Abstracts

There is limited experience with the use of bitemporal depth electrodes in children with refractory epilepsy. We report our experience in 10 children with temporal lobe epilepsy who underwent EEG monitoring with bitemporal depth electrodes to evaluate its role in seizure localization and correlate with information from other modalities., Patients were identified from the epilepsy surgery database and a systematic, retrospective chart review was carried out of children with temporal lobe epilepsy who underwent bitemporal depth electrode evaluation between 1990 and 2005. Variables analyzed included (1) patient age at initial seizure and at time of surgery; (2) post-operative follow-up period; (3) seizure semiology; (4) ictal and interictal findings on scalp EEG; (5) brain imaging; (6) the indication for depth electrodes; (7) depth electrode interical and ictal findings; (8) type of surgery performed; (9) surgical pathology; and (10) seizure outcome., Ten children (6 females) underwent bitemporal depth electrode evaluation. Only 1 of these patients underwent a simultaneous subdural grid evaluation. Indications for invasive evaluation included: (1) evidence of bitemporal EEG seizure patterns without localizing seizure semiology (7 patients); (2) possible neocortical onset (1 patient); (3) EEG focus and lesion incongruence (1 patient); (4) non localizable EEG ictal pattern with a lesional MRI (1 patient).
Nine children (ages 11-18 years) underwent focal resection: 8 had standard anterior temporal lobectomy with resection of mesial temporal structures. The post-operative follow-up period ranged from 3 months to 26 months (mean 14.6 months). Of these, 8 remain seizure free (Engel I) and 1 patient remains refractory (Engel IV). This latter patient had a normal MRI and was found to have a lateral temporal focus; he underwent surgical resection of the superior temporal structures. The patient who did not undergo surgery was found to seizures arising independently from either temporal region without clear side predominance. Six patients were found to have hippocampal sclerosis on pathology., Bitemporal depth electrodes are useful diagnostic tools for children with temporal lobe epilepsy and unclear seizure localizations. In conjunction with imaging data, their use has been successful in achieving excellent surgical outcomes in the pediatric population.,