1
|
Zhang Y, Hu Z, Wang Y, Lou M, Ma R, Gong M, Dong J, Zheng G, Wang B. Numerical investigation of nanoparticle deposition in the olfactory region among pediatric nasal airways with adenoid hypertrophy. Comput Biol Med 2023; 167:107587. [PMID: 37890422 DOI: 10.1016/j.compbiomed.2023.107587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/28/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023]
Abstract
To understand inhaled nanoparticle transport and deposition characteristics in pediatric nasal airways with adenoid hypertrophy (AH), with a specific emphasis on the olfactory region, virtual nanoparticle inhalation studies were conducted on anatomically accurate child nasal airway models. The computational fluid-particle dynamics (CFPD) method was employed, and numerical simulations were performed to compare the airflow and nanoparticle deposition patterns between nasal airways with nasopharyngeal obstruction before adenoidectomy and healthy nasal airways after virtual adenoidectomy. The influence of different inhalation rates and exhalation phase on olfactory regional nanoparticle deposition features was systematically analyzed. We found that nasopharyngeal obstruction resulted in significant uneven airflow distribution in the nasal cavity. The deposited nanoparticles were concentrated in the middle meatus, septum, inferior meatus and nasal vestibule. The deposition efficiency (DE) in the olfactory region decreases with increasing nanoparticle size (1-10 nm) during inhalation. After adenoidectomy, the pediatric olfactory region DE increased significantly while nasopharynx DE dramatically decreased. When the inhalation rate decreased, the deposition pattern in the olfactory region significantly altered, exhibiting an initial rise followed by a subsequent decline, reaching peak deposition at 2 nm. During exhalation, the pediatric olfactory region DE was substantially lower than during inhalation, and the olfactory region DE in the pre-operative models were found to be significantly higher than that of the post-operative models. In conclusions, ventilation and particle deposition in the olfactory region were significantly improved in post-operative models. Inhalation rate and exhalation process can significantly affect nanoparticle deposition in the olfactory region.
Collapse
Affiliation(s)
- Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China
| | - Zhenzhen Hu
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China; School of Engineering, RMIT University, Bundoora, VIC, 3083, Australia
| | - Yusheng Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China
| | - Miao Lou
- Department of Otorhinolaryngology Head and Neck Surgery, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi, 710068, China
| | - Ruiping Ma
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China
| | - Minjie Gong
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, 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.
| | - Guoxi Zheng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China.
| | - Botao Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China.
| |
Collapse
|
2
|
Wei H, Wan L, Zhang Y, Li Y, Xu W, Li Y, Han D. Value of Opening the Middle Meatus in Patients With Nasal Airway Obstruction. EAR, NOSE & THROAT JOURNAL 2023; 102:NP489-NP498. [PMID: 36916238 DOI: 10.1177/01455613231163737] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
OBJECTIVES While surgeries to correct the anatomical malformations that cause nasal airway obstruction (NAO) are generally successful, the outcomes of such procedures are often unsatisfactory. The aim of the present study was to assess the value of opening the middle meatus in patients with NAO. METHODS Thirty-four patients with nasal obstruction due to nasal septal deviation were included in this study. After randomization, the middle meatus was either opened or not opened during septoplasty. The patients were evaluated through pre- and postoperative rhinomanometry and acoustic rhinometry. The Visual Analog Scale (VAS) scores of subjective symptoms along with responses to the 20-item Sinonasal Outcome Test (SNOT-20) were obtained before surgery and three months after surgery. RESULTS The VAS scores and SNOT-20 responses improved significantly in both groups after surgery. The effective treatment rate based on the nasal congestion score (NCS) was 64.7% in the single group (septoplasty alone) and 100% in the combined group (septoplasty in conjunction with opening the middle meatus), and the difference was statistically significant (P = .018). In both groups, surgery significantly improved nasal flow, resistance, minimal cross-sectional area, cross-sectional area 6 cm (CA6) from the anterior nostril and nasal volume. Nasal volume and CA6 after surgery were statistically different between the 2 groups (P = .004 and .019, respectively). CONCLUSIONS Opening the middle meatus may further improve the subjective perception of patency on the basis of septoplasty.
Collapse
Affiliation(s)
- Hongzheng Wei
- Department of Otolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Department of Allergy, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Beijing Key Laboratory of Nasal Diseases, Beijing Institute of Otolaryngology, Beijing, People's Republic of China
| | - Lianqi Wan
- Department of Otolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Department of Allergy, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Beijing Key Laboratory of Nasal Diseases, Beijing Institute of Otolaryngology, Beijing, People's Republic of China
| | - Yuan Zhang
- Department of Otolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Department of Allergy, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Beijing Key Laboratory of Nasal Diseases, Beijing Institute of Otolaryngology, Beijing, People's Republic of China
| | - Yanru Li
- Department of Otolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
| | - Wen Xu
- Department of Otolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
| | - Yunchuan Li
- Department of Otolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Beijing Key Laboratory of Nasal Diseases, Beijing Institute of Otolaryngology, Beijing, People's Republic of China
| | - Demin Han
- Department of Otolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Beijing, People's Republic of China
- Beijing Key Laboratory of Nasal Diseases, Beijing Institute of Otolaryngology, Beijing, People's Republic of China
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
Song H, Li X, Huang H, Xie C, Qu W. Postoperative virtual pressure difference as a new index for the risk assessment of liver resection from biomechanical analysis. Comput Biol Med 2023; 157:106725. [PMID: 36913851 DOI: 10.1016/j.compbiomed.2023.106725] [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: 11/09/2022] [Revised: 02/21/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023]
Abstract
In the realm of hepatectomy, traditional methods for postoperative risk assessment are limited in their ability to provide comprehensive and intuitive evaluations of donor risk. To address this issue, there is a need for the development of more multifaceted indicators to assess the risk in hepatectomy donors. In an effort to improve postoperative risk assessments, a computational fluid dynamics (CFD) model was developed to analyze blood flow properties, such as streamlines, vorticity, and pressure, in 10 eligible donors. By comparing the correlation between vorticity, maximum velocity, postoperative virtual pressure difference and TB, a novel index - postoperative virtual pressure difference - was proposed from a biomechanical perspective. This index demonstrated a high correlation (0.98) with total bilirubin values. Donors who underwent right liver lobe resections had greater pressure gradient values than those who underwent left liver lobe resected donors due to the denser streamlines and higher velocity and vorticity values of the former group. Compared with traditional medical methods, the biofluid dynamic analysis using CFD offers advantages in terms of accuracy, efficiency, and intuition.
Collapse
Affiliation(s)
- Hongqing Song
- University of Science and Technology Beijing, Beijing, 100083, China
| | - Xiaofan Li
- University of Science and Technology Beijing, Beijing, 100083, China
| | - Hao Huang
- Liver Transplantation Section, Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Chiyu Xie
- University of Science and Technology Beijing, Beijing, 100083, China
| | - Wei Qu
- Liver Transplantation Section, Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China.
| |
Collapse
|
5
|
Numerical study on the distribution of nitric oxide concentration in the nasal cavity of healthy people during breathing. Nitric Oxide 2023; 130:12-21. [PMID: 36417988 DOI: 10.1016/j.niox.2022.11.002] [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: 09/08/2022] [Revised: 11/12/2022] [Accepted: 11/18/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND In the nasal cavity, nitric oxide (NO) is involved in many physiological functions, including antibacterial and antiviral activity, promotion of nasal mucociliary clearance, and regulation of blood vessel expansion in the nasal mucosa. We investigated the distribution of NO concentration in the nasal cavity of healthy individuals during breathing. METHODS A three-dimensional numerical model of the nasal airway, including the bilateral maxillary sinuses, was created to simulate NO distribution in the nasal cavity during normal breathing. The effect of different nasal airflow velocities and NO concentrations in the maxillary sinus on NO distribution in the nasal cavity was evaluated. The NO concentration in the nasal exhalation of 50 healthy people in Dalian was measured using an NO analyzer, and the growth rate of the NO concentration in the nasal cavity was measured under breath-holding conditions. RESULTS The distribution of NO concentration in the nasal cavity of healthy people during breathing was obtained from numerical simulation results. Lower the airflow rate, higher was the NO concentration and greater was the diffusion range in the nasal cavity. The NO concentration in the nasal cavity increased with an increase in its concentration in the maxillary sinus, indicating a linear relationship. The NO concentration in the nasal exhalation of healthy people in Dalian and the growth rate of the NO concentration in the nasal cavity under breath-holding conditions were obtained through experiments. The numerical results correspond with the experimental results. CONCLUSIONS The NO entered the nasal cavity mainly by diffusion and followed the convection flow of the respiratory air in the nasal cavity. NO concentration in the nasal cavity was related to the respiratory airflow velocity and NO concentration in the maxillary sinus. During inspiration, NO was present only in the nasal airway posterior to the maxillary sinus ostium, whereas during exhalation, the exhaled NO diffusely distributed throughout the nasal cavity.
