Assessment of the Infant Airway with Videorecorded Flexible Laryngoscopy and the Objective Analysis of Vocal Fold Abduction

Abstract

Accurate diagnosis of upper airway abnormalities by flexible laryngoscopy in infants is hampered by rapid laryngeal motion and lack of patient cooperation. This study evaluates the added role of videorecorded flexible laryngoscopy and the objective measurement of vocal fold abduction in improving the diagnosis of upper airway abnormalities in infants. Seventy-eight infants had videorecorded flexible laryngoscopy performed as part of their evaluation of a suspected airway disorder. These recordings were reviewed by three otolaryngologists for confirmation of the clinical diagnosis. From the video image, the maximum angle of vocal fold abduction was measured with image analysis software. Of 78 patients 40 had supraglottic or glottic abnormalities, 9 had nasal or nasopharyngeal obstruction, 9 had subglottic abnormalities (diagnosed subsequent to videolaryngoscopy), and 15 patients had normal findings on examination. Of those with laryngeal abnormalities, laryngomalacia was the most common diagnosis (23 of 78). Vocal fold paralysis was present in 4 patients. A separate group (9 of 78) of patients was identified as having symmetric bilateral limitation of vocal fold abduction. Laryngeal dyskinesia was diagnosed in these 9 patients. The mean values of maximal vocal fold abduction were as follows: (1) normals, 59.5 degrees; (2) laryngomalacia, 57.0 degrees; (3) paralysis, 26.6 degrees; and (4) incomplete abduction with laryngeal dyskinesia, 27.6 degrees. Videolaryngoscopy is a valuable tool for documentation, parent education, and analysis of infant laryngeal abnormalities. Repeat viewing of the video examination and frame-by-frame analysis improve the diagnostic accuracy. Using this approach, we have calculated the anterior glottic abduction angle in the normal and abnormal Infant larynx. In addition, we have identified a group of infants with incomplete abduction of the vocal folds that appears to be different from that found in vocal cord paralysis.