Influence of unilateral and bilateral vocal cordectomy on airflow across cadaveric equine larynges at different Rakestraw grades of arytenoid abduction.
Abstract: To assess the effect of vocal cordectomy on airflow across equine larynges at different Rakestraw grades of arytenoid abduction using a unidirectional airflow model. Methods: Ex vivo, repeated measures. Methods: Twenty cadaveric equine larynges. Methods: The right arytenoid cartilage was maximally abducted in all larynges. Each larynx was assigned a Rakestraw grade A or B, and the left arytenoid was abducted accordingly. Each larynx was tested under 3 conditions: intact, left vocal cordectomy (LVC), and bilateral vocal cordectomy (BVC). Translaryngeal pressure and airflow were measured, and digital video footage was obtained. Translaryngeal impedance (TLI) was calculated, and the arytenoid left-to-right quotient angle (LRQ) and rima glottis cross-sectional area (CSA) were measured from standardized still images. Results: Vocal cordectomy reduced TLI by 14.5% in LVC in comparison with intact larynges at Rakestraw grade B (P = .014). In Rakestraw grade A position, neither unilateral nor bilateral vocal cordectomy had any effect on TLI. Regardless of Rakestraw allocation, both LVC and BVC increased CSA in comparison with intact larynges (P < .005), with BVC larynges experiencing a greater effect than LVC (P < .0001). Conclusions: Using a unilateral airflow model, LVC improved TLI in larynges where arytenoid position approximated Rakestraw grade B. However, when the arytenoid position approximated Rakestraw grade A, there was no effect on TLI following LVC or BVC. Conclusions: Surgeons considering a vocal cordectomy should take into account the degree of arytenoid abduction before performing the procedure, as it may not be warranted from a TLI point of view.
© 2022 The Authors. Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.
Publication Date: 2022-05-24 PubMed ID: 35608018PubMed Central: PMC9546136DOI: 10.1111/vsu.13823Google Scholar: Lookup
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Summary
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The research investigates the impact of removing the vocal cords (vocal cordectomy) on airflow across horse larynges using a one-way airflow model. The study highlights the importance of taking into account the level of arytenoid abduction before performing a vocal cordectomy, as it may not be necessary depending on translaryngeal impedance (the measure of resistance to airflow).
Study Objective and Methods
- The goal of the study was to determine the influence of vocal cord removal both, on one side (unilateral) and on both sides (bilateral), on airflow across horse larynges at different levels of arytenoid abduction (side-to-side movement). These measurements were taken from twenty cadaveric (dead) horse larynges in a controlled lab setting.
- The study employed the use of the Rakestraw grading system. This system is used to determine the level of arytenoid abduction, grade A represents a normal adjust position, and grade B is when the arytenoid cartilage’s ability to move is compromised. The Rakestraw grade assigned dictated the level of abduction for the left arytenoid.
- Each larynx was tested under three different conditions; intact (no surgical removal of vocal cords), left vocal cordectomy (LVC), and bilateral vocal cordectomy (BVC). During these tests, measurements were taken for translaryngeal pressure, airflow, and digital videos were recorded. The left-to-right quotient angle (LRQ) and the cross-sectional area (CSA) of the rima glottis (the space between the vocal cords) were measured, and the translaryngeal impedance (TLI) was computed.
Results and Conclusion
- The results from the LVC tests showed a reduction in TLI by 14.5%, but only in larynges at Rakestraw grade B. This indicates that a single-sided vocal cordectomy at this grade resulted in improved airflow.
- In contrast, neither unilateral (LVC) nor bilateral (BVC) vocal cordectomy had any effect on the TLI at Rakestraw grade A.
- Regardless of the Rakestraw allocation, both LVC and BVC increased the cross-sectional area (CSA) in comparison with intact larynges, but those with BVC recorded a more significant effect.
- It is deduced from the study that surgeons contemplating a vocal cordectomy should consider the level of arytenoid abduction. The procedure may not be justified from the TLI viewpoint if the arytenoid is in Rakestraw grade A position, as there is no perceptible effect on TLI.
Cite This Article
APA
Lean NE, Bertin FR, Ahern BJ.
(2022).
Influence of unilateral and bilateral vocal cordectomy on airflow across cadaveric equine larynges at different Rakestraw grades of arytenoid abduction.
Vet Surg, 51(6), 974-981.
https://doi.org/10.1111/vsu.13823 Publication
Researcher Affiliations
- School of Veterinary Science, University of Queensland, Gatton, Queensland.
- School of Veterinary Science, University of Queensland, Gatton, Queensland.
- School of Veterinary Science, University of Queensland, Gatton, Queensland.
MeSH Terms
- Animals
- Arytenoid Cartilage / surgery
- Cadaver
- Horse Diseases / surgery
- Horses / surgery
- Humans
- Laryngoplasty / methods
- Laryngoplasty / veterinary
- Larynx / surgery
- Vocal Cords / surgery
Conflict of Interest Statement
The authors declare no conflict of interest related to this report.
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Citations
This article has been cited 1 times.- Tucker ML, Wilson DG, Bergstrom DJ, Carmalt JL. Computational fluid dynamic analysis of upper airway procedures in equine larynges. Front Vet Sci 2023;10:1139398.
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