title: A computational study of the role of the aortic arch in idiopathic unilateral vocal-fold paralysis.
abstract: Unilateral vocal-fold paralysis (UVP) occurs when one of the vocal folds becomes paralyzed due to damage to the recurrent laryngeal nerve (RLN). Individuals with UVP experience problems with speaking, swallowing, and breathing. Nearly two-thirds of all cases of UVP is associated with impaired function of the left RLN, which branches from the vagus nerve within the thoracic cavity and loops around the aorta before ascending to the larynx within the neck. We hypothesize that this path predisposes the left RLN to a supraphysiological, biomechanical environment, contributing to onset of UVP. Specifically, this research focuses on the identification of the contribution of the aorta to onset of left-sided UVP. Important to this goal is determining the relative influence of the material properties of the RLN and the aorta in controlling the biomechanical environment of the RLN. Finite element analysis was used to estimate the stress and strain imposed on the left RLN as a function of the material properties and loading conditions. The peak stress and strain in the RLN were quantified as a function of RLN and aortic material properties and aortic blood pressure using Spearman rank correlation coefficients. The material properties of the aortic arch showed the strongest correlation with peak stress [ρ = -0.63, 95% confidence interval (CI), -1.00 to -0.25] and strain (ρ = -0.62, 95% CI, -0.99 to -0.24) in the RLN. Our results suggest an important role for the aorta in controlling the biomechanical environment of the RLN and potentially in the onset of left-sided UVP that is idiopathic.
authors.affiliation: Graduate Interdisciplinary Program of Biomedical Engineering, University of Arizona, Tucson, Arizona;
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Williams
authors.affiliation: Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona;
authors.forename: Avinash
authors.initials: A
authors.lastname: Ayylasomayajula
authors.affiliation: Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona;
authors.forename: Reza
authors.initials: R
authors.lastname: Behkam
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri;
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Bierhals
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri;
authors.forename: M Eileen
authors.initials: ME
authors.lastname: Jacobs
authors.affiliation: Truman State University, Kirksville, Missouri;
authors.forename: Julia D
authors.initials: JD
authors.lastname: Edgar
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, Missouri;
authors.forename: Randal C
authors.initials: RC
authors.lastname: Paniello
authors.affiliation: Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, Voice Laboratory, University of Utah, Salt Lake City, Utah;
authors.forename: Julie M
authors.initials: JM
authors.lastname: Barkmeier-Kraemer
authors.affiliation: Graduate Interdisciplinary Program of Biomedical Engineering, University of Arizona, Tucson, Arizona; Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona; Department of Biomedical Engineering, University of Arizona, Tucson, Arizona; and BIO5 Institute, University of Arizona, Tucson, Arizona jpv1@email.arizona.edu.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Vande Geest
mesh_terms: D001013:Aorta, Thoracic / Q000503:physiopathology*; D062186:Arterial Pressure / Q000502:physiology; D006801:Humans; D007830:Larynx / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000503:physiopathology; D012009:Recurrent Laryngeal Nerve / Q000503:physiopathology; D014630:Vagus Nerve / Q000503:physiopathology; D014826:Vocal Cord Paralysis / Q000503:physiopathology*
keywords: biomechanics; finite element; nerve; recurrent laryngeal nerve; vocal-fold paralysis