Computational fluid dynamics modeling of pharyngeal airway resistance based on cone-beam computed tomography

Research output: Contribution to journalArticle

Abstract

Background: Oral appliances for treating patients with sleep related disorders such as snoring and disturbed sleep could alter the morphology of the pharyngeal airway and thus its flow dynamics as well as airway patency. Splint therapy, i.e., positioning the mandibular condyles in centric relation (CR) with maxillary anterior guided orthotics (MAGO), with regard to pharyngeal airway patency, is causing increased attention. The goal of this work is to quantitatively examine the fluid dynamic changes within the pharyngeal airway when the mandible is positioned in CR and its association with airway patency. Materials and Methods: Patient-specific computational fluid dynamics models were reconstructed from pre- and post- treatment high-resolution cone-beam computed tomography images for two patients who had undergone MAGO therapy. The minimal cross-sectional area and total volume of the pharyngeal airway were measured in the pre- and post-treatment for a total of four models. These two subjects were chosen out of 18 patients based on the airway volume changes in pre- and post-treatment. Subject 1 had a dramatic increase in the airway volume, whereas subject 2 kept a similar airway volume following the therapy. Both subjects anecdotally reported improvement in snoring, breathing and overall sleep quality. Results: We examined three parameters, i.e., the classically defined resistance of airway in terms of pressure drop, the minimal cross-sectional area, and the pharyngeal airway volume. We also proposed a new fluid dynamic parameter: the percentage area of higher vorticity, to be correlated with the clinical efficacy of the appliance for airway patency. All four parameters could be used as index factors for subject 1 to explain the measurable clinical outcomes and the subjective report regarding quality of breathing, snoring cessation, and improvement in sleep of the patient. But only the minimal cross-sectional area and percentage area of higher vorticity could explain the clinical observations and subjective outcome in subject 2 who reported similar effects after the treatment. Conclusion: Splint therapy expanded the minimal cross-sectional area in both subjects, but did not necessarily influence the pharyngeal airway volume. The airway shape changed in terms of the percentage area of higher vorticity and the minimal cross-sectional area. Further studies are needed to assess the clinical efficacy of MAGO in reducing or eliminating the sleep-related breathing difficulties and snoring.

Original languageEnglish (US)
Article number1950045
JournalJournal of Mechanics in Medicine and Biology
Volume19
Issue number6
DOIs
StatePublished - Sep 1 2019

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Tomography
Cones
Computational fluid dynamics
Orthotics
Vorticity
Fluid dynamics
Pressure drop
Dynamic models
Sleep

Keywords

  • Patient-specific computational fluid dynamics
  • maxillary anterior guided orthotics (MAGO)
  • percentage area of higher vorticity
  • pharyngeal airway resistance
  • splint therapy

ASJC Scopus subject areas

  • Biomedical Engineering

Cite this

@article{c7f7263a5206457ea72db672b29df27a,
title = "Computational fluid dynamics modeling of pharyngeal airway resistance based on cone-beam computed tomography",
abstract = "Background: Oral appliances for treating patients with sleep related disorders such as snoring and disturbed sleep could alter the morphology of the pharyngeal airway and thus its flow dynamics as well as airway patency. Splint therapy, i.e., positioning the mandibular condyles in centric relation (CR) with maxillary anterior guided orthotics (MAGO), with regard to pharyngeal airway patency, is causing increased attention. The goal of this work is to quantitatively examine the fluid dynamic changes within the pharyngeal airway when the mandible is positioned in CR and its association with airway patency. Materials and Methods: Patient-specific computational fluid dynamics models were reconstructed from pre- and post- treatment high-resolution cone-beam computed tomography images for two patients who had undergone MAGO therapy. The minimal cross-sectional area and total volume of the pharyngeal airway were measured in the pre- and post-treatment for a total of four models. These two subjects were chosen out of 18 patients based on the airway volume changes in pre- and post-treatment. Subject 1 had a dramatic increase in the airway volume, whereas subject 2 kept a similar airway volume following the therapy. Both subjects anecdotally reported improvement in snoring, breathing and overall sleep quality. Results: We examined three parameters, i.e., the classically defined resistance of airway in terms of pressure drop, the minimal cross-sectional area, and the pharyngeal airway volume. We also proposed a new fluid dynamic parameter: the percentage area of higher vorticity, to be correlated with the clinical efficacy of the appliance for airway patency. All four parameters could be used as index factors for subject 1 to explain the measurable clinical outcomes and the subjective report regarding quality of breathing, snoring cessation, and improvement in sleep of the patient. But only the minimal cross-sectional area and percentage area of higher vorticity could explain the clinical observations and subjective outcome in subject 2 who reported similar effects after the treatment. Conclusion: Splint therapy expanded the minimal cross-sectional area in both subjects, but did not necessarily influence the pharyngeal airway volume. The airway shape changed in terms of the percentage area of higher vorticity and the minimal cross-sectional area. Further studies are needed to assess the clinical efficacy of MAGO in reducing or eliminating the sleep-related breathing difficulties and snoring.",
keywords = "Patient-specific computational fluid dynamics, maxillary anterior guided orthotics (MAGO), percentage area of higher vorticity, pharyngeal airway resistance, splint therapy",
author = "Premaraj, {Thyagaseely Sheela} and Siyeong Ju and Sundaralingam Premaraj and Kim, {Sung K.} and Linxia Gu",
year = "2019",
month = "9",
day = "1",
doi = "10.1142/S0219519419500453",
language = "English (US)",
volume = "19",
journal = "Journal of Mechanics in Medicine and Biology",
issn = "0219-5194",
publisher = "World Scientific Publishing Co. Pte Ltd",
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T1 - Computational fluid dynamics modeling of pharyngeal airway resistance based on cone-beam computed tomography

