PMC5296954_01
Flow-volume curve during forced maneuvers. The plateau of both the inspiratory and expiratory phases shown during forced maneuvers is suggestive of fixed central or upper airway obstruction
12948_2017_60_Fig1_HTML.jpg
PMC5296954_01_12948_2017_60_Fig1_HTML.jpg
Fig1
Forced-expiratory volume in one second (FEV1) was 2.03 L (83% of the predicted value), forced vital capacity (FVC) was 2.89 L (101% of the predicted value) and FEV1/FVC ratio was 0.70, 89% of the predicted value (Fig. 1). 
Inspective bronchoscopy revealing a subglottic tracheal stenosis
12948_2017_60_Fig2_HTML.jpg
PMC5296954_01_12948_2017_60_Fig2_HTML.jpg
Fig2
The patient was further evaluated with flexible bronchoscopy, which confirmed a subglottic tracheal stenosis extended for 15 mm with an internal diameter of 6 mm (Fig. 2).
Rigid bronchoscopy showing the upper tracheal circumferential stenosis. a Before procedure and b restored patency immediately after the procedure
12948_2017_60_Fig3_HTML.jpg
PMC5296954_01_12948_2017_60_Fig3_HTML.jpg
Fig3
The patient underwent rigid bronchoscopy with mucosal biopsies, mechanical dilatation laser-assisted (diode laser) and balloon to correct the stenosis, which reached an internal diameter of 13 mm after the procedure (Fig. 3).