A new simple three-dimensional method to characterize upper airway in orthognathic surgery patient

Objectives: To develop and validate a new reproducible 3D upper airway analysis based on skeletal structures not involved in the modification, which occur during orthognathic surgery. Methods: From retrospective cohort of orthognathic surgically treated patients, pre- and postsurgical CBCT-scans of 10 post-pubertal patients were randomly selected. Two operators identified the landmarks, calculated the airway volumes, cross sections and linear measurements on the 10 scans twice at two different time intervals. Statistical analysis included test for normal distribution, technical error measurements, and intra- and inter-observers reliability. Results: Intra- and inter-observer reliability was excellent for volumes and cross sections. The entire data sets exhibited normal distribution. Technical error of measurements showed an error in the range of 1.6 to 10.2% for volume, 1.6 to 12.2% for cross-sectional measurements, and 0.3 to 2.5% for linear measurements. No systematic errors were detected. Conclusions: This new proposed definition of upper airway boundaries was shown to be technical feasible and tested to be reliable in measuring upper airway in patients undergoing orthognathic surgery.