AU - Premaraj, Thyagaseely Sheela

AU - Ju, Siyeong

AU - Premaraj, Sundaralingam

AU - Kim, Sung K.

AU - Gu, Linxia

PY - 2019/9/1

Y1 - 2019/9/1

N2 - Background: Oral appliances for treating patients with sleep related disorders such as snoring and disturbed sleep could alter the morphology of the pharyngeal airway and thus its flow dynamics as well as airway patency. Splint therapy, i.e., positioning the mandibular condyles in centric relation (CR) with maxillary anterior guided orthotics (MAGO), with regard to pharyngeal airway patency, is causing increased attention. The goal of this work is to quantitatively examine the fluid dynamic changes within the pharyngeal airway when the mandible is positioned in CR and its association with airway patency. Materials and Methods: Patient-specific computational fluid dynamics models were reconstructed from pre- and post- treatment high-resolution cone-beam computed tomography images for two patients who had undergone MAGO therapy. The minimal cross-sectional area and total volume of the pharyngeal airway were measured in the pre- and post-treatment for a total of four models. These two subjects were chosen out of 18 patients based on the airway volume changes in pre- and post-treatment. Subject 1 had a dramatic increase in the airway volume, whereas subject 2 kept a similar airway volume following the therapy. Both subjects anecdotally reported improvement in snoring, breathing and overall sleep quality. Results: We examined three parameters, i.e., the classically defined resistance of airway in terms of pressure drop, the minimal cross-sectional area, and the pharyngeal airway volume. We also proposed a new fluid dynamic parameter: the percentage area of higher vorticity, to be correlated with the clinical efficacy of the appliance for airway patency. All four parameters could be used as index factors for subject 1 to explain the measurable clinical outcomes and the subjective report regarding quality of breathing, snoring cessation, and improvement in sleep of the patient. But only the minimal cross-sectional area and percentage area of higher vorticity could explain the clinical observations and subjective outcome in subject 2 who reported similar effects after the treatment. Conclusion: Splint therapy expanded the minimal cross-sectional area in both subjects, but did not necessarily influence the pharyngeal airway volume. The airway shape changed in terms of the percentage area of higher vorticity and the minimal cross-sectional area. Further studies are needed to assess the clinical efficacy of MAGO in reducing or eliminating the sleep-related breathing difficulties and snoring.

AB - Background: Oral appliances for treating patients with sleep related disorders such as snoring and disturbed sleep could alter the morphology of the pharyngeal airway and thus its flow dynamics as well as airway patency. Splint therapy, i.e., positioning the mandibular condyles in centric relation (CR) with maxillary anterior guided orthotics (MAGO), with regard to pharyngeal airway patency, is causing increased attention. The goal of this work is to quantitatively examine the fluid dynamic changes within the pharyngeal airway when the mandible is positioned in CR and its association with airway patency. Materials and Methods: Patient-specific computational fluid dynamics models were reconstructed from pre- and post- treatment high-resolution cone-beam computed tomography images for two patients who had undergone MAGO therapy. The minimal cross-sectional area and total volume of the pharyngeal airway were measured in the pre- and post-treatment for a total of four models. These two subjects were chosen out of 18 patients based on the airway volume changes in pre- and post-treatment. Subject 1 had a dramatic increase in the airway volume, whereas subject 2 kept a similar airway volume following the therapy. Both subjects anecdotally reported improvement in snoring, breathing and overall sleep quality. Results: We examined three parameters, i.e., the classically defined resistance of airway in terms of pressure drop, the minimal cross-sectional area, and the pharyngeal airway volume. We also proposed a new fluid dynamic parameter: the percentage area of higher vorticity, to be correlated with the clinical efficacy of the appliance for airway patency. All four parameters could be used as index factors for subject 1 to explain the measurable clinical outcomes and the subjective report regarding quality of breathing, snoring cessation, and improvement in sleep of the patient. But only the minimal cross-sectional area and percentage area of higher vorticity could explain the clinical observations and subjective outcome in subject 2 who reported similar effects after the treatment. Conclusion: Splint therapy expanded the minimal cross-sectional area in both subjects, but did not necessarily influence the pharyngeal airway volume. The airway shape changed in terms of the percentage area of higher vorticity and the minimal cross-sectional area. Further studies are needed to assess the clinical efficacy of MAGO in reducing or eliminating the sleep-related breathing difficulties and snoring.

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KW - maxillary anterior guided orthotics (MAGO)

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KW - pharyngeal airway resistance

KW - splint therapy

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