Caracterización de estructuras anatómicas de la laringe por ultrasonografía / Characterization of anatomical structures of the larynx by ultrasonography

La laringe es un órgano impar situado en la línea mediana del cuello, compuesto por cartílagos, músculos y ligamentos. La TC y la RM se realizan como técnicas de imagen de primera elección en el estudio de la laringe, no obstante, no están exentas de limitaciones. La ecografía es un método accesible, de alta resolución y presenta una relativa buena visualización de las diferentes estructuras de la laringe. El objetivo del trabajo fue determinar las características de estructuras anatómicas de la laringe identificables ecográficamente. En este trabajo de carácter observacional descriptivo de corte transversal prospectivo se estudiaron 20 pacientes, sin patología laríngea con edades entre 20 y 35 años, ambos sexos. Se realizó ecografía laríngea utilizando transductor ecográfico Phillips® con sonda lineal de 4 a 12 MHz, preset de partes blandas.En todos los casos se pudo identificar y medir los cartílagos tiroides, cricoides y epiglotis; y en gran porcentaje de estos las cuerdas vocales, bandas ventriculares y comisura anterior. El cartílago aritenoides solo fue visible en un 85% de los casos.La ecografía se presenta como un método auxiliar útil en el estudio de la anatomía de la laringe, proponiendo el seguimiento y realización de estudios ulteriores que puedan complementar este estudio y su validez.

The larynx is an odd organ located in the midline of the neck, composed of cartilage, muscles and ligaments. CT and MRI are performed as first-choice imaging techniques in the larynx study; however, they are not without limitations. Ultrasound is an accessible, high-resolution method with a relatively good visualization of the different structures of the larynx. The objective of the work was to determine the characteristics of ultrasoundly identifiable larynx anatomical structures.In this prospective cross-sectional descriptive observational work, 20 patients were studied, without laryngeal pathology aged between 20 and 35 years, both sexes. Laryngeal ultrasound was performed using Phillips® ultrasound transducer with linear probe from 4 to 12 MHz, soft parts presetThyroid cartilage, cricoids and epiglotis could be identified and measured in all cases, and in a large percentage of these the vocal cords, ventricular bands and anterior corner. Aritenoid cartilage was only visible in 85% of cases.Ultrasound is presented as a useful auxiliary method in the study of the anatomy of the larynx, proposing the follow-up and conduct of further studies that may complement this study and its validity

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.

comparison of the ratio of patient's height to thyromental distance with the modified Mallampati and the upper lip bite test in predicting difficult laryngoscopy

The aim of the present study was to compare the ability to predict difficult visualization of the larynx from the following preoperative airway predictive indices, in isolation and combination: modified Mallampati test [MMT], the ratio of height to thyromental distance [RHTMD] and the Upper-Lip-Bite test [ULBT]. We collected data on 603 consecutive patients scheduled for elective surgery under general anesthesia requiring endotracheal intubation and then evaluated all three factors before surgery. An experienced anesthesiologist, not informed of the recorded preoperative airway evaluation, performed the laryngoscopy and grading [as per Cormack and Lehane's classification]. Sensitivity, specificity, and positive and negative predictive value, Receiver operating characteristic [ROC] Curve and the area under ROC curve [AUC] for each airway predictor in isolation and in combination were determined. Difficult laryngoscopy [Grade 3 or 4] occurred in 41 [6.8%] patients. The main endpoint of the present study, the AUC of the ROC, was significantly lower for the MMT [AUC, 0.511; 95% CI, 0.470-0.552] than the ULBT [AUC, 0.709; 95% CI, 0.671-0.745, P=0.002] and the RHTMD score [AUC, 0.711; 95% CI, 0.673-0.747, P=0.001]. There was no significant difference between the AUC of the ROC for the ULBT and the RHTMD score. By using discrimination analysis, the optimal cutoff point for the RHTMD for predicting difficult laryngoscopy was 21.06 [sensitivity, 75.6%; specificity, 58.5%]. The RHTMD is comparable with ULBT for prediction of difficult laryngoscopy in general population

The incidence of the foramen thyroideum in the South African population / Incidencia del foramen tiroideo en la población de sudáfrica

The foramen thyroideum is described as an occasional opening existing in one or both laminae of the thyroid cartilage which may or may not contain a neurovascular component. Foramen thryoideum was first described in the literature by Segond in 1847. Some authors consider its existence a structural variation rather than an anomaly, with classical texts of anatomy providing little detail when describing this foramen. This study was undertaken to investigate the incidence and characteristics of the foramen thyroideum in the South African population. A total of 80 formalin fixed cadaveric laryngeal specimens (obtained from the Department of Clinical Anatomy, University of KwaZulu-Natal, South Africa) were dissected. Larynges were dissected with the aid of a Stemi DV 4 light microscope. The incidence, location, dimensions and contents of the foramen thyroideum were recorded. The horizontal and vertical extent of each foramen was measured with a digital caliper. Six of the 80 (7.5 percent) specimens examined had distinctly identifiable foramina. Five of the six cases (4 male, 1 female) displayed bilateral foramina (6.3 percent), with one case (1 female) of a unilateral foramen (1.3 percent). Of the larynges that had bilateral foramina, a single case presented with two foramina on the same (right) thyroid lamina. A total of twelve foramina were observed. Gender distribution of foramen thyroideum was: male: right 5, left 4; female: right 2, left 1. Preceding investigators of the foramen thyroideum have rightly indicated that awareness of its presence is of paramount importance in order to preserve the structures that traverse it and also to comprehensively treat or contain laryngeal cancer.

