Variations in the origin of the superior laryngeal artery and their clinical significance: a case report with a proposal for a new classification / Variaciones en el origen de la arteria laríngea superior y su significado clínico: reporte de un caso con una nueva propuesta de clasificación

SUMMARY: The superior laryngeal artery is the primary vessel providing the blood supply to the larynx. Commonly, it is derived from the superior thyroid artery. Different variations in the origin have been described in the current literature; knowledge of such variations is crucial for various surgical interventions of the larynx and surgical procedures in the lateral region of the neck regarding the carotid triangle. It should be noted that radiological studies, such as selective angiography of the thyroid gland, can also be misleading in cases of variations. Herein, we describe a case of bilateral superior laryngeal artery originating directly from the external carotid artery of the neck. The arteries at first have a transverse course and then pierce through the thyrohyoid membrane alongside internal laryngeal nerves. Moreover, we also review the known variations in the origin of the superior laryngeal artery and propose a new classification of all known variations.

RESUMEN: La arteria laríngea superior es el vaso principal que proporciona el suministro de sangre a la laringe. Comúnmente, se deriva de la arteria tiroidea superior. Han sido descritas diferentes variaciones en su origen y el conocimiento de éstas resulta crucial para las intervenciones quirúrgicas realizadas en la laringe, como también en los procedimientos quirúrgicos que se llevan a cabo en la región lateral del cuello, respecto al triángulo carotídeo. Cabe señalar que los estudios radiológicos, como la angiografía selectiva de la glándula tiroides, también pueden ser engañosos en casos de variaciones anatómicas. Aquí, describimos un caso de arteria laríngea superior bilateral que se originaba directamente de la arteria carótida externa. Las arterias al inicio tenían un curso transversal y luego atravezaban la membrana tirohioidea junto con los nervios laríngeos internos. Revisamos también las variaciones conocidas en el origen de la arteria laríngea superior y proponemos una nueva clasificación de todas las variaciones conocidas.

Estudio comparativo de laringes humanas y de cerdos: hacia un modelo de entrenamiento quirúrgico / Comparative study of human and pig larynxes: towards a surgical training model

Introducción: La laringe de cerdo doméstico tiene similitudes con la laringe humana. La capacidad elástica de las cuerdas vocales del cerdo demuestran tener la mayor similitud con la humana comparado con otros animales por lo que se ha propuesto usar las laringes de cerdo como modelo de entrenamiento quirúrgico. Objetivo: Determinar las diferencias y similitudes anatómicas e histológicas entre la laringe del cerdo y la humana. Material y método: Se realizaron mediciones por 4 observadores en 5 laringes porcinas cuyos resultados se compararon con los descritos en la literatura para las laringes humanas. Además se realizaron cortes histológicos para visualizar fibras elásticas, mucinas neutras y mucinas ácidas. Resultados: El cartílago tiroides porcino mide entre las astas superiores 37,55 ±7,30 mm, entre astas inferiores 31,33 ±3,27 mm, desde la prominencia laríngea al borde posterior 34,32 ±7,30 mm. En el cartílago cricoides, desde el borde superior-inferior en el arco anterior 7,28 ±2,21 mm, altura borde superior-inferior pared posterior 27,47 ±3,40 mm, ancho máximo pared posterior 30,99 ±4,51 mm, diámetro interior anteroposterior (borde cefálico) 30,90 ±2,12 mm, diámetro interior anteroposterior (borde caudal) 21,78 ±2,55 mm, diámetro interior derecha-izquierda (borde cefálico) 18,11 ±2,13 mm, diámetro interior derecha-izquierda (borde caudal) 21,10 ±2,40 mm. Histológicamente, la laringe de cerdo y humana presentan leves diferencias en cuanto al epitelio de cada porción de la laringe, a pesar de que el tipo de cartílago es el mismo en ambas especies. Conclusión: Si bien existen diferencias anatómicas e histológicas entre la laringe de cerdo y el humano, el modelo porcino es una alternativa útil, accesible y de bajo costo para el entrenamiento en cirugía laringotraqueal y microcirugía laríngea.

