Dp(16)1Yey mouse model of Down syndrome. Sci Rep 2020; 10:21323. [PMID: 33288820 PMCID: PMC7721723 DOI: 10.1038/s41598-020-78278-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
A high prevalence of obstructive sleep apnea (OSA) has been reported in Down syndrome (DS) owing to the coexistence of multiple predisposing factors related to its genetic abnormality, posing a challenge for the management of OSA. We hypothesized that DS mice recapitulate craniofacial abnormalities and upper airway obstruction of human DS and can serve as an experimental platform for OSA research. This study, thus, aimed to quantitatively characterize the upper airway as well as craniofacial abnormalities in Dp(16)1Yey (Dp16) mice. Dp16 mice demonstrated craniofacial hypoplasia, especially in the ventral part of the skull and the mandible, and rostrally positioned hyoid. These changes were accompanied with a shorter length and smaller cross-sectional area of the upper airway, resulting in a significantly reduced upper airway volume in Dp16 mice. Our non-invasive approach, a combination of computational fluid dynamics and high-resolution micro-CT imaging, revealed a higher negative pressure inside the airway of Dp16 mice compared to wild-type littermates, showing the potential risk of upper airway collapse. Our study indicated that Dp16 mice can be a useful model to examine the pathophysiology of increased upper airway collapsibility of DS and to evaluate the efficacy of therapeutic interventions for breathing and sleep anomalies.
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Affiliation(s)
- Tatsunori Takahashi
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 3155 Porter Drive, Room 2141, Palo Alto, CA, 94304, USA.,Department of Medicine, Jacobi Medical Center, Albert Einstein College of Medicine, 1400 Pelham Parkway South, Bronx, NY, 10461, USA
| | - Noriaki Sakai
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 3155 Porter Drive, Room 2141, Palo Alto, CA, 94304, USA.
| | - Tomonori Iwasaki
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima, Kagoshima, 8908544, Japan
| | - Timothy C Doyle
- The Neuroscience Community Labs, Wu Tsai Neurosciences Institute, Stanford University, 318 Campus Drive, Suite S170, Stanford, CA, 94305, USA
| | - William C Mobley
- Department of Neurosciences, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Seiji Nishino
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 3155 Porter Drive, Room 2141, Palo Alto, CA, 94304, USA
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16
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Morphologic and Aerodynamic Changes of Upper Airway in Pediatric Hemifacial Microsomia Patients Undergoing Distraction Osteogenesis. J Craniofac Surg 2020; 31:2132-2135. [PMID: 33136841 DOI: 10.1097/scs.0000000000006899] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Current studies on hemifacial microsomia (HFM) patients undergoing unilateral distraction osteogenesis (DO) mainly confined to description of facial morphology. This study was to investigate the effect of unilateral DO on upper airway in pediatric HFM patients using computational fluid dynamics. The investigators implemented the present retrospective study composed of 20 patients (age 9.5 ± 2.5 years, 11 males, 9 females) with moderate HFM performed unilateral DO on the ramus of mandible. Computational fluid dynamics models of the upper airway were obtained based on the computed tomography data sets which were taken before and 6 months after distraction. Morphologic and aerodynamic parameters were respectively computed and compared at peak inspiration. Paired t-tests were used to compare the differences between the before and after parameters with the significance set at P < 0.05. The authors observed that after DO, oropharynx and nasopharynx were the major expanded regions, average pressure increased in all cross-sections, average velocity decreased significantly except in the superior border of the epiglottis plane, and the airflow resistance significantly reduced in the whole upper airway (P < 0.05). The results indicate that unilateral DO may expand the constricted oropharynx and nasopharynx, obtain a relatively symmetrical airway shape and decrease the airflow resistance which consequently reduce the workload necessary for breathing and facilitate inspiration.
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17
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Cherobin GB, Voegels RL, Pinna FR, Gebrim EMMS, Bailey RS, Garcia GJM. Rhinomanometry Versus Computational Fluid Dynamics: Correlated, but Different Techniques. Am J Rhinol Allergy 2020; 35:245-255. [PMID: 32806938 DOI: 10.1177/1945892420950157] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Past studies reported a low correlation between rhinomanometry and computational fluid dynamics (CFD), but the source of the discrepancy was unclear. Low correlation or lack of correlation has also been reported between subjective and objective measures of nasal patency. OBJECTIVE This study investigates (1) the correlation and agreement between nasal resistance derived from CFD (RCFD) and rhinomanometry (RRMN), and (2) the correlation between objective and subjective measures of nasal patency. METHODS Twenty-five patients with nasal obstruction underwent anterior rhinomanometry before and after mucosal decongestion with oxymetazoline. Subjective nasal patency was assessed with a 0-10 visual analog scale (VAS). CFD simulations were performed based on computed tomography scans obtained after mucosal decongestion. To validate the CFD methods, nasal resistance was measured in vitro (REXPERIMENT) by performing pressure-flow experiments in anatomically accurate plastic nasal replicas from 6 individuals. RESULTS Mucosal decongestion was associated with a reduction in bilateral nasal resistance (0.34 ± 0.23 Pa.s/ml to 0.19 ± 0.24 Pa.s/ml, p = 0.003) and improved sensation of nasal airflow (bilateral VAS decreased from 5.2 ± 1.9 to 2.6 ± 1.9, p < 0.001). A statistically significant correlation was found between VAS in the most obstructed cavity and unilateral airflow before and after mucosal decongestion (r = -0.42, p = 0.003). Excellent correlation was found between RCFD and REXPERIMENT (r = 0.96, p < 0.001) with good agreement between the numerical and in vitro values (RCFD/REXPERIMENT = 0.93 ± 0.08). A weak correlation was found between RCFD and RRMN (r = 0.41, p = 0.003) with CFD underpredicting nasal resistance derived from rhinomanometry (RCFD/RRMN = 0.65 ± 0.63). A stronger correlation was found when unilateral airflow at a pressure drop of 75 Pa was used to compare CFD with rhinomanometry (r = 0.76, p < 0.001). CONCLUSION CFD and rhinomanometry are moderately correlated, but CFD underpredicts nasal resistance measured in vivo due in part to the assumption of rigid nasal walls. Our results confirm previous reports that subjective nasal patency correlates better with unilateral than with bilateral measurements and in the context of an intervention.