El foramen tiroideo se describe como una apertura ocasional existente en una o ambas láminas del cartílago tiroides, la cual puede o no contener un componente neurovascular. El foramen tiroideo fue descrito por primera vez en la literatura por Segond en 1847. Algunos autores consideran su existencia como una variación estructural y no una anomalía, los textos clásicos de anatomía proporcionan pocos detalles al describir este foramen. Este estudio se realizó para investigar la incidencia y características del foramen tiroideo en la población Sudafricana. Fueron disecados 80 especímenes cadavéricos de larínge fijados con formalina (obtenidos del Departamento de Anatomía Clínica de la Universidad de KwaZulu-Natal, Sudáfrica). Las laringes fueron disecadas con la ayuda de un microscopio de luz Stemi DV 4. La incidencia, localización, dimensiones y contenido del foramen tiroideo fueron registradas. La extensión horizontal y vertical de cada foramen se midieron con un caliper digital. Seis de los 80 (7,5 por ciento) especímenes examinados tenían foramen tiroideos claramente identificables. Cinco de los seis casos (cuatro hombres y una mujer) mostraron forámenes bilaterales (6,3 por ciento), y un caso (una mujer) foramen unilateral (1,3 por ciento). De las laringes que presentaron forámenes bilaterales, un solo caso presentó dos forámenes en la misma lámina del cartílago tiroides (derecha). La distribución por sexo del foramen tiroídeo en hombres fue 5 derechos y 4 izquierdos, mientras que en mujeres 2 derechos y 1 izquierdo. Los resultados indican que el conocimiento de la presencia del foramen tiroideo es de vital importancia para preservar las estructuras que lo atraviesan y también para el tratamiento de integral o contención del cáncer de laringe.

An assessment of the ratio of height to thyromental distance compared to thyromental distance as a predictive test for prediction of difficult tracheal intubation in Thai patients.

BACKGROUND AND RATIONALE: Preoperative evaluation is important in the detection of patients at risk for difficult tracheal intubation. Thyromental distance (TMD) is often used for these purposes, but its value as an indicator for difficult intubation is questionable, as it varies with patient size and body proportions. The purpose of the present study was to evaluate and compare the accuracies of the ratio of patient's height to TMD (ratio of height to TMD = RHTMD) and TMD alone in the prediction of difficult tracheal intubation in Thai patients. MATERIAL AND METHODS: The authors collected data on 382 consecutive patients scheduled to receive general anesthesia requiring endotracheal intubation for elective surgery. Thyromental distance and RHTMD were evaluated preoperatively. Difficult intubation was defined in the present study by Cormack and Lehane grade 3 or 4. The optimal predictive value was chosen using a receiver operating characteristic (ROC) curve. The areas under the ROC curves (AUC) of TMD and RHTMD were compared to determine the performance of the different predictive tests used. The sensitivity, specificity, and positive and negative predictive values of each of the predictive tests were calculated according to standard formulae. RESULTS: Difficult intubation occurred in 42 patients (10.9 %). The predictive advantage of RHTMD has a similar specificity with improved sensitivity in comparison with TMD. The AUC of RHTMD was significantly greater than the AUC of TMD (p = 0.00). The authors concluded that RHTMD had better accuracy in predicting difficult intubation than TMD.

Cateterismo retrogrado transtraqueal para la intubación difícil / Inverse endotracheal intubation in the management of difficult airway

El presente estudio se llevó a efecto en el Hospital de traumatología magdalena de las Salinas de IMSS. Se estudiaron a 60 pacientes de ambos sexos, ASA I-IV, sometidos a cirugía electiva o de urgencia de tipo traumatológico u ortopédico en quienes la indicación de anestesia general era absoluta, además de sospecharse que por sus características anatómicas y/o estado físico la posibilidad de presentar un intubación endotraqueal por tracción inversa, resultado efectiva en el 100 por ciento de los casos, con mínimas complicaciones y escasa repercusión sobre los signos vitales, lo que nos permitió proponer a esta técnica como una alternativa útil, fácil y segura para pacientes a quienes por los indicadores existentes se prevea la posibilidad de intentos repetidos durante la intubación