Abstract: Objective · To evaluate the application of 3D-CT airway reconstruction images to predicting difficult airway in patients with odontogenic infections. Methods · A retrospective analysis was performed on patients with odontogenic infections who were treated by incision and drainage under general anesthesia at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from August 2017 to July 2019, and patients who were evaluated as difficult airway receiving awake tracheal intubation were selected as the case group (n=27). From the “Hospital Inpatient System”, patients who were evaluated as non-difficult airway receiving fast induction were selected as the control group (n=27). Maxillofacial CT scans of all the patients were collected. The Dolphin Imaging software version 11.9 Premium was used to perform 3D-CT reconstruction of the airway. The upper airway was divided into oropharynx and hypopharynx, and the oropharynx was divided into velopharynx and glossopharyngeal. The indicators such as airway volume, median sagittal area, minimal cross-sectional area, and thickness of pharyngeal soft tissue were collected. The indicators of the difference between the two groups were compared and selected. Logistic regression analysis was conducted to investigate the association of these factors with difficult airway. Results · The volume of velopharynx and hypopharynx, the median sagittal area of velopharynx, oropharynx and hypopharynx, the mean cross-sectional area of velopharynx and hypopharynx, the minimal cross-sectional area and its lateral dimension of oropharyngeal of patients in the case group were significantly smaller than those of the controls (P<0.05). Thickness of pharyngeal soft tissue in the most inferior-anterior point of the second and the third cervical vertebrae of patients in the case group was significantly higher than that of the controls (P<0.05). The Logistic regression analysis showed that the median sagittal area of velopharynx, oropharynx and hypopharynx, the volume and mean cross-sectional area of hypopharynx, and thickness of pharyngeal soft tissue in the most inferior-anterior point of the second and the third cervical vertebrae of patients were related to difficult airway in patients with odontogenic infections (P<0.05). Conclusion · Airway 3D-CT reconstruction can clearly show the airway anatomy of patients with odontogenic infections. The median sagittal area of pharynx, the volume and mean cross-sectional area of hypopharynx, and thickness of pharyngeal soft tissue in the most inferior-anterior point of the second and the third cervical vertebrae may will be used as predictors of difficult airway in patients with odontogenic infections.

Key words: difficult airway, odontogenic infections, 3D-CT reconstruction