Late tension pneumocephalus following frontal craniotomy.

Tension pneumocephalus is an uncommon but life-threatening complication of craniotomy which requires urgent diagnosis and treatment. It most often occurs perioperatively following subsequent anaesthesia using nitrous oxide. All previously reported postoperative cases followed posterior fossa or upper spinal cord surgery. Only two cases associated with frontal craniotomy have been reported since 1972, both occurring intraoperatively.