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Affiliation(s)
- Giancarlo B Cherobin
- Department of Ophtalmology and Otorhinolaryngology, Universidade de São Paulo, São Paulo, Brazil
| | - Richard L Voegels
- Department of Ophtalmology and Otorhinolaryngology, Universidade de São Paulo, São Paulo, Brazil
| | - Fábio R Pinna
- Department of Ophtalmology and Otorhinolaryngology, Universidade de São Paulo, São Paulo, Brazil
| | - Eloisa M M S Gebrim
- Department of Radiology, Radiology Institute (InRad), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Ryan S Bailey
- Department of Biomedical Engineering, Marquette University and The Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Guilherme J M Garcia
- Department of Biomedical Engineering, Marquette University and The Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
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18
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Shirazawa Y, Iwasaki T, Ooi K, Kobayashi Y, Yanagisawa-Minami A, Oku Y, Yokura A, Ban Y, Suga H, Kawashiri S, Yamasaki Y. Relationship between pharyngeal airway depth and ventilation condition in mandibular setback surgery: A computational fluid dynamics study. Orthod Craniofac Res 2020; 23:313-322. [PMID: 32056328 DOI: 10.1111/ocr.12371] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 12/27/2022]
Abstract
OBJECTIVES This study aimed to determine the anteroposterior depth (APD) of the pharyngeal airway (PA) where post-operative PA obstruction was predicted, using computer fluid dynamics (CFD), in order to prevent obstructive sleep apnoea after mandibular setback surgery. SETTINGS AND SAMPLE POPULATION Nineteen skeletal Class III patients (8 men; mean age, 26.7 years) who required mandibular setback surgery had computed tomography images taken before and 6 months after surgery. METHODS The APD of each site of the four cross-sectional reference planes (retropalatal airway [RA], second cervical vertebral airway, oropharyngeal airway and third cervical vertebral airway) were measured. The Maximum negative pressure (Pmax) of the PA was measured at inspiration using CFD, based on a three-dimensional PA model. Intersite differences were determined using analysis of variance and the Friedman test with Bonferroni correction. The relationship between APD and Pmax was evaluated by Spearman correlation coefficients and non-linear regression analysis. RESULTS The smallest PA site was the RA. Pmax was significantly correlated with the APD of the RA (rs = .628, P < .001). The relationship between Pmax and the APD-RA was fitted to a curve, which showed an inversely proportional relationship of Pmax to the square of the APD-RA. Pmax substantially increased even with a slight reduction of the APD-RA. In particular, when the APD-RA was 7 mm or less, Pmax increased greatly, suggesting that PA obstruction was more likely to occur. CONCLUSIONS The results of this study suggest that APD-RA is a useful predictor of good PA ventilation after surgery.
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Affiliation(s)
- Yoshito Shirazawa
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Tomonori Iwasaki
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Kazuhiro Ooi
- Department of Oral and Maxillofacial Surgery, School of Medical Science, Kanazawa University Graduate, Kanazawa-City, Japan
| | - Yutaka Kobayashi
- Department of Oral and Maxillofacial Surgery, School of Medical Science, Kanazawa University Graduate, Kanazawa-City, Japan
| | - Ayaka Yanagisawa-Minami
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Yoichiro Oku
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Anna Yokura
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Yuusuke Ban
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Hokuto Suga
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Shuichi Kawashiri
- Department of Oral and Maxillofacial Surgery, School of Medical Science, Kanazawa University Graduate, Kanazawa-City, Japan
| | - Youichi Yamasaki
- Department of Pediatric Dentistry, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
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19
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Garcia GJM, Woodson BT. The collapsing anatomical structure is not always the primary site of flow limitation in obstructive sleep apnea. J Clin Sleep Med 2020; 16:345-346. [PMID: 32003741 DOI: 10.5664/jcsm.8270] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Guilherme J M Garcia
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, Wisconsin
| | - B Tucker Woodson
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
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20
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Yanagisawa-Minami A, Sugiyama T, Iwasaki T, Yamasaki Y. Primary site identification in children with obstructive sleep apnea by computational fluid dynamics analysis of the upper airway. J Clin Sleep Med 2020; 16:431-439. [PMID: 31992411 DOI: 10.5664/jcsm.8224] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES Obstructive sleep apnea (OSA) is a respiratory disorder caused by the obstruction of the upper airway during sleep. The identification of the primary site of OSA is essential to determine treatment strategy. This study aimed to establish computational fluid dynamics (CFD) analysis for determining the clinical severity of OSA and the primary site of OSA. METHODS Twenty children (mean age, 6 years) were divided into OSA and control groups according to their apnea-hypopnea index. Three-dimensional airways were constructed from computed tomography data. The pharyngeal airway morphology and the pressure and velocity of the upper airway were evaluated using CFD analysis. RESULTS The maximum velocity and negative pressure of the upper airway in the OSA group were significantly correlated with the severity of OSA (rs = .741, P < .001; rs = -.653, P = .002). A velocity higher than 12 m/s indicated the primary site of OSA. In addition, we found that the primary site of OSA is not necessarily the same as the collapsible conduit site. CONCLUSIONS CFD analysis allows both the evaluation of the disease severity of OSA and the identification of the primary site of OSA in children. The primary site of OSA is not necessarily the same as the collapsible conduit site; therefore, CFD analysis can be used to identify the appropriate intervention for treating OSA.
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Affiliation(s)
- Ayaka Yanagisawa-Minami
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka, Kagoshima, Kagoshima, Japan
| | - Takeshi Sugiyama
- Department of Pediatrics, Yamanashi University Graduate School of Medicine, Yamanashi, Japan.,Pediatrics, Ichinomiya-Nishi Hospital, Aichi, Japan
| | - Tomonori Iwasaki
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka, Kagoshima, Kagoshima, Japan
| | - Youichi Yamasaki
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka, Kagoshima, Kagoshima, Japan
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21
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How does distraction osteogenesis maxillary expansion (DOME) reduce severity of obstructive sleep apnea? Sleep Breath 2019; 24:287-296. [DOI: 10.1007/s11325-019-01948-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 08/30/2019] [Accepted: 09/18/2019] [Indexed: 10/25/2022]
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22
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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: 11] [Impact Index Per Article: 2.2] [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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23
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Sul B, Oppito Z, Jayasekera S, Vanger B, Zeller A, Morris M, Ruppert K, Altes T, Rakesh V, Day S, Robinson R, Reifman J, Wallqvist A. Assessing Airflow Sensitivity to Healthy and Diseased Lung Conditions in a Computational Fluid Dynamics Model Validated In Vitro. J Biomech Eng 2019; 140:2668581. [PMID: 29305603 DOI: 10.1115/1.4038896] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Indexed: 12/16/2022]
Abstract
Computational models are useful for understanding respiratory physiology. Crucial to such models are the boundary conditions specifying the flow conditions at truncated airway branches (terminal flow rates). However, most studies make assumptions about these values, which are difficult to obtain in vivo. We developed a computational fluid dynamics (CFD) model of airflows for steady expiration to investigate how terminal flows affect airflow patterns in respiratory airways. First, we measured in vitro airflow patterns in a physical airway model, using particle image velocimetry (PIV). The measured and computed airflow patterns agreed well, validating our CFD model. Next, we used the lobar flow fractions from a healthy or chronic obstructive pulmonary disease (COPD) subject as constraints to derive different terminal flow rates (i.e., three healthy and one COPD) and computed the corresponding airflow patterns in the same geometry. To assess airflow sensitivity to the boundary conditions, we used the correlation coefficient of the shape similarity (R) and the root-mean-square of the velocity magnitude difference (Drms) between two velocity contours. Airflow patterns in the central airways were similar across healthy conditions (minimum R, 0.80) despite variations in terminal flow rates but markedly different for COPD (minimum R, 0.26; maximum Drms, ten times that of healthy cases). In contrast, those in the upper airway were similar for all cases. Our findings quantify how variability in terminal and lobar flows contributes to airflow patterns in respiratory airways. They highlight the importance of using lobar flow fractions to examine physiologically relevant airflow characteristics.
