Table 2. Causes of obstruction of the upper respiratory tract.

	n (%)
Acquired glottic stenosis	12 (60%)
Laryngeal neoplasia	3 (15%)
Tracheal stenosis	2 (10%)
Vocal cord immobility	1 (5%)
Craniofacial alterations	1 (5%)
Laryngeal membrane	1 (5%)