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Root ZT, Schneller AR, Lepley TJ, Wu Z, Zhao K. Computational Fluid Dynamics and Its Potential Applications for the ENT Clinician. Facial Plast Surg 2024; 40:323-330. [PMID: 38224693 DOI: 10.1055/s-0043-1778072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024] Open
Abstract
This article is an examination of computational fluid dynamics in the field of otolaryngology, specifically rhinology. The historical development and subsequent application of computational fluid dynamics continues to enhance our understanding of various sinonasal conditions and surgical planning in the field today. This article aims to provide a description of computational fluid dynamics, the methods for its application, and the clinical relevance of its results. Consideration of recent research and data in computational fluid dynamics demonstrates its use in nonhistological disease pathology exploration, accompanied by a large potential for surgical guidance applications. Additionally, this article defines in lay terms the variables analyzed in the computational fluid dynamic process, including velocity, wall shear stress, area, resistance, and heat flux.
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Affiliation(s)
- Zachary T Root
- Department of Otolaryngology - Head & Neck Surgery, The Ohio State University, Columbus, Ohio
| | - Aspen R Schneller
- Department of Otolaryngology - Head & Neck Surgery, The Ohio State University, Columbus, Ohio
| | - Thomas J Lepley
- Department of Otolaryngology - Head & Neck Surgery, The Ohio State University, Columbus, Ohio
| | - Zhenxing Wu
- Department of Otolaryngology - Head & Neck Surgery, The Ohio State University, Columbus, Ohio
| | - Kai Zhao
- Department of Otolaryngology - Head & Neck Surgery, The Ohio State University, Columbus, Ohio
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2
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Burgos MA, Bastir M, Pérez-Ramos A, Sanz-Prieto D, Heuzé Y, Maréchal L, Esteban-Ortega F. Assessing nasal airway resistance and symmetry: An approach to global perspective through computational fluid dynamics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024:e3830. [PMID: 38700070 DOI: 10.1002/cnm.3830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/18/2024] [Accepted: 04/15/2024] [Indexed: 05/05/2024]
Abstract
This study aimed to explore the variability in nasal airflow patterns among different sexes and populations using computational fluid dynamics (CFD). We focused on evaluating the universality and applicability of dimensionless parameters R (bilateral nasal resistance) and ϕ (nasal flow asymmetry), initially established in a Caucasian Spanish cohort, across a broader spectrum of human populations to assess normal breathing function in healthy airways. In this retrospective study, CT scans from Cambodia (20 males, 20 females), Russia (20 males, 18 females), and Spain (19 males, 19 females) were analyzed. A standardized CFD workflow was implemented to calculate R-ϕ parameters from these scans. Statistical analyses were conducted to assess and compare these parameters across different sexes and populations, emphasizing their distribution and variances. Our results indicated no significant sex-based differences in the R parameter across the populations. However, moderate sexual dimorphism in the ϕ parameter was observed in the Cambodian group. Notably, no geographical differences were found in either R or ϕ parameters, suggesting consistent nasal airflow characteristics across the diverse human groups studied. The study also emphasized the importance of using dimensionless variables to effectively analyze the relationships between form and function in nasal airflow. The observed consistency of R-ϕ parameters across various populations highlights their potential as reliable indicators in both medical practice and further CFD research, particularly in diverse human populations. Our findings suggest the potential applicability of dimensionless CFD parameters in analyzing nasal airflow, highlighting their utility across diverse demographic and geographic contexts. This research advances our understanding of nasal airflow dynamics and underscores the need for additional studies to validate these parameters in broader population cohorts. The approach of employing dimensionless parameters paves the way for future research that eliminates confounding size effects, enabling more accurate comparisons across different populations and sexes. The implications of this study are significant for the advancement of personalized medicine and the development of diagnostic tools that accommodate individual variations in nasal airflow.
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Affiliation(s)
- Manuel A Burgos
- Department of Thermal and Fluid Engineering, Fluid Mechanics and Thermal Engineering Group, Polytechnic University of Cartagena, Cartagena, Spain
| | - Markus Bastir
- Department of Paleobiology, Paleoanthropology Group, National Museum of Natural Sciences - Spanish National Research Council, Madrid, Spain
| | - Alejandro Pérez-Ramos
- Faculty of Science, Department of Ecology and Geology, Paleobiology, Paleoclimatology and Paleogeography Group, University of Málaga, Málaga, Spain
- Faculty of Science, Department of Surgery, Paleobiology, Paleoclimatology and Paleogeography Group, University of Málaga, Málaga, Spain
| | - Daniel Sanz-Prieto
- Department of Thermal and Fluid Engineering, Fluid Mechanics and Thermal Engineering Group, Polytechnic University of Cartagena, Cartagena, Spain
- Faculty of Sciences, Department of Biology, Autonomous University of Madrid, Madrid, Spain
| | - Yann Heuzé
- PACEA UMR 5199, University of Bordeaux, French National Centre for Scientific Research, Ministère de la Culture, Pessac, France
| | - Laura Maréchal
- PACEA UMR 5199, University of Bordeaux, French National Centre for Scientific Research, Ministère de la Culture, Pessac, France
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Xiao Q, Bates AJ, Doorly DJ. Effects of decongestion on nasal cavity air conditioning efficiency: a CFD cohort study. Sci Rep 2024; 14:8482. [PMID: 38605156 DOI: 10.1038/s41598-024-58758-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/02/2024] [Indexed: 04/13/2024] Open
Abstract
Decongestion reduces blood flow in the nasal turbinates, enlarging the airway lumen. Although the enlarged airspace reduces the trans-nasal inspiratory pressure drop, symptoms of nasal obstruction may relate to nasal cavity air-conditioning. Thus, it is necessary to quantify the efficiency of nasal cavity conditioning of the inhaled air. This study quantifies both overall and regional nasal air-conditioning in a cohort of 10 healthy subjects using computational fluid dynamics simulations before and after nasal decongestion. The 3D virtual geometry model was segmented from magnetic resonance images (MRI). Each subject was under two MRI acquisitions before and after the decongestion condition. The effects of decongestion on nasal cavity air conditioning efficiency were modelled at two inspiratory flowrates: 15 and 30 L min-1 to represent restful and light exercise conditions. Results show inhaled air was both heated and humidified up to 90% of alveolar conditions at the posterior septum. The air-conditioning efficiency of the nasal cavity remained nearly constant between nostril and posterior septum but dropped significantly after posterior septum. In summary, nasal cavity decongestion not only reduces inhaled air added heat by 23% and added moisture content by 19%, but also reduces the air-conditioning efficiency by 35% on average.
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Affiliation(s)
- Qiwei Xiao
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Alister J Bates
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| | - Denis J Doorly
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, UK, SW7 2AZ.
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Emmerling J, Vahaji S, Morton DAV, Fletcher DF, Inthavong K. Scale resolving simulations of the effect of glottis motion and the laryngeal jet on flow dynamics during respiration. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 247:108064. [PMID: 38382308 DOI: 10.1016/j.cmpb.2024.108064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/27/2023] [Accepted: 02/05/2024] [Indexed: 02/23/2024]
Abstract
BACKGROUND AND OBJECTIVE The movement of the respiratory walls has a significant impact on airflow through the respiratory tract. The majority of computational fluid dynamics (CFD) studies assume a static geometry which may not provide a realistic flow field. Furthermore, many studies use Reynolds Averaged Navier-Stokes (RANS) turbulence models that do not resolve turbulence structure. Combining the application of advanced scale-resolving turbulence models with moving respiratory walls using CFD will provide detailed insights into respiratory flow structures. METHODS This study simulated a complete breathing cycle involving inhalation and exhalation in a nasal cavity to trachea geometry that incorporated moving glottis walls. A second breathing cycle was simulated with static glottis walls for comparison. A recently developed hybrid RANS-LES turbulence model, the Stress-Blended Eddy Simulation (SBES), was incorporated to resolve turbulent flow structures in fine detail for both transient simulations. Transient results were compared with steady-state RANS simulations for the same respiratory geometry. RESULTS Glottis motion caused substantial effects on flow structure through the complete breathing cycle. Significant flow structure and velocity variations were observed due to glottal motion, primarily in the larynx and trachea. Resolved turbulence structures using SBES showed an intense mixing section in the glottis region during inhalation and in the nasopharynx during expiration, which was not present in the RANS simulations. CONCLUSION Transient simulations of a realistic breathing cycle uncovered flow structures absent in simulations with a constant flow rate. Furthermore, the incorporation of glottis motion impacted airflow characteristics that suggest rigid respiratory walls do not accurately describe respiratory flow. Future research in respiratory airflow should be conducted using transient scale-resolving models in conjunction with moving respiratory walls to capture flow structures in detail.
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Affiliation(s)
- Jake Emmerling
- School of Engineering, Deakin University, Waurn Ponds 3216, Australia
| | - Sara Vahaji
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - David A V Morton
- School of Engineering, Deakin University, Waurn Ponds 3216, Australia
| | - David F Fletcher
- School of Chemical and Biomolecular Engineering, University of Sydney, NSW 2006, Australia
| | - Kiao Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia.
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Bastir M, Sanz-Prieto D, Burgos MA, Pérez-Ramos A, Heuzé Y, Maréchal L, Evteev A, Toro-Ibacache V, Esteban-Ortega F. Beyond skeletal studies: A computational analysis of nasal airway function in climate adaptation. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024:e24932. [PMID: 38516761 DOI: 10.1002/ajpa.24932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 03/01/2024] [Accepted: 03/12/2024] [Indexed: 03/23/2024]
Abstract
OBJECTIVES Ecogeographic variation in human nasal anatomy has historically been analyzed on skeletal morphology and interpreted in the context of climatic adaptations to respiratory air-conditioning. Only a few studies have analyzed nasal soft tissue morphology, actively involved in air-conditioning physiology. MATERIALS AND METHODS We used in vivo computer tomographic scans of (N = 146) adult individuals from Cambodia, Chile, Russia, and Spain. We conducted (N = 438) airflow simulations during inspiration using computational fluid dynamics to analyze the air-conditioning capacities of the nasal soft tissue in the inflow, functional, and outflow tract, under three different environmental conditions: cold-dry; hot-dry; and hot-humid. We performed statistical comparisons between populations and sexes. RESULTS Subjects from hot-humid regions showed significantly lower air-conditioning capacities than subjects from colder regions in all the three conditions, specifically within the isthmus region in the inflow tract, and the anterior part of the internal functional tract. Posterior to the functional tract, no differences were detected. No differences between sexes were found in any of the tracts and under any of the conditions. DISCUSSION Our statistical analyses support models of climatic adaptations of anterior nasal soft tissue morphology that fit with, and complement, previous research on dry skulls. However, our results challenge a morpho-functional model that attributes air-conditioning capacities exclusively to the functional tract located within the nasal cavity. Instead, our findings support studies that have suggested that both, the external nose and the intra-facial soft tissue airways contribute to efficiently warming and humidifying air during inspiration. This supports functional interpretations in modern midfacial variation and evolution.