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Affiliation(s)
- Bora Sul
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, Fort Detrick, MD 21702
| | - Zachary Oppito
- Mechanical Engineering Department, Rochester Institute of Technology, Rochester, NY 14623
| | - Shehan Jayasekera
- Mechanical Engineering Department, Rochester Institute of Technology, Rochester, NY 14623
| | - Brian Vanger
- Mechanical Engineering Department, Rochester Institute of Technology, Rochester, NY 14623
| | - Amy Zeller
- Mechanical Engineering Department, Rochester Institute of Technology, Rochester, NY 14623
| | - Michael Morris
- Department of Medicine, San Antonio Military Medical Center, JBSA Fort Sam Houston, San Antonio, TX 78234
| | - Kai Ruppert
- Radiology Department, University of Pennsylvania, Philadelphia, PA 19104
| | - Talissa Altes
- Department of Radiology, University of Missouri, Columbia, MO 65211
| | - Vineet Rakesh
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, Fort Detrick, MD 21702
| | - Steven Day
- Mechanical Engineering Department, Rochester Institute of Technology, Rochester, NY 14623
| | - Risa Robinson
- Mechanical Engineering Department, Rochester Institute of Technology, Rochester, NY 14623
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, Fort Detrick, MD 21702 e-mail:
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, Fort Detrick, MD 21702
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Iwasaki T, Suga H, Minami-Yanagisawa A, Hashiguchi-Sato M, Sato H, Yamamoto Y, Shirazawa Y, Tsujii T, Kanomi R, Yamasaki Y. Upper airway in children with unilateral cleft lip and palate evaluated with computational fluid dynamics. Am J Orthod Dentofacial Orthop 2019; 156:257-265. [PMID: 31375236 DOI: 10.1016/j.ajodo.2018.09.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 09/01/2018] [Accepted: 09/01/2018] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Children with unilateral cleft lip and palate (UCLP) exhibit snoring and mouth breathing. They are also reported to show obstructive sleep apnea syndrome. However, their upper airway ventilation condition is not clearly understood. Therefore, this study was performed to evaluate upper airway ventilation condition in children with UCLP with the use of computational fluid dynamics. METHODS Twenty-one children (12 boys, 9 girls; mean age 9.1 years) with UCLP and 25 children (13 boys, 12 girls; mean age 9.2 years) without UCLP who required orthodontic treatment underwent cone-beam computed tomography (CBCT). Nasal resistance and upper airway ventilation condition were evaluated with the use of computational fluid dynamics from CBCT data. The groups were compared with the use of Mann-Whitney U tests and Student t tests. RESULTS Nasal resistance of the UCLP group (0.97 Pa/cm3/s) was significantly higher than that of the control group (0.26 Pa/cm3/s; P < 0.001). Maximal pressure of the upper airway (335.02 Pa) was significantly higher in the UCLP group than in the control group (67.57 Pa; P < 0.001). Pharyngeal airway (from choanae to base of epiglottis) pressure in the UCLP group (140.46 Pa) was significantly higher than in the control group (15.92 Pa; P < 0.02). CONCLUSIONS Upper airway obstruction in children with UCLP resulted from both nasal and pharyngeal airway effects.
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Affiliation(s)
- Tomonori Iwasaki
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan.
| | - Hokuto Suga
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Ayaka Minami-Yanagisawa
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Makiko Hashiguchi-Sato
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Hideo Sato
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Yuushi Yamamoto
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Yoshito Shirazawa
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | - Toshiya Tsujii
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
| | | | - Youichi Yamasaki
- Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima-City, Japan
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Ng JH, Song YL, Yap AUJ. Effects of bicuspid extractions and incisor retraction on upper airway of Asian adults and late adolescents: A systematic review. J Oral Rehabil 2019; 46:1071-1087. [PMID: 31281971 PMCID: PMC6851666 DOI: 10.1111/joor.12854] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/23/2019] [Accepted: 06/28/2019] [Indexed: 12/17/2022]
Abstract
OBJECTIVES This systematic review aimed to assess the effects of bicuspid extractions and incisor retraction on airway dimension, hyoid position and breathing of adults and late adolescents. METHODS The review was conducted according to PRISMA guidelines. Eight databases including PubMed, EMBASE, Web of Science and Scopus were searched to August 2018. Minimum age of participants was 16 years. The intervention was dual-arch bicuspid extractions with incisor retraction. Outcomes were airway dimension, hyoid position and breathing assessment. RESULTS All nine publications meeting inclusion criteria were from Asia. They were divided into three Asian subregions. All East Asian lateral cephalometric studies reported anteroposterior airway narrowing at the oropharynx and sometimes the hypopharynx. However, the narrowing was small, comparable to measurement errors, and highly variable. Two out of three East Asian computed tomography (CT) studies described reductions in airway dimensions. The single functional breathing study showed increased simulated flow resistance after incisor retraction in East Asians. South Asian studies had mixed findings, with some reporting significant airway narrowing. The single study from West Asia found no significant airway or hyoid changes. CONCLUSIONS Airway response to bicuspid extractions and incisor retraction varied substantially when assessed with cephalometry. CT measurements present larger effect sizes and smaller variations, providing stronger evidence of airway narrowing. Orthodontic extractions for incisor retraction may be more frequently indicated in Asia, and East Asians seem particularly susceptible to airway narrowing and postero-inferior hyoid movement with incisor retraction. Better designed CT studies are needed for confirmation due to small effect size and large variability.
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Affiliation(s)
- Jing Hao Ng
- National Dental Centre Singapore, Singapore, Singapore
| | - Yi Lin Song
- National Dental Centre Singapore, Singapore, Singapore
| | - Adrian U J Yap
- National Dental Centre Singapore, Singapore, Singapore.,Department of Dentistry, Ng Teng Fong General Hospital, National University Health System, Singapore, Singapore.,Faculty of Dentistry, National University of Singapore, Singapore, Singapore
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Suga H, Iwasaki T, Mishima K, Nakano H, Ueyama Y, Yamasaki Y. Evaluation of the effect of oral appliance treatment on upper-airway ventilation conditions in obstructive sleep apnea using computational fluid dynamics. Cranio 2019; 39:209-217. [DOI: 10.1080/08869634.2019.1596554] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Hokuto Suga
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tomonori Iwasaki
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Katsuaki Mishima
- Department of Oral and Maxillofacial Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Hiroyuki Nakano
- Department of Dentistry and Oral Surgery, Division of Medicine for Function and Morphology of Sensory Organs, Faculty of Medicine, Osaka Medical College, Osaka, JAPAN
| | - Yoshiya Ueyama
- Department of Oral and Maxillofacial Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Youichi Yamasaki
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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Zhu L, Liu H, Fu Z, Yin J. Computational fluid dynamics analysis of H-uvulopalatopharyngoplasty in obstructive sleep apnea syndrome. Am J Otolaryngol 2019; 40:197-204. [PMID: 30553601 DOI: 10.1016/j.amjoto.2018.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 11/27/2018] [Accepted: 12/05/2018] [Indexed: 11/26/2022]
Abstract
PURPOSE To explore the impact of H-uvulopalatopharyngoplasty (H-UPPP) in obstructive sleep apnea syndrome (OSAS) and gain insights into the potential mechanism underlying improvement by H-UPPP. METHODS In a cohort of 11 OSAS patients, computational fluid dynamics (CFD) models of the upper airway were obtained using commercial software from computed tomography (CT) datasets before and after H-UPPP. Morphological and numerical parameters were respectively computed and compared during the peak tidal inspiratory flow. The correlations among polysomnography endpoints, airway dimensions, and pre- and post-operative airflow properties were analyzed with Spearman's rank correlation. RESULTS The preoperative minimum cross-sectional area was significantly increased by 89.56% (p < .05), with a positive correlation to the apnea hypoapnea index (AHI) (r = 0.974). However, the capacity of all pharyngeal regions was not significantly altered (p > .05). Following H-UPPP, we observed a significant increase in pressure and reduction of velocity (p < .05) in the previously constricted areas. The change in pressure and velocity were significantly correlated with AHI (r = 0.922 and r = 0.946, respectively). In addition, the pressure drop in the constricted area, oropharynx, and hypopharynx were also significantly decreased (p < .05). CONCLUSIONS H-UPPP is capable of expanding the constricted region of the velopharynx and can decrease the airway resistance which will in turn decrease the workload necessary for breathing and facilitate inspiration.
