The Role of Airway Fluoroscopy in the Evaluation of Stridor in Children
Arch Otolaryngol Head Neck Surg. 2003;129:305–309. Rudman DT, Elmaraghy CA, Shiels WE, Wiet GJ. Division of Pediatric Otolaryngology, Department of Otolaryngology, Columbus Children's Hospital, The Ohio State University College of Medicine and Public Health, Columbus, OH.
This prospective study was aimed to determine the role of airway fluoroscopy in comparison with other diagnostic methods to diagnose the site of partial airway obstruction in children with stridor. Study design included comparing direct laryngoscopy and bronchoscopy with nasopharyngoscopy, airway fluoroscopy, and plain films. Over a 34-month period, 64 children with a mean age of 1.8 years (range, 1 wk to 12 y), and male-female ratio of 3:2, were evaluated for stridor. After a thorough review of clinical history and physical examination, anteroposterior and lateral radiographs of the soft tissues of the neck and chest were performed. Airway fluoroscopy was performed and fluoroscopic times ranged from 1 to 2 minutes at 4 to 7 mR/min. After evaluating movements of the hemidiaphragms and observing for focal air trapping, imaging of the airway from the nasopharynx to the main bronchi was performed in anteroposterior, oblique, and lateral projections. Spot images and videofluoroscopy were obtained. Direct laryngoscopy and bronchoscopy were performed because of severity, progression of symptoms, clinical features, or certain radiographic abnormalities. General anesthesia was induced through inhalational technique while maintaining spontaneous ventilation to allow the assessment of dynamic airway characteristics such as respiratory-phase variability and vocal cord mobility. Flexible fiberoptic laryngoscopy used either a neonatal (1.8-mm) or pediatric (3.2-mm) endoscope. Among these children, 52 (81%) had a history of intubation, 53 (83%) had a history of gastroesophageal reflux disease, and 95% had progression of symptoms. Significant associated symptoms included 31 patients (48%) with retractions, 44 (69%) with shortness of breath, and 63 (98%) with active stridor. The primary diagnoses included subglottic stenosis in 22 patients, laryngomalacia in 9, airway foreign body in 8, normal airway in 6, tracheal stenosis in 4, laryngeal granuloma, respiratory failure, and gastroesophageal reflux in 3 each, tracheomalacia and subglottic hemangioma in 2 each, and glottic web and glossoptosis in 1 each. Nasopharyngoscopy was more sensitive for supraglottic and glottic lesions, detecting 89% (8 of 9) and 71% (5 of 7), respectively, but was less sensitive in detecting subglottic lesions, detecting only 33% (10 of 30). Airway fluoroscopy was less sensitive to supraglottic and glottic lesions, detecting only 33% (3 of 9) and 14% (1 of 7), respectively, but was much more sensitive in detecting subglottic, tracheal, and bronchial lesions, detecting 80% (24 of 30), 73% (8 of 11), and 80% (8 of 10), respectively. Plain films were the least sensitive of any diagnostic modality, with a sensitivity of 0% (0 of 9) for supraglottic, 0% (0 of 7) for glottic, 33% (10 of 30) for subglottic, 0% (0 of 11) for tracheal, and 40% (4 of 10) for bronchial sites of obstruction. These results showed that airway fluoroscopy had a sensitivity of 80% for subglottic, 73% for tracheal, and 80% for bronchial sites of obstruction. However, it was less sensitive for supraglottic and glottic sites, 33% and 14%, respectively. Overall, airway fluoroscopy was far more sensitive than plain films for diagnosing the site of obstruction. The authors conclude that airway fluoroscopy is a quick, noninvasive, and dynamic study of the entire airway that provides important additional information to the clinical history and physical examination, and is a valuable adjunct to flexible fiberoptic laryngoscopy. In the opinion of the authors, airway fluoroscopy was far superior to plain films and therefore could serve as a cost-effective screening tool in the evaluation of stridor in children, especially for lesions of the lower airway. Clinicians must recognize that stridor is not a diagnosis but a symptom caused by turbulent airflow through a partially obstructed airway. Such partial obstruction can be fixed or dynamic with varying pathologic mechanisms, including congenital, traumatic, iatrogenic, inflammatory, and neoplastic etiologies. The appropriate initial diagnostic approach is not uniform in all children who present with this symptom. Although an individualized approach is necessary, it is unquestionable that a detailed review of clinical history and physical examination are important. Flexible fiberoptic laryngoscopy and bronchoscopy are the definitive techniques but are associated with the risk of anesthesia. Moreover, arranging for these procedures in an emergency situation could entail crucially valuable extra time. Before any invasive diagnostic procedure is undertaken, consideration should be given to noninvasive imaging procedures. Radiopaque foreign bodies can be easily observed on plain chest roentgenograms. However, plain chest films might not be of much help in other conditions that lead to stridor. Computed tomography and magnetic resonance imaging might be useful in some, but the time required to schedule these and the expense make them cost-ineffective as screening tools. In their study, Rudman and colleagues have shown that simple fluoroscopy provides dynamic images of the airways and can evaluate multiple sites of obstruction simultaneously. These observations are in agreement with several other publications that have shown the important value of fluoroscopy in evaluating stridor in children.