Relationships between Airway Morphology and Sleep Breathing Indices in Jaw Deformity Patients

Purpose: The purpose of this study was to clarify how sleep breathing indices and airway morphology vary according to skeletal classification and the relationships between airway morphology and sleep breathing indices. Method: Forty-four non-syndromic female Japanese patients, who were diagnosed with jaw deformities and underwent surgical orthodontic treatment were enrolled in this study. Using the Alice 5 diagnostic sleep system (Philips Respironics; Murrysville, PA), the apnea hypopnea index (AHI), apnea index (AI), and 4% oxygen desaturation index (4%ODI) were evaluated in each patient before they underwent orthognathic surgery. The following dimensions were measured on 2D CT images: the cross-sectional area at the level of the hard palate (HP), the cross-sectional area at the top of the uvula (TU), the cross-sectional area at the base of the tongue (BE). The following volumes were measured on 3D CT images: the volume of the upper airway (total volume), the volume of the region between the level of the hard palate and the top of the uvula (HPTU volume), the volume of the region between the top of the uvula and the base of the epiglottis (TP-BE volume). Result: There were no significant differences in airway morphology or sleep breathing indices among the three groups. Negative correlations were detected between HP-TU volume and 4%ODI, and between the HP area and AHI (p<0.05). Conclusion: Our results establish that upper airway morphology also has important effects on the nocturnal breathing of jaw deformity patients.