We report the case of a 43-year-old woman who presented with a spontaneous pneumocephalus, 37 years after a mastoidectomy. Clinical examination showed a cerebrospinal fluid leak, meningeal herniation in the superior part of the middle ear, and an audible noise from her ear when she stood up due to the entrance of air into the cranium. A computed tomography scan and magnetic resonance imaging showed the complete destruction of the tegmen tympani and the pneumocephalus in the temporal lobe. The patient underwent an emergency operation via a double middle-ear and subtemporal approach. The meningoencephalocoele and pneumocephalus were probably due to long term pressure upon too thin a tegmen tympani.

Pneumocephalus should be considered as a potential delayed post-operative complication of middle-ear surgery. Computed tomography and magnetic resonance imaging scanning supply accurate information and enable a planned surgical approach; they also allow a pathophysiological understanding and a correlation between the clinical signs and the radiological and peri-operative findings.