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Affiliation(s)
- Markus Bastir
- Paleoanthropology Group, Department of Paleobiology, National Museum of Natural Sciences-Spanish National Research Council, Madrid, Spain
| | - Daniel Sanz-Prieto
- Paleoanthropology Group, Department of Paleobiology, National Museum of Natural Sciences-Spanish National Research Council, Madrid, Spain
- Fluid Mechanics and Thermal Engineering Group, Department of Thermal and Fluid Engineering, Polytechnic University of Cartagena, Cartagena, Spain
- Department of Biology, Faculty of Sciences, Autonomous University of Madrid, Madrid, Spain
| | - Manuel A Burgos
- Fluid Mechanics and Thermal Engineering Group, Department of Thermal and Fluid Engineering, Polytechnic University of Cartagena, Cartagena, Spain
| | - Alejandro Pérez-Ramos
- Paleobiology, Paleoclimatology, and Paleogeography Group, Department of Ecology and Geology, Faculty of Science, University of Málaga, Malaga, Spain
| | - Yann Heuzé
- CNRS, Ministère de la Culture, PACEA, Université de Bordeaux, Pessac, France
| | - Laura Maréchal
- CNRS, Ministère de la Culture, PACEA, Université de Bordeaux, Pessac, France
| | - Andrej Evteev
- Anuchin Research Institute and Museum of Anthropology, Lomonosov Moscow State University, Moscow, Russia
| | - Viviana Toro-Ibacache
- Center for Quantitative Analysis in Dental Anthropology, Faculty of Dentistry, University of Chile, Santiago, Chile
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Johnsen SG. Computational Rhinology: Unraveling Discrepancies between In Silico and In Vivo Nasal Airflow Assessments for Enhanced Clinical Decision Support. Bioengineering (Basel) 2024; 11:239. [PMID: 38534513 DOI: 10.3390/bioengineering11030239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 02/09/2024] [Accepted: 02/17/2024] [Indexed: 03/28/2024] Open
Abstract
Computational rhinology is a specialized branch of biomechanics leveraging engineering techniques for mathematical modelling and simulation to complement the medical field of rhinology. Computational rhinology has already contributed significantly to advancing our understanding of the nasal function, including airflow patterns, mucosal cooling, particle deposition, and drug delivery, and is foreseen as a crucial element in, e.g., the development of virtual surgery as a clinical, patient-specific decision support tool. The current paper delves into the field of computational rhinology from a nasal airflow perspective, highlighting the use of computational fluid dynamics to enhance diagnostics and treatment of breathing disorders. This paper consists of three distinct parts-an introduction to and review of the field of computational rhinology, a review of the published literature on in vitro and in silico studies of nasal airflow, and the presentation and analysis of previously unpublished high-fidelity CFD simulation data of in silico rhinomanometry. While the two first parts of this paper summarize the current status and challenges in the application of computational tools in rhinology, the last part addresses the gross disagreement commonly observed when comparing in silico and in vivo rhinomanometry results. It is concluded that this discrepancy cannot readily be explained by CFD model deficiencies caused by poor choice of turbulence model, insufficient spatial or temporal resolution, or neglecting transient effects. Hence, alternative explanations such as nasal cavity compliance or drag effects due to nasal hair should be investigated.
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Viegas J, Cardoso EM, Bonneau L, Esteves AF, Ferreira CL, Alves G, Santos-Silva AJ, Vitale M, Arosa FA, Taborda-Barata L. A Novel Bionebulizer Approach to Study the Effects of Natural Mineral Water on a 3D In Vitro Nasal Model from Allergic Rhinitis Patients. Biomedicines 2024; 12:408. [PMID: 38398010 PMCID: PMC10886703 DOI: 10.3390/biomedicines12020408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Sulfurous thermal waters (STWs) are used as a complementary treatment for allergic rhinitis. However, there is scant data on the effects of STW on nasal epithelial cells, and in vitro models are warranted. The main aim of this study was to evaluate the dose and time effects of exposure to 3D nasal inserts (MucilAirTM-HF allergic rhinitis model) with STW or isotonic sodium chloride solution (ISCS) aerosols. Transepithelial electrical resistance (TEER) and histology were assessed before and after nebulizations. Chemokine/cytokine levels in the basal supernatants were assessed by enzyme-linked immunosorbent assay. The results showed that more than four daily nebulizations of four or more minutes compromised the normal epithelial integrity. In contrast, 1 or 2 min of STW or ISCS nebulizations had no toxic effect up to 3 days. No statistically significant changes in release of inflammatory chemokines MCP-1/CCL2 > IL-8/CXCL8 > MIP-1α/CCL3, no meaningful release of "alarmins" (IL-1α, IL-33), nor of anti-inflammatory IL-10 cytokine were observed. We have characterized safe time and dose conditions for aerosol nebulizations using a novel in vitro 3D nasal epithelium model of allergic rhinitis patients. This may be a suitable in vitro setup to mimic in vivo treatments of chronic rhinitis with STW upon triggering an inflammatory stimulus in the future.
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Affiliation(s)
- Joana Viegas
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
| | - Elsa M. Cardoso
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
- ESS-IPG-School of Health Sciences, Polytechnic Institute of Guarda, Rua da Cadeia, 6300-307 Guarda, Portugal
| | - Lucile Bonneau
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
| | - Ana Filipa Esteves
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
| | - Catarina L. Ferreira
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
- Faculty of Health Sciences, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal;
| | - Gilberto Alves
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
- Faculty of Health Sciences, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal;
| | - António Jorge Santos-Silva
- Faculty of Health Sciences, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal;
- Unhais da Serra Thermal Spa, Avenida das Termas, 6215-574 Unhais da Serra, Portugal
| | - Marco Vitale
- Faculty of Medicine and Surgery, University Vita-Salute San Raffaele, 20132 Milan, Italy;
- FoRST—Fondazione per la Ricerca Scientifica Termale, 00198 Rome, Italy
| | - Fernando A. Arosa
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
- Faculty of Health Sciences, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal;
| | - Luís Taborda-Barata
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal; (J.V.); (E.M.C.); (L.B.); (A.F.E.); (C.L.F.); (G.A.); (F.A.A.)
- Faculty of Health Sciences, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal;
- UBIAir—Clinical & Experimental Lung Centre, University of Beira Interior, Estrada Municipal 506, 6200-284 Covilhã, Portugal
- CACB—Clinical Academic Centre of Beiras, Estrada Municipal 506, 6200-284 Covilhã, Portugal
- Department of Immunoallergology, Cova da Beira University Hospital Centre, Alameda Pêro da Covilhã, 6200-251 Covilhã, Portugal
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Na Y, Kwon KW, Jang YJ. Impact of nasal septal perforation on the airflow and air-conditioning characteristics of the nasal cavity. Sci Rep 2024; 14:2337. [PMID: 38281976 PMCID: PMC10822863 DOI: 10.1038/s41598-024-52755-4] [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: 07/18/2023] [Accepted: 01/23/2024] [Indexed: 01/30/2024] Open
Abstract
We investigated (1) how nasal septal perforations (NSPs) modify nasal airflow and air-conditioning characteristics and (2) how the modifications of nasal airflow are influenced by the size and location of the NSP. Computed tomography scans of 14 subjects with NSPs were used to generate nasal cavity models. Virtual repair of NSPs was conducted to examine the sole effect of NSPs on airflow. The computational fluid dynamics technique was used to assess geometric and airflow parameters around the NSPs and in the nasopharynx. The net crossover airflow rate, the increased wall shear stress (WSS) and the surface water-vapor flux on the posterior surface of the NSPs were not correlated with the size of the perforation. After the virtual closure of the NSPs, the levels in relative humidity (RH), air temperature (AT) and nasal resistance did not improve significantly both in the choanae and nasopharynx. A geometric parameter associated with turbinate volume, the surface area-to-volume ratio (SAVR), was shown to be an important factor in the determination of the RH and AT, even in the presence of NSPs. The levels of RH and AT in the choanae and nasopharynx were more influenced by SAVR than the size and location of the NSPs.
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Affiliation(s)
- Yang Na
- Department of Mechanical Engineering, Konkuk University, Seoul, 05029, Korea
| | - Kyung Won Kwon
- Department of Otolaryngology, Asan Medical Center, University of Ulsan, College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
| | - Yong Ju Jang
- Department of Otolaryngology, Asan Medical Center, University of Ulsan, College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea.
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Khatri H, Salati H, Wong E, Bradshaw K, Inthavong K, Sacks R, Singh N. Modelling the effects of post-FESS middle turbinate synechiae on sinonasal physiology: A computational fluid dynamics study. Auris Nasus Larynx 2023; 50:911-920. [PMID: 37137797 DOI: 10.1016/j.anl.2023.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/23/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023]
Abstract
OBJECTIVE(S) Chronic rhinosinusitis (CRS) is common and often requires surgical intervention. Surgical failure may lead to persistent symptoms and recalcitrant disease, often secondary to synechiae between the middle turbinate (MT) and lateral nasal wall. Synechiae prevention techniques have been extensively investigated, however evidence for the effect of synechiae on sinonasal physiology is lacking. We aimed to model the effects of MT synechiae on a post-functional endoscopic sinus surgery (FESS) sinonasal cavity using computational fluid dynamics (CFD). METHODS DICOM data from a CT-sinus of a healthy 25-year-old female was segmented to create a three-dimensional model. Virtual surgery was performed to simulate a "full-house" FESS procedure. Multiple models were created, each with a single unilateral virtual MT synechia of varying extent. CFD analysis was performed on each model and compared with a post-FESS control model without synechiae. Airflow velocity, humidity and mucosal surface and air temperature values were calculated. RESULTS All synechiae models demonstrated aberrant downstream sinonasal airflow. There was reduced ventilation of the ipsilateral frontal, ethmoid and sphenoid sinuses, with a concentrated central "jet" in the middle meatus region. Effects were proportionate to the size of synechiae. The impact on bulk inspired airflow was negligible. CONCLUSION Post-FESS synechiae between the MT and lateral nasal wall significantly disrupt local downstream sinus ventilation and nasal airflow. These findings may explain the persistent symptoms seen in post-FESS CRS patients with MT synechiae, reinforcing the importance of prevention and adhesiolysis. Larger cohort studies with multiple models of actual post-FESS patients with synechiae are required to validate these findings.
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Affiliation(s)
- Hershil Khatri
- Department of Otolaryngology, University of Sydney, Sydney, NSW, Australia
| | - Hana Salati
- School of Engineering, Royal Melbourne Institute of Technology, Melbourne, Vic, Australia
| | - Eugene Wong
- Department of Otolaryngology, University of Sydney, Sydney, NSW, Australia
| | - Kimberley Bradshaw
- Department of Otolaryngology, University of Sydney, Sydney, NSW, Australia
| | - Kiao Inthavong
- School of Engineering, Royal Melbourne Institute of Technology, Melbourne, Vic, Australia.
| | - Raymond Sacks
- Department of Otolaryngology, University of Sydney, Sydney, NSW, Australia
| | - Narinder Singh
- Department of Otolaryngology, University of Sydney, Sydney, NSW, Australia
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Boyuklieva R, Zagorchev P, Pilicheva B. Computational, In Vitro, and In Vivo Models for Nose-to-Brain Drug Delivery Studies. Biomedicines 2023; 11:2198. [PMID: 37626694 PMCID: PMC10452071 DOI: 10.3390/biomedicines11082198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/27/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Direct nose-to-brain drug delivery offers the opportunity to treat central nervous system disorders more effectively due to the possibility of drug molecules reaching the brain without passing through the blood-brain barrier. Such a delivery route allows the desired anatomic site to be reached while ensuring drug effectiveness, minimizing side effects, and limiting drug losses and degradation. However, the absorption of intranasally administered entities is a complex process that considerably depends on the interplay between the characteristics of the drug delivery systems and the nasal mucosa. Various preclinical models (in silico, in vitro, ex vivo, and in vivo) are used to study the transport of drugs after intranasal administration. The present review article attempts to summarize the different computational and experimental models used so far to investigate the direct delivery of therapeutic agents or colloidal carriers from the nasal cavity to the brain tissue. Moreover, it provides a critical evaluation of the data available from different studies and identifies the advantages and disadvantages of each model.
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Affiliation(s)
- Radka Boyuklieva
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
- Research Institute, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
| | - Plamen Zagorchev
- Research Institute, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
- Department of Medical Physics and Biophysics, Faculty of Pharmacy, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria
| | - Bissera Pilicheva
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
- Research Institute, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
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11
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Na Y, Kwon KW, Jang YJ. Impact of the Location of Nasal Septal Deviation on the Nasal Airflow and Air Conditioning Characteristics. Facial Plast Surg 2023; 39:393-400. [PMID: 36564036 DOI: 10.1055/s-0042-1759764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The location of nasal septal deviation (NSD) directly impacts nasal physiology. The objective is to examine, using computational fluid dynamics (CFD), the difference in the airflow and air conditioning characteristics according to the location of NSD. Twenty patients with septal deviation were divided into two: 10 caudal septal deviation (CSD) and 10 posterior septal deviation (PSD). Physiological variables were compared and numerical models for nasal cavity were created with CT scans. Cases with CSD had distinctive features including restricted airflow partition, larger nasal resistance, and decreased surface heat flux in the more obstructed side (MOS), and lower humidity and air temperature in the lesser obstructed side (LOS). Physiological differences were observed according to the location of septal deviation, CSD cases exhibit significantly more asymmetric airflow characteristics and air conditioning capacity between LOS and MOS.
