Three-Dimensional Conebeam CT Analysis of Pharyngeal Airway Changes After Orthognathic Surgery

OBJECTIVE: The purpose of this study was to examine volumetric changes of the airway with orthognathic surgery. Airway changes are described quantitatively as well as qualitatively through 3-Dsuperimpositions.METHODS: 45 total patients are in three groups: maxillary surgery only (n=17), mandibular surgery only (n=17), and two-jaw surgery (n=11). CBCTs were obtained pre-surgical, "immediate" post-surgical (median=19 days), and "long-term" post-surgical (median=203 days).CONCLUSIONS: Maxillary surgery group-a 7mm surgical advancement looks to be the point at which the airway volume begins to decrease, but it was not supported by statistical tests. At248 days on average after surgery (t2-t0), the nasopharynx appears to be affected the most by LeFort surgery. Mandibular surgery group-a 7-8mm advancement appears to be the point at which the airway stops increasing; this was not supported by statistical tests in this study. At about 248 days after surgery (t2), those subjects that had a mandibular advancement, had the greatest effect on the oropharynx. In the mandibular setback group at about 248 days after surgery, the nasopharynx slightly decreases and the oropharynx slightly increases. The hypopharynx does not seem to be affected. Two-jaw surgery group-the two-jaw surgery group has effects that are more complicated than in simply determining the distance it is moved ordisplaced. Color map-three-dimensional superimpositions provide a viable alternative for qualitatively describing changes between timepoints. Further works needs to be done to develop reproducible landmarks to reliably use color maps