Tension pneumocephalus.

Sixteen patients with intracranial air under tension and severe neurological symptoms following trauma and neurosurgical procedures were reviewed. Computed tomography (CT) was performed in cadavers following selective air injections into the epidural, subdural, and subarachnoid spaces. The characteristic CT appearance of air in the various intracranial compartments is illustrated. The typical "peaking" of the frontal lobes in subdural tension pneumocephalus is explained by bridging veins entering the superior sagittal sinus. Stretching and rupturing of these veins may be implicated as a cause for a concomitant subdural hematoma. The various mechanisms causing tension pneumocephalus and its appropriate therapy are discussed.