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McDaniel LS, Poynot WJ, Gonthier KA, Dunham ME, Crosby ATW. Image-Based 3-Dimensional Characterization of Laryngotracheal Stenosis in Children. OTO Open 2018; 2:2473974X17753583. [PMID: 30480204 PMCID: PMC6239028 DOI: 10.1177/2473974x17753583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/01/2017] [Accepted: 12/22/2017] [Indexed: 12/03/2022] Open
Abstract
Objectives Describe a technique for the description and classification of
laryngotracheal stenosis in children using 3-dimensional reconstructions of
the airway from computed tomography (CT) scans. Study Design Cross-sectional. Setting Academic tertiary care children’s hospital. Subjects and Methods Three-dimensional models of the subglottic airway lumen were created using CT
scans from 54 children undergoing imaging for indications other than airway
disease. The base lumen models were deformed in software to simulate
subglottic airway segments with 0%, 25%, 50%, and 75% stenoses for each
subject. Statistical analysis of the airway geometry was performed using
metrics extracted from the lumen centerlines. The centerline analysis was
used to develop a system for subglottic stenosis assessment and
classification from patient-specific airway imaging. Results The scaled hydraulic diameter gradient metric derived from intersectional
changes in the lumen can be used to accurately classify and quantitate
subglottic stenosis in the airway based on CT scan imaging. Classification
is most accurate in the clinically relevant 25% to 75% range of
stenosis. Conclusions Laryngotracheal stenosis is a complex diagnosis requiring an understanding of
the airway lumen configuration, anatomical distortions of the airway
framework, and alterations of respiratory aerodynamics. Using image-based
airway models, we have developed a metric that accurately captures
subglottis patency. While not intended to replace endoscopic evaluation and
existing staging systems for laryngotracheal stenosis, further development
of these techniques will facilitate future studies of upper airway
computational fluid dynamics and the clinical evaluation of airway
disease.
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Affiliation(s)
- Lee S McDaniel
- School of Public Health, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - William J Poynot
- Department of Mechanical & Industrial Engineering, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Keith A Gonthier
- Department of Mechanical & Industrial Engineering, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Michael E Dunham
- Department of Otolaryngology-Head and Neck Surgery, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - And Tyler W Crosby
- Department of Otolaryngology-Head and Neck Surgery, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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Naughton JP, Lee AY, Ramos E, Wootton D, Stupak HD. Effect of Nasal Valve Shape on Downstream Volume, Airflow, and Pressure Drop: Importance of the Nasal Valve Revisited. Ann Otol Rhinol Laryngol 2018; 127:745-753. [PMID: 30191730 DOI: 10.1177/0003489418791597] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The relative importance of the nasal valve relative to the remainder of the nasal airway remains unknown. The goal of this article was to objectively measure the shape of the nasal inlet and its effect on downstream airflow and nasal cavity volume using a physical model and a physiologic flow model. METHODS A patient who had isolated nasal valve surgery and had pre- and postoperative computed tomography scans available for analysis was studied. Nasal inlet shape measurements, computational fluid dynamics, and nasal volume analysis were performed using the computed tomography data. In addition, a physical model was used to determine the effect of nasal obstruction on downstream soft tissue. RESULTS The postoperative shape of the nasal inlet was improved in terms of length and degree of tortuosity. Whereas the operated-on region at the nasal inlet showed an only 25% increase in cross-sectional area postoperatively, downstream nonoperated sites in the nasal cavity revealed increases in area ranging from 33% to 51%. Computational fluid dynamics analysis showed that airway resistance decreased by 42%, and pressure drop was reduced by 43%. Intraluminal mucosal expansion was found with nasal obstruction in the physical model. CONCLUSION By decreasing the degree of bending and length at the nasal valve, inspiratory downstream nonoperated sites of the nasal cavity showed improvement in volume and airflow, suggesting that the nasal valve could play an oversized role in modulating the aerodynamics of the airway. This was confirmed with the physical model of nasal obstruction on downstream mucosa.
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Affiliation(s)
- John P Naughton
- 1 Department of Otorhinolaryngology-Head & Neck Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Andrew Y Lee
- 1 Department of Otorhinolaryngology-Head & Neck Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Eric Ramos
- 2 Department of Mechanical Engineering, The Cooper Union, New York, New York, USA
| | - David Wootton
- 2 Department of Mechanical Engineering, The Cooper Union, New York, New York, USA
| | - Howard D Stupak
- 1 Department of Otorhinolaryngology-Head & Neck Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
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Zwicker D, Yang K, Melchionna S, Brenner MP, Liu B, Lindsay RW. Validated reconstructions of geometries of nasal cavities from CT scans. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aac6af] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Subramaniam DR, Arens R, Wagshul ME, Sin S, Wootton DM, Gutmark EJ. Biomechanics of the soft-palate in sleep apnea patients with polycystic ovarian syndrome. J Biomech 2018; 76:8-15. [PMID: 29793766 DOI: 10.1016/j.jbiomech.2018.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 05/01/2018] [Accepted: 05/07/2018] [Indexed: 11/28/2022]
Abstract
Highly compliant tissue supporting the pharynx and low muscle tone enhance the possibility of upper airway occlusion in children with obstructive sleep apnea (OSA). The present study describes subject-specific computational modeling of flow-induced velopharyngeal narrowing in a female child with polycystic ovarian syndrome (PCOS) with OSA and a non-OSA control. Anatomically accurate three-dimensional geometries of the upper airway and soft-palate were reconstructed for both subjects using magnetic resonance (MR) images. A fluid-structure interaction (FSI) shape registration analysis was performed using subject-specific values of flow rate to iteratively compute the biomechanical properties of the soft-palate. The optimized shear modulus for the control was 38 percent higher than the corresponding value for the OSA patient. The proposed computational FSI model was then employed for planning surgical treatment for the apneic subject. A virtual surgery comprising of a combined adenoidectomy, palatoplasty and genioglossus advancement was performed to estimate the resulting post-operative patterns of airflow and tissue displacement. Maximum flow velocity and velopharyngeal resistance decreased by 80 percent and 66 percent respectively following surgery. Post-operative flow-induced forces on the anterior and posterior faces of the soft-palate were equilibrated and the resulting magnitude of tissue displacement was 63 percent lower compared to the pre-operative case. Results from this pilot study indicate that FSI computational modeling can be employed to characterize the mechanical properties of pharyngeal tissue and evaluate the effectiveness of various upper airway surgeries prior to their application.