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Affiliation(s)
- Yang Na
- Department of Mechanical Engineering, Konkuk University, Seoul, Korea
| | - Kyung Won Kwon
- Department of Otolaryngology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
| | - Yong Ju Jang
- Department of Otolaryngology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
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12
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Hu Z, Dong J, Lou M, Zhang J, Ma R, Wang Y, Gong M, Wang B, Tong Z, Ren H, Zheng G, Zhang Y. Effect of different degrees of adenoid hypertrophy on pediatric upper airway aerodynamics: a computational fluid dynamics study. Biomech Model Mechanobiol 2023; 22:1163-1175. [PMID: 37256522 DOI: 10.1007/s10237-023-01707-4] [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: 05/28/2022] [Accepted: 02/22/2023] [Indexed: 06/01/2023]
Abstract
To improve the diagnostic accuracy of adenoid hypertrophy (AH) in children and prevent further complications in time, it is important to study and quantify the effects of different degrees of AH on pediatric upper airway (UA) aerodynamics. In this study, based on computed tomography (CT) scans of a child with AH, UA models with different degrees of obstruction (adenoidal-nasopharyngeal (AN) ratio of 0.9, 0.8, 0.7, and 0.6) and no obstruction (AN ratio of 0.5) were constructed through virtual surgery to quantitatively analyze the aerodynamic characteristics of UA with different degrees of obstruction in terms of the peak velocity, pressure drop (△P), and maximum wall shear stress (WSS). We found that two obvious whirlpools are formed in the anterior upper part of the pediatric nasal cavity and in the oropharynx, which is caused by the sudden increase in the nasal cross-section area, resulting in local flow separation and counterflow. In addition, when the AN ratio was ≥ 0.7, the airflow velocity peaked at the protruding area in the nasopharynx, with an increase 1.1-2.7 times greater than that in the nasal valve area; the △P in the nasopharynx was significantly increased, with an increase 1.1-6.8 times greater than that in the nasal cavity; and the maximum WSS of the posterior wall of the nasopharynx was 1.1-4.4 times larger than that of the nasal cavity. The results showed that the size of the adenoid plays an important role in the patency of the pediatric UA.
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Affiliation(s)
- Zhenzhen Hu
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Jingliang Dong
- Institute for Sustainable Industries & Liveable Cities, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia
- First Year College, Victoria University, Footscray Park Campus, Footscray, VIC, 3011, Australia
- School of Engineering, RMIT University, Bundoora, VIC, 3083, Australia
| | - Miao Lou
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Jingbin Zhang
- Department of Imaging, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ruiping Ma
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Yusheng Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Minjie Gong
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Botao Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Zhenbo Tong
- School of Energy and Environment, Southeast University, Nanjing, China
| | - Hongxian Ren
- School of Energy and Environment, Southeast University, Nanjing, China
| | - Guoxi Zheng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China.
| | - Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China.
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13
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Kuga K, Kizuka R, Khoa ND, Ito K. Effect of transient breathing cycle on the deposition of micro and nanoparticles on respiratory walls. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 236:107501. [PMID: 37163889 DOI: 10.1016/j.cmpb.2023.107501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/09/2023] [Accepted: 03/20/2023] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND OBJECTIVE From various perspectives (e.g. inhalation exposure and drug delivery), it is important to provide insights into the behavior of inhaled particles in the human respiratory system. Although most of the experimental and numerical studies have relied on an assumption of steady inhalation, the transient breathing profile is a key factor in particle deposition in the respiratory tract. In this study, particle transportation and deposition were predicted in a realistic human airway model during a breathing cycle and the effects of steady-state and transient flows on the deposition fraction were observed using computational fluid dynamics. METHODS Two transient breathing cycles with different respiratory durations were considered to evaluate the effects of respiration duration on particle transport and deposition characteristics. Two types of steady breathing conditions with corresponding steady-state respiratory volumes were reproduced. The Lagrangian discrete phase model approach was used to investigate particle transportation and deposition under transient breathing conditions. Additionally, the Eulerian approach was used to analyze the transport of nanoparticles in the gas phase. A total of >50,000 monodispersed particles with aerodynamic diameters ranging between 2 nm and 10 μm were selected for comprehensive deposition predictions for particle sizes ranging from the nano- to microscale. RESULTS The predicted results were compared with the experimental data. The particle deposition fraction in the nasal cavity and tracheal regions showed differences between the steady and transient simulations. In addition, particle analysis under steady inhalation conditions cannot accurately predict particle transportation and deposition in the lower airway. Furthermore, the breathing cycle had a significant effect on the deposition fraction of the particles and the behavior of the inhaled particles. CONCLUSIONS Transient simulation mimicking the breathing cycle was observed to be an important factor in accurately predicting the transportation and deposition of particles in the respiratory tract.
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Affiliation(s)
- Kazuki Kuga
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan.
| | - Ryusei Kizuka
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga-shi, Fukuoka 816-8580, Japan
| | - Nguyen Dang Khoa
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga-shi, Fukuoka 816-8580, Japan
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
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Liu J, Shao Y, Li J, Zhu L, Gong X, Xue L, Shen J, Li Y. New approach to establish a surgical planning in infantile vallecular cyst synchronous with laryngomalacia based on aerodynamic analysis. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107335. [PMID: 36638553 DOI: 10.1016/j.cmpb.2023.107335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/15/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVES A large proportion of infants with vallecular cyst (VC) have coexisting laryngomalacia (LM). Feeding difficulties, regurgitation, occasional cough, and sleep-disordered breathing are the common symptoms in moderate to severe cases. The surgical management of these cases is more challenging and remains controversial. The purpose of this study is to help surgeons select the effective surgical strategies by computer-aided design (CAD) and computational fluid dynamics (CFD) simulations of the upper airway flow characteristics. METHODS The three dimensional (3D) geometric model of the upper airway was reconstructed based on two dimensional (2D) medical images of the patient with VC accompanied with LM. Virtual surgeries were carried out preoperatively to simulate three possible post-operative states in silico. The different outcomes of virtual surgical strategies were predicted based on computational evaluations of airway fluid dynamics including pressure, resistance, velocity, and wall shear stress (WSS). RESULTS The CFD results of this study suggested the importance of the angle between the rim of epiglottis and arytenoid epiglottic (AE) fold. There was a small impact on the upper airway flow field while the VC was removed and the angle of epiglottis was unchanged. The partial lifting of epiglottis can further improve the flow field. With performing supraglottoplasty (SGP) and the marsupialization of VC, epiglottis was completely recovered, and the flow field was significantly improved. The clinical symptoms of this patient improved greatly after surgeries and no recurrence or growth retardation were noted during 1-year follow-up. The clinical prognosis was consistent with the prediction of the CFD results. CONCLUSIONS The state of epiglottis needs to be carefully checked to evaluate the necessity of performing further SGP in the patients with VC accompanied with LM. CFD and CAD could be developed as a new approach to help surgeons predict the post-operative outcomes through quantification of the airflow dynamics, and make the optimal and individualized surgical approaches for patients with airway obstruction.
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Affiliation(s)
- Jinlong Liu
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yuancheng Shao
- Rensselaer Polytechnic Institute, Troy, NY 12180, United States
| | - Junyang Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Limin Zhu
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Xiaolei Gong
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Lianyan Xue
- Diagnostic Imaging Center, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Juanya Shen
- China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 200240, China; Key Laboratory for Power Machinery and Engineering, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Youjin Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.
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15
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Hebbink RHJ, Wessels BJ, Hagmeijer R, Jain K. Computational analysis of human upper airway aerodynamics. Med Biol Eng Comput 2023; 61:541-553. [PMID: 36538266 DOI: 10.1007/s11517-022-02716-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 11/07/2022] [Indexed: 12/24/2022]
Abstract
There is a considerable interest in understanding transient human upper airway aerodynamics, especially in view of assessing the effects of various ventilation therapies. Experimental analyses in a patient-specific manner pose challenges as the upper airway consists of a narrow confined region with complex anatomy. Pressure measurements are feasible, but, for example, PIV experiments require special measures to accommodate for the light refraction by the model. Computational fluid dynamics can bridge the gap between limited experimental data and detailed flow features. This work aims to validate the use of combined lattice Boltzmann method and a large eddy scale model for simulating respiration, and to identify clinical features of the flow and show the clinical potential of the method. Airflow was computationally analyzed during a realistic, transient, breathing profile in an upper airway geometry ranging from nose to trachea, and the resulting pressure calculations were compared against in vitro experiments. Simulations were conducted on meshes containing about 1 billion cells to ensure accuracy and to capture intrinsic flow features. Airway pressures obtained from simulations and in vitro experiments are in good agreement both during inhalation and exhalation. High velocity pharyngeal and laryngeal jets and recirculation in the region of the olfactory cleft are observed. Graphical Abstract The Lattice-Boltzmann Method combined with Large Eddy Simulations was used to compute the aerodynamics in a human upper airway geometry. The left side of this graphical abstract shows the velocity and vorticity (middle figure in bottom row, and right figure of the right bottom figure) profiles at peak exhalation. The simulations were validated against experiments on a 3D-print of the geometry (shown in the top figures on the right hand side). The pressure drop (right bottom corner) shows a good agreement between experiments and simulations.
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Affiliation(s)
- Rutger H J Hebbink
- Engineering Fluid Dynamics, Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Bas J Wessels
- Engineering Fluid Dynamics, Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Rob Hagmeijer
- Engineering Fluid Dynamics, Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Kartik Jain
- Engineering Fluid Dynamics, Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
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16
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Makhlynets N, Ozhogan Z, Pantus A, Pyuryk M, Fedorov S. INFLUENCE OF BAD HABITS ON THE DEVELOPMENT OF ACQUIRED DEFORMATIONS IN THE MAXILLOFACIAL AREA. WIADOMOSCI LEKARSKIE (WARSAW, POLAND : 1960) 2023; 76:1650-1658. [PMID: 37622510 DOI: 10.36740/wlek202307120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
OBJECTIVE The aim: Identifying the relationship between the presence of oral habit and acquired maxillomandibular anomalies, influence of oral habits on the skeleton and muscular system formation in children. PATIENTS AND METHODS Materials and methods: We conducted clinical, radiological methods of examination of 60 patients aged 9-12 with acquired maxillomandibular anomalies, 15 persons aged 9-12 years without maxillomandibular anomalies and acquired deformities (norm group) and 15 persons aged 9-12 years with hereditary syndromes, which are combined with bone deformities in the maxillofacial area (comparison group). RESULTS Results: Clinical examination showed that oral habits were manifested in 98.3% of patients. The results of clinical and radiological examination, analysis of cephalometric parameters and data on the thickness of the masticatory muscles on symmetrical areas of the face confirm the relationship between chronic oral habits and formation of acquired maxillomandibular anomalies; confirm the presence of acquired rather than congenital deformity of the facial skeleton, which is associated with changes in the thickness of the masticatory muscles on the part of the deformation та compensatory muscle hypertrophy on the opposite side. CONCLUSION Conclusions: The oral habit should be considered as one of the triggers in the development of acquired deformities of the maxillofacial area.
