In addition, CT studies of the upper airway have also observed profound improvements in the lateral dimension and a considerable reduction of the upper airway length following surgery. The latter phenomenon is suggested to contribute structurally to a decreased airway collapsibility following MMA surgery. Many of the above mentioned changes in upper airway dimensions and skeletal structures have been correlated with OSA improvements. However, at present there is unfortunately insufficient data to support a relation between OSA improvements like AHI values and changes in the upper airway and its surrounding bony structures.