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Affiliation(s)
| | - Raanan Arens
- Division of Respiratory and Sleep Medicine, The Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Mark E Wagshul
- Gruss Magnetic Resonance Research Center, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Sanghun Sin
- Division of Respiratory and Sleep Medicine, The Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA
| | - David M Wootton
- Department of Mechanical Engineering, The Cooper Union for the Advancement of Science and Art, New York, NY, USA
| | - Ephraim J Gutmark
- Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, USA; UC Department of Otolaryngology - Head and Neck Surgery, Cincinnati, OH, USA.
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Slaats MALJ, Loterman D, van Holsbeke C, Vos W, Van Hoorenbeeck K, de Backer J, de Backer W, Wojciechowski M, Boudewyns A, Verhulst S. The Role of Functional Respiratory Imaging in Treatment Selection of Children With Obstructive Sleep Apnea and Down Syndrome. J Clin Sleep Med 2018; 14:651-659. [PMID: 29609707 DOI: 10.5664/jcsm.7064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 01/17/2018] [Indexed: 12/14/2022]
Abstract
STUDY OBJECTIVES The complexity of the pathogenesis of obstructive sleep apnea (OSA) in children with Down syndrome (DS) is illustrated by a prevalence of residual OSA after adenotonsillectomy. The aim of this study was to investigate whether upper airway imaging combined with computation fluid dynamics could characterize treatment outcome after adenotonsillectomy in these children. METHODS Children with DS and OSA were prospectively included. All children underwent an evaluation of the upper airway and an ultra-low dose computed tomography scan of the upper airway before adenotonsillectomy. The upper airway tract was extracted from the scan and combined with computational fluid dynamics. Results were evaluated using control polysomnography after adenotonsillectomy. RESULTS Thirty-three children were included: 18 boys, age 4.3 ± 2.3 years, median body mass index z-score 0.6 (-2.9 to 3.0), and median obstructive apnea-hypopnea index was 15.7 (3-70) events/h. The minimal upper airway cross-sectional area was significantly smaller in children with more severe OSA (P = .03). Nineteen children underwent a second polysomnography after adenotonsillectomy. Seventy-nine percent had persistent OSA (obstructive apneahypopnea index > 2 events/h). A greater than 50% decrease in obstructive apnea-hypopnea index was observed in 79% and these children had a significantly higher volume of the regions below the tonsils. CONCLUSIONS This is the first study to characterize treatment outcome in children with DS and OSA using computed tomography upper airway imaging. At baseline, children with more severe OSA had a smaller upper airway. Children with a less favorable response to adenotonsillectomy had a smaller volume of regions below the tonsils, which could be due to enlargement of the lingual tonsils, glossoptosis, or macroglossia. COMMENTARY A commentary on this article appears in this issue on page 501.
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Affiliation(s)
| | | | | | - Wim Vos
- Technology, Biomedical Physics, FluidDA, Kontich, Belgium
| | | | - Jan de Backer
- Technology, Biomedical Physics, FluidDA, Kontich, Belgium
| | - Wilfried de Backer
- Department of Pulmonology, University Hospital Antwerp, Antwerp, Belgium
| | | | - An Boudewyns
- Department of Pediatrics, University Hospital Antwerp, Antwerp, Belgium
| | - Stijn Verhulst
- Department of Pediatrics, Pediatric Sleep Lab at Antwerp University Hospital, Antwerp, Belgium
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Mukaihara K, Hasegawa-Moriyama M, Iwasaki T, Yamasaki Y, Kanmura Y. Evaluation of the pharyngeal airway using computational fluid dynamics in patients with acromegaly. Laryngoscope Investig Otolaryngol 2018; 3:133-138. [PMID: 29721547 PMCID: PMC5915828 DOI: 10.1002/lio2.151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/06/2018] [Accepted: 03/01/2018] [Indexed: 12/11/2022] Open
Abstract
Objectives Perioperative airway management may be particularly challenging in patients with acromegaly undergoing trans‐sphenoidal pituitary surgery (TSS). Management for airway obstruction is required prior to pituitary surgery to minimize perioperative hypoxia. The purpose of this retrospective study was to evaluate airway obstruction by simulation of computational fluid dynamics (CFD) using computed tomography (CT) images in patients who had undergone TSS. Methods CT images of the nasopharyngeal airways of patients with acromegaly (n = 5) or nonfunctional pituitary adenoma (n = 6) undergoing TSS from April 2012 to January 2017 were used to construct these airways in three dimensions. Estimated airflow pressure and velocity in the retropalatal airway (RA), oropharyngeal airway (OA), and hypopharyngeal airway (HA) were simulated using CFD. Results Estimated pharyngeal airflow pressure in the HA, OA, and RA was significantly greater in patients with acromegaly than in those with nonfunctional pituitary adenomas whereas the estimated pharyngeal airflow velocity was significantly impaired only in the RA of patients with acromegaly. Minimum postoperative SpO2 both within 3 hours and from 3 to 12 hours after the end of anesthesia was significantly lower in the patients with acromegaly. Additionally, estimated volume of tongue and pharyngeal airflow pressure in the HA, OA, and RA correlated with minimum postoperative SpO2. Conclusion Pharyngeal airflow pressure estimated from CT images is high in patients with acromegaly, and these values correlate with postoperative minimum values for SpO2. Preoperative evaluation of CT images by CFD can predict difficulty in airway management and perioperative hypoxia. Level of Evidence 4.
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Affiliation(s)
- Keika Mukaihara
- Department of Anesthesiology and Critical Care Medicine Graduate School of Medical and Dental Sciences, Kagoshima University Kagoshima Japan
| | - Maiko Hasegawa-Moriyama
- Department of Anesthesiology and Critical Care Medicine Graduate School of Medical and Dental Sciences, Kagoshima University Kagoshima Japan
| | - Tomonori Iwasaki
- Department of Pediatric Dentistry Graduate School of Medical and Dental Sciences, Kagoshima University Kagoshima Japan
| | - Youichi Yamasaki
- Department of Pediatric Dentistry Graduate School of Medical and Dental Sciences, Kagoshima University Kagoshima Japan
| | - Yuichi Kanmura
- Department of Anesthesiology and Critical Care Medicine Graduate School of Medical and Dental Sciences, Kagoshima University Kagoshima Japan
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Subramaniam DR, Mylavarapu G, Fleck RJ, Amin RS, Shott SR, Gutmark EJ. Effect of airflow and material models on tissue displacement for surgical planning of pharyngeal airways in pediatric down syndrome patients. J Mech Behav Biomed Mater 2017; 71:122-135. [DOI: 10.1016/j.jmbbm.2017.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 03/04/2017] [Accepted: 03/06/2017] [Indexed: 12/01/2022]
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Slaats M, Vos W, Van Holsbeke C, De Backer J, Loterman D, De Backer W, Boudewyns A, Verhulst S. Predicting the effect of treatment in paediatric OSA by clinical examination and functional respiratory imaging. Pediatr Pulmonol 2017; 52:799-805. [PMID: 28267299 DOI: 10.1002/ppul.23684] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 12/15/2016] [Accepted: 02/09/2017] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The aim of this study was to investigate whether functional respiratory imaging (FRI) or clinical examination could predict treatment outcome for obstructive sleep apnea (OSA) in normal-weight, non-syndromic children. METHODS Normal weight children diagnosed with OSA by polysomnography were prospectively included. All children got a thorough evaluation and an ultra-low dose computed tomography scan of the upper airway (UA). A 3-D reconstruction was built combined with computational fluid dynamics for FRI. Decisions on the need and type of surgery were based upon findings during drug-induced sleep endoscopy. A second polysomnography was performed 3-12 months after surgery. RESULTS Ninety-one children were included: 62 boys, 5.0 ± 2.7 years, and BMI z-score of -0.1 ± 1.2. Children with more severe OSA had a smaller volume of the overlap region between the adenoids and tonsils. Nineteen out of 60 patients had persistent OSA (oAHI >2/h). A lower conductance in the UA and a higher tonsil score predicted successful treatment. CONCLUSIONS A less constricted airway, as characterized by both FRI and a lower tonsil score, was associated with a less favorable response to (adeno) tonsillectomy. Further studies after treatment using FRI and DISE are warranted to further characterize the UA of these subjects.
