Abstracts

Rationale: The current surgical success rates are 45-55% in pediatric and adult patients with extratemporal epilepsy. We reviewed the presurgical evaluative data and results of epilepsy surgery in pediatric patients who received extratemporal resective surgery in our institution. Methods: The twenty six patients (males 15, females 11, mean age 11.5 years, age of onset of seizure 3.8 years, mean age of operation 9.3 years, duration of op from onset 5.5 years, mean age after operation 2.3 years) who received extratemporal lobe surgery in our institution between October 2003 to May 2008 were reviewed. Preoperative evaluation to determine the anatomical location of the ictal onset zone employed video-EEG monitoring and neuroimagings such as Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), interictal/ictal Single Photon Emission Computed Tomography (SPECT), MR Spectroscopy (MRS) and these studies were used to delineate possible localized malformed cerebral cortex. We also performed intraoperative electrocorticography (EcoG), intracranial EEG monitoring. Developmental test was taken at pre- and post-operatively. Results: Postoperative outcome as defined by Engel classification were as follows; class I in 19(73%), II in 1(3.8%), III in 1(3.8%), and IV in 5(19.2%) patients. Most common pathology from resected tissues was cortical dysplasia and microdysgenesis. 20 patients received frontal, 2 patients received parietal, and 4 patients received occipital lobectomy. 19 patients (73%) exhibited localized foci upon preoperative video EEG monitoring, as well as MRI and PET images, and 18 patients showed localization of the lesion in interictal SPECT. In patients whom postsurgical outcomes were outstanding (Engel class I), marked improvement in developmental outcome was noted. Postsurgical complications were noted in 9 cases, without lasting sequelae. Conclusions: We achieved a seizure-free rate of 73% in pharmacoresistant epileptic pediatric patients after extratemporal lobectomy. From this experience, we recommend early surgical intervention in pediatric patients with medically refractory seizure who possess focal epileptogenic foci of extratemporal lobe origin, as we can expect higher success rate and fewer postsurgical complications compared to those reported in adults. The Multimodal investigation utilizing MRI, special PