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Received Mar 13, 2018; Accepted May 25, 2018
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1. Introduction
Subglottic stenosis is a disease that involves narrowing of the airway around the cricoid cartilage which can lead to airway compromise. There are various causes of subglottic stenosis, including trauma, neoplastic, infectious, systemic inflammatory disorders or congenital anomalies [1]. However, despite extensive evaluation, many cases of subglottic stenosis are deemed idiopathic. Idiopathic subglottic stenosis (ISS) represents a spectrum of disease with an unclear underlying pathophysiology and a significant challenge for clinical management.
Proposed factors from retrospective and observational studies include a role of hormones [2], growth factors [3], aberrant immune activation [4], and even bacteria [4] contributing to the disease. However, several studies have implicated a potential role of gastroesophageal reflux disease [5–7] (GERD). The leading hypothesis is that reflux of gastric contents into the upper airway contributes to the development of ISS. For example, in a prior study of 33 patients with laryngeal or tracheal stenosis, abnormal esophageal acid exposure was found in 56% [8]. Of note, among the 26 patients in this study who were tested off acid suppression, 23 (88%) had abnormal esophageal acid exposure. In another study which included 74 pediatric patients with subglottic stenosis using both upper and lower esophageal pH probe testing [9], it was noted that 32% of patients had pH of <4.0 in the lower esophagus for greater than 10% of study time, while only 20% of patients tested had pH of <4.0 in the upper esophagus greater than 3% of study time [9]. However, this study included 11 patients who had undergone prior Nissen fundoplication and 23 with bronchopulmonary dysplasia. In another prospective study of 22 patients with ISS, 7 of 10 patients were found to have reflux by 24-hour pH testing [5]. In addition, 59% of patients had detectable pepsin in laryngeal/tracheal tissue whereas none was found in the control group. However, there was no correlation between presence of reflux and pepsin. In a retrospective review of 37 ISS patients undergoing interval endoscopic balloon dilation, a higher prevalence of gastroesophageal reflux symptoms was noted in...