Introduction: The domestic pig larynx has similarities with the human larynx. The elastic capacity of the vocal folds of the pig has the greater similarity with the human one compared with other animals. It has been proposed to use the porcine larynx as a model for surgical training. Aim: To determine the anatomical and histological differences and similarities between the pig larynx and the human larynx. Material and method: Measurements were made by 4 observers in 5 porcine larynxes whose results were compared with those described in the literature. In addition, histological sections were performed to visualize elastic fibers, neutral mucins and acid mucins. Results: The porcine thyroid cartilage measured 37.55 ±7.30 mm between the upper horns, 31.33 ±3.27 mm between lower horns and 34.32 ±7.30 mm from the laryngeal prominence to the posterior margin. In the cricoid cartilage, from the upper-lower edge in the anterior arch 7.28 ±2.21mm, height upper-lower edge posterior wall 27.47 ±3.40 mm, maximum posterior wall width 30.99 ±4.51 mm, anteroposterior inner diameter (head margin) 30.90 ±2.12 mm, inner diameter anteroposterior (caudal edge) 21.78 ±2.55 mm, inner diameter right-left (head edge) 18.11 ±2.13 mm, inner diameter right-left (caudal edge) 21.10 ±2.40 mm. Histologically, the pig and human larynxes present slight differences in the epithelium of each portion of the larynx, despite the fact that type of cartilage is the same in both species. Conclusions: Although there are anatomical and histological differences between the pig larynx and the human larynx, the porcine model is a useful, accessible and low cost alternative for training in laryngotracheal surgery and laryngeal microsurgery.

Pathological and Immunohistochemical Findings in Broilers Inoculated with a Low Virulent Strain of Infectious Laryngotracheitis Virus

This study was carried out to describe clinical, gross and histopathological findings in the respiratory tract in chickens infected intranasally with A96 strain of infectious laryngotracheitis virus (ILTV). In addition, the presence of ILTV antigens in formalin-fixed and paraffin-embedded larynx and trachea tissues was investigated with the immunoperoxidase (IP) method in the infected chickens. At various days of viral infection, nares, larynx, trachea, lungs and air sacs tissue samples of the infected chickens were obtained and fixed with formalin and embedded in paraffin. The cross sections were stained with hematoxylineosin, and the larynx and trachea sections were also stained with the IP method. Mild rales and gasping were observed in only 4 of 35 chickens. The virus caused mild inflammatory changes in the respiratory tract. It was shown that clinical, gross and histopathological findings were not specific for differential diagnosis of the disease. However, ILTV antigens were detected by the IP method in formalin-fixed and paraffin-embedded larynx and trachea sections. These results revealed that the study use of the IP method might be useful for the diagnosis of ILTV infections with non-specific lesions.

Linfáticos da laringe / Lymphatics of the larynx

Realizamos 147 injeçöes de diferentes corantes e/ou contraste radiopaco, em 77 laringes de cäes a fim de se estudar os linfáticos da submucosa da laringe e suas eventuais vias preferencias de drenagem. Os corantess utilizados (Blue Patent V, Azul da Prússia e Tinta Nankin) e/ou contraste radiopaco (Hypaque) foram previamente injetados em regiöes topográficas selecionadas. O estudo foi realizado em cäes anestesiados ou recém-sacrificados, e em laringes extirpadas. A drenagem linfática foi também estudada em cäes submetidos a ligadura prévia de eferentes linfáticos aos linfonodos cervicais. Em laringes isoladas, o estudo dos linfáticos e suas vias de drenagem foi realizado sob lupa estereoscópica, antes e após a desidrataçäo e diafanizaçäo das peças. O autor descreve os caminhos descritos pelos linfáticos da submucosa da laringe até encontrar as vias de drenagem: via superior, via média e via inferior.