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Numerical Assessment of the Impact and Relative Importance of the Underlying Biomechanics of the Eustachian Tube Phenotype to Overall Tubal Function and Diagnostics

Torres-Rodriguez, Justo Juvian
http://orcid.org/0000-0002-8348-595X
http://rave.ohiolink.edu/etdc/view?acc_num=osu1555428830144956

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Biomedical Engineering.
With an estimated $5.3 billion in treatment costs, Otitis media (OM, any inflammation of the middle ear) is the most common disease for which children receive medical treatment in the US and the development of chronic OM is due to dysfunction of an upper respiratory airway, the Eustachian tube (ET). The ET is a collapsible respiratory airway that connects the middle ear with the nasopharynx and is composed of a lumen, surrounding mucosa and cartilaginous tissues as well as the tensor and levator veli palatini muscles that cause deformation/rotation of ET tissues and lumen dilation. ET dysfunction (ETD) causes OM to persist long after the initial infection, which is particularly common in children and cleft-palate infants where physiological ET function and anatomy are underdeveloped and upper respiratory infections are common. Current treatment therapies do not target the underlying biomechanical mechanisms responsible for ETD and there is a lack of literature that establishes the specificity and sensitivity of ETD diagnostic procedures to specific biomechanics. As a result, most studies that attempt to quantify these mechanics provide theories, do not assess the impact and relative importance of several mechanics, or do not account for all ET mechanics, particularly the ET’s medial rotation. There is a significant clinical need to 1) fully understand the underlying mechanics of ET function and 2) develop new diagnostic procedures that identify patient-specific mechanisms of ETD (i.e. ETD phenotype) and 3) develop therapeutic procedures that are based on a given patient’s ETD phenotype and can resolve the underlying pathological mechanics. In this dissertation we use novel computational simulations of ET function in adults and children to provide an understanding of how several properties influence the ET phenotype and diagnosis. Our results predict that tensor activation is essential to ET function, in accordance with literature, and that levator-induced ET rotation provides significant benefits to ET dilation in adults only. Monitoring the ET rotations can serve as a diagnostic marker of ETD only in older subjects with the requisite adult ET anatomy. We show that increased cartilage and mucosa tissue stiffness significantly hinders ET function, especially in young children. These results indicate that reduction of the elastic modulus) of the cartilage could be a viable treatment goal, even when stiff mucosa tissues hinder ET function. Stiffness reduction of mucosa tissues can help alleviate ETD, particularly when muscle function or medial rotations are low in adults. Lastly, we predict that the diagnostic output of sonotubometry, a non-invasive test that measures the acoustic transmission trend through the ET lumen as a marker of ET dilation, is mainly specific and sensitive to tensor activation. However, measurement of the sonotubometry peak area can provide information on cartilage stiffness in adults, as well as mucosa stiffness in children. The innovative aspect of this work is that we have created a method that uses state-of-the-art technology to provide quantified data on previously unknown or theorized relationships of the underlying structural-fluid and structural-acoustic interactions that take place during ET function and sonotubometry, while addressing the limitations of previous studies. Future efforts should evaluate the efficacy of current and proposed therapeutic methods to modify the ET mechanics identified here, which would solve an episode of ETD. We expect that this new information causes a severely needed paradigm shift in the diagnosis and treatment of ETD that enables the clinician to identify and treat the patient’s ETD phenotype in routine clinical practice.
Samir Ghadiali, PhD (Advisor)
Alan Litsky, PhD (Committee Member)
Jun Liu, PhD (Committee Member)
183 p.
Biomedical Engineering
Eustachian Tube; Computational Simulations; Biomechanics; Finite Element Analysis; Sonotubometry

Recommended Citations

Citations

  • Torres-Rodriguez, J. J. (2019). Numerical Assessment of the Impact and Relative Importance of the Underlying Biomechanics of the Eustachian Tube Phenotype to Overall Tubal Function and Diagnostics [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555428830144956

    APA Style (7th edition)

  • Torres-Rodriguez, Justo. Numerical Assessment of the Impact and Relative Importance of the Underlying Biomechanics of the Eustachian Tube Phenotype to Overall Tubal Function and Diagnostics. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1555428830144956.

    MLA Style (8th edition)

  • Torres-Rodriguez, Justo. "Numerical Assessment of the Impact and Relative Importance of the Underlying Biomechanics of the Eustachian Tube Phenotype to Overall Tubal Function and Diagnostics." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555428830144956

    Chicago Manual of Style (17th edition)

osu1555428830144956
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This open access ETD is published by The Ohio State University and OhioLINK.