Abstracts

Rationale: A paucity of data exists on long term sequelae of adverse events during invasive EEG monitoring. A series of 3 patients with intractable and disabling epilepsy were studied with invasive EEG monitoring to identify ictal onsets. These patients postoperatively with invasive recording electrodes in place experienced idiopathic cerebral edema and herniation to varied degrees and EEG recordings were continued during these times. Ultimately, in 1 case, the patient had an outcome of longterm seizure freedom, and in the other 2 cases, there were significant seizure reductions after focal resections were done and the cerebral edema resolved. Therefore all patients ultimately achieved a good clinical baseline without significant additional long term neurologic signs and overall improved seizure control. This article reviews the clinicopathologic details of these cases in this unique series. Methods: In a suburban Epilepsy center, 3 disabled and intractable epilepsy patients required invasive EEG monitoring and management to delineate ictal onsets to guide possible focal resections since they had failed numerous anti-seizure medications and/or VNS. The patients had MRI neuroimgaging, metabolic imaging, Interictal surface EEG and invasive interictal and ictal recordings for data sets. Two (2) different surgeons performed surgical procedures in these cases. Retrospectively, those with resultant herniation or cerebral edema were descriptively analyzed. Results: While the patients developed lethargy or focal neurologic signs or acute neurological defecits and clinical and radiological evidence of cerebral edema or midline shift/herniation syndromes, the decision was made in all cases (100%) to persist with invasive EEG monitoring. Long term follow up after multiple years showed a favorable outcome. Conclusions: Our case series delineates that in a series of intractable epilepsy cases, invasive monitoring performed even after development of cerebral edema and clinicoradiologic herniation syndromes after invasive electrode placement or ultimately focal resection may be associated with amelioration of seizure control and favorable long term outcome.