Fig. 1

Consort diagram displaying patient exclusion criteria. Patients were identified using Calgary Voice Clinic laryngoscopy data and Interventional Pulmonary Medicine bronchoscopy data. Patients were excluded if they had no subglottic involvement, insufficient information in the EMR, was a pediatric patient, or from out of province/northern Alberta. Patients were then classified into idiopathic, iatrogenic, autoimmune, congenital, or traumatic subtypes with breakdown of their distribution noted. Idiopathic SGS were the primary subtype of interest and further analysis performed regarding prevalence and incidence geographic distribution. EMR = electronic medical record, SGS = subglottic stenosis