Effects of Orthognathic Surgery on Posterior Airway Volume and Development of Obstructive Sleep Apnea

Objectives: This study aimed to compare preoperative and postoperative polysomnography (PSG) measurements and evaluated the changes in posterior airway space (PAS) volume according to the movements performed in orthognathic surgery. Materials and Methods: The mean age of the 14 patients included in this prospective observational study was 29.57 ± 8.05 years, 9 were female and 5 were male. Patients scheduled to undergo bimaxillary surgery, underwent overnight PSG in the sleep laboratory 1 week before and 3 months after the operation. PSG included the following: Apnea- Hypopnea Index (AHI) (/h), sleep onset (min), sleep efficiency (%), sleep stages (SS) 1 (%) - 2 (%) - 3 (%), rapid eye movement sleep (REM) (%) and oxygen saturation. For all patients, 3D cone beam computed tomography (CBCT) images were acquired 1 week before and 3 months after surgery. The pharyngeal airway was divided into two regions, the nasopharynx (NPV) and oropharynx (OPV). These regions were defined using the posterior nasal spine, posterior part of the ala of vomer and cervical vertebra. Preoperative and postoperative data obtained from CBCT and PSG were compared. Results: In the comparison between AHI changes; the rate of decrease in NPV score was higher in patients with high AHI scores compared to others (p: 0,006). In patients with decreased AHI, the change in REM % was higher than the other groups (p: 0,019). Conclusion: Orthognathic surgery causes changes in posterior airway volume and these changes cause changes in polysomonography data. In this study, it was concluded that NPV decreased more in patients with increased AHI values.