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Affiliation(s)
| | - Zinovii Ozhogan
- IVANO-FRANKIVSK NATIONAL MEDICAL UNIVERSITY, IVANO-FRANKIVSK, UKRAINE
| | - Andrii Pantus
- IVANO-FRANKIVSK NATIONAL MEDICAL UNIVERSITY, IVANO-FRANKIVSK, UKRAINE
| | - Markiyan Pyuryk
- IVANO-FRANKIVSK NATIONAL MEDICAL UNIVERSITY, IVANO-FRANKIVSK, UKRAINE
| | - Serhiy Fedorov
- IVANO-FRANKIVSK NATIONAL MEDICAL UNIVERSITY, IVANO-FRANKIVSK, UKRAINE
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17
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Hongyu L, Yulin L, Wanye T, Xiaoguang LI, Fenghe Z, Qing L. Structural and functional changes of nasal cavity and maxillary sinus in patients with skeletal class III malocclusion 1 year after bimaxillary surgery. Orthod Craniofac Res 2022. [PMID: 36404137 DOI: 10.1111/ocr.12622] [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: 09/05/2022] [Revised: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 11/22/2022]
Abstract
PURPOSE This study aimed to analyse changes in the nasal cavity and maxillary sinus structure and function in patients with skeletal class III malocclusion 1 year after bimaxillary surgery. MATERIALS AND METHODS In this study, cone-beam computed tomography (CBCT) images of 20 patients (10 men and 10 women; mean age 24.3 ± 3.4 years) with skeletal class III malocclusion who underwent Le Fort I osteotomy and bilateral sagittal split osteotomy were obtained before and 1 year after the surgery. CBCT data were stored opened with element 3D (E3D) to establish a nasal airway model (the paranasal sinus includes only the maxillary sinus). Ansys (ANSYS) software is used for simulation and analysis. RESULTS The maxillary sinus and nasal cavity volumes decreased significantly 1 year after the surgery. After surgery, the volume of nasal cavity decreased by 13.5%, and the average volume of maxillary sinus decreased by 7.8%. There was no significant difference in the degree of deviation of the septum and nasal cavity resistance, and air distribution in the maxillary sinus did not change. The nasal cavity wall shear stress change was similar to that before surgery. CONCLUSIONS The maxillary sinus volume and nasal cavity volume of patients with skeletal class III malocclusion changed significantly after bimaxillary surgery, but there was no significant change in nasal ventilation function 1 year after surgery.
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Affiliation(s)
- Li Hongyu
- School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China.,Shandong Key Laboratory of Oral Tissue Regeneration, Jinan, China.,Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, China
| | - Liu Yulin
- Institute of Thermal Science and Technology, Shandong University, Jinan, China
| | - Tan Wanye
- Department of Oral and Maxillofacial Surgery, Qilu Hospital of Shandong University & Institute of Stomatology, Jinan, China
| | - L I Xiaoguang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Zhang Fenghe
- School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China.,Shandong Key Laboratory of Oral Tissue Regeneration, Jinan, China.,Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, China
| | - Li Qing
- School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China.,Shandong Key Laboratory of Oral Tissue Regeneration, Jinan, China.,Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, China
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18
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Na Y, Kim YJ, Kim HY, Jung YG. Improvements in airflow characteristics and effect on the NOSE score after septoturbinoplasty: A computational fluid dynamics analysis. PLoS One 2022; 17:e0277712. [PMID: 36395146 PMCID: PMC9671303 DOI: 10.1371/journal.pone.0277712] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 11/01/2022] [Indexed: 11/19/2022] Open
Abstract
Septoturbinoplasty is a surgical procedure that can improve nasal congestion symptoms in patients with nasal septal deviation and inferior turbinate hypertrophy. However, it is unclear which physical domains of nasal airflow after septoturbinoplasty are related to symptomatic improvement. This work employs computational fluid dynamics modeling to identify the physical variables and domains associated with symptomatic improvement. Sixteen numerical models were generated using eight patients' pre- and postoperative computed tomography scans. Changes in unilateral nasal resistance, surface heat flux, relative humidity, and air temperature and their correlations with improvement in the Nasal Obstruction Symptom Evaluation (NOSE) score were analyzed. The NOSE score significantly improved after septoturbinoplasty, from 14.4 ± 3.6 to 4.0 ± 4.2 (p < 0.001). The surgery not only increased the airflow partition on the more obstructed side (MOS) from 31.6 ± 9.6 to 41.9 ± 4.7% (p = 0.043), but also reduced the unilateral nasal resistance in the MOS from 0.200 ± 0.095 to 0.066 ± 0.055 Pa/(mL·s) (p = 0.004). Improvement in the NOSE score correlated significantly with the reduction in unilateral nasal resistance in the preoperative MOS (r = 0.81). Also, improvement in the NOSE score correlated better with the increase in surface heat flux in the preoperative MOS region from the nasal valve to the choanae (r = 0.87) than in the vestibule area (r = 0.63). Therefore, unilateral nasal resistance and mucous cooling in the preoperative MOS can explain the perceived improvement in symptoms after septoturbinoplasty. Moreover, the physical domain between the nasal valve and the choanae might be more relevant to patient-reported patency than the vestibule area.
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Affiliation(s)
- Yang Na
- Department of Mechanical Engineering, Konkuk University, Gwangjin-gu, Seoul, Korea
| | - Youn-Ji Kim
- Department of Mechanical Engineering, Konkuk University, Gwangjin-gu, Seoul, Korea
| | - Hyo Yeol Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul, Korea
| | - Yong Gi Jung
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul, Korea
- * E-mail:
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Rosenbaum A, Faba G, Varas J, Andrade T. Septoplasty Training During the COVID-19 Era: Development and Validation of a Novel Low-Cost Simulation Model. OTO Open 2022; 6:2473974X221128928. [PMID: 36274921 PMCID: PMC9583211 DOI: 10.1177/2473974x221128928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 09/04/2022] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE In a context of increasingly limited surgical exposition, enhanced by the coronavirus disease 2019 (COVID-19) pandemic context, the objective of this article is to explain the development of a novel low-cost and simple replication animal-based septoplasty training model for otolaryngology residents, to assess its face and construct validity, and to validate a specific rating scale for each task. STUDY DESIGN Experimental study. SETTING Surgical simulation laboratory. METHODS Septoplasty experts divided the procedure into key tasks. A simulator model to perform tasks was developed using pig ears to imitate human nasal septum cartilage, and a Specific Rating Scale was constructed. Trainees and faculty performed all tasks in the model. The participants were videotaped, and operative time, hand movements, and path length were recorded using a motion sensor device. Two blinded experts evaluated the videos with Global and Specific Rating Scales. All participants answered a satisfaction survey. RESULTS Fifteen subjects were recruited (7 trainees and 8 faculty). Significantly higher Global Rating Scale score, shorter operative time and path length, and fewer hand movements were observed in the faculty group. The satisfaction survey showed high applicability to a real scenario (mean score of 4.6 out of 5). Specific Rating Scale showed construct and concurrent validity and high reliability. CONCLUSION This simulation model and its specific rating scale can be accurately used as a validated surgical assessment tool for endonasal septoplasty skills. Its low cost and simple replicability make it a potentially useful tool in any otolaryngology surgical training program.
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Affiliation(s)
- Andrés Rosenbaum
- Department of Otolaryngology, School of
Medicine, Pontifical Catholic University of Chile, Santiago, Chile
| | - Gabriel Faba
- Department of Otolaryngology, School of
Medicine, Pontifical Catholic University of Chile, Santiago, Chile
| | - Julián Varas
- Center for Simulation and Experimental
Surgery, School of Medicine, Pontifical Catholic University of Chile, Santiago,
Chile
| | - Tomás Andrade
- Department of Otolaryngology, School of
Medicine, Pontifical Catholic University of Chile, Santiago, Chile,Tomás Andrade, MD, Department of
Otolaryngology, School of Medicine, Pontifical Catholic University of Chile,
Diagonal Paraguay 362, 7th Floor, Santiago, Chile.
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20
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Characterization of Transition Phenomenon Inside a Simple Nasal Cavity Using a Range of Transition Coefficients. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2022. [DOI: 10.1007/s13369-022-07227-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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21
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Huang A, Chen W, Wu C, Lee T, Huang C, Kuo H. Characterization of nasal aerodynamics and air conditioning ability using CFD and its application to improve the empty nose syndrome (ENS) submucosal floor implant surgery – Part I methodology. J Taiwan Inst Chem Eng 2022. [DOI: 10.1016/j.jtice.2022.104481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Schmidt N, Behrbohm H, Goubergrits L, Hildebrandt T, Brüning J. Comparison of rhinomanometric and computational fluid dynamic assessment of nasal resistance with respect to measurement accuracy. Int J Comput Assist Radiol Surg 2022; 17:1519-1529. [PMID: 35821562 DOI: 10.1007/s11548-022-02699-9] [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: 01/11/2022] [Accepted: 06/05/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE Computational fluid dynamics (CFD)-based calculation of intranasal airflow became an important method in rhinologic research. Current evidence shows weak to moderate correlation as well as a systematic underprediction of nasal resistance by numerical simulations. In this study, we investigate whether these differences can be explained by measurement uncertainties caused by rhinomanometric devices and procedures. Furthermore, preliminary findings regarding the impact of tissue movements are reported. METHODS A retrospective sample of 17 patients, who reported impaired nasal breathing and for which rhinomanometric (RMM) measurements using two different devices as well as computed tomography scans were available, was investigated in this study. Three patients also exhibited a marked collapse of the nasal valve. Agreement between both rhinomanometric measurements as well as between rhinomanometry and CFD-based calculations was assessed using linear correlation and Bland-Altman analyses. These analyses were performed for the volume flow rates measured at trans-nasal pressure differences of 75 and 150 Pa during inspiration and expiration. RESULTS The correlation between volume flow rates measured using both RMM devices was good (R2 > 0.72 for all breathing states), and no relevant differences in measured flow rates was observed (21.6 ml/s and 14.8 ml/s for 75 and 150 Pa, respectively). In contrast, correlation between RMM and CFD was poor (R2 < 0.5) and CFD systematically overpredicted RMM-based flow rate measurements (231.8 ml/s and 328.3 ml/s). No differences between patients with and without nasal valve collapse nor between inspiration and expiration were observed. CONCLUSION Biases introduced during RMM measurements, by either the chosen device, the operator or other aspects as for example the nasal cycle, are not strong enough to explain the gross differences commonly reported between RMM- and CFD-based measurement of nasal resistance. Additionally, tissue movement during breathing is most likely also no sufficient explanation for these differences.
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Affiliation(s)
- Nora Schmidt
- Department of Otorhinolaryngology and Facial Plastic Surgery, Park-Klinik Weissensee, Schönstraße 80, 13086, Berlin, Germany.
| | - Hans Behrbohm
- Department of Otorhinolaryngology and Facial Plastic Surgery, Park-Klinik Weissensee, Schönstraße 80, 13086, Berlin, Germany
| | - Leonid Goubergrits
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Hildebrandt
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jan Brüning
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Numerical Simulation of Aspergillus Niger Spore Deposition in Nasal Cavities of a Population in Northwest China. ATMOSPHERE 2022. [DOI: 10.3390/atmos13060911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: As common pathogens in the human respiratory tract, fungal-spore-related health risks have been challenging to evaluate properly. This paper presents numerical simulations of particle deposition of Aspergillus niger spores in human nasal cavities. Methods: 30 healthy adults (including 60 nasal chambers) who lived in northwest China were recruited to conduct a nasal cavity numerical simulation using computational fluid dynamics–discrete phase model (CFD-DPM). The deposition rate in each anatomic area and its influencing variables, such as body position and respiratory flow rate, were analyzed. Results: (1) Under a resting condition, only about 5.57% ± 1.51% Aspergillus niger spores were deposited in the nasal cavity, while most of them escaped from the nasopharynx, and 0.31% ± 0.20% spores entered the maxillary sinus; (2) under an exercising condition, spores deposited in the nasal cavity were about 2.09 times as many as that in the resting state; (3) in a lying position, the A. niger spores deposited evenly on the lateral wall of the nasal cavity and the sinus when compared with a standing position. However, the deposition rate in each anatomic area did not change significantly.
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Inthavong K, Fletcher DF, Khamooshi M, Vahaji S, Salati H. Wet surface wall model for latent heat exchange during evaporation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3581. [PMID: 35142094 PMCID: PMC9285617 DOI: 10.1002/cnm.3581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/31/2022] [Accepted: 02/05/2022] [Indexed: 06/14/2023]
Abstract
Air conditioning is a dual heat and mass transfer process, and the human nasal cavity achieves this through the mucosal wall surface, which is supplied with an energy source through the sub-epithelial network of capillaries. Computational studies of air conditioning in the nasal cavity have included temperature and humidity, but most studies solved these flow parameters separately, and in some cases, a constant mucosal surface temperature was used. Recent developments demonstrated that both heat and mass transfer need to be modeled. This work expands on existing modeling efforts in accounting for the nasal cavity's dual heat and mass transfer process by introducing a new subwall model, given in the Supplementary Materials. The model was applied to a pipe geometry, and a human nasal cavity was recreated from CT-scans, and six inhalation conditions were studied. The results showed that when the energy transfer from the latent heat of evaporation is included, there is a cooling effect on the mucosal surface temperature.
