Unilateral Tension Pneumocephalus of the Sylvian Fissure: A Rare Neurosurgical Complication.

Tension pneumocephalus is an uncommon complication of neurosurgical procedures. We report a patient who presented with headache, vomiting, left hemiparesis and rhinorrhea 30 days after correction of a recurrent nasal cerebrospinal fluid fistula and shunt placement. A computed tomography scan revealed a massive collection of air with air-fluid level in the right sylvian fissure and midline shift. A right pterional craniotomy was performed and a small corticectomy resulted in evacuation of air from the sylvian fissure. A dural graft from the previous surgery was recognized to be acting as a ball-valve mechanism, trapping air from the nasal cavity. It was removed and the cranial defect was corrected with a split calvarial bone graft. Follow-up brain computed tomography revealed complete resolution of pneumocephalus. After surgery there was progressive improvement of neurological symptoms over 10 days, and the patient was asymptomatic after 1 month of follow-up.