Cost-efficient localization of seizures of mesiotemporal onset with foramen-ovale electrodes.

Foramen ovale (FO) electrodes can identify mesiotemporal lobe (MTL) seizure onsets but are infrequently used in the USA. Ten patients with presumed MTL ictal onset, unlocalized noninvasively, had FO electrodes inserted during long term monitoring for epilepsy. Placement was facilitated by intraoperative use of oblique submental and modified Caldwell view fluoroscopy. Eighty percent of patients had ictal localization by FO electrodes. This led to anterior temporal lobectomy in six with 83% being seizure free after follow-up of 20-32 months. The mean total costs of placing these electrodes was approximately half that of subdural strips and a quarter that of depth electrodes. Foramen ovale electrodes represent a cost-effective and efficient method of seizure localization when noninvasive workup suggests but is not definitive for MTL origin.