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Affiliation(s)
- Kiao Inthavong
- Mechanical and Automotive EngineeringSchool of Engineering, RMIT UniversityBundooraVictoriaAustralia
| | - David F. Fletcher
- School of Chemical and Biomolecular EngineeringThe University of SydneySydneyNew South WalesAustralia
| | - Mehrdad Khamooshi
- Mechanical and Automotive EngineeringSchool of Engineering, RMIT UniversityBundooraVictoriaAustralia
| | - Sara Vahaji
- Mechanical and Automotive EngineeringSchool of Engineering, RMIT UniversityBundooraVictoriaAustralia
| | - Hana Salati
- Mechanical and Automotive EngineeringSchool of Engineering, RMIT UniversityBundooraVictoriaAustralia
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25
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Corda JV, Shenoy BS, Ahmad KA, Lewis L, K P, Khader SMA, Zuber M. Nasal airflow comparison in neonates, infant and adult nasal cavities using computational fluid dynamics. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 214:106538. [PMID: 34848078 DOI: 10.1016/j.cmpb.2021.106538] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/29/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND OBJECTIVE Neonates are preferential nasal breathers up to 3 months of age. The nasal anatomy in neonates and infants is at developing stages whereas the adult nasal cavities are fully grown which implies that the study of airflow dynamics in the neonates and infants are significant. In the present study, the nasal airways of the neonate, infant and adult are anatomically compared and their airflow patterns are investigated. METHODS Computational Fluid Dynamics (CFD) approach is used to simulate the airflow in a neonate, an infant and an adult in sedentary breathing conditions. The healthy CT scans are segmented using MIMICS 21.0 (Materialise, Ann arbor, MI). The patient-specific 3D airway models are analyzed for low Reynolds number flow using ANSYS FLUENT 2020 R2. The applicability of the Grid Convergence Index (GCI) for polyhedral mesh adopted in this work is also verified. RESULTS This study shows that the inferior meatus of neonates accounted for only 15% of the total airflow. This was in contrast to the infants and adults who experienced 49 and 31% of airflow at the inferior meatus region. Superior meatus experienced 25% of total flow which is more than normal for the neonate. The highest velocity of 1.8, 2.6 and 3.7 m/s was observed at the nasal valve region for neonates, infants and adults, respectively. The anterior portion of the nasal cavity experienced maximum wall shear stress with average values of 0.48, 0.25 and 0.58 Pa for the neonates, infants and adults. CONCLUSIONS The neonates have an underdeveloped nasal cavity which significantly affects their airway distribution. The absence of inferior meatus in the neonates has limited the flow through the inferior regions and resulted in uneven flow distribution.
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Affiliation(s)
- John Valerian Corda
- Department of Aeronautical and Automobile Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, India
| | - B Satish Shenoy
- Department of Aeronautical and Automobile Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, India
| | - Kamarul Arifin Ahmad
- Department of Aerospace Engineering, Universiti Putra Malaysia, Jalan Universiti 1 Serdang, Seri Kembangan, Selangor 43400, Malaysia
| | - Leslie Lewis
- Department of Paediatrics, Kasturba Medical College and Hospital, Manipal 576104, India
| | - Prakashini K
- Department of Radio Diagnosis, Kasturba Medical College and Hospital, Manipal 576104, India
| | - S M Abdul Khader
- Department of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, India
| | - Mohammad Zuber
- Department of Aeronautical and Automobile Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, India.
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26
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Basu S, Akash M, Hochberg N, Senior B, Joseph-McCarthy D, Chakravarty A. From SARS-CoV-2 infection to COVID-19 morbidity: an in silico projection of virion flow rates to the lower airway via nasopharyngeal fluid boluses. RHINOLOGY ONLINE 2022. [DOI: 10.4193/rhinol/21.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: While the nasopharynx is initially the dominant upper airway infection site for SARS-CoV-2, the physiologic mechanism launching the infection at the lower airway is still not well-understood. Based on the rapidity of infection progression to the lungs, it has been hypothesized that the nasopharynx may be acting as the primary seeding zone for subsequent contamination of the lower airway via aspiration of virus-laden boluses of nasopharyngeal fluids. Methodology: To examine the plausibility of the aspiration-driven mechanism, we have computationally tracked the inhalation process in three anatomic airway reconstructions and have quantified the nasopharyngeal liquid volume transmitted to the lower airspace during each aspiration. Results: Extending the numerical trends on aspiration volume to earlier records on aspiration frequencies indicates a total aspirated nasopharyngeal liquid volume of 0.3 – 0.76 ml/day. Subsequently, for mean sputum viral load, our modeling projects that the number of virions reaching the lower airway will range over 2.1×106 – 5.3×106 /day; for peak viral load, the corresponding number hovers between 7.1×108 – 1.8×109. Conclusions: The virion transmission findings fill in a key piece of the mechanistic puzzle on the systemic progression of SARS-CoV-2, and subjectively point to health conditions like dysphagia, with proclivity to increased aspiration, as some of the potential underlying risk factors for aggressive lung infections.
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Moshksayan K, Bahmanzadeh H, Faramarzi M, Sadrizadeh S, Ahmadi G, Abouali O. In-silico investigation of airflow and micro-particle deposition in human nasal airway pre- and post-virtual transnasal sphenoidotomy surgery. Comput Methods Biomech Biomed Engin 2021; 25:1000-1014. [PMID: 34919000 DOI: 10.1080/10255842.2021.1995720] [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: 10/19/2022]
Abstract
Sphenoid sinus, located posterior to the nasal cavity, is difficult to reach for a surgery. Several operation procedures are available for sphenoidotomy, including endoscopic surgeries. Although the endoscopic sinus surgery is minimally invasive with low post-operative side effects, further optimization is required. Transnasal sphenoidotomy is a low invasive alternative to transethmoidal sphenoidotomy, but it still needs to be studied to understand its effects on the airflow pattern and the particle deposition. In this work, we simulated airflow and the micro-particle deposition in the nasal airway of a middle-aged man to investigate the change in particle deposition in the sphenoid sinus after virtual transnasal sphenoidotomy surgery. The results demonstrated that after transnasal sphenoidotomy, particle deposition in the targeted sphenoid sinus was an order of magnitude lower than that observed after virtual transethmoidal sphenoidotomy surgery. In addition, the diameter of the particles for the peak deposition fraction in the targeted sinus was shifted to smaller diameters after the transnasal sphenoidotomy surgery compared with that in the post-transethmoidal condition. These results suggest that the endoscopic transnasal sphenoidotomy can be a better procedure for sphenoid surgeries as it decreases the chance of bacterial contaminations and consequently lowers the surgical side effects and recovery time.
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Affiliation(s)
- Khashayar Moshksayan
- Shiraz University, Shiraz, Fars, Iran.,University of Texas at Austin, Austin, TX, USA
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Computational Fluid Dynamics Modeling of Nasal Obstruction and Associations with Patient-Reported Outcomes. Plast Reconstr Surg 2021; 148:592e-600e. [PMID: 34550944 DOI: 10.1097/prs.0000000000008328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Nasal obstruction is a common problem, with significant impact on quality of life. Accurate diagnosis may be challenging because of the complex and dynamic nature of the involved anatomy. Computational fluid dynamics modeling has the ability to identify specific anatomical defects, allowing for a targeted surgical approach. The goal of the current study is to better understand nasal obstruction as it pertains to disease-specific quality of life by way of a novel computational fluid dynamics model of nasal airflow. METHODS Fifty-three patients with nasal obstruction underwent computational fluid dynamics modeling based on computed tomographic imaging. Nasal resistance was compared to demographic data and baseline subjective nasal patency based on Nasal Obstructive Symptom Evaluation scores. RESULTS Mean Nasal Obstructive Symptom Evaluation score among all patients was 72.6. Nasal Obstructive Symptom Evaluation score demonstrated a significant association with nasal resistance in patients with static obstruction (p = 0.03). There was a positive correlation between Nasal Obstructive Symptom Evaluation score and nasal resistance in patients with static bilateral nasal obstruction (R2 = 0.32) and poor correlation in patients with dynamic bilateral obstruction caused by nasal valve collapse (R2 = 0.02). Patients with moderate and severe bilateral symptoms had significantly higher nasal resistance compared to those with unilateral symptoms (p = 0.048). CONCLUSIONS Nasal obstruction is a multifactorial condition in most patients. This study shows correlation between simulated nasal resistance and Nasal Obstructive Symptom Evaluation score in a select group of patients. There is currently no standardized diagnostic algorithm or gold standard objective measure of nasal airflow; however, computational fluid dynamics may better inform treatment planning and surgical techniques on an individual basis. CLINICAL QUESTION/LEVEL OF EVIDENCE Risk, V.
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Omura K, Han B, Nishijima H, Aoki S, Ebihara T, Kondo K, Otori N, Kojima H, Yamasoba T, Kikuta S. Heterogeneous distribution of mature olfactory sensory neurons in human olfactory epithelium. Int Forum Allergy Rhinol 2021; 12:266-277. [PMID: 34538025 DOI: 10.1002/alr.22885] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND The olfactory cleft (OC) comprising the olfactory epithelium (OE) is the most important anatomical location for olfactory function. Endoscopic sinus surgery (ESS) is used to treat diseases related to the OC and improve olfactory dysfunction. However, iatrogenic OE injury occasionally occurs. Comprehensive knowledge of the olfactory region is required to avoid damage to the OE during endoscopic procedures. METHODS Immunohistochemistry was performed on olfactory mucosa obtained from the unaffected side of olfactory neuroblastoma surgical specimens. The OE was defined as the epithelium containing mature olfactory sensory neurons (OSNs). The distribution and cell kinetics of the OE were examined. RESULTS The OE was selectively localized to the anterior two-thirds of the superior turbinate (ST) and in the nasal septum (NS) just opposite to the ST; the OE was not detected within the mucosa of the superior meatus. The density of mature OSNs was high at the ethmoid tegmen but gradually decreased with distance from the ethmoid tegmen. The extent of cell death and proliferation was relatively even across the OE. Analysis of airflow profiles revealed that resection of inferior ST does not decrease airflow to the OC. CONCLUSION The results indicate that the distribution and degree of differentiation of mature OSNs are heterogenous throughout the OE. Epithelial resection of the anterior or superior ST has the potential to damage olfactory function. Resection of the inferior or posterior ST or widening of the superior meatus is a safer alternative that does not damage mature OSNs or alter airflow to the OC.
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Affiliation(s)
- Kazuhiro Omura
- Department of Otorhinolaryngology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Bing Han
- Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hironobu Nishijima
- Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Satoshi Aoki
- Department of Otorhinolaryngology, Dokkyo Medical University Saitama Medical Center, Koshigaya, Saitama, Japan
| | - Teru Ebihara
- Department of Otorhinolaryngology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Kenji Kondo
- Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Nobuyoshi Otori
- Department of Otorhinolaryngology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Hiromi Kojima
- Department of Otorhinolaryngology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Tatsuya Yamasoba
- Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shu Kikuta
- Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Xu C, Zheng X, Shen S. A numerical study of the effects of ambient temperature and humidity on the particle growth and deposition in the human airway. ENVIRONMENTAL RESEARCH 2021; 200:111751. [PMID: 34303679 DOI: 10.1016/j.envres.2021.111751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/25/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
A numerical study was conducted on the effects of ambient temperature and humidity on the transportation of sodium chloride particles (100 nm-1 μm) in a human airway model ranging from the nasal cavity to bronchi. A mucus-tissue structure was adopted to model the mass and heat transfer on the airway surface boundary. The temperature and humidity distributions of the respiratory flow were calculated and then the interaction between the particle and water vapor was further analyzed. It was predicted that the particle size grew to the ratio of 5-6 under subsaturation conditions because of hygroscopicity, which shifted the deposition efficiency in opposite directions on dependence of the initial particle size. However, the particles could be drastically raised to 40 times of the initial 100 nm diameter if the supersaturation-induced condensation was established, that was prone to occur under the cold-dry condition, and consequently promoted the deposition significantly. Such behavior might effectively contribute to the revitalized coronavirus disease 2019 (COVID-19) pandemic in addition to the more active virus itself in winter.