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Affiliation(s)
- Monique Slaats
- Department of Paediatrics, Antwerp University Hospital, Edegem, Belgium.,Laboratory of Experimental Medicine and Paediatrics (LEMP), University of Antwerp, Universiteitsplein 1, Antwerp, Belgium
| | | | | | | | | | - Wilfried De Backer
- Laboratory of Experimental Medicine and Paediatrics (LEMP), University of Antwerp, Universiteitsplein 1, Antwerp, Belgium.,Department of Respiratory Medicine, Antwerp University Hospital, Edegem, Belgium
| | - An Boudewyns
- Department of Otorhinolaryngology, Antwerp University Hospital, Edegem, Belgium
| | - Stijn Verhulst
- Department of Paediatrics, Antwerp University Hospital, Edegem, Belgium.,Laboratory of Experimental Medicine and Paediatrics (LEMP), University of Antwerp, Universiteitsplein 1, Antwerp, Belgium
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Zheng Z, Liu H, Xu Q, Wu W, Du L, Chen H, Zhang Y, Liu D. Computational fluid dynamics simulation of the upper airway response to large incisor retraction in adult class I bimaxillary protrusion patients. Sci Rep 2017; 7:45706. [PMID: 28387372 PMCID: PMC5384277 DOI: 10.1038/srep45706] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 03/02/2017] [Indexed: 12/16/2022] Open
Abstract
The changes of the upper airway after large retraction of the incisors in adult class I bimaxillary protrusion patients were assessed mainly focused on the anatomic variation and ignored the functional changes. This study aimed to investigate the changes of the upper airway in adult class I bimaxillary protrusion patients after extraction treatment using the functional images based on computational fluid dynamics (CFD). CFD was implemented after 3D reconstruction based on the CBCT of 30 patients who have completed extraction treatment. After treatment, pressure drop in the minimum area, oropharynx, and hypopharynx increased significantly. The minimum pressure and the maximum velocity mainly located in the hypopharynx in pre-treatment while they mostly occured in the oropharynx after treatment. Statistically significant correlation between pressure drop and anatomic parameters, pressure drop and treatment outcomes was found. No statistical significance changes in pressure drop and volume of nasopharynx was found. This study suggested that the risk of pharyngeal collapsing become higher after extraction treatment with maximum anchorage in bimaxillary protrusion adult patients. Those adverse changes should be taken into consideration especially for high-risk patients to avoid undesired weakening of the respiratory function in clinical treatment.
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Affiliation(s)
- Zhe Zheng
- Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China
| | - Hong Liu
- Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China
| | - Qi Xu
- Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China
| | - Wei Wu
- Department of Stomatology, Weifang People's Hospital, Weifang, 261041, China
| | - Liling Du
- Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China
| | - Hong Chen
- Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China
| | - Yiwen Zhang
- Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China
| | - Dongxu Liu
- Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China
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Alsufyani NA, Noga ML, Witmans M, Major PW. Upper airway imaging in sleep-disordered breathing: role of cone-beam computed tomography. Oral Radiol 2017. [DOI: 10.1007/s11282-017-0280-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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38
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Farhood Z, Isley JW, Ong AA, Nguyen SA, Camilon TJ, LaRosa AC, White DR. Adenotonsillectomy outcomes in patients with Down syndrome and obstructive sleep apnea. Laryngoscope 2017; 127:1465-1470. [DOI: 10.1002/lary.26398] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Zachary Farhood
- Department of Otolaryngology-Head & Neck Surgery; Saint Louis University; St. Louis MO U.S.A
| | - Jonathan W. Isley
- Department of Otolaryngology-Head & Neck Surgery; Saint Louis University; St. Louis MO U.S.A
| | - Adrian A. Ong
- Department of Otolaryngology-Head & Neck Surgery; Medical University of South Carolina; Charleston SC U.S.A
| | - Shaun A. Nguyen
- Department of Pediatrics; Medical University of South Carolina; Charleston SC U.S.A
| | - Terence J. Camilon
- Department of Otolaryngology-Head & Neck Surgery; Saint Louis University; St. Louis MO U.S.A
| | - Angela C. LaRosa
- Department of Otolaryngology; University at Buffalo, The State University of New York; Buffalo NY U.S.A
| | - David R. White
- Department of Otolaryngology-Head & Neck Surgery; Saint Louis University; St. Louis MO U.S.A
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Anatomically correct visualization of the human upper airway using a high-speed long range optical coherence tomography system with an integrated positioning sensor. Sci Rep 2016; 6:39443. [PMID: 27991580 PMCID: PMC5171831 DOI: 10.1038/srep39443] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 11/22/2016] [Indexed: 01/28/2023] Open
Abstract
The upper airway is a complex tissue structure that is prone to collapse. Current methods for studying airway obstruction are inadequate in safety, cost, or availability, such as CT or MRI, or only provide localized qualitative information such as flexible endoscopy. Long range optical coherence tomography (OCT) has been used to visualize the human airway in vivo, however the limited imaging range has prevented full delineation of the various shapes and sizes of the lumen. We present a new long range OCT system that integrates high speed imaging with a real-time position tracker to allow for the acquisition of an accurate 3D anatomical structure in vivo. The new system can achieve an imaging range of 30 mm at a frame rate of 200 Hz. The system is capable of generating a rapid and complete visualization and quantification of the airway, which can then be used in computational simulations to determine obstruction sites.
