Laryngeal Trauma

Laryngeal trauma is rare but potentially fatal. Initial evaluation includes efficient history and physical examination, imaging, bedside flexible laryngoscopy, and if necessary, operative endoscopic evaluation. Multiple classification systems exist for laryngeal trauma, and each has its merits. We recommend a patient-centered approach, rather than using the classification alone. Secure airways are the primary goal of acute management, with awake tracheostomy more often indicated over oral intubation compared with traumas not involving the larynx. More severe injuries typically require surgical intervention. Early intervention results in optimal voice and airway outcomes.

Length of the Cricoid and Trachea in Children: Predicting Intubation Depth to Prevent Subglottic Stenosis

OBJECTIVE

Define the length of the subglottis and trachea in children to predict a safe intubation depth.

METHODS

Patients <18 years undergoing rigid bronchoscopy from 2013 to 2020 were included. The carina and inferior borders of the cricoid and true vocal folds were marked on a bronchoscope and distances were measured. Patient age, weight, height, and chest height were recorded. Four styles of cuffed pediatric endotracheal tubes (ETT) were measured and potential positions of each cuff and tip were calculated within each trachea using five depth of intubation scenarios. Multivariate linear regression was performed to identify predictors of subglottic and tracheal length.

RESULTS

Measurements were obtained from 210 children (141 male, 69 female), mean (SD) age 3.21 (3.66) years. Patient height was the best predictor of subglottic length (R² : 0.418): Length_sg (mm) = 0.058 * height (cm) + 2.8, and tracheal length (R² : 0.733): Length_t (mm) = 0.485 * height (cm) + 21.3. None of the depth of intubation scenarios maintained a cuff-free subglottis for all ETT styles investigated. A formula for depth of intubation: Length_di (mm) = 0.06 * height (cm) + 8.8 found that no ETT cuffs would be in the subglottis and all tips would be above the carina.

CONCLUSION

Current strategies for determining appropriate depth of intubation pose a high risk of subglottic ETT cuff placement. Placing the inferior border of the vocal cords 0.06 * height (cm) + 8.8 from the superior border of the inflated ETT cuff may prevent subglottic cuff placement and endobronchial intubation.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Surgical management of an infantile elliptical cricoid: Endoscopic posterior laryngotracheoplasty utilizing a resorbable plate

The cricoid is a circular "ring" of cartilage in the airway. When the lateral walls of the cricoid approximate, it takes the shape of an ellipse. In severe cases, this also reduces the glottic aperture and causes respiratory distress, stridor, and failure to thrive. The elliptical cricoid has limited surgical options outside of open laryngotracheal procedures and tracheostomy. Recently, alternatives to autologous grafts have been utilized in airway reconstruction to reduce harvest site morbidity and increase operating room efficiency. Herein a case is presented that demonstrates the successful use of a resorbable plate in augmenting the posterior larynx in an infant with a severely elliptical cricoid to avoid a tracheostomy.

The pediatric airway: Historical concepts, new findings, and what matters

New observations from novel imaging techniques regarding the anatomy, dimensions, and shape of the pediatric airway have emerged and provide insight for potential changes in the clinical management of the airway in infants and children. These new findings are challenging the historical concepts of a funnel-shaped upper airway with the cricoid ring as the narrowest dimension. Although these tenets have been accepted and used to guide clinical practice in airway management, there are limited clinical investigations in children to support the validity of these concepts. Imaging modalities such as magnetic resonance imaging, computed tomography (CT) scanning, multi-detector CT imaging, and videobronchoscopy suggest the need to revisit the historical view of the pediatric airway. This manuscript reviews the historical evolution of pediatric airway studies, summarizes important scientific observations from recent investigations relevant to our clinical understanding of pediatric airway anatomy, and discusses the importance of these findings for pediatric airway management.

A comparative prospective cohort study comparing physical exam to ultrasound for identifying the cricoid cartilage

Applying cricoid pressure is a common practice when intubating patients thought to be at risk of pulmonary aspiration. Recently, the perceived benefits of applying cricoid pressure have been questioned. Prior research has shown that cricoid pressure is applied incorrectly and that palpation of adjacent anatomy of the cricothyroid membrane is also inaccurate. We compared physical palpation to ultrasound for identifying the location of the cricoid cartilage using a total of 50 assessments. The median distance to target was 10 mm. We concluded that palpation is an inaccurate method to locate the cricoid cartilage in the studied population.

