[Case of postoperative subdural tension pneumocephalus].

In this paper, a case with subdural tension pneumocephalus secondary to bifrontal craniotomy and VP shunt for ruptured Acom aneurysm is reported. In this patient, the mechanisms for entry of air into the subdural space and producing mass effect (Tension pneumocephalus) seem to be one way valve mechanism and negative pressure due to excess of CSF drainage owing to shunting system. Only 29 reported cases of tension pneumocephalus following surgery were found in an extensive review of the literature. We discussed about the clinical symptoms and signs, therapy, and especially about the mechanisms leading to this condition, and prevention for it.