Causes of Laryngotracheal Stenosis
There are a number of problems that can cause an airway obstruction leading to stridor, including a mass obstructing the airway, tracheal stenosis and vocal cord immobility.

A benign or cancerous tumor or an inflammatory or infectious growth can cause an obstruction of the airway. When scar or inflammatory tissue builds up in the voice box or trachea, it can narrow your breathing passage. This can occur following placement of a breathing tube, after throat trauma, as a result of an autoimmune disease or the cause can be unknown. If both of your vocal folds do not move, then they do not open during breathing and can restrict the airflow through the voice box.