Incremental change in cross sectional area in small endotracheal tubes: A call for more size options

OBJECTIVE

To elucidate the relatively large incremental percent change (IPC) in cross sectional area (CSA) in currently available small endotracheal tubes (ETTs), and to make recommendation for lesser incremental change in CSA in these smaller ETTs, in order to minimize iatrogenic airway injury.

METHODS

The CSAs of a commercially available line of ETTs were calculated, and the IPC of the CSA between consecutive size ETTs was calculated and graphed. The average IPC in CSA with large ETTs was applied to calculate identical IPC in the CSA for a theoretical, smaller ETT series, and the dimensions of a new theoretical series of proposed small ETTs were defined.

RESULTS

The IPC of CSA in the larger (5.0-8.0 mm inner diameter (ID)) ETTs was 17.07%, and the IPC of CSA in the smaller ETTs (2.0-4.0 mm ID) is remarkably larger (38.08%). Applying the relatively smaller IPC of CSA from larger ETTs to a theoretical sequence of small ETTs, starting with the 2.5 mm ID ETT, suggests that intermediate sizes of small ETTs (ID 2.745 mm, 3.254 mm, and 3.859 mm) should exist.

CONCLUSION

We recommend manufacturers produce additional small ETT size options at the intuitive intermediate sizes of 2.75 mm, 3.25 mm, and 3.75 mm ID in order to improve airway management for infants and small children.

Cartilage invasion patterns in laryngeal cancer

The cartilaginous invasion determines the T and is one of the most common sources of mistake in tumor staging. Also it is of great importance when planning any therapeutic alternative. In the latest revision of the TNM classification a clear distinction is made between infiltration of cartilage without going through it, considered a T3 recently and that would be a T4 according to the previous classification, and those going through the cartilage, classified as T4a. While this classification makes the difference in depth of infiltration, it does not emphasize the extent of invasion. This paper provides a detailed description of the laryngeal cartilage tumor infiltration by whole organ serial section in which the invasion is considered both horizontal (transcartilaginous) and vertical (extent of invasion) and establishing patterns of three-dimensional infiltration of the cartilage. This is a cross-sectional study of prevalence. 275 records of patients treated for laryngeal squamous cell carcinoma between 1995 and 2000 were reviewed. The pathological processing of laryngectomy surgical specimens was performed following the method of whole organ serial section described by G. F. Tucker. The following patterns of cartilaginous infiltration were defined: (1) transcartilaginous infiltration; (2a) partial focal infiltration of the cartilage: infiltration not going through the cartilage but occupying one third or less of its extent; (2b) partial extensive infiltration of the cartilage: infiltration occupying two thirds or more of its length and (3) no cartilage infiltration: tumor in contact with the cartilage (paraglottic space) but without affecting it. 161 patients met the inclusion criteria. The most frequent tumor location was supraglottic (58 cases) followed by glottic (47). 109 patients (67.7 %) were treated with total laryngectomy. Partial surgical techniques were performed in the remaining cases. TNM tumor staging was performed according to the results of pathological study (pTNM). 72.06 % (116) were classified as advanced laryngeal tumors (pT3 and pT4). 46 % of patients showed some extent of laryngeal cartilage infiltration (thyroid, cricoid, arytenoids, epiglottis). The cartilage most frequently infiltrated was the thyroid in 48 patients (29.8 %) and when it is affected, in most cases (66.7 %), the infiltration is transcartilaginous. The next most common pattern is partial focal infiltration (27 %). In the cricoid cartilage, the most common pattern of infiltration is focal partial infiltration (52.6 %). Of the 19 cases with infiltration of the cricoid, there are 12 cases with extra laryngeal invasion through a cricothyroid membrane perforation. The study of laryngeal cancer by laryngeal whole serial section has been proved to be very useful in offering a high precision pTNM staging and a detailed description of the infiltration of cartilage. We have seen that when the thyroid cartilage is infiltrated the tumor often passes through the cartilage. However, there are cases where the tumor is extremely aggressive, being very widespread in cartilage thickness without actually crossing it. The isolated infiltration of the cricoid cartilage is exceptional.