Table of Contents Author Guidelines Submit a Manuscript
BioMed Research International
Volume 2019, Article ID 6932047, 11 pages
https://doi.org/10.1155/2019/6932047
Research Article

Juvenile Ovine Ex Vivo Larynges: Phonatory, Histologic, and Micro CT Based Anatomic Analyses

1Division for Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head and Neck Surgery, Medical School, University Hospital, FAU Erlangen-Nürnberg, Waldstrasse 1, 91054 Erlangen, Germany
2Laboratory for Molecular Biology, Department of Otorhinolaryngology, Head and Neck Surgery, Medical School, University Hospital, FAU Erlangen-Nürnberg, Waldstrasse 1, 91054 Erlangen, Germany
3Division of Phoniatrics, ENT University Hospital Graz, Medical University Graz, Auenbruggerplatz 26, Graz 8036, Austria

Correspondence should be addressed to Michael Döllinger; ed.negnalre-ku@regnilleod.leahcim

Received 8 November 2018; Accepted 11 February 2019; Published 4 March 2019

Academic Editor: Jan Plzak

Copyright © 2019 Michael Döllinger et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

It is well known that the phonatory process changes during the life span. However, detailed investigations on potential factors concerned are rare. To deal with this issue, we performed extended biomechanical, macro anatomical, and histological analyses of the contributing laryngeal structures in ex vivo juvenile sheep models. Altogether twelve juvenile sheep larynges were analyzed within the phonatory experiments. Three different elongation levels and 16 different flow levels were applied to achieve a large variety of phonatory conditions. Vocal fold dynamics and acoustical and subglottal signals could be analyzed for 431 experimental runs. Subsequently, for six juvenile larynges microcomputed tomography following virtual 3D reconstruction was performed. The remaining six juvenile larynges as well as six ex vivo larynges from old sheep were histologically and immunohistologically analyzed. Results for juveniles showed more consistent dynamical behavior compared to old sheep larynges due to vocal fold tissue alterations during the life span. The phonatory process in juvenile sheep seems to be more effective going along with a greater dynamic range. These findings are supported by the histologically detected higher amounts of elastin and hyaluronic acid in the lamina propria of the juvenile sheep. The 3D reconstructions of the thyro-arytenoid muscles (TAM) showed a symmetrical shape. Intraindividual volume and surface differences of the TAM were small and comparable to those of aged sheep. However, TAM dimensions were statistically significant smaller for juvenile larynges. Finally, topographical landmarks were introduced for later comparison with other individuals and species. This work resulted in detailed functional, immunohistological, and anatomical information that was not yet reported. This data will also provide reference information for therapeutic strategies regarding aging effects, e.g. laryngeal muscle treatment by functional electrical stimulation.