[Clinical study on intracranial air in the severe head injury]

Intracranial air tends to be neglected in severe head injury, because other lesions are more life threatening. We retrospectively studied patients of severe head injury with pneumocephalus. We studied 250 patients' (Glasgow Coma Scale score < or = 8 on admission) computed tomography (CT) scans and found 77 patients with pneumocephalus. These patients' medical records and neuroimagings were studied. The air was most frequently located in the subarachnoid spaces followed by subdural and epidural spaces. Intraparenchymal and intraventricular location were rare. Sphenoid or petrous bone fracture was common. In the cases with petrous or paranasal sinus bone fracture, opacification of these structures were statistically significant. In conclusion, pneumocephalus is common in the severe head injury and most frequently located in the subarachnoid spaces, however, the precise location of air is unclear in many cases. Bone CT scan is useful and opacification of air containing structures suggests the possibility of skull base fractures.