Frontal Cortex Electrical Changes during Infratentorial Neurosurgery: A Case Series

The posterior fossa is usually discussed as a separate entity from supratentorial structures, with no distinct correlation described, between infratentorial manipulation and changes in supratentorial cortical electrophysiology. We report a series of four cases of infratentorial tumour surgeries showing abrupt slowing of frontal cortical electrical activity intraoperatively which were ruled out from being artefactual. In three of the cases, the changes were transient with no lasting effects on postoperative outcome. In one case, patient had prolonged recovery after anaesthetic withdrawal and poorer neurological outcome. A mechanism involving reticular formation and its effect of cortical electrical activity has been proposed based on previous neurophysiology literature.