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40
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Wootton DM, Sin S, Luo H, Yazdani A, McDonough JM, Wagshul ME, Isasi CR, Arens R. Computational fluid dynamics upper airway effective compliance, critical closing pressure, and obstructive sleep apnea severity in obese adolescent girls. J Appl Physiol (1985) 2016; 121:925-931. [PMID: 27445297 DOI: 10.1152/japplphysiol.00190.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/18/2016] [Indexed: 11/22/2022] Open
Abstract
Obstructive sleep apnea syndrome (OSAS) is associated with anatomical abnormalities restricting upper airway size and functional factors decreasing pharyngeal dilator activity in sleep. In this study we hypothesized that OSAS is also associated with altered pharyngeal mechanical compliance during wakefulness. Five OSAS and six control obese girls between 14 and 18 years of age were studied. All underwent polysomnography, critical closing pressure (Pcrit) studies, and dynamic MRI of the upper airway during awake tidal breathing. Effective airway compliance was defined as the slope of cross-sectional area vs. average pressure between maximum inspiration and maximum expiration along the pharyngeal airway. Pharyngeal pressure fields were calculated by using image-based computational fluid dynamics and nasal resistance. Spearman correlations were calculated to test associations between apnea-hypopnea index (AHI), Pcrit, and airway compliance. Effective compliances in the nasopharynx (CNP) and velopharynx (CVP) were lower and negative in OSAS compared with controls: -4.4 vs. 1.9 (mm2/cmH2O, P = 0.012) and -2.1 vs. 3.9 (mm2/cmH2O, P = 0.021), respectively, suggesting a strong phasic pharyngeal dilator activity during inspiration in OSAS compared with controls. For all subjects, CNP and AHI correlated negatively (rS = -0.69, P = 0.02), and passive Pcrit correlated with CNP (rS = -0.76, P = 0.006) and with AHI (rS = 0.86, P = 0.0006). Pharyngeal mechanics obtained during wakefulness could be used to characterize subjects with OSAS. Moreover, negative effective compliance during wakefulness and its correlation to AHI and Pcrit suggest that phasic dilator activity of the upper pharynx compensates for negative pressure loads in these subjects.
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Affiliation(s)
- David M Wootton
- Department of Mechanical Engineering, The Cooper Union for the Advancement of Science and Art, New York, New York;
| | - Sanghun Sin
- Children's Hospital at Montefiore, New York, New York
| | - Haiyan Luo
- Department of Mechanical Engineering, The Cooper Union for the Advancement of Science and Art, New York, New York
| | - Alireza Yazdani
- Department of Mechanical Engineering, The Cooper Union for the Advancement of Science and Art, New York, New York
| | | | | | | | - Raanan Arens
- Children's Hospital at Montefiore, New York, New York; Albert Einstein College of Medicine, New York, New York
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41
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Characterizing human nasal airflow physiologic variables by nasal index. Respir Physiol Neurobiol 2016; 232:66-74. [PMID: 27431449 DOI: 10.1016/j.resp.2016.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 11/21/2022]
Abstract
Although variations in nasal index (NI) have been reported to represent adaptation to climatic conditions, assessments of NI with airflow variables have not been rigorously investigated. This study uses computational fluid dynamics modeling to investigate the relationship between NI and airflow variables in 16 subjects with normal nasal anatomy. Airflow simulations were conducted under constant inspiratory pressure. Nasal resistance (NR) against NI showed weak association from nostrils to anterior inferior turbinate (R(2)=0.26) and nostril to choanae (R(2)=0.12). NI accounted for 38% and 41% of the respective variation in wall shear stress (WSS) and heat flux (HF) at the nasal vestibule, and 52% and 49% of variability in WSS and HF across the entire nose. HF and WSS had strong correlation with NI<80, and weakly correlated with NI>80; these differences in HF and WSS for NI<80 and NI>80 were not statistically significant. Results suggest strong relationship between NI and both WSS and HF but not NR, particularly in subjects with NI<80.
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42
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Nguyen T, Phillips C, Paniagua B. The use of SPHARM-PDM and mean latitude axis to evaluate airway changes. Angle Orthod 2016; 86:943-948. [PMID: 27138685 DOI: 10.2319/110815-753.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To introduce new 3-D imaging techniques to characterize shape and volume changes of the oropharyngeal space after bilateral sagittal split osteotomy (BSSO) advancement. MATERIALS AND METHODS Longitudinal cone-beam computed tomography (CBCT) scans were obtained for 20 patients undergoing BSSO advancement at three time points (T1 = presurgery, T2 = splint removal, and T3 = 1 year after surgery). Segmentation of the airway was performed using the following boundaries: hard palate/posterior nasal spine superiorly and lower border of C3 to the base of the epiglottis inferiorly. For shape measurements, point-based correspondent models and mean latitude axis were obtained for all the data using SPHARM-PDM software. All 3-D correspondent models were rigidly registered using Procrustes alignment. Absolute distance maps and corresponding vector maps were calculated to show shape and vector differences between each correspondent point. Mean latitude axis is a new imaging method to calculate minimum cross-sectional areas along the long axis of the airway independent of head position/alignment. RESULTS The airway volume increased (P < .01) after BSSO advancement (2973.9 mm3 ± 27882.0) and was stable (-439.9 mm3 ± 3308.8) 1 year post-op. 3-D color maps and semitransparency overlays showed more lateral than anteroposterior expansion of the airway after BSSO advancement. Mean latitude axis was used to measure minimum cross-sectional area, showing a statistically significant increase (52.7 mm2 ± 46.7) (P < .01) after surgery and remained stable (-10.3 mm2 ± 43.3) 1 year after surgery. CONCLUSIONS SPHARM-PDM and mean latitude axis are useful tools to assess airway shape change. BSSO advancement produces a significant increase in pharyngeal airway volume and minimum cross-sectional area. The airway space increased more transversely than anteroposteriorly.
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Neelapu BC, Kharbanda OP, Sardana HK, Balachandran R, Sardana V, Kapoor P, Gupta A, Vasamsetti S. Craniofacial and upper airway morphology in adult obstructive sleep apnea patients: A systematic review and meta-analysis of cephalometric studies. Sleep Med Rev 2016; 31:79-90. [PMID: 27039222 DOI: 10.1016/j.smrv.2016.01.007] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 01/15/2016] [Accepted: 01/24/2016] [Indexed: 12/14/2022]
Abstract
Obstructive sleep apnea (OSA) is one of the common sleep breathing disorders in adults, characterised by frequent episodes of upper airway collapse during sleep. Craniofacial disharmony is an important risk factor for OSA. Overnight polysomnography (PSG) study is considered to be the most reliable confirmatory investigation for OSA diagnosis, whereas the precise localization of site of obstruction to the airflow cannot be detected. Identifying the cause of OSA in a particular ethnic population/individual subject helps to understand the etiological factors and effective management of OSA. The objective of the meta-analysis is to elucidate altered craniofacial anatomy on lateral cephalograms in adult subjects with established OSA. Significant weighted mean difference with insignificant heterogeneity was found for the following parameters: anterior lower facial height (ALFH: 2.48 mm), position of hyoid bone (Go-H: 5.45 mm, S-H: 6.89 mm, GoGn-H: 11.84°, GoGn-H: 7.22 mm, N-S-H: 2.14°), and pharyngeal airway space (PNS-Phw: -1.55 mm, pharyngeal space: -495.74 mm2 and oro-pharyngeal area: -151.15 mm2). Significant weighted mean difference with significant heterogeneity was found for the following parameters: cranial base (SN: -2.25 mm, S-N-Ba: -1.45°), position and length of mandible (SNB: -1.49° and Go-Me: -5.66 mm) respectively, maxillary length (ANS-PNS: -1.76 mm), tongue area (T: 366.51 mm2), soft palate area (UV: 125.02 mm2), and upper airway length (UAL: 5.39 mm). This meta-analysis supports the relationship between craniofacial disharmony and obstructive sleep apnea. There is a strong evidence for reduced pharyngeal airway space, inferiorly placed hyoid bone and increased anterior facial heights in adult OSA patients compared to control subjects. The cephalometric analysis provides insight into anatomical basis of the etiology of OSA that can influence making a choice of appropriate therapy.
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Affiliation(s)
- Bala Chakravarthy Neelapu
- Academy of Scientific & Innovative Research (AcSIR), India; CSIR-Central Scientific Instruments Organisation, Chandigarh, 160030, India
| | - Om Prakash Kharbanda
- Division of Orthodontics and Dentofacial Deformities, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Harish Kumar Sardana
- Academy of Scientific & Innovative Research (AcSIR), India; CSIR-Central Scientific Instruments Organisation, Chandigarh, 160030, India
| | - Rajiv Balachandran
- Division of Orthodontics and Dentofacial Deformities, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Viren Sardana
- Academy of Scientific & Innovative Research (AcSIR), India; CSIR-Central Scientific Instruments Organisation, Chandigarh, 160030, India
| | - Priyanka Kapoor
- Faculty of Dentistry, Jamia Millia Islamia, New Delhi, 110025, India
| | - Abhishek Gupta
- Academy of Scientific & Innovative Research (AcSIR), India; CSIR-Central Scientific Instruments Organisation, Chandigarh, 160030, India
| | - Srikanth Vasamsetti
- Academy of Scientific & Innovative Research (AcSIR), India; CSIR-Central Scientific Instruments Organisation, Chandigarh, 160030, India
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Subramaniam DR, Mylavarapu G, McConnell K, Fleck RJ, Shott SR, Amin RS, Gutmark EJ. Upper Airway Elasticity Estimation in Pediatric Down Syndrome Sleep Apnea Patients Using Collapsible Tube Theory. Ann Biomed Eng 2015; 44:1538-52. [PMID: 26314989 DOI: 10.1007/s10439-015-1430-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 08/13/2015] [Indexed: 01/10/2023]
Abstract
Elasticity of the soft tissues surrounding the upper airway lumen is one of the important factors contributing to upper airway disorders such as snoring and obstructive sleep apnea. The objective of this study is to calculate patient specific elasticity of the pharynx from magnetic resonance (MR) images using a 'tube law', i.e., the relationship between airway cross-sectional area and transmural pressure difference. MR imaging was performed under anesthesia in children with Down syndrome (DS) and obstructive sleep apnea (OSA). An airway segmentation algorithm was employed to evaluate changes in airway cross-sectional area dilated by continuous positive airway pressure (CPAP). A pressure-area relation was used to make localized estimates of airway wall stiffness for each patient. Optimized values of patient specific Young's modulus for tissue in the velopharynx and oropharynx, were estimated from finite element simulations of airway collapse. Patient specific deformation of the airway wall under CPAP was found to exhibit either a non-linear 'hardening' or 'softening' behavior. The localized airway and tissue elasticity were found to increase with increasing severity of OSA. Elasticity based patient phenotyping can potentially assist clinicians in decision making on CPAP and airway or tissue elasticity can supplement well-known clinical measures of OSA severity.
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Affiliation(s)
| | - Goutham Mylavarapu
- Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA
| | - Keith McConnell
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Robert J Fleck
- Division of Pediatric Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Sally R Shott
- Department of Pediatric Otolaryngology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Ephraim J Gutmark
- Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA. .,UC Department of Otolaryngology-Head and Neck Surgery, Cincinnati, OH, USA.
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45
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Davidson Ward SL, Amin R, Arens R, Davis S, Gutmark E, Superfine R, Wong B, Zdanski C, Khoo MCK. Pediatric sleep-related breathing disorders: advances in imaging and computational modeling. IEEE Pulse 2015; 5:33-9. [PMID: 25437473 DOI: 10.1109/mpul.2014.2339293] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We understand now that sleep of sufficient length and quality is required for good health. This is particularly true for infants and children, who have the added physiologic task of growth and development, as compared to their adult counterparts. Sleep-related breathing disorders (SRBDs) are common in childhood and if unrecognized and not treated can result in significant morbidity. For example, children with obstructive sleep apnea (OSA) can exhibit behavioral, mood, and learning difficulties. If left untreated, alterations in the function of the autonomic nervous system and a chronic inflammatory state result, contributing to the risk of heart disease, stroke, glucose intolerance, and hypertension in adulthood.
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46
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Slaats MA, Van Hoorenbeeck K, Van Eyck A, Vos WG, De Backer JW, Boudewyns A, De Backer W, Verhulst SL. Upper airway imaging in pediatric obstructive sleep apnea syndrome. Sleep Med Rev 2015; 21:59-71. [DOI: 10.1016/j.smrv.2014.08.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 08/12/2014] [Accepted: 08/12/2014] [Indexed: 11/28/2022]
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47
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Luo H, Sin S, McDonough JM, Isasi CR, Arens R, Wootton DM. Computational fluid dynamics endpoints for assessment of adenotonsillectomy outcome in obese children with obstructive sleep apnea syndrome. J Biomech 2014; 47:2498-503. [PMID: 24840295 DOI: 10.1016/j.jbiomech.2014.03.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/12/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND Improvements in obstructive sleep apnea syndrome (OSAS) severity may be associated with improved pharyngeal fluid mechanics following adenotonsillectomy (AT). The study objective is to use image-based computational fluid dynamics (CFD) to model changes in pharyngeal pressures after AT, in obese children with OSAS and adenotonsillar hypertrophy. METHODS Three-dimensional models of the upper airway from nares to trachea, before and after AT, were derived from magnetic resonance images obtained during wakefulness, in a cohort of 10 obese children with OSAS. Velocity, pressure, and turbulence fields during peak tidal inspiratory flow were computed using commercial software. CFD endpoints were correlated with polysomnography endpoints before and after AT using Spearman׳s rank correlation (rs). RESULTS Apnea hypopnea index (AHI) decreases after AT was strongly correlated with reduction in maximum pressure drop (dPTAmax) in the region where tonsils and adenoid constrict the pharynx (rs=0.78, P=0.011), and with decrease of the ratio of dPTAmax to flow rate (rs=0.82, P=0.006). Correlations of AHI decrease to anatomy, negative pressure in the overlap region (including nasal flow resistance), or pressure drop through the entire pharynx, were not significant. In a subgroup of subjects with more than 10% improvement in AHI, correlations between flow variables and AHI decrease were stronger than in all subjects. CONCLUSIONS The correlation between change in dPTAmax and improved AHI suggests that dPTAmax may be a useful index for internal airway loading due to anatomical narrowing, and may be better correlated with AHI than direct airway anatomic measurements.
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Affiliation(s)
- Haiyan Luo
- Department of Mechanical Engineering, The Cooper Union for the Advancement of Science and Art, 41 Cooper Square, New York, NY, USA
| | - Sanghun Sin
- Division of Respiratory and Sleep Medicine, Albert Einstein College of Medicine, The Children׳s Hospital at Montefiore, Bronx, NY, USA
| | - Joseph M McDonough
- Division of Pulmonary Medicine, The Children׳s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Carmen R Isasi
- Department of Epidemiology & Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Raanan Arens
- Division of Respiratory and Sleep Medicine, Albert Einstein College of Medicine, The Children׳s Hospital at Montefiore, Bronx, NY, USA
| | - David M Wootton
- Department of Mechanical Engineering, The Cooper Union for the Advancement of Science and Art, 41 Cooper Square, New York, NY, USA.
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