A case of widespread subcutaneous and mediastinal emphysema following extraction of a mandibular third molar: Changes in emphysema on CT scans

Spreading patterns of subcutaneous emphysema and mediastinal emphysema can be detected on computed tomography (CT). As many studies have reported that CT is performed several hoursto several days after the onset of emphysema, CT findings immediately after onset remain unclear. Especially, the time course of emphysema from onset to resolution is poorly understood.We observed the time course of emphysema by CT, starting immediately after the development of emphysema in the head, neck, and mediastinum. Emphysema was caused by the useof an air turbine handpiece during extraction of a lower impacted third molar. A CT scan obtained immediately after onset showed severe emphysema extending to many head and neck spaces, including the retropharyngeal space to the mediastinum. The next day, emphysema in the parapharygeal space, the retropharyngeal space, and the anterior cervical space rapidlydecreased. After a week, the emphysema had nearly disappeared on the CT scan, except for part of the masticator space.