Laryngomalacia is the most common etiology of upper airway obstruction in infancy and early childhood, and is usually benign in nature.1 Carbon dioxide laser supraglottoplasty was considered an effective procedure to treat severe laryngomalacia.2,3 However, 0-29% of patients with severe laryngomalacia did not respond to laser supraglottoplasty, especially those with co-existing pharyngomalacia.2 Therefore, the concept of DPLM was introduced by Froehlich P. et al. in 1997. It was considered as a result of the discoordinate process of the upper airway muscles, and therefore persistent respiratory distress after laser supraglottoplasty.