1. OSA patient who presents with absolute skeletal transverse hypoplasia presenting with crossbite.2. Mild OSA or upper airway resistance syndrome (UARS) patients who do not have malocclusion, but complain of persistent nasal obstruction in the setting of narrow, high-arch palate, and whoeither have underwent previous nasal surgery, or do not present with significant septal deviation or inferior turbinate hypertrophy.3. Moderate to severe OSA patients as phase I, preceding other operations including palatal surgery (e.g., UPPP, MMA, or upper airway stimulation).