Abstracts

Rationale: Up to 90% of patients with tuberous sclerosis complex (TSC) have epilepsy, with a significant proportion of them having medication-resistant epilepsy despite new anticonvulsants. For children whose epilepsy is medically refractory, surgical resection of the epileptogenic tubers may offer seizure freedom. However, the unambiguous identification of the epileptogenic tuber(s) among the many can be challenging in children with TSC. Consequently, TSC patients often require invasive EEG monitoring or are denied surgery altogether. Methods: In addition to video-EEG, magnetic resonance imaging (MRI), and fluoro-deoxyglucose positron emission tomography (FDG-PET), 28 children with TSC and intractable epilepsy referred to our center from 2000 to 2007 for pre-surgical evaluation had magnetoencephalography (MEG) and FDG-PET/MRI co-registration to non-invasively localize the epileptogenic zones. Results: Eighteen underwent surgical resection based on the concordance of these test results, with the final resection zone confirmed by intraoperative electrocorticography. No patient underwent extraoperative intracranial recording. Twelve were seizure-free postoperatively (67%), with average follow-up of 3.4 years. Younger age and shorter seizure duration predicted postoperative seizure freedom. Conversely older age and longer seizure duration were associated with continued seizures postoperatively or being denied surgery altogether due to non-lateralizing or bilateral independent epileptogenic zones. Conclusions: Without utilizing invasive intracranial recording, MEG and FDG-PET/MRI co-registration non-invasively localized the epileptogenic zones in children with TSC and intractable epilepsy, with 67% postoperative seizure freedom. Seizure freedom after surgery correlated with younger age and shorter seizure duration, and appeared to suggest early consideration for epilepsy surgery may lead to more seizure freedom in children with TSC and intractable epilepsy.