PHARYNGEAL AIRWAY VOLUME FOLLOWING ...

after surgery, the upper retropalatal space significantly
decreased 4.2mm while the narrowest retropalatal, lowest
retropalatal, and narrowest retroglossal airway spaces
increased 2.9mm, 3.7mm, and 4.4mm, respectively. 42 Over the
average 34 month follow-up period (range= 6 months to 9
years 3 months), the upper retropalatal space increased
3.9mm, almost returning to presurgical value, while the
other areas remained stable. 42
Computed Tomography Study
Recognizing that measurements taken from a lateral
cephalogram do not evaluate changes in the transverse
dimension, Fairburn et al. 44 examined transverse and
sagittal airway changes 3 to 6 months after MMA. In all
patients, the mandible was advanced 10mm following by
advancement of the maxilla to achieve a Class I occlusion.
Helical computed tomography (CT) scans were obtained before
and after surgery. This radiography modality scans the
airway via axial slices every 2.5mm from the base of the
skull to the trachea. Measurements were taken every 10mm
(or every 4 th axial slice) from the level of the hard palate
to the hyoid bone. At each level, the transverse airway
dimensions significantly increased except at the level of
the hyoid bone with the greatest change at the retroglossal
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