Synchronous video laryngoscopy and sonography of the larynx in children.

Unlike laryngoscopy, laryngeal sonography is easily applicable, well tolerated by young children and less exhausting for the examiner. The aim of this study was to determine if sonography can adequately visualize the laryngeal structures and vocal fold movements of children. Synchronic video laryngoscopy and sonography of the larynx were performed in 35 children (aged 2-8 years) without a laryngeal disease. 10 investigators at differing stages of otolaryngological training were tasked with identifying vocal fold movement and specific anatomical structures after seeing (1) the sonography-only video and (2) the sonography video with a laryngoscopy video overlay. The percentage of correct identification of the structures and the vocal cord movement with and without additional video-overlay was compared. A sonographical view of the larynx could be found and the following anatomical structures were identified: subcutaneous fat tissue, left and right sternohyoid and thyrohyoid muscles, thyroid cartilage, left and right vocal folds, left and right paraglottic spaces, left and right side arytenoid cartilages, and rima glottides. Concerning the evaluation of the videos amongst the investigators: they identified >80 % of vocal fold movement and the targeted anatomical structures except the arytenoid cartilages (only up to 63 %), having the sonography only. In combination with the laryngoscopy video-overlay, investigator detection rates significantly improved (>90 % of vocal fold movement, p < 0.001; >90 % in most anatomical structures, (p < 0,001). Laryngeal sonography is a helpful diagnostic tool to identify laryngeal structures and the movement of the vocal folds in children.