Diagnosis of Laryngomalacia by Fiberoptic Endoscopy
Laryngomalacia is the most common cause of congenital stridor. It is usually a benign disorder resolving spontaneously by 12 to 18 months of age. The diagnosis of laryngomalacia requires dynamic visualization of the glottic and supraglottic area.
Since the introduction of video-recorded fiberoptic flexible laryngoscopy (FFL), the following two approaches have emerged for the endoscopic evaluation of congenital stridor, especially for laryngomalacia: a clinic-based awake laryngoscopy; and a drugassisted technique (DAT) using sedation and anesthesia. The awake technique (WT) is performed while the infant is held in a sitting position; topical anesthesia is applied to the nose, and endoscopy is performed to the level of the vocal cords. In the DAT, the patient is supine, and inspections of the subglottic area and the tracheobronchial tree are possible.
The differences between these methods may affect the diagnostic reliability and accuracy of largyn-goscopy. Lesions missed during performance of the WT’ have been observed on a following DAT. Body position, level of agitation, crying, and the degree of consciousness may all modify the dynamic motion of the glottic and supraglottic structures, and may shorten the time for careful inspection over several breaths. This influences the physician’s interpretation and ability to make the correct diagnosis. Sedation interferes with the diagnosis by its effects on muscle tone, structural collapsibility, agitation, and increased secretions. The effect of these factors and of the specific technique on the reliability of diagnosing laryngomalacia is unknown. No study has yet compared the two techniques regarding their accuracy in diagnosing laryngomalacia. The purpose of this study was to compare the two techniques for diagnosing laryngomalacia by investigating their sensitivity and specificity, and the rates of false-positive results (ie, overdiagnosis) and false-negative results (ie, missed diagnosis or underscoring) for each technique. During the study period, all infants with congenital stridor who were referred for evaluation were seen by the pediatric otolaryngologist (A.D.) who performed an awake FFL. When no cause for the stridor was found or when laryngomalacia was diagnosed, the patient underwent a second endoscopy using the DAT. Forty-two consecutive infants met these criteria. Each infant underwent the two procedures < 10 days apart.