Symptomatic pneumocephalus after translabyrinthine acoustic neuroma excision and nitrous oxide anesthesia

Abstract

The authors describe a case in which generalized grand mal seizures developed in the recovery room 90 minutes after discontinuation of nitrous oxide anesthesia for translabyrinthine removal of an acoustic neuroma. A computerized tomography (CT) scan showed a large collection of subarachnoid air. None of the factors known to predispose to the development of pneumocephalus provided an adequate explanation for the mechanism of entry of air into the cranium. Consideration of middle ear mechanics and the solubility properties of nitrous oxide anesthesia suggested an explanation.