Tracheomalacia.

Tracheomalacia is a rare tracheal problem that leads to collapse of the airway and expiratory flow obstruction. Expiratory CT scans are the diagnostic test of choice in adults. Chronic obstructive pulmonary disease is the most common cause of adult tracheomalacia. Plication of the membranous wall to polypropylene mesh to recreate the normal airway shape (membranous wall tracheoplasty) is an effective treatment in adults.