Some people have facial deformities that may cause the sleep apnea. It simply may be that their jaw is smaller than it should be or they could have a smaller opening at the back of the throat. Some people have enlarged tonsils, a large tongue or some other tissues partially blocking the airway. Fixing a deviated septum may help to open the nasal passages. Removing the tonsils and adenoids or polyps may help also.
Children are much more likely to have their tonsils and adenoids removed.
There are several other surgical treatments . Usually a surgeon will ask the patient to be on CPAP for at least month to see if they get better. If CPAP cannot help then surgery is probably not the right thing to do. These treatments include, removing excess tissue to clear the airway, moving the tongue forward, and moving the upper and lower jaw forward. There and other procedures try to increase the size of the upper airway.