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Affiliation(s)
- Chang Xu
- Department of Engineering Physics, Tsinghua University, Beijing, China; Beijing Key Laboratory of City Integrated Emergency Response Science, Beijing, China
| | - Xin Zheng
- Department of Engineering Physics, Tsinghua University, Beijing, China.
| | - Shifei Shen
- Department of Engineering Physics, Tsinghua University, Beijing, China; Anhui Province Key Laboratory of Human Safety, Hefei, Anhui, China
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31
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Inthavong K, Shang Y, Del Gaudio JM, Wise SK, Edwards TS, Bradshaw K, Wong E, Smith M, Singh N. Inhalation and deposition of spherical and pollen particles after middle turbinate resection in a human nasal cavity. Respir Physiol Neurobiol 2021; 294:103769. [PMID: 34352383 DOI: 10.1016/j.resp.2021.103769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 10/20/2022]
Abstract
Middle turbinate resection significantly alters the anatomy and redistributes the inhaled air. The superior half of the main nasal cavity is opened up, increasing accessibility to the region. This is expected to increase inhalation dosimetry to the region during exposure to airborne particles. This study investigated the influence of middle turbinate resection on the deposition of inhaled pollutants that cover spherical and non-spherical particles (e.g. pollen). A computational model of the nasal cavity from CT scans, and its corresponding post-operative model with virtual surgery performed was created. Two constant flow rates of 5 L/min, and 15 L/min were simulated under a laminar flow field. Inhaled particles including pollen (non-spherical), and a spherical particle with reference density of 1000 kg/m3 were introduced in the surrounding atmosphere. The effect of surgery was most prominent in the less patent cavity side, since the change in anatomy was proportionally greater relative to the original airway space. The left cavity produced an increase in particle deposition at a flow rate of 15 L/min. The main particle deposition mechanisms were inertial impaction, and to a lesser degree gravitational sedimentation. The results are expected to provide insight into inhalation efficiency of different aerosol types, and the likelihood of deposition in different nasal cavity surfaces.
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Affiliation(s)
- Kiao Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Yidan Shang
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - John M Del Gaudio
- Department of Otolaryngology-Head and Neck Surgery Emory University, Atlanta, GA, USA
| | - Sarah K Wise
- Department of Otolaryngology-Head and Neck Surgery Emory University, Atlanta, GA, USA
| | - Thomas S Edwards
- Department of Otolaryngology-Head and Neck Surgery Emory University, Atlanta, GA, USA
| | - Kimberley Bradshaw
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
| | - Eugene Wong
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
| | - Murray Smith
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
| | - Narinder Singh
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia; Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Westmead, NSW 2145, Australia
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Abstract
Nasal decongestant reduces blood flow to the nasal turbinates, reducing tissue volume and increasing nasal airway patency. This study maps the changes in nasal anatomy and measures how these changes affect nasal resistance, flow partitioning between superior and inferior cavity, flow patterns and wall shear stress. High-resolution MRI was applied to capture nasal anatomy in 10 healthy subjects before and after application of a topical decongestant. Computational fluid dynamics simulated nasal airflow at steady inspiratory flow rates of 15 L.min[Formula: see text] and 30 L.min[Formula: see text]. The results show decongestion mainly increases the cross-sectional area in the turbinate region and SAVR is reduced (median approximately 40[Formula: see text] reduction) in middle and lower parts of the cavity. Decongestion reduces nasal resistance by 50[Formula: see text] on average, while in the posterior cavity, nasal resistance decreases by a median factor of approximately 3 after decongestion. We also find decongestant regularises nasal airflow and alters the partitioning of flow, significantly decreasing flow through the superior portions of the nasal cavity. By comparing nasal anatomies and airflow in their normal state with that when pharmacologically decongested, this study provides data for a broad range of anatomy and airflow conditions, which may help characterize the extent of nasal variability.
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33
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Senanayake P, Salati H, Wong E, Bradshaw K, Shang Y, Singh N, Inthavong K. The impact of nasal adhesions on airflow and mucosal cooling - A computational fluid dynamics analysis. Respir Physiol Neurobiol 2021; 293:103719. [PMID: 34147672 DOI: 10.1016/j.resp.2021.103719] [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: 12/27/2020] [Revised: 06/01/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
Nasal adhesions are a known postoperative complication following surgical procedures for nasal airway obstruction (NAO); and are a common cause of surgical failure, with patients often reporting significant NAO, despite relatively minor adhesion size. Division of such nasal adhesions often provides much greater relief than anticipated, based on the minimal reduction in cross-sectional area associated with the adhesion. The available literature regarding nasal adhesions provides little evidence examining their quantitative and qualitative effects on nasal airflow using objective measures. This study examined the impact of nasal adhesions at various anatomical sites on nasal airflow and mucosal cooling using computational fluid dynamics (CFD). A high-resolution CT scan of the paranasal sinuses of a 25-year-old, healthy female patient was segmented to create a three-dimensional nasal airway model. Virtual nasal adhesions of 2.5 mm diameter were added to various locations within the nasal cavity, representing common sites seen following NAO surgery. A series of models with single adhesions were created. CFD analysis was performed on each model and compared with a baseline no-adhesion model, comparing airflow and heat and mass transfer. The nasal adhesions resulted in no significant change in bulk airflow patterns through the nasal cavity. However, significant changes were observed in local airflow and mucosal cooling around and immediately downstream to the nasal adhesions. These were most evident with anterior nasal adhesions at the internal valve and anterior inferior turbinate. Postoperative nasal adhesions create local airflow disruption, resulting in reduced local mucosal cooling on critical surfaces, explaining the exaggerated perception of nasal obstruction. In particular, anteriorly located adhesions created greater disruption to local airflow and mucosal cooling, explaining their associated greater subjective sensation of obstruction.
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Affiliation(s)
- Praween Senanayake
- Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Sydney, NSW, Australia
| | - Hana Salati
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - Eugene Wong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - Kimberley Bradshaw
- Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Sydney, NSW, Australia
| | - Yidan Shang
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - Narinder Singh
- Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Sydney, NSW, Australia; Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
| | - Kiao Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia.
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Lim ZF, Rajendran P, Musa MY, Lee CF. Nasal airflow of patient with septal deviation and allergy rhinitis. Vis Comput Ind Biomed Art 2021; 4:14. [PMID: 34014417 PMCID: PMC8137764 DOI: 10.1186/s42492-021-00080-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/27/2021] [Indexed: 12/30/2022] Open
Abstract
A numerical simulation of a patient’s nasal airflow was developed via computational fluid dynamics. Accordingly, computerized tomography scans of a patient with septal deviation and allergic rhinitis were obtained. The three-dimensional (3D) nasal model was designed using InVesalius 3.0, which was then imported to (computer aided 3D interactive application) CATIA V5 for modification, and finally to analysis system (ANSYS) flow oriented logistics upgrade for enterprise networks (FLUENT) to obtain the numerical solution. The velocity contours of the cross-sectional area were analyzed on four main surfaces: the vestibule, nasal valve, middle turbinate, and nasopharynx. The pressure and velocity characteristics were assessed at both laminar and turbulent mass flow rates for both the standardized and the patient’s model nasal cavity. The developed model of the patient is approximately half the size of the standardized model; hence, its velocity was approximately two times more than that of the standardized model.
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Affiliation(s)
- Zi Fen Lim
- School of Aerospace Engineering, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
| | - Parvathy Rajendran
- School of Aerospace Engineering, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia. .,Faculty of Engineering & Computing, First City University College, 47800, Selangor, Malaysia.
| | - Muhamad Yusri Musa
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
| | - Chih Fang Lee
- School of Aerospace Engineering, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
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35
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Numerical simulation of unsteady airflow in a nasal cavity for various sizes of maxillary sinus opening in a virtual endoscopic surgery. Respir Physiol Neurobiol 2021; 291:103690. [PMID: 33989811 DOI: 10.1016/j.resp.2021.103690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/01/2021] [Accepted: 05/09/2021] [Indexed: 11/22/2022]
Abstract
Functional endoscopic sinus surgery (FESS) is performed to treat sinusitis when treatment with medication fails. In the present study, three different virtual maxillary sinus endoscopic surgeries were performed on a realistic 3-D computational model of the nasal cavity of an adult male under the supervision of a specialist. They included only uncinectomy, uncinectomy + 8mm Middle Meatal Antrostomy (MMA) and uncinectomy + 18 mm MMA. Simulations were performed for two human activity respiratory rates, including rest and moderate activities, and effects of different surgeries and respiratory rates on maxillary sinus were investigated. It was found that after endoscopic sinus surgery, the volume of air entering the maxillary sinus increased significantly, and as the size of the MMA increased, or the breathing condition changed from rest to moderate activity, this volume of air increased. For the rest condition, on average for both nasal passages, for uncinectomy +8 mm MMA, around 15 % of the inhaled flow and 7 % of the exhaled flow enter the maxillary sinuses. For uncinectomy +18 mm MMA, these values are 24 % and 14 %, respectively. As human activity increases, a lower portion of inhaled and exhaled air enters the maxillary sinuses. For the moderate activity condition, on average for both nasal passages, for uncinectomy +8 mm MMA, around 11 % of the inhaled flow and 6 % of the exhaled flow rate enters the maxillary sinus. For uncinectomy +18 mm MMA, these values are 16 % and 8%, respectively. Comparing the steady and unsteady simulation results showed that the quasi-steady flow assumption could predict the flow in the maxillary sinus and the volume of air entering the sinuses, almost at any moment of respiration, with acceptable accuracy.
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36
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Basu S. Computational characterization of inhaled droplet transport to the nasopharynx. Sci Rep 2021; 11:6652. [PMID: 33758241 PMCID: PMC7988116 DOI: 10.1038/s41598-021-85765-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 03/05/2021] [Indexed: 01/31/2023] Open
Abstract
How human respiratory physiology and the transport phenomena associated with inhaled airflow in the upper airway proceed to impact transmission of SARS-CoV-2, leading to the initial infection, stays an open question. An answer can help determine the susceptibility of an individual on exposure to a COVID-2019 carrier and can also provide a preliminary projection of the still-unknown infectious dose for the disease. Computational fluid mechanics enabled tracking of respiratory transport in medical imaging-based anatomic domains shows that the regional deposition of virus-laden inhaled droplets at the initial nasopharyngeal infection site peaks for the droplet size range of approximately 2.5-19 [Formula: see text]. Through integrating the numerical findings on inhaled transmission with sputum assessment data from hospitalized COVID-19 patients and earlier measurements of ejecta size distribution generated during regular speech, this study further reveals that the number of virions that may go on to establish the SARS-CoV-2 infection in a subject could merely be in the order of hundreds.
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Affiliation(s)
- Saikat Basu
- Department of Mechanical Engineering, South Dakota State University, Brookings, SD, 57007, USA.
- Department of Otolaryngology / Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA.
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Xavier R, Menger DJ, de Carvalho HC, Spratley J. An Overview of Computational Fluid Dynamics Preoperative Analysis of the Nasal Airway. Facial Plast Surg 2021; 37:306-316. [PMID: 33556971 DOI: 10.1055/s-0041-1722956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Evaluation of the nasal airway is crucial for every patient with symptoms of nasal obstruction as well as for every patient with other nasal symptoms. This assessment of the nasal airway comprises clinical examination together with imaging studies, with the correlation between findings of this evaluation and symptoms reported by the patient being based on the experience of the surgeon. Measuring nasal airway resistance or nasal airflow can provide additional data regarding the nasal airway, but the benefit of these objective measurements is limited due to their lack of correlation with patient-reported evaluation of nasal breathing. Computational fluid dynamics (CFD) has emerged as a valuable tool to assess the nasal airway, as it provides objective measurements that correlate with patient-reported evaluation of nasal breathing. CFD is able to evaluate nasal airflow and measure variables such as heat transfer or nasal wall shear stress, which seem to reflect the activity of the nasal trigeminal sensitive endings that provide sensation of nasal breathing. Furthermore, CFD has the unique capacity of making airway analysis of virtual surgery, predicting airflow changes after trial virtual modifications of the nasal airway. Thereby, CFD can assist the surgeon in deciding surgery and selecting the surgical techniques that better address the features of each specific nose. CFD has thus become a trend in nasal airflow assessment, providing reliable results that have been validated for analyzing airflow in the human nasal cavity. All these features make CFD analysis a mainstay in the armamentarium of the nasal surgeon. CFD analysis may become the gold standard for preoperative assessment of the nasal airway.