Collapse
|
6
|
Numerical Analysis of Nasal Flow Characteristics with Microparticles. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:8706978. [PMID: 36046012 PMCID: PMC9424028 DOI: 10.1155/2022/8706978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/22/2022] [Indexed: 11/18/2022]
Abstract
This study was to investigate the airflow characteristics in nasal cavity under different conditions and analyze the effects of different respiratory intensity, particle diameter, and particle density on the deposition of particles carried by airflow in the nasal cavity, respectively. The three-dimensional geometric model of the nasal cavity was established based on typical medical images. The SST k-ω turbulence model in the computational fluid dynamics (CFD) was used to simulate the airflow in the nasal cavity, and the deposition of particles in the airflow was analyzed with the Lagrange discrete phase model. The results showed that the air in the nasal cavity flows in the left and right nasal passages through the perforation in front of the nasal septum and forms a vortex structure at the perforation site, and the particle deposition efficiencies (DE) under perforation nasal cavity are higher than that under normal nasal cavity. Different parameters had different effects on the particle DE. The results showed that the DE of particles with smaller size (≤2.5 μm) is lower; the higher the respiration intensity, the greater the influence on the DE of the larger particle size; and the larger particle density (>1550 kg·m−3) has little effect on the DE of larger particle size (DP = 10 μm). The results agree well with the corresponding research data.
Collapse
|
7
|
Yoo H, Sim T. Automated Machine Learning (AutoML)-based Surface Registration Methodology for Image-guided Surgical Navigation System. Med Phys 2022; 49:4845-4860. [PMID: 35543150 DOI: 10.1002/mp.15696] [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: 10/20/2021] [Revised: 04/05/2022] [Accepted: 04/19/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND While the surface registration technique has the advantage of being relatively safe and the operation time is short, it generally has the disadvantage of low accuracy. PURPOSE This research proposes automated machine learning (AutoML)-based surface registration to improve the accuracy of image-guided surgical navigation systems. METHODS The state-of-the-art surface registration concept is that first, using a neural network model, a new point-cloud that matches the facial information acquired by a passive probe of an optical tracking system (OTS) is extracted from the facial information obtained by computerized tomography (CT). Target registration error (TRE) representing the accuracy of surface registration is then calculated by applying the iterative closest point (ICP) algorithm to the newly extracted point-cloud and OTS information. In this process, the hyperparameters used in the neural network model and ICP algorithm are automatically optimized using Bayesian Optimization with Expected Improvement to yield improved registration accuracy. RESULTS Using the proposed surface registration methodology, the average TRE for the targets located in the sinus space and nasal cavity of the soft phantoms is (0.939 ± 0.375) mm, which shows 57.8 % improvement compared to the average TRE of (2.227 ± 0.193) mm calculated by the conventional surface registration method (p < 0.01). The performance of the proposed methodology is evaluated, and the average TREs computed by the proposed methodology and the conventional method are (0.767 ± 0.132) mm and (2.615 ± 0.378) mm, respectively. Additionally, for one healthy adult, the clinical applicability of the AutoML-based surface registration is also presented. CONCLUSION Our findings showed that the registration accuracy could be improved while maintaining the advantages of the surface registration technique. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Hakje Yoo
- Korea University Research Institute for Medical Bigdata Science, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Taeyong Sim
- Department of Artificial Intelligence, Sejong University, 209, Neungdong-ro, Gwangjin-gu, Seoul, 05006, Republic of Korea
| |
Collapse
|
8
|
Comparison of Sinus Deposition from an Aqueous Nasal Spray and Pressurised MDI in a Post-Endoscopic Sinus Surgery Nasal Replica. Pharm Res 2022; 39:317-327. [PMID: 35137359 PMCID: PMC8881262 DOI: 10.1007/s11095-021-03129-2] [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: 07/09/2021] [Accepted: 10/17/2021] [Indexed: 11/16/2022]
Abstract
Background Optimising intranasal distribution and retention of topical therapy is essential for effectively managing patients with chronic rhinosinusitis, including those that have had functional endoscopic sinus surgery (FESS). This study presents a new technique for quantifying in vitro experiments of fluticasone propionate deposition within the sinuses of a 3D-printed model from a post-FESS patient. Methods Circular filter papers were placed on the sinus surfaces of the model. Deposition of fluticasone on the filter paper was quantified using high-performance liquid chromatography (HPLC) assay-based techniques. The deposition patterns of two nasal drug delivery devices, an aqueous nasal spray (Flixonase) and metered dose inhaler (Flixotide), were compared. The effects of airflow (0 L/min vs. 12 L/min) and administration angle (30° vs. and 45°) were evaluated. Results Inhaled airflow made little difference to sinus deposition for either device. A 45° administration angle improved frontal sinus deposition with the nasal spray and both ethmoidal and sphenoidal deposition with the inhaler. The inhaler provided significantly better deposition within the ethmoid sinuses (8.5x) and within the maxillary sinuses (3.9x) compared with the nasal spray under the same conditions. Conclusion In the post-FESS model analysed, the inhaler produced better sinus deposition overall compared with the nasal spray. The techniques described can be used and adapted for in vitro performance testing of different drug formulations and intranasal devices under different experimental conditions. They can also help validate computational fluid dynamics modelling and in vivo studies.
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Deruyver L, Rigaut C, Lambert P, Haut B, Goole J. The importance of pre-formulation studies and of 3D-printed nasal casts in the success of a pharmaceutical product intended for nose-to-brain delivery. Adv Drug Deliv Rev 2021; 175:113826. [PMID: 34119575 DOI: 10.1016/j.addr.2021.113826] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/19/2021] [Accepted: 06/07/2021] [Indexed: 02/08/2023]
Abstract
This review aims to cement three hot topics in drug delivery: (a) the pre-formulation of new products intended for nose-to-brain delivery; (b) the development of nasal casts for studying the efficacy of potential new nose-to-brain delivery systems at the early of their development (pre-formulation); (c) the use of 3D printing based on a wide variety of materials (transparent, biocompatible, flexible) providing an unprecedented fabrication tool towards personalized medicine by printing nasal cast on-demand based on CT scans of patients. This review intends to show the links between these three subjects. Indeed, the pathway selected to administrate the drug to the brain not only influence the formulation strategies to implement but also the design of the cast, to get the most convincing measures from it. Moreover, the design of the cast himself influences the choice of the 3D-printing technology, which, in its turn, bring more constraints to the nasal replica design. Consequently, the formulation of the drug, the cast preparation and its realisation should be thought of as a whole and not separately.
Collapse
Affiliation(s)
- Laura Deruyver
- Laboratoire de Pharmacie Galénique et de Biopharmacie, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Clément Rigaut
- TIPs (Transfers, Interfaces and Processes), Université libre de Bruxelles, Brussels, Belgium
| | - Pierre Lambert
- TIPs (Transfers, Interfaces and Processes), Université libre de Bruxelles, Brussels, Belgium
| | - Benoît Haut
- TIPs (Transfers, Interfaces and Processes), Université libre de Bruxelles, Brussels, Belgium
| | - Jonathan Goole
- Laboratoire de Pharmacie Galénique et de Biopharmacie, Université libre de Bruxelles (ULB), Brussels, Belgium.
| |
Collapse
|
11
|
Salati H, Khamooshi M, Vahaji S, Christo FC, Fletcher DF, Inthavong K. N95 respirator mask breathing leads to excessive carbon dioxide inhalation and reduced heat transfer in a human nasal cavity. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:081913. [PMID: 34552313 PMCID: PMC8450908 DOI: 10.1063/5.0061574] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/06/2021] [Indexed: 05/16/2023]
Abstract
Face masks and respirators are used to filter inhaled air, which may contain airborne droplets and high particulate matter (PM) concentrations. The respirators act as a barrier to the inhaled and exhaled air, which may change the nasal airflow characteristics and air-conditioning function of the nose. This study aims to investigate the nasal airflow dynamics during respiration with and without an N95 respirator driven by airflow through the nasal cavity to assess the effect of the respirator on breathing conditions during respiration. To achieve the objective of this study, transient computational fluid dynamics simulations have been utilized. The nasal geometry was reconstructed from high-resolution Computed Tomography scans of a healthy 25-year-old female subject. The species transport method was used to analyze the airflow, temperature, carbon dioxide (CO2), moisture content (H2O), and temperature distribution within the nasal cavity with and without an N95 respirator during eight consecutive respiration cycles with a tidal volume of 500 ml. The results demonstrated that a respirator caused excessive CO2 inhalation by approximately 7 × greater per breath compared with normal breathing. Furthermore, heat and mass transfer in the nasal cavity was reduced, which influences the perception of nasal patency. It is suggested that wearers of high-efficiency masks that have minimal porosity and low air exchange for CO2 regulation should consider the amount of time they wear the mask.
Collapse
Affiliation(s)
| | - Mehrdad Khamooshi
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Australia
| | - Sara Vahaji
- School of Engineering, Faculty of Science Engineering and Built Environment, Deakin University, Victoria, Australia
| | - Farid C. Christo
- School of Engineering, Faculty of Science Engineering and Built Environment, Deakin University, Victoria, Australia
| | - David F. Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006 Australia
| | - Kiao Inthavong
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Australia
- Author to whom correspondence should be addressed:
| |
Collapse
|
12
|
Das S, Pal TK, Jana RN, Giri B. Ascendancy of electromagnetic force and Hall currents on blood flow carrying Cu-Au NPs in a non-uniform endoscopic annulus having wall slip. Microvasc Res 2021; 138:104191. [PMID: 34097918 DOI: 10.1016/j.mvr.2021.104191] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/04/2021] [Accepted: 05/21/2021] [Indexed: 01/21/2023]
Abstract
This article aims to outline the characteristics of the blood flow conveying copper (Cu) and gold (Au) nanoparticles (NPs) through a non-uniform endoscopic annulus with wall slip under the action of electromagnetic force and Hall currents. The flow of blood with the suspension of hybrid nanoparticles in the annulus is induced by the peristaltic pumping. The governing equations are modeled and then simplified with the postulate of lubrication theory. The resulting non-dimensional momentum equation after simplification is solved analytically by employing the He's homotopy perturbation method (HPM) with the computational software Mathematica program (version 11). The influential role of emerging physical parameters on the physiological features related to the blood flow is inferred graphically and physically. The analytical outcomes reveal that Hall parameter has a diminishing behavior on the blood flow while the inverse impact is endured for mounting Hartmann number. Electromagnetic field and Hall currents offer a superlative mode for regulating blood flow at the time of surgery. An increment in the volume fraction of nanoparticles causes a drop in the blood temperature profile. The trapping phenomenon is also explored with the help of contours. An expansion in Hartmann number reduces the size of entrapped bolus and ultimately vanishes when Hartmann number is very large. This prospective model may be applicable in electromagnetic micro-pumps, medical simulation devices, heart-lung machine (HLM), drug carrying and drug transport systems, cancer diagnosis, tumor selective photothermal therapy, etc.
Collapse
Affiliation(s)
- S Das
- Department of Mathematics, University of Gour Banga, Malda 732 103, India.
| | - T K Pal
- Department of Mathematics, University of Gour Banga, Malda 732 103, India
| | - R N Jana
- Department of Applied Mathematics, Vidyasagar University, Midnapore 721 102, India
| | - B Giri
- Department of Physiology, University of Gour Banga, Malda 732 103, India
| |
Collapse
|
13
|
Li L, Han D, Zang H, London NR. Aerodynamics Analysis of the Impact of Nasal Surgery on Patients with Obstructive Sleep Apnea and Nasal Obstruction. ORL J Otorhinolaryngol Relat Spec 2021; 84:62-69. [PMID: 34058743 DOI: 10.1159/000516243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 03/26/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the effects of nasal surgery on airflow characteristics in patients with obstructive sleep apnea (OSA) by comparing the alterations of airflow characteristics within the nasal and palatopharyngeal cavities. METHODS Thirty patients with OSA and nasal obstruction who underwent nasal surgery were enrolled. A pre- and postoperative 3-dimensional model was constructed, and alterations of airflow characteristics were assessed using the method of computational fluid dynamics. The other subjective and objective clinical indices were also assessed. RESULTS By comparison with the preoperative value, all postoperative subjective symptoms statistically improved (p < 0.05), while the Apnea-Hypopnea Index (AHI) changed little (p = 0.492); the postoperative airflow velocity and pressure in both nasal and palatopharyngeal cavities, nasal and palatopharyngeal pressure differences, and total upper airway resistance statistically decreased (all p < 0.01). A significant difference was derived for correlation between the alteration of simulation metrics with subjective improvements (p < 0.05), except with the AHI (p > 0.05). CONCLUSION Nasal surgery can decrease the total resistance of the upper airway and increase the nasal airflow volume and subjective sleep quality in patients with OSA and nasal obstruction. The altered airflow characteristics might contribute to the postoperative reduction of pharyngeal collapse in a subset of OSA patients.
Collapse
Affiliation(s)
- Lifeng Li
- Department of Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China,
| | - Demin Han
- Department of Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Hongrui Zang
- Department of Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Nyall R London
- Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.,Sinonasal and Skull Base Tumor Program, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, Maryland, USA
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
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.
Collapse
|
16
|
Particle deposition in the paranasal sinuses following endoscopic sinus surgery. Comput Biol Med 2019; 116:103573. [PMID: 31999554 DOI: 10.1016/j.compbiomed.2019.103573] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 11/21/2022]
Abstract
Optimizing intranasal distribution and retention of topical therapy is essential in the management of patients with chronic rhinosinusitis, including those that have had functional endoscopic sinus surgery (FESS). Computational fluid dynamics analysis has not previously been used to investigate sinus nasal spray delivery in the complete post-operative sinonasal geometries of patients who have undergone FESS. Models of sinonasal cavities were created from postoperative magnetic resonance imaging scans in four patients, three of whom underwent a comprehensive FESS, the other a modified endoscopic Lothrop procedure. Spray simulations were conducted at different flow rates (5 L/min, 10 L/min and 15 L/min) using sixteen particle sizes ranging from 4 μm to 70μm, spray velocity of 10 m/s and plume angle of 15°. Two different spray insertion angles were compared. Airflow distribution in the sinuses was closely related to the patient's nasal geometry and surgical intervention, in particular a unique crossflow between nasal chambers was present for the Lothrop patient. Sinus deposition was generally more effective with inhalational transport of low-inertia particles outside of the range produced by many standard nasal sprays or nebulizer. This was true except in the Lothrop patient, since previous surgery had been performed removing most of the septum where high-inertia particles would normally deposit. For sinuses receiving minimal airflow, particle penetration was diminished and successful deposition in the region became more restricted by device parameters. Further research is needed to validate these findings and explore other spray variables in a wider spectrum of patients to ascertain a multi-level approach to optimizing drug delivery in the sinuses.
Collapse
|
17
|
Inthavong K. From indoor exposure to inhaled particle deposition: A multiphase journey of inhaled particles. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s42757-019-0046-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
AbstractIndoor air quality and its effect on respiratory health are reliant on understanding the level of inhalation exposure, particle inhalability, and particle deposition in the respiratory airway. In the indoor environment, controlling airflow through different ventilation systems can reduce inhalation exposure. This produces a wide variety of complex flow phenomena, such as recirculation, coanda flow, separation, and reattachment. Airborne particles drifting through the air, that move within the breathing region become inhaled into nasal cavity the nostrils. Studies have developed the aspiration efficiency to assist in predicting the fraction of inhaled particles. Inside the nasal cavity, micron and submicron particle deposition occurs in very different ways (inertial impaction, sedimentation, diffusion) and different locations. In addition, fibrous particles such as asbestos are influenced by tumbling effects and its deposition mechanism can include interception. Indoor fluid-particle dynamics related to inhalation exposure and eventual deposition in the respiratory airway is presented. This study involves multi-disciplinary fields involving building science, fluid dynamics, computer science, and medical imaging disciplines. In the future, an integrated approach can lead to digital/in-silico representations of the human respiratory airway able to predict the inhaled particle exposure and its toxicology effect.
Collapse
|
18
|
Kumar H, Jain R. Review: The role of computational simulation in understanding the postoperative sinonasal environment. Clin Biomech (Bristol, Avon) 2019; 68:212-220. [PMID: 31325767 DOI: 10.1016/j.clinbiomech.2018.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 01/12/2018] [Accepted: 01/17/2018] [Indexed: 02/07/2023]
Abstract
Nasal surgery improves symptoms in a majority of patients for whom medical treatment has failed. In rhinosinusitis patients, endoscopic sinus surgery aims to alleviate obstruction and re-establish mucociliary clearance. Surgery alters the structure-function relationship within the nasal passage, which is difficult to assess clinically. Computational modelling has been used to investigate this relationship by simulating air flow and environmental variables inside realistic three-dimensional models of the human nasal airway but many questions remain unanswered and need further investigation. The application of computational models to improve pre-surgical planning and post-surgical treatment may not be currently possible due to the absence of knowledge correlating the model-predicted parameters to physiological variables. Links between these parameters to patient outcomes are yet to be established. This article reviews the recent application of computational modelling to understand the nasal structure-function relationship following surgery in patients with sinusitis and nasal obstruction.
Collapse
Affiliation(s)
- Haribalan Kumar
- Auckland Bioengineering Institute, The University of Auckland, New Zealand.
| | - Ravi Jain
- Department of surgery, The University of Auckland, New Zealand
| |
Collapse
|
19
|
Kumar H, Jain R. Review: The role of computational simulation in understanding the postoperative sinonasal environment. Clin Biomech (Bristol, Avon) 2019; 66:2-10. [PMID: 30195934 DOI: 10.1016/j.clinbiomech.2018.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 01/29/2018] [Accepted: 02/01/2018] [Indexed: 02/07/2023]
Abstract
Nasal surgery improves symptoms in a majority of patients for whom medical treatment has failed. In rhinosinusitis patients, endoscopic sinus surgery aims to alleviate obstruction and re-establish mucociliary clearance. Surgery alters the structure-function relationship within the nasal passage, which is difficult to assess clinically. Computational modelling has been used to investigate this relationship by simulating air flow and environmental variables inside realistic three-dimensional models of the human nasal airway but many questions remain unanswered and need further investigation. The application of computational models to improve pre-surgical planning and post-surgical treatment may not be currently possible due to the absence of knowledge correlating the model-predicted parameters to physiological variables. Links between these parameters to patient outcomes are yet to be established. This article reviews the recent application of computational modelling to understand the nasal structure-function relationship following surgery in patients with sinusitis and nasal obstruction.
Collapse
Affiliation(s)
- Haribalan Kumar
- Auckland Bioengineering Institute, The University of Auckland, New Zealand.
| | - Ravi Jain
- Department of surgery, The University of Auckland, New Zealand
| |
Collapse
|
20
|
Inthavong K, Chetty A, Shang Y, Tu J. Examining mesh independence for flow dynamics in the human nasal cavity. Comput Biol Med 2018; 102:40-50. [PMID: 30245276 DOI: 10.1016/j.compbiomed.2018.09.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/12/2018] [Accepted: 09/12/2018] [Indexed: 02/06/2023]
Abstract
Increased computational resources provide new opportunities to explore sophisticated respiratory modelling. A survey of recent publications showed a steady increase in the number of mesh elements used in computational models over time. Complex geometries such as the nasal cavity exhibit sharp gradients and irregular curvatures, leading to abnormal flow development across their surfaces. As such, a robust method for examining the near-wall mesh resolution is required. The non-dimensional wall unit y+ (often used in turbulent flows) was used as a parameter to evaluate the near-wall mesh in laminar flows. Mesh independence analysis from line profiles showed that the line location had a significant influence on the result. Furthermore, using a single line profile as a measure for mesh convergence was unsuitable for representing the entire flow field. To improve this, a two-dimensional (2D) cross-sectional plane subtraction method where scalar values (such as the velocity magnitude) on a cross-sectional plane were interpolated onto a regularly spaced grid was proposed. The new interpolated grid values from any two meshed models could then be compared for changes caused by the different meshed models. The application of this method to three-dimensional (3D) volume subtraction was also demonstrated. The results showed that if the near-wall mesh was sufficiently refined, then narrow passages were less reliant on the overall mesh size. However, in wider passages, velocity magnitudes were sensitive to mesh size, requiring a more refined mesh.
Collapse
Affiliation(s)
| | | | - Yidan Shang
- RMIT University, School of Engineering, Australia
| | - Jiyuan Tu
- RMIT University, School of Engineering, Australia
| |
Collapse
|
21
|
Covello V, Pipolo C, Saibene A, Felisati G, Quadrio M. Numerical simulation of thermal water delivery in the human nasal cavity. Comput Biol Med 2018; 100:62-73. [PMID: 29975856 DOI: 10.1016/j.compbiomed.2018.06.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/24/2018] [Accepted: 06/25/2018] [Indexed: 11/29/2022]
Abstract
This work describes an extensive numerical investigation of thermal water delivery for the treatment of inflammatory disorders in the human nasal cavity. The numerical simulation of the multiphase air-droplets flow is based upon the Large Eddy Simulation (LES) technique, with droplets of thermal water described via a Lagrangian approach. Droplet deposition is studied for different sizes of water droplets, corresponding to two different thermal treatments, i.e. aerosol and inhalation. Numerical simulations are conducted on a patient-specific anatomy, employing two different grid sizes, under steady inspiration at two breathing intensities. The results are compared with published in vivo and in vitro data. The effectiveness of the various thermal treatments is then assessed qualitatively and quantitatively, by a detailed analysis of the deposition patterns of the droplets. Discretization effects on the deposition dynamics are addressed. The level of detail of the present work, together with the accuracy afforded by the LES approach, leads to an improved understanding of how the mixture of air-water droplets is distributed within the nose and the paranasal sinuses.
Collapse
Affiliation(s)
- V Covello
- Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156, Milano, Italy
| | - C Pipolo
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudini 8, 20142, Milano, Italy
| | - A Saibene
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudini 8, 20142, Milano, Italy
| | - G Felisati
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudini 8, 20142, Milano, Italy
| | - M Quadrio
- Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156, Milano, Italy.
| |
Collapse
|
22
|
Ma J, Dong J, Shang Y, Inthavong K, Tu J, Frank-Ito DO. Air conditioning analysis among human nasal passages with anterior anatomical variations. Med Eng Phys 2018; 57:19-28. [PMID: 29706484 DOI: 10.1016/j.medengphy.2018.04.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 04/06/2018] [Accepted: 04/16/2018] [Indexed: 11/19/2022]
Abstract
A major functional role of the nasal cavity is air conditioning of the inspired environmental air to near alveolar conditions. It is well known that the anatomical disparities among nasal passages can change airflow patterns to a great extent. However, its effect on nasal air conditioning performance remains largely unexplored. This research investigated the nasal air conditioning performance among nasal models with distinct vestibule phenotypes, including subjects with and without vestibule notches. For the mass transfer, we used a two-film theory model to determine the species transport. Airflow patterns, heat and mass transfer between the inhaled airflow and the nasal mucosa were analysed and compared. Results showed that the nasal air conditioning performance is closely related to nasal passage structures. The anatomical variations, especially the geometry changes in the anterior vestibule region, can increase both heat and mass transfer rate between nasal mucous and respiratory air at the vicinity of the notched regions, while for other regions such as the anterior superior nasal cavity, the heat transfer is greatly reduced to even zero heat flux due to lack of active airflow passing.
Collapse
Affiliation(s)
- Jiawei Ma
- School of Engineering, RMIT University, Bundoora, VIC 3083, Australia
| | - Jingliang Dong
- School of Engineering, RMIT University, Bundoora, VIC 3083, Australia
| | - Yidan Shang
- School of Engineering, RMIT University, Bundoora, VIC 3083, Australia
| | - Kiao Inthavong
- School of Engineering, RMIT University, Bundoora, VIC 3083, Australia
| | - Jiyuan Tu
- School of Engineering, RMIT University, Bundoora, VIC 3083, Australia.
| | - Dennis O Frank-Ito
- Division of Head & Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, NC 27710, USA
| |
Collapse
|
23
|
A generalised porous medium approach to study thermo-fluid dynamics in human eyes. Med Biol Eng Comput 2018; 56:1823-1839. [PMID: 29564696 DOI: 10.1007/s11517-018-1813-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 03/02/2018] [Indexed: 10/17/2022]
Abstract
The present work describes the application of the generalised porous medium model to study heat and fluid flow in healthy and glaucomatous eyes of different subject specimens, considering the presence of ocular cavities and porous tissues. The 2D computational model, implemented into the open-source software OpenFOAM, has been verified against benchmark data for mixed convection in domains partially filled with a porous medium. The verified model has been employed to simulate the thermo-fluid dynamic phenomena occurring in the anterior section of four patient-specific human eyes, considering the presence of anterior chamber (AC), trabecular meshwork (TM), Schlemm's canal (SC), and collector channels (CC). The computational domains of the eye are extracted from tomographic images. The dependence of TM porosity and permeability on intraocular pressure (IOP) has been analysed in detail, and the differences between healthy and glaucomatous eye conditions have been highlighted, proving that the different physiological conditions of patients have a significant influence on the thermo-fluid dynamic phenomena. The influence of different eye positions (supine and standing) on thermo-fluid dynamic variables has been also investigated: results are presented in terms of velocity, pressure, temperature, friction coefficient and local Nusselt number. The results clearly indicate that porosity and permeability of TM are two important parameters that affect eye pressure distribution. Graphical abstract Velocity contours and vectors for healthy eyes (top) and glaucomatous eyes (bottom) for standing position.
Collapse
|
24
|
de Gabory L, Reville N, Baux Y, Boisson N, Bordenave L. Numerical simulation of two consecutive nasal respiratory cycles: toward a better understanding of nasal physiology. Int Forum Allergy Rhinol 2018; 8:676-685. [PMID: 29337433 DOI: 10.1002/alr.22086] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/27/2017] [Accepted: 12/14/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Computational fluid dynamic (CFD) simulations have greatly improved the understanding of nasal physiology. We postulate that simulating the entire and repeated respiratory nasal cycles, within the whole sinonasal cavities, is mandatory to gather more accurate observations and better understand airflow patterns. METHODS A 3-dimensional (3D) sinonasal model was constructed from a healthy adult computed tomography (CT) scan which discretized in 6.6 million cells (mean volume, 0.008 mm3 ). CFD simulations were performed with ANSYS©FluentTMv16.0.0 software with transient and turbulent airflow (k-ω model). Two respiratory cycles (8 seconds) were simulated to assess pressure, velocity, wall shear stress, and particle residence time. RESULTS The pressure gradients within the sinus cavities varied according to their place of connection to the main passage. Alternations in pressure gradients induced a slight pumping phenomenon close to the ostia but no movement of air was observed within the sinus cavities. Strong movements were observed within the inferior meatus during expiration contrary to the inspiration, as in the olfactory cleft at the same time. Particle residence time was longer during expiration than inspiration due to nasal valve resistance, as if the expiratory phase was preparing the next inspiratory phase. Throughout expiration, some particles remained in contact with the lower turbinates. The posterior part of the olfactory cleft was gradually filled with particles that did not leave the nose at the next respiratory cycle. This pattern increased as the respiratory cycle was repeated. CONCLUSION CFD is more efficient and reliable when the entire respiratory cycle is simulated and repeated to avoid losing information.
Collapse
Affiliation(s)
- Ludovic de Gabory
- Ear, Nose, and Throat (ENT) Department, University Hospital of Bordeaux, Hôpital Pellegrin, Bordeaux, France.,Centre d'Investigation Clinique et d'Innovation Technologique de Bordeaux (CIC-IT 14-01), University Hospital of Bordeaux, France.,University of Bordeaux, Bordeaux, France
| | - Nicolas Reville
- Ear, Nose, and Throat (ENT) Department, University Hospital of Bordeaux, Hôpital Pellegrin, Bordeaux, France.,University of Bordeaux, Bordeaux, France
| | - Yannick Baux
- OPTIFLUIDES, Computational Fluid Dynamics Unit, Villeurbanne, France
| | - Nicolas Boisson
- OPTIFLUIDES, Computational Fluid Dynamics Unit, Villeurbanne, France
| | - Laurence Bordenave
- Centre d'Investigation Clinique et d'Innovation Technologique de Bordeaux (CIC-IT 14-01), University Hospital of Bordeaux, France.,University of Bordeaux, Bordeaux, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), Bioingénierie tissulaire U1026, Bordeaux, France
| |
Collapse
|
25
|
|
26
|
Naseri A, Shaghaghian S, Abouali O, Ahmadi G. Numerical investigation of transient transport and deposition of microparticles under unsteady inspiratory flow in human upper airways. Respir Physiol Neurobiol 2017; 244:56-72. [PMID: 28673875 DOI: 10.1016/j.resp.2017.06.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 06/19/2017] [Accepted: 06/19/2017] [Indexed: 11/29/2022]
Abstract
In the present study, unsteady airflow patterns and particle deposition in healthy human upper airways were simulated. A realistic 3-D computational model of the upper airways including the vestibule to the end of the trachea was developed using a series of CT scan images of a healthy human. Unsteady simulations of the inhaled and exhaled airflow fields in the upper airway passages were performed by solving the Navier-Stokes and continuity equations for low breathing rates corresponding to low and moderate activities. The Lagrangian trajectory analysis approach was utilized to investigate the transient particle transport and deposition under cyclic breathing condition. Particles were released uniformly at the nostrils' entrance during the inhalation phase, and the total and regional depositions for various micro-particle sizes were evaluated. The transient particle deposition fractions for various regions of the human upper airways were compared with those obtained from the equivalent steady flow condition. The presented results revealed that the equivalent constant airflow simulation can approximately predict the total particle deposition during cyclic breathing in human upper airways. While the trends of steady and unsteady model predictions for local deposition were similar, there were noticeable differences in the predicted amount of deposition. In addition, it was shown that a steady simulation cannot properly predict some critical parameters, such as the penetration fraction. Finally, the presented results showed that using a detached nasal cavity (commonly used in earlier studies) for evaluation of total deposition fraction of particles in the nasal cavity was reasonably accurate for the steady flow simulations. However, in transient simulation for predicting the deposition fraction in a specific region, such as the nasal cavity, using the full airway system geometry becomes necessary.
Collapse
Affiliation(s)
- Arash Naseri
- School of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Sana Shaghaghian
- School of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Omid Abouali
- School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
| | - Goodarz Ahmadi
- Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, USA
| |
Collapse
|
27
|
Xi J, Si XA, Peters S, Nevorski D, Wen T, Lehman M. Understanding the mechanisms underlying pulsating aerosol delivery to the maxillary sinus: In vitro tests and computational simulations. Int J Pharm 2017; 520:254-266. [PMID: 28189854 DOI: 10.1016/j.ijpharm.2017.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 01/15/2017] [Accepted: 02/05/2017] [Indexed: 01/05/2023]
Abstract
BACKGROUND Pulsating aerosol delivery has been demonstrated in depositing medications into paranasal sinuses. However, its mechanisms are not fully understood. Influences of the nasal anatomy and sound frequency on intrasinus delivery are not yet clear. OBJECTIVES This study aimed to gain a better understanding of the mechanisms for enhanced intrasinus delivery with pulsating sound. Specifically, effects of the pulsation frequency, ostium size, and sinus shape on the intrasinus dosage and resonance frequency would be examined. METHODS AND MATERIALS Both experiments and computational modeling were conducted to understand the pulsating aerosol delivery in both idealized (two-bottle) and realistic nose-sinus models. A computational model of intrasinus pulsation delivery was developed using COMSOL and was cross-validated with both experimental and theoretical results. RESULTS In contrast to previous studies, seemingly erratic relations between the intrasinus dosage and ostium diameter were observed in experiments, which suggested a more complicated particle transport mechanism. Improved agreement was achieved when grouping the ostium size and sinus volume into the resonance frequency, and therefore, validated the hypothesis that intrasinus deposition strongly depends on the resonance frequency. Extensive computational simulations revealed that the deposition was highest at the resonance frequency and decreased gradually at off-resonance frequencies. The resonance frequency depended on the ostium and sinus morphology, but was independent of the nasal cavity. CONCLUSION Results of this study verified the hypothesis of resonance being the mechanism for enhanced particle deposition in the maxillary sinus. A better knowledge of the relationship between sinus dosages, pulsating frequency, and nasal morphometry is essential for improving the design of intrasinus delivery devices.
Collapse
Affiliation(s)
- Jinxiang Xi
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA.
| | - Xiuhua April Si
- Department of Mechanical Engineering, California Baptist University, Riverside, CA, USA
| | - Shannon Peters
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA
| | - Dannielle Nevorski
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA
| | - Tianshu Wen
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA
| | - Mark Lehman
- Department of Speech-Language Pathology, Central Michigan University, Mount Pleasant, MI, USA
| |
Collapse
|
28
|
Choi KJ, Jang DW, Ellison MD, Frank-Ito DO. Characterizing airflow profile in the postoperative maxillary sinus by using computational fluid dynamics modeling: A pilot study. Am J Rhinol Allergy 2016; 30:29-36. [PMID: 26867527 DOI: 10.2500/ajra.2016.30.4266] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Maxillary antrostomy is commonly performed during endoscopic sinus surgery. Little is known about the association surrounding recalcitrant maxillary sinusitis, antrostomy size, and intranasal airflow changes. Furthermore, the interaction between sinus mucosa and airflow is poorly understood. This study used computational fluid dynamics (CFD) modeling to investigate postoperative airflow characteristics between diseased and nondiseased maxillary sinuses in subjects with recurrent disease. METHODS A retrospective review of patients from a tertiary-level academic rhinology practice was performed. Seven subjects with endoscopic evidence of postoperative maxillary sinus disease that presented as chronic unilateral crusting at least 1 year after bilateral maxillary antrostomies were selected. A three-dimensional model of each subject's sinonasal cavity was created from postoperative computed tomographies and used for CFD analysis. RESULTS Although the variables investigated between diseased and nondiseased sides were not statistically significant, the diseased side in six subjects had a smaller antrostomy, and five of these subjects had both reduced nasal unilateral airflow and increased unilateral nasal resistance on the diseased side. The ratio of posterior wall shear stress (WSS) of the maxillary sinus to the total WSS was higher on the diseased side in six subjects. Results also showed strong correlations between antrostomy and CFD variables on the diseased side than on the nondiseased side. CONCLUSION This pilot study showed that the majority of the simulated sinonasal models exhibited common characteristics on the side with persistent disease, such as smaller antrostomy, reduced nasal airflow, increased nasal resistance, and increased posterior WSS. Although statistical significance was not established, this study provided preliminary insight into variables to consider in a larger cohort study.
Collapse
Affiliation(s)
- Kevin J Choi
- Department of Surgery, Division of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, North Carolina, USA
| | | | | | | |
Collapse
|
29
|
Jain R, Kumar H, Tawhai M, Douglas R. The impact of endoscopic sinus surgery on paranasal physiology in simulated sinus cavities. Int Forum Allergy Rhinol 2016; 7:248-255. [PMID: 27869357 DOI: 10.1002/alr.21879] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 10/05/2016] [Accepted: 10/18/2016] [Indexed: 01/25/2023]
Abstract
BACKGROUND Surgery improves symptoms for the majority of chronic rhinosinusitis (CRS) patients; however, physiological changes in the sinus cavities remain poorly characterized. Direct measurement of changes in airflow, pressure, temperature, humidity, and intranasal spray distribution following surgery is technically challenging. Accordingly, we have used computational fluid dynamic modeling to quantify how these parameters change postoperatively. METHODS Computed tomography images from a normal control, a patient with CRS preoperatively and postoperatively, and a patient following an endoscopic Lothrop procedure (ELP) were used to create 4 three-dimensional models of the sinus cavities. Changes in physiologic parameters and topical drug distribution were modeled (inhaled air at 16°C and 10% humidity) at the maxillary ostium, frontal recess, and sphenoid ostium. RESULTS Large differences were seen between models. Following surgery, the maxillary ostia were found on average to be cooler (by 2.4°C), with an increased airflow (0.26 m/second; from 0 m/second), and a 9% reduction in absolute humidity. Sphenoid ostial parameters followed a similar trend. Significant changes in frontal recess physiology were seen following ELP in which the recess was 4.2°C cooler, had increased airflow (0.76 m/second) and a 17% reduction in absolute humidity. Topical drug distribution increased with surgery, particularly after ELP. CONCLUSION Surgery changes the geometry and physiology of the paranasal sinuses. These changes are likely to have an impact on wound healing, mucociliary function, and microbial ecology in postoperative cavities. Application of this model to further understand the effects of surgery may help to optimize surgical techniques and improve topical drug delivery.
Collapse
Affiliation(s)
- Ravi Jain
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Haribalan Kumar
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Merryn Tawhai
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Richard Douglas
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
30
|
Kumar H, Jain R, Douglas RG, Tawhai MH. Airflow in the Human Nasal Passage and Sinuses of Chronic Rhinosinusitis Subjects. PLoS One 2016; 11:e0156379. [PMID: 27249219 PMCID: PMC4889048 DOI: 10.1371/journal.pone.0156379] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 05/13/2016] [Indexed: 11/18/2022] Open
Abstract
Endoscopic surgery is performed on patients with chronic inflammatory disease of the paranasal sinuses to improve sinus ventilation. Little is known about how sinus surgery affects sinonasal airflow. In this study nasal passage geometry was reconstructed from computed tomographic imaging from healthy normal, pre-operative, and post-operative subjects. Transient air flow through the nasal passage during calm breathing was simulated. Subject-specific differences in ventilation of the nasal passage were observed. Velocity magnitude at ostium was different between left and right airway. In FESS, airflow in post-surgical subjects, airflow at the maxillary sinus ostium was upto ten times higher during inspiration. In a Lothrop procedure, airflow at the frontal sinus ostium can be upto four times higher during inspiration. In both post-operative subjects, airflow at ostium was not quasi-steady. The subject-specific effect (of surgery) on sinonasal interaction evaluated through airflow simulations may have important consequences for pre- and post-surgical assessment and surgical planning, and design for improvement of the delivery efficiency of nasal therapeutics.
Collapse
Affiliation(s)
- Haribalan Kumar
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- * E-mail:
| | - Ravi Jain
- Department of surgery, The University of Auckland, Auckland, New Zealand
| | - Richard G. Douglas
- Department of surgery, The University of Auckland, Auckland, New Zealand
| | - Merryn H. Tawhai
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
31
|
A computational analysis of nasal vestibule morphologic variabilities on nasal function. J Biomech 2016; 49:450-7. [PMID: 26830439 DOI: 10.1016/j.jbiomech.2016.01.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/17/2015] [Accepted: 01/09/2016] [Indexed: 11/20/2022]
Abstract
Although advances in computational modeling have led to increased understanding of nasal airflow, not much is known about the effects of normal sinonasal anatomic variabilities on nasal function. In this study, three distinct variations in the human nasal vestibule airspace that have not been previously described were identified. Computational fluid dynamics modeling of nasal airflow profile in each identified variation of nasal vestibule phenotype was conducted to assess the role of these phenotypes on nasal physiology. Three-dimensional reconstructions of the nasal geometry in sixteen subjects with normal radiographic sinonasal images were created and each respective unilateral nasal cavity was classified as Notched, Standard, or Elongated phenotype based nasal vestibule morphology. Steady state, laminar and incompressible flow simulations were performed in the nasal geometries under physiological, pressure-driven conditions with constant inspiratory pressure. Results showed that at localized regions of the unilateral nasal cavity, average resistance was significantly different among nasal vestibule phenotypes. However, global comparison from nostril to choana showed that average resistance was not significantly different across phenotypes; suggesting that with normal anatomic variations, the nose has a natural compensatory mechanism that modulates localized airflow in order to achieve a desired amount of global airflow.
Collapse
|
32
|
Cisonni J, Lucey AD, King AJC, Islam SMS, Lewis R, Goonewardene MS. Numerical simulation of pharyngeal airflow applied to obstructive sleep apnea: effect of the nasal cavity in anatomically accurate airway models. Med Biol Eng Comput 2015; 53:1129-39. [PMID: 26429351 DOI: 10.1007/s11517-015-1399-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 09/19/2015] [Indexed: 11/26/2022]
Abstract
Repetitive brief episodes of soft-tissue collapse within the upper airway during sleep characterize obstructive sleep apnea (OSA), an extremely common and disabling disorder. Failure to maintain the patency of the upper airway is caused by the combination of sleep-related loss of compensatory dilator muscle activity and aerodynamic forces promoting closure. The prediction of soft-tissue movement in patient-specific airway 3D mechanical models is emerging as a useful contribution to clinical understanding and decision making. Such modeling requires reliable estimations of the pharyngeal wall pressure forces. While nasal obstruction has been recognized as a risk factor for OSA, the need to include the nasal cavity in upper-airway models for OSA studies requires consideration, as it is most often omitted because of its complex shape. A quantitative analysis of the flow conditions generated by the nasal cavity and the sinuses during inspiration upstream of the pharynx is presented. Results show that adequate velocity boundary conditions and simple artificial extensions of the flow domain can reproduce the essential effects of the nasal cavity on the pharyngeal flow field. Therefore, the overall complexity and computational cost of accurate flow predictions can be reduced.
Collapse
Affiliation(s)
- Julien Cisonni
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia.
| | - Anthony D Lucey
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia
| | - Andrew J C King
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia
| | - Syed Mohammed Shamsul Islam
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia
- School of Dentistry/Oral Health Centre of Western Australia, University of Western Australia, Crawley, WA, Australia
| | - Richard Lewis
- Perth Head and Neck Surgery, Nedlands, WA, Australia
| | - Mithran S Goonewardene
- School of Dentistry/Oral Health Centre of Western Australia, University of Western Australia, Crawley, WA, Australia
| |
Collapse
|
33
|
Wofford MR, Kimbell JS, Frank-Ito DO, Dhandha V, McKinney KA, Fleischman GM, Ebert CS, Zanation AM, Senior BA. A computational study of functional endoscopic sinus surgery and maxillary sinus drug delivery. Rhinology 2015. [PMID: 25756077 DOI: 10.4193/rhin13.065] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Topical medication is increasingly used following functional endoscopic sinus surgery (FESS). Information on particle sizes that maximise maxillary sinus (MS) delivery is conflicting, and the effect of antrostomy size on delivery is unclear. The purpose of this study was to estimate antrostomy and particle size effects on topical MS drug delivery. METHODOLOGY Sinonasal reconstructions were created from a pre- and a post-FESS CT scan in each of four chronic rhinosinusitis patients. Additional models were created from each post-FESS reconstruction representing four alternative antrostomy sizes. Airflow and particle deposition were simulated in each reconstruction using computational fluid dynamics for nebulised and sprayed delivery. RESULTS MS ventilation and drug delivery increased following FESS, the largest virtual antrostomy led to greatest delivery, and MS delivery was sensitive to particle size. Particles within a 5-18 μm and 5-20 μm size range led to peak MS deposition for nebulised and sprayed particles, respectively. Post-FESS increases in drug delivery varied across individuals and within individuals by the type of antrostomy created. CONCLUSION Our findings suggest that FESS, particularly with larger antrostomies, improves topical drug delivery, and that certain particle sizes improve this delivery. Further research is needed to contextualise these findings with other post-surgical effects.
Collapse
|
34
|
Quadrio M, Pipolo C, Corti S, Messina F, Pesci C, Saibene AM, Zampini S, Felisati G. Effects of CT resolution and radiodensity threshold on the CFD evaluation of nasal airflow. Med Biol Eng Comput 2015; 54:411-9. [PMID: 26059996 DOI: 10.1007/s11517-015-1325-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 06/01/2015] [Indexed: 11/30/2022]
Abstract
The article focuses on the robustness of a CFD-based procedure for the quantitative evaluation of the nasal airflow. CFD ability to yield robust results with respect to the unavoidable procedural and modeling inaccuracies must be demonstrated to allow this tool to become part of the clinical practice in this field. The present article specifically addresses the sensitivity of the CFD procedure to the spatial resolution of the available CT scans, as well as to the choice of the segmentation level of the CT images. We found no critical problems concerning these issues; nevertheless, the choice of the segmentation level is potentially delicate if carried out by an untrained operator.
Collapse
Affiliation(s)
- Maurizio Quadrio
- Department of Aerospace Science and Technologies, Politecnico Milano, Via La Masa 34, 20156, Milan, Italy.
| | - Carlotta Pipolo
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudinì 8, 20142, Milan, Italy
| | - Stefano Corti
- Department of Aerospace Science and Technologies, Politecnico Milano, Via La Masa 34, 20156, Milan, Italy
| | - Francesco Messina
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudinì 8, 20142, Milan, Italy
| | - Chiara Pesci
- Department of Aerospace Science and Technologies, Politecnico Milano, Via La Masa 34, 20156, Milan, Italy
| | - Alberto M Saibene
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudinì 8, 20142, Milan, Italy
| | - Samuele Zampini
- Department of Aerospace Science and Technologies, Politecnico Milano, Via La Masa 34, 20156, Milan, Italy
| | - Giovanni Felisati
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudinì 8, 20142, Milan, Italy
| |
Collapse
|
35
|
Numerical simulation of airflow and micro-particle deposition in human nasal airway pre- and post-virtual sphenoidotomy surgery. Comput Biol Med 2015; 61:8-18. [PMID: 25862997 DOI: 10.1016/j.compbiomed.2015.03.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/19/2015] [Accepted: 03/14/2015] [Indexed: 11/23/2022]
Abstract
In the present study, the effects of endoscopic sphenoidotomy surgery on the flow patterns and deposition of micro-particles in the human nasal airway and sphenoid sinus were investigated. A realistic model of a human nasal passage including nasal cavity and paranasal sinuses was constructed using a series of CT scan images of a healthy subject. Then, a virtual sphenoidotomy by endoscopic sinus surgery was performed in the left nasal passage and sphenoid sinus. Transient airflow patterns pre- and post-surgery during a full breathing cycle (inhalation and exhalation) were simulated numerically under cyclic flow condition. The Lagrangian approach was used for evaluating the transport and deposition of inhaled micro-particles. An unsteady particle tracking was performed for the inhalation phase of the breathing cycle for the case that particles were continuously entering into the nasal airway. The total deposition pattern and sphenoid deposition fraction of micro-particles were evaluated and compared for pre- and post-surgery cases. The presented results show that sphenoidotomy increased the airflow into the sphenoid sinus, which led to increased deposition of micro-particles in this region. Particles up to 25 μm were able to penetrate into the sphenoid in the post-operation case, and the highest deposition in the sphenoid for the resting breathing rate occurred for 10 μm particles at about 1.5%.
Collapse
|
36
|
Wofford MR, Kimbell JS, Frank-Ito DO, Dhandha V, McKinney KA, Fleischman GM, Ebert CS, Zanation AM, Senior BA. A computational study of functional endoscopic sinus surgery and maxillary sinus drug delivery. Rhinology 2015; 53:41-8. [PMID: 25756077 DOI: 10.4193/rhino13.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Topical medication is increasingly used following functional endoscopic sinus surgery (FESS). Information on particle sizes that maximise maxillary sinus (MS) delivery is conflicting, and the effect of antrostomy size on delivery is unclear. The purpose of this study was to estimate antrostomy and particle size effects on topical MS drug delivery. METHODOLOGY Sinonasal reconstructions were created from a pre- and a post-FESS CT scan in each of four chronic rhinosinusitis patients. Additional models were created from each post-FESS reconstruction representing four alternative antrostomy sizes. Airflow and particle deposition were simulated in each reconstruction using computational fluid dynamics for nebulised and sprayed delivery. RESULTS MS ventilation and drug delivery increased following FESS, the largest virtual antrostomy led to greatest delivery, and MS delivery was sensitive to particle size. Particles within a 5-18 μm and 5-20 μm size range led to peak MS deposition for nebulised and sprayed particles, respectively. Post-FESS increases in drug delivery varied across individuals and within individuals by the type of antrostomy created. CONCLUSION Our findings suggest that FESS, particularly with larger antrostomies, improves topical drug delivery, and that certain particle sizes improve this delivery. Further research is needed to contextualise these findings with other post-surgical effects.
Collapse
|
37
|
Frank-Ito DO, Schulz K, Vess G, Witsell DL. Changes in aerodynamics during vocal cord dysfunction. Comput Biol Med 2015; 57:116-22. [DOI: 10.1016/j.compbiomed.2014.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/03/2014] [Accepted: 12/05/2014] [Indexed: 12/01/2022]
|
38
|
Krasnozhen VN, Shcherbakov DA, Garskova YA. [The paranasal sinuses as the nitric oxide depot]. Vestn Otorinolaringol 2015. [PMID: 28635895 DOI: 10.17116/otorino20158049-13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This paper was designed to report the currently available data on physiology of the nasal cavity and paranasal sinuses together with the results of national and international investigations on the computer modeling of the air flow in these structures. Also discussed are the gas composition in the paranasal sinuses and the potential factors responsible for the changes in the concentration of nitric oxide with the chemical formula of NO in the nasal cavity and paranasal sinuses.
Collapse
Affiliation(s)
- V N Krasnozhen
- Kazan State Medical Academy, Russian Ministry of Heath, Kazan, Russia, 420012
| | - D A Shcherbakov
- All-Russian Centre of Eye and Plastic Surgery, Russian Ministry of Health, Ufa, Russia, 450075
| | - Yu A Garskova
- Kazan State Medical Academy, Russian Ministry of Heath, Kazan, Russia, 420012
| |
Collapse
|
39
|
Faramarzi M, Baradaranfar MH, Abouali O, Atighechi S, Ahmadi G, Farhadi P, Keshavarzian E, Behniafard N, Baradaranfar A. Numerical investigation of the flow field in realistic nasal septal perforation geometry. ALLERGY & RHINOLOGY 2014; 5:70-7. [PMID: 24988523 PMCID: PMC4124581 DOI: 10.2500/ar.2014.5.0090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The computational fluid dynamics (CFD) are used to evaluate the physiological function of the nose. We evaluated the aerodynamics of the nasal cavity in a patient with septal perforation (SP), pre- and postvirtual repair. Three-dimensional nasal models were reconstructed, and then a wide range of the pressure drops and flow rates were analyzed. The airflow velocity is higher in the central region and is lower around the boundary of the SP. The air velocity in the SP increases as the pressure drop increases. Furthermore, at the anterior part of the SP, the shear stress is higher in the upper part. In addition, the repair of SP does not affect the total nasal airflow rate and the velocity contour patterns. The potential usage of the CFD technique as a predictive technique to explore the details and a preoperative assessment tool to help in clinical decision making in nasal surgery is emphasized.
Collapse
Affiliation(s)
- Mohammad Faramarzi
- Department of Otolaryngology, Head and Neck Surgery, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
The effect of a middle meatal antrostomy on nitric oxide ventilation in the maxillary sinus. Respir Physiol Neurobiol 2013; 192:7-16. [PMID: 24333403 DOI: 10.1016/j.resp.2013.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 11/30/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
Abstract
The effects of middle meatal antrostomy (MMA) on air and nitric oxide exchange in the human maxillary sinus were quantified using the computational fluid dynamics technique. One full period of respiration was considered in the anatomically correct numerical domain. The simulation results showed that MMA did not cause any noticeable change in the velocity or pressure fields at a global level but induced local velocity as high as 0.21m/s inside the maxillary. Therefore, enlargement of the ostium area by MMA allows inspiratory and expiratory nasal airflow to induce significant convective flows in the sinus, which in turn enhances gas exchange dramatically. At the end of the inspiration phase, NO concentration in the maxillary sinus decreased to about 54% of the initial value. NO concentration decreased only by about 30% during the expiration phase. This difference in reduction rate is thought to result from the difference in airflow velocity in the extended ostium during inspiration vs. expiration.
Collapse
|
41
|
Wei Z, Xu Z, Li B, Xu F. Numerical simulation of airway dimension effects on airflow patterns and odorant deposition patterns in the rat nasal cavity. PLoS One 2013; 8:e77570. [PMID: 24204875 PMCID: PMC3810392 DOI: 10.1371/journal.pone.0077570] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 09/04/2013] [Indexed: 11/27/2022] Open
Abstract
The sense of smell is largely dependent on the airflow and odorant transport in the nasal cavity, which in turn depends on the anatomical structure of the nose. In order to evaluate the effect of airway dimension on rat nasal airflow patterns and odorant deposition patterns, we constructed two 3-dimensional, anatomically accurate models of the left nasal cavity of a Sprague-Dawley rat: one was based on high-resolution MRI images with relatively narrow airways and the other was based on artificially-widening airways of the MRI images by referencing the section images with relatively wide airways. Airflow and odorant transport, in the two models, were determined using the method of computational fluid dynamics with finite volume method. The results demonstrated that an increase of 34 µm in nasal airway dimension significantly decreased the average velocity in the whole nasal cavity by about 10% and in the olfactory region by about 12% and increased the volumetric flow into the olfactory region by about 3%. Odorant deposition was affected to a larger extent, especially in the olfactory region, where the maximum odorant deposition difference reached one order of magnitude. The results suggest that a more accurate nasal cavity model is necessary in order to more precisely study the olfactory function of the nose when using the rat.
Collapse
Affiliation(s)
- Zehong Wei
- Division of Biomedical Photonics, Wuhan National Laboratory of Optoelectronics, Wuhan, China
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Zhixiang Xu
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Bo Li
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Fuqiang Xu
- Division of Biomedical Photonics, Wuhan National Laboratory of Optoelectronics, Wuhan, China
- State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
- * E-mail:
| |
Collapse
|
42
|
Quadrio M, Pipolo C, Corti S, Lenzi R, Messina F, Pesci C, Felisati G. Review of computational fluid dynamics in the assessment of nasal air flow and analysis of its limitations. Eur Arch Otorhinolaryngol 2013; 271:2349-54. [PMID: 24100883 DOI: 10.1007/s00405-013-2742-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 09/26/2013] [Indexed: 10/26/2022]
Abstract
Nasal breathing difficulties (NBD) are a widespread medical condition, yet decisions pertaining to the surgical treatment of chronic NBD still imply a significant degree of subjective judgement of the surgeon. The current standard objective examinations for nasal flow, e.g., rhinomanometry and acoustic rhinomanometry, do not suffice to reliably direct the surgeon on the extent of any necessary surgery. In the last two decades, several groups have therefore considered the numerical simulation of nasal airflow. Currently, these analyses take many hours of labor from the operator, and require a huge amount of computer time and the use of expensive commercial software. Most often, their results are insufficiently validated so that virtual surgery, which is the eventual application, is still absent in clinical practice. Very recently, however, attempts at considering the finest details of the flow are beginning to appear, for example unsteady turbulent simulations validated through laboratory measurements through particle image velocimetry. In this paper, we first discuss recent developments in how computational fluid dynamics (CFD) is helping surgeons improve their understanding of nasal physiology and the effect of surgical modifications on the airflow in the nasal cavity. In a second part, the procedural and modeling challenges that still prevent CFD from being routinely used in clinical practice are surveyed and critically discussed.
Collapse
Affiliation(s)
- Maurizio Quadrio
- Department of Aeronautical Engineering, Politecnico di Milano, via La Masa 34, 20156, Milan, Italy
| | | | | | | | | | | | | |
Collapse
|
43
|
Frank DO, Zanation AM, Dhandha VH, McKinney KA, Fleischman GM, Ebert CS, Senior BA, Kimbell JS. Quantification of airflow into the maxillary sinuses before and after functional endoscopic sinus surgery. Int Forum Allergy Rhinol 2013; 3:834-40. [PMID: 24009143 DOI: 10.1002/alr.21203] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 05/24/2013] [Accepted: 06/18/2013] [Indexed: 11/10/2022]
Abstract
BACKGROUND The effects of increases in maxillary sinus (MS) airflow following functional endoscopic sinus surgery (FESS) are unknown. The goal of this study was to quantify the effects of FESS on airflow into the MS in a cohort of patients with chronic rhinosinusitis, and compare MS flow rate with patient-reported outcome measures. METHODS A pilot study was conducted in which preoperative and postoperative computed tomography scans of 4 patients undergoing bilateral or unilateral FESS were used to create 3-dimensional (3D) reconstructions of the nasal airway and paranasal sinuses using Mimics™ (Materialise, Inc.). The size of the maxillary antrostomies post-FESS ranged from 107 to 160 mm(2). Computational meshes were generated from the 3D reconstructions, and steady-state, laminar, inspiratory airflow was simulated in each mesh using the computational fluid dynamics (CFD) software Fluent™ (ANSYS, Inc.) under physiologic, pressure-driven conditions. Airflow into the MS was estimated from the simulations and was compared preoperatively and postoperatively. In addition, patients completed preoperative and postoperative Rhinosinusitis Outcome Measure-31 (RSOM-31) questionnaires and scores were compared with MS airflow rates. RESULTS CFD simulations predicted that average airflow rate into post-FESS MS increased by 18.5 mL/second, and that average flow velocity into the MS more than quadrupled. Simulation results also showed that MS flow rate trended with total RSOM-31 and all domain scores. CONCLUSION CFD simulations showed that the healed maxillary antrostomy after FESS can greatly enhance airflow into the MS. Our pilot study suggests that to some extent, increasing airflow into the MS may potentially improve chronic rhinosinusitis patients' quality of life pre-FESS and post-FESS.
Collapse
Affiliation(s)
- Dennis O Frank
- Department of Otolaryngology-Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Hybrid mesh for nasal airflow studies. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:727362. [PMID: 23983811 PMCID: PMC3747603 DOI: 10.1155/2013/727362] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 11/24/2022]
Abstract
The accuracy of the numerical result is closely related to mesh density as well as its distribution. Mesh plays a very significant role in the outcome of numerical simulation. Many nasal airflow studies have employed unstructured mesh and more recently hybrid mesh scheme has been utilized considering the complexity of anatomical architecture. The objective of this study is to compare the results of hybrid mesh with unstructured mesh and study its effect on the flow parameters inside the nasal cavity. A three-dimensional nasal cavity model is reconstructed based on computed tomographic images of a healthy Malaysian adult nose. Navier-Stokes equation for steady airflow is solved numerically to examine inspiratory nasal flow. The pressure drop obtained using the unstructured computational grid is about 22.6 Pa for a flow rate of 20 L/min, whereas the hybrid mesh resulted in 17.8 Pa for the same flow rate. The maximum velocity obtained at the nasal valve using unstructured grid is 4.18 m/s and that with hybrid mesh is around 4.76 m/s. Hybrid mesh reported lower grid convergence index (GCI) than the unstructured mesh. Significant differences between unstructured mesh and hybrid mesh are determined highlighting the usefulness of hybrid mesh for nasal airflow studies.
Collapse
|
45
|
Standardization of Malaysian adult female nasal cavity. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:519071. [PMID: 23840279 PMCID: PMC3697144 DOI: 10.1155/2013/519071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 05/31/2013] [Indexed: 11/17/2022]
Abstract
This research focuses on creating a standardized nasal cavity model of adult Malaysian females. The methodology implemented in this research is a new approach compared to other methods used by previous researchers. This study involves 26 females who represent the test subjects for this preliminary study. Computational fluid dynamic (CFD) analysis was carried out to better understand the characteristics of the standardized model and to compare it to the available standardized Caucasian model. This comparison includes cross-sectional areas for both half-models as well as velocity contours along the nasal cavities. The Malaysian female standardized model is larger in cross-sectional area compared to the standardized Caucasian model thus leading to lower average velocity magnitudes. The standardized model was further evaluated with four more Malaysian female test subjects based on its cross-sectional areas and average velocity magnitudes along the nasal cavities. This evaluation shows that the generated model represents an averaged and standardized model of adult Malaysian females.
Collapse
|
46
|
Abstract
Balloon dilation technology (BDT), also known as balloon sinuplasty, has been in clinical use since September, 2005. Prior to BDT, surgeons performed a procedure called FESS, or functional endoscopic sinus surgery, for patients with chronic sinusitis. As is true with any new technology or procedure in medicine, a debate often ensues between early adopters and mainstream practitioners. Over the past 7 years, much has been discussed, debated, and learned about BDT. What follows is a review of the origins of the BDT: the theory, technology, indications and applications; and a review of the pertinent outcomes literature. Independent of how one feels about BDT, the evidence strongly supports its safety, efficacy, and growing popularity among patients and physicians alike.
Collapse
Affiliation(s)
- Peter J Catalano
- St. Elizabeth's Medical Center, 736 Cambridge Street, SMC 8th Floor, Brighton, MA 02135, USA.
| |
Collapse
|
47
|
Kim SK, Na Y, Kim JI, Chung SK. Patient specific CFD models of nasal airflow: overview of methods and challenges. J Biomech 2012; 46:299-306. [PMID: 23261244 DOI: 10.1016/j.jbiomech.2012.11.022] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 11/09/2012] [Indexed: 11/30/2022]
Abstract
Respiratory physiology and pathology are strongly dependent on the airflow inside the nasal cavity. However, the nasal anatomy, which is characterized by complex airway channels and significant individual differences, is difficult to analyze. Thus, commonly adopted diagnostic tools have yielded limited success. Nevertheless, with the rapid advances in computer resources, there have been more elaborate attempts to correlate airflow characteristics in human nasal airways with the symptoms and functions of the nose by computational fluid dynamics study. Furthermore, the computed nasal geometry can be virtually modified to reflect predicted results of the proposed surgical technique. In this article, several computational fluid mechanics (CFD) issues on patient-specific three dimensional (3D) modeling of nasal cavity and clinical applications were reviewed in relation to the cases of deviated nasal septum (decision for surgery), turbinectomy, and maxillary sinus ventilation (simulated- and post-surgery). Clinical relevance of fluid mechanical parameters, such as nasal resistance, flow allocation, wall shear stress, heat/humidity/NO gas distributions, to the symptoms and surgical outcome were discussed. Absolute values of such parameters reported by many research groups were different each other due to individual difference of nasal anatomy, the methodology for 3D modeling and numerical grid, laminar/turbulent flow model in CFD code. But, the correlation of these parameters to symptoms and surgery outcome seems to be obvious in each research group with subject-specific models and its variations (virtual- and post-surgery models). For the more reliable, patient-specific, and objective tools for diagnosis and outcomes of nasal surgery by using CFD, the future challenges will be the standardizations on the methodology for creating 3D airway models and the CFD procedures.
Collapse
Affiliation(s)
- Sung Kyun Kim
- Department of Mechanical Engineering, Konkuk University, Seoul, Republic of Korea.
| | | | | | | |
Collapse
|
48
|
Fifty years of publishing in biomedical engineering: reflections after 7-year editorship. Med Biol Eng Comput 2012. [DOI: 10.1007/s11517-012-1000-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
49
|
Impacts of fluid dynamics simulation in study of nasal airflow physiology and pathophysiology in realistic human three-dimensional nose models. Clin Exp Otorhinolaryngol 2012. [PMID: 23205221 PMCID: PMC3506767 DOI: 10.3342/ceo.2012.5.4.181] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
During the past decades, numerous computational fluid dynamics (CFD) studies, constructed from CT or MRI images, have simulated human nasal models. As compared to rhinomanometry and acoustic rhinometry, which provide quantitative information only of nasal airflow, resistance, and cross sectional areas, CFD enables additional measurements of airflow passing through the nasal cavity that help visualize the physiologic impact of alterations in intranasal structures. Therefore, it becomes possible to quantitatively measure, and visually appreciate, the airflow pattern (laminar or turbulent), velocity, pressure, wall shear stress, particle deposition, and temperature changes at different flow rates, in different parts of the nasal cavity. The effects of both existing anatomical factors, as well as post-operative changes, can be assessed. With recent improvements in CFD technology and computing power, there is a promising future for CFD to become a useful tool in planning, predicting, and evaluating outcomes of nasal surgery. This review discusses the possibilities and potential impacts, as well as technical limitations, of using CFD simulation to better understand nasal airflow physiology.
Collapse
|
50
|
Kimbell JS, Garcia GJM, Frank DO, Cannon DE, Pawar SS, Rhee JS. Computed nasal resistance compared with patient-reported symptoms in surgically treated nasal airway passages: a preliminary report. Am J Rhinol Allergy 2012; 26:94-98. [PMID: 22643935 DOI: 10.2500/ajra.2012.26.3766] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. METHODS Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). RESULTS In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. CONCLUSION These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated.
Collapse
Affiliation(s)
- Julia S Kimbell
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, 27599, USA
| | | | | | | | | | | |
Collapse
|