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Affiliation(s)
- Rui Xavier
- Department of Otorhinolaryngology, Hospital Luz Arrabida, Porto, Portugal
| | - Dirk-Jan Menger
- Department of Otorhinolaringology, University Medical Center, Utrecht, The Netherlands
| | - Henrique Cyrne de Carvalho
- Department of Medicine, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Jorge Spratley
- Department of Otorhinolaringology, Faculdade de Medicina da Universidade do Porto, Centro Hospitalar e Universitário S. João and Centro de Investigação em Tecnologias e Serviços de Saúde (CINTESIS), Porto, Portugal
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Issakhov A, Zhandaulet Y, Abylkassymova A, Issakhov A. A numerical simulation of air flow in the human respiratory system for various environmental conditions. Theor Biol Med Model 2021; 18:2. [PMID: 33407610 PMCID: PMC7789411 DOI: 10.1186/s12976-020-00133-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 11/16/2020] [Indexed: 11/27/2022] Open
Abstract
The functions of the nasal cavity are very important for maintaining the internal environment of the lungs since the inner walls of the nasal cavity control the temperature and saturation of the inhaled air with water vapor until the nasopharynx is reached. In this paper, three-dimensional computational studies of airflow transport in the models of the nasal cavity were carried out for the usual inspiratory velocity in various environmental conditions. Three-dimensional numerical results are compared with experimental data and calculations of other authors. Numerical results show that during normal breathing, the human nose copes with heat and relative moisture metabolism in order to balance the intra-alveolar conditions. It is also shown in this paper that a normal nose can maintain balance even in extreme conditions, for example, in cold and hot weather. The nasal cavity accelerates heat transfer by narrowing the air passages and swirls from the nasal concha walls of the inner cavity.
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Affiliation(s)
- Alibek Issakhov
- Al-Farabi Kazakh National University, av. al-Farabi 71, 050040, Almaty, Republic of Kazakhstan. .,Kazakh British Technical University, Almaty, Republic of Kazakhstan.
| | - Yeldos Zhandaulet
- Al-Farabi Kazakh National University, av. al-Farabi 71, 050040, Almaty, Republic of Kazakhstan.,Kazakh British Technical University, Almaty, Republic of Kazakhstan
| | - Aizhan Abylkassymova
- Al-Farabi Kazakh National University, av. al-Farabi 71, 050040, Almaty, Republic of Kazakhstan.,Kazakh British Technical University, Almaty, Republic of Kazakhstan
| | - Assylbek Issakhov
- Al-Farabi Kazakh National University, av. al-Farabi 71, 050040, Almaty, Republic of Kazakhstan.,Kazakh British Technical University, Almaty, Republic of Kazakhstan
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39
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Nasal air conditioning following total inferior turbinectomy compared to inferior turbinoplasty - A computational fluid dynamics study. Clin Biomech (Bristol, Avon) 2021; 81:105237. [PMID: 33272646 DOI: 10.1016/j.clinbiomech.2020.105237] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/10/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND The aim of this study was to use computational fluid dynamics (CFD) to investigate the effects on nasal heat exchange and humidification of two different surgical techniques for reducing the inferior turbinate under different environmental conditions. METHODS Virtual surgery using two techniques of turbinate reduction was performed in eight nasal airway obstruction patients. Bilateral nasal airway models for each patient were compared: 1) Pre-operative 2) Post inferior turbinoplasty 3) Post total inferior turbinate resection (ITR). Two representative healthy models were included. Three different environmental conditions were investigated 1) ambient air 2) cold, dry air 3) hot, humid air. CFD modelling of airflow and conditioning was performed under steady-state, laminar, inspiratory conditions. FINDINGS Nasal conditioning is significantly altered following inferior turbinate reduction surgery, particularly with ITR under cold, dry inspired air (CDA). The degree of impairment is minor under the simulated range of environmental conditions (temperature = 12-40 °C; relative humidity = 13-80%). Streams of significantly colder air are found in the nasopharynx and more prevalent under CDA in ITR. These are related to high velocity flow streams, which remain cool in their centre throughout the widened inferior nasal cavity. INTERPRETATION Reduced air-mucosal heat exchange and moisture carrying capacity occurs under cooler temperatures in patients following inferior turbinate surgery. The clinical impact in extremely cold and dry conditions in groups with poor baseline respiratory function, respiratory illness, or endurance athletes is of special interest.
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40
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Effect of inhalation on oropharynx collapse via flow visualisation. J Biomech 2020; 118:110200. [PMID: 33548657 DOI: 10.1016/j.jbiomech.2020.110200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 11/28/2020] [Accepted: 12/11/2020] [Indexed: 11/21/2022]
Abstract
Computational fluid dynamics (CFD) modelling has made significant contributions to the analysis and treatment of obstructive sleep apnoea (OSA). While several investigations have considered the flow field within the airway and its effect on airway collapse, the effect of breathing on the pharynx region is still poorly understood. We address this gap via a combined experimental and numerical study of the flow field within the pharynx and its impacts upon airway collapse. Two 3D experimental models of the upper airway were constructed based upon computerised tomography scans of a specific patient diagnosed with severe OSA; (i) a transparent, rigid model for flow visualisation, and (ii) a semi-flexible model for understanding the effect of flow on pharynx collapse. Validated simulation results for this geometry indicate that during inhalation, negative pressure (with respect to atmospheric pressure) caused by vortices drives significant narrowing of the pharynx. This narrowing is strongly dependent upon whether inhalation occurs through the nostrils. Thus, the methodology presented here can be used to improve OSA treatment by improving the design methodology for personalised, mandibular advancement splints (MAS) that minimise OSA during sleep.
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41
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Can computational fluid dynamic models help us in the treatment of chronic rhinosinusitis. Curr Opin Otolaryngol Head Neck Surg 2020; 29:21-26. [PMID: 33315616 DOI: 10.1097/moo.0000000000000682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW The aim of this study was to review the recent literature (January 2017-July 2020) on computational fluid dynamics (CFD) studies relating to chronic rhinosinusitis (CRS), including airflow within the pre and postoperative sinonasal cavity, virtual surgery, topical drug and saline delivery (sprays, nebulizers and rinses) and olfaction. RECENT FINDINGS Novel CFD-specific parameters (heat flux and wall shear stress) are highly correlated with patient perception of nasal patency. Increased ostial size markedly improves sinus ventilation and drug delivery. New virtual surgery tools allow surgeons to optimize interventions. Sinus deposition of nasal sprays is more effective with smaller, low-inertia particles, outside of the range produced by many commercially available products. Saline irrigation effectiveness is improved using greater volume, with liquid entering sinuses via 'flooding' of ostia rather than direct jet entry. SUMMARY CFD has provided new insights into sinonasal airflow, air-conditioning function, the nasal cycle, novel measures of nasal patency and the impact of polyps and sinus surgery on olfaction. The deposition efficiency of topical medications on sinus mucosa can be markedly improved through parametric CFD experiments by optimising nasal spray particle size and velocity, nozzle angle and insertion location, while saline irrigation effectiveness can be optimized by modelling squeeze bottle volume and head position. More sophisticated CFD models (inhalation and exhalation, spray particle and saline irrigation) will increasingly provide translational benefits in the clinical management of CRS.
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42
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Calmet H, Inthavong K, Owen H, Dosimont D, Lehmkuhl O, Houzeaux G, Vázquez M. Computational modelling of nasal respiratory flow. Comput Methods Biomech Biomed Engin 2020; 24:440-458. [PMID: 33175592 DOI: 10.1080/10255842.2020.1833865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CFD has emerged as a promising diagnostic tool for clinical trials, with tremendous potential. However, for real clinical applications to be useful, overall statistical findings from large population samples (e.g., multiple cases and models) are needed. Fully resolved solutions are not a priority, but rather rapid solutions with fast turn-around times are desired. This leads to the issue of what are the minimum modelling criteria for achieving adequate accuracy in respiratory flows for large-scale clinical applications, with a view to rapid turnaround times. This study simulated a highly-resolved solution using the large eddy simulation (LES) method as a reference case for comparison with lower resolution models that included larger time steps and no turbulence modelling. Differences in solutions were quantified by pressure loss, flow resistance, unsteadiness, turbulence intensity, and hysteresis effects from multiple cycles. The results demonstrated that sufficient accuracy could be achieved with lower resolution models if the mean flow was considered. Furthermore, to achieve an established transient result unaffected by the initial start-up quiescent effects, the results need to be taken from at least the second respiration cycle. It was also found that the exhalation phase exhibited strong turbulence. The results are expected to provide guidance for future modelling efforts for clinical and engineering applications requiring large numbers of cases using simplified modelling approaches.
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Affiliation(s)
- H Calmet
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - K Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Melbourne, Australia
| | - H Owen
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - D Dosimont
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - O Lehmkuhl
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - G Houzeaux
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - M Vázquez
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
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43
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Kimura S, Miura S, Sera T, Yokota H, Ono K, Doorly DJ, Schroter RC, Tanaka G. Voxel-based simulation of flow and temperature in the human nasal cavity. Comput Methods Biomech Biomed Engin 2020; 24:459-466. [PMID: 33095062 DOI: 10.1080/10255842.2020.1836166] [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: 10/23/2022]
Abstract
The nasal airway is an extremely complex structure, therefore grid generation for numerical prediction of airflow in the nasal cavity is time-consuming. This paper describes the development of a voxel-based model with a Cartesian structured grid, which is characterized by robust and automatic grid generation, and the simulation of the airflow and air-conditioning in an individual human nasal airway. Computed tomography images of a healthy adult nose were used to reconstruct a virtual three-dimensional model of the nasal airway. Simulations of quiet restful inspiratory flow were then performed using a Neumann boundary condition for the energy equation to adequately resolve the flow and heat transfer. General agreements of airflow patterns, which were a high-speed jet posterior to the nasal valve and recirculating flow that occupied the anterior part of the upper cavity, and temperature distributions of the airflow and septum wall were confirmed by comparing in-vivo measurements with numerical simulation results.
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Affiliation(s)
- Shinya Kimura
- Graduate School of Engineering, Chiba University, Chiba, Japan
| | - Shuta Miura
- Graduate School of Engineering, Chiba University, Chiba, Japan
| | - Toshihiro Sera
- Department of Mechanical Engineering, Kyushu University, Fukuoka, Japan
| | - Hideo Yokota
- Image Processing Research Team, Center for Advanced Photonics, RIKEN, Wako, Japan
| | - Kenji Ono
- Interdisciplinary Computational Science Section, Research Institute for Information Technology, Kyushu University, Fukuoka, Japan
| | - Denis J Doorly
- Department of Aeronautics, Imperial College London, London, UK
| | | | - Gaku Tanaka
- Graduate School of Engineering, Chiba University, Chiba, Japan
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44
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Na Y, Chung SK, Byun S. Numerical study on the heat-recovery capacity of the human nasal cavity during expiration. Comput Biol Med 2020; 126:103992. [PMID: 32987204 DOI: 10.1016/j.compbiomed.2020.103992] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/29/2020] [Accepted: 09/13/2020] [Indexed: 12/31/2022]
Abstract
The characteristics of the thermal field in the human nasal cavity during the expiration period were investigated using computational fluid dynamics. Heat and water-vapor recovery features were quantitatively investigated under realistic distributions of the epithelial surface and air temperature. A constant expiratory flow rate of 250 mL/s was assumed. The epithelial surface temperature was approximately 34.3-34.4 °C in the nasopharynx and 33.5-33.6 °C in the vestibule region, and these values are in good agreement with the measurement data in the literature. We observed that heat-recovery from the exhaled air mostly occurred in the posterior turbinate region, and the amount of heat recovered is estimated to be approximately 1/3 of the heat supply during inspiration. Because of this heat transfer from the exhaled air to the epithelial surface, the temperature of the epithelial surface increased in this region, and the exhaled air temperature dropped through the turbinate airway. Water-vapor recovery primarily occurs in the posterior segments of the turbinates; however, the amount of water-vapor transfer was approximately 1/5 of that in inspiration. Accordingly, the relative humidity of the exhaled air remained constant throughout the airway.
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Affiliation(s)
- Yang Na
- Department of Mechanical Engineering, Konkuk University, Seoul 05029, Republic of Korea.
| | - Seung-Kyu Chung
- Department of Otorhinolaryngology: Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul, Republic of Korea
| | - Seongsu Byun
- Department of Mechanical Engineering, Konkuk University, Seoul 05029, Republic of Korea
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45
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Radics BL, Makan G, Coppens T, André N, Page C, Dégrugilliers L, Bayat SK, Gingl Z, Gyurkovits Z, M Tóth T, Hantos Z, Bayat S. Effect of nasal airway nonlinearities on oscillometric resistance measurements in infants. J Appl Physiol (1985) 2020; 129:591-598. [PMID: 32702268 DOI: 10.1152/japplphysiol.00128.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Oscillometric measurements of respiratory system resistance (Rrs) in infants are usually made via the nasal pathways, which not only significantly contribute to overall Rrs but also introduce marked flow (V')-dependent changes. We employed intrabreath oscillometry in casts of the upper airways constructed from head CT images of 46 infants. We examined oscillometric nasal resistance (Rn) in upper airway casts with no respiratory flow (R0) and the effect of varying V' on Rn by simulating tidal breathing. A characteristic nonlinear relationship was found between Rn and V', exhibiting segmental linearity and a prominent breakpoint (V'bp) after log-log transformation. V'bp was linearly related to the preceding value of end-expiratory volume acceleration (V″eE; on average r2 = 0.96, P < 0.001). Rn depended on V', and R at end-expiration (ReE) showed a strong dependence on V″eE in every cast (r2 = 0.994, P < 001) with considerable interindividual variability. The intercept of the linear regression of ReE versus V″eE was found to be a close estimate of R0. These findings were utilized in reanalyzed Rrs data acquired in vivo in a small group of infants (n = 15). Using a graphical method to estimate R0 from ReE, we found a relative contribution of V'-dependent nonlinearity to total resistance of up to 33%. In conclusion, we propose a method for correcting the acceleration-dependent nonlinearity error in ReE. This correction can be adapted to estimate R0 from a single intrabreath oscillometric measurement, which would reduce the masking effects of the upper airways on the changes in the intrathoracic resistance.NEW & NOTEWORTHY Oscillometric measurements of respiratory system resistance (Rrs) in infants are usually made via the nasal pathways, which not only significantly contribute to overall Rrs but also introduce marked flow acceleration-dependent distortions. Here, we propose a method for correcting flow acceleration-dependent nonlinearity error based on in vitro measurements in 3D-printed upper airway casts of infants as well as in vivo measurements. This correction can be adapted to estimate Rrs from a single intrabreath oscillometric measurement.
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Affiliation(s)
- Bence L Radics
- Department of Pulmonology, University of Szeged, Szeged, Hungary
| | - Gergely Makan
- Department of Technical Informatics, University of Szeged, Szeged, Hungary
| | | | - Nicolas André
- Department of Otorhinolaryngology, Amiens University Hospital, Amiens, France
| | - Cyril Page
- Department of Otorhinolaryngology, Amiens University Hospital, Amiens, France
| | - Loïc Dégrugilliers
- Department of Pediatric Intensive Care, Amiens University Hospital, Amiens, France
| | | | - Zoltán Gingl
- Department of Technical Informatics, University of Szeged, Szeged, Hungary
| | - Zita Gyurkovits
- Department of Obstetrics and Gynaecology, University of Szeged, Szeged, Hungary
| | - Tivadar M Tóth
- Department of Mineralogy, Geochemistry, and Petrology, University of Szeged, Szeged, Hungary
| | - Zoltan Hantos
- County Hospital for Chest Diseases, Deszk, Hungary.,Department of Anaesthesiology and Intensive Therapy, Semmelweis University, Budapest, Hungary
| | - Sam Bayat
- Department of Pulmonology and Physiology, Grenoble University Hospital, Grenoble, France.,Inserm UA7 STROBE Laboratory, Grenoble, France
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Bastir M, Megía I, Torres-Tamayo N, García-Martínez D, Piqueras FM, Burgos M. Three-dimensional analysis of sexual dimorphism in the soft tissue morphology of the upper airways in a human population. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 171:65-75. [PMID: 31837016 DOI: 10.1002/ajpa.23944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 09/17/2019] [Accepted: 09/24/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Several studies have analyzed the sexual dimorphism of the skeletal cranial airways. This study aimed to quantify the three-dimensional (3D) morphology of the soft tissues of the upper airways in a human population. We addressed hypotheses about morphological features related to respiratory and energetic aspects of nasal sexual dimorphism. METHODS We reconstructed 3D models of 41 male and female soft tissue nasal airways from computed tomography data. We measured 280 landmarks and semilandmarks for 3D-geometric morphometric analyses to test for differences in size and 3D morphology of different functional compartments of the soft tissue airways. RESULTS We found statistical evidence for sexual dimorphism: Males were larger than females. 3D features indicated taller and wider inflow tracts, taller outflow tracts and slightly taller internal airways in males. These characteristics are compatible with greater airflow in males. DISCUSSION The differences in 3D nasal airway morphology are compatible with the respiratory-energetics hypothesis according to which males differ from females because of greater energetic demands. Accordingly, structures related to inflow and outflow of air show stronger signals than structures relevant for air-conditioning.
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Affiliation(s)
- Markus Bastir
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - Irene Megía
- Departamento de Prehistoria y Arqueología, Campus de Cantoblanco, Universidad Autónoma de Madrid, Madrid, Spain
| | - Nicole Torres-Tamayo
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | | | - Francisco M Piqueras
- Servicio de Otorrinolaringología, Hospital General Universitario Morales Meseguer, Murcia, Spain
| | - Manuel Burgos
- Universidad Politécnica de Cartagena, Departamento de Ingeniería Térmica y de Fluidos, Cartagena, Spain
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47
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Dang Khoa N, Phuong NL, Ito K. Numerical modeling of nanoparticle deposition in realistic monkey airway and human airway models: a comparative study. Inhal Toxicol 2020; 32:311-325. [DOI: 10.1080/08958378.2020.1800148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Nguyen Dang Khoa
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, Japan
| | - Nguyen Lu Phuong
- Faculty of Environment, University of Natural resources and Environment, Ho Chi Minh City, Vietnam
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, Fukuoka, Japan
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48
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Ormiskangas J, Valtonen O, Kivekäs I, Dean M, Poe D, Järnstedt J, Lekkala J, Harju T, Saarenrinne P, Rautiainen M. Assessment of PIV performance in validating CFD models from nasal cavity CBCT scans. Respir Physiol Neurobiol 2020; 282:103508. [PMID: 32739458 DOI: 10.1016/j.resp.2020.103508] [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: 04/14/2020] [Revised: 07/08/2020] [Accepted: 07/26/2020] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of our study was to investigate how well Particle Image Velocimetry (PIV) measurements could serve Computational Fluid Dynamics (CFD) model validation for nasal airflow. MATERIAL AND METHODS For the PIV measurements, a silicone model of the nose based on cone beam computed tomography (CBCT) scans of a patient was made. Corresponding CFD calculations were conducted with laminar and two turbulent models (k-ω and k-ω SST). RESULTS CFD and PIV results corresponded well in our study. Especially, the correspondence of CFD calculations between the laminar and turbulent models was found to be even stronger. When comparing CFD with PIV, we found that the results were most convergent in the wider parts of the nasal cavities. CONCLUSION PIV measurements in realistically modelled nasal cavities succeed acceptably and CFD calculations produce corresponding results with PIV measurements. Greater model scaling is, however, necessary for better validations with PIV and comparisons of competing CFD models.
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Affiliation(s)
- Jaakko Ormiskangas
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Faculty of Engineering and Natural Sciences, Automation Technology and Mechanical Engineering Unit, Tampere University, Tampere, Finland.
| | - Olli Valtonen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Department of Otorhinolaryngology - Head and Neck Surgery, Tampere University Hospital, Tampere, Finland
| | - Ilkka Kivekäs
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Department of Otorhinolaryngology - Head and Neck Surgery, Tampere University Hospital, Tampere, Finland
| | - Marc Dean
- Texas Tech University Health Sciences Center, Lubbock, Texas, USA; Ear & Sinus Institute, Fort Worth, Texas, USA
| | - Dennis Poe
- Boston Children's Hospital, Department of Otolaryngology, Boston, Massachusetts, USA
| | - Jorma Järnstedt
- Medical Imaging Centre, Department of Radiology, Tampere University Hospital, Tampere, Finland
| | - Jukka Lekkala
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Teemu Harju
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Department of Otorhinolaryngology - Head and Neck Surgery, Tampere University Hospital, Tampere, Finland
| | - Pentti Saarenrinne
- Faculty of Engineering and Natural Sciences, Automation Technology and Mechanical Engineering Unit, Tampere University, Tampere, Finland
| | - Markus Rautiainen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Department of Otorhinolaryngology - Head and Neck Surgery, Tampere University Hospital, Tampere, Finland
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49
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Hosseini S, Schuman TA, Walenga R, Wilkins JV, Babiskin A, Golshahi L. Use of anatomically-accurate 3-dimensional nasal airway models of adult human subjects in a novel methodology to identify and evaluate the internal nasal valve. Comput Biol Med 2020; 123:103896. [PMID: 32768043 DOI: 10.1016/j.compbiomed.2020.103896] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/17/2020] [Accepted: 06/27/2020] [Indexed: 11/15/2022]
Abstract
The optimal method for radiographic evaluation of the internal nasal valve (INV) has not been established. The objective of this study was to develop a method to assess the cross-sectional area and the angle of the INV using anatomically-accurate 3D digital nasal airway models. Axial CT images of the paranasal sinuses of twenty adult subjects with healthy nasal airways (50% female and 50% age ≥ 50) were used to create the models. Patients with significant radiographic evidence of sinonasal disease were excluded. A primary cutting plane that passed through the edge of the nasal bone, upper lateral cartilage, and the head of the inferior turbinate was defined in coronal view. This primary coronal cutting plane was then rotated in 5° increments anteriorly while ensuring the anatomic criteria for the INV were still met. The cutting plane resulting in the minimum INV area was identified as the optimal cutting plane and the total cross-sectional area of INV in this plane,198.79 ± 54.57 mm2, was significantly less than the areas obtained using the existing methods for radiographic evaluation of the INV. The angle between the optimal cutting plane and nasal dorsum was 75.00 ± 10.26°, and the corresponding INV angle was 10.77 ± 6.02°.
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Affiliation(s)
- Sana Hosseini
- Department of Mechanical and Nuclear Engineering, VCU, Richmond, VA, USA
| | - Theodore A Schuman
- Department of Otolaryngology- Head and Neck Surgery, VCU Health, Richmond, VA, USA
| | - Ross Walenga
- Division of Quantitative Methods and Modeling, Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - John V Wilkins
- Department of Mechanical and Nuclear Engineering, VCU, Richmond, VA, USA
| | - Andrew Babiskin
- Division of Quantitative Methods and Modeling, Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Laleh Golshahi
- Department of Mechanical and Nuclear Engineering, VCU, Richmond, VA, USA.
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Characterization of the Airflow within an Average Geometry of the Healthy Human Nasal Cavity. Sci Rep 2020; 10:3755. [PMID: 32111935 PMCID: PMC7048824 DOI: 10.1038/s41598-020-60755-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 02/17/2020] [Indexed: 11/08/2022] Open
Abstract
This study's objective was the generation of a standardized geometry of the healthy nasal cavity. An average geometry of the healthy nasal cavity was generated using a statistical shape model based on 25 symptom-free subjects. Airflow within the average geometry and these geometries was calculated using fluid simulations. Integral measures of the nasal resistance, wall shear stresses (WSS) and velocities were calculated as well as cross-sectional areas (CSA). Furthermore, individual WSS and static pressure distributions were mapped onto the average geometry. The average geometry featured an overall more regular shape that resulted in less resistance, reduced WSS and velocities compared to the median of the 25 geometries. Spatial distributions of WSS and pressure of the average geometry agreed well compared to the average distributions of all individual geometries. The minimal CSA of the average geometry was larger than the median of all individual geometries (83.4 vs. 74.7 mm²). The airflow observed within the average geometry of the healthy nasal cavity did not equal the average airflow of the individual geometries. While differences observed for integral measures were notable, the calculated values for the average geometry lay within the distributions of the individual parameters. Spatially resolved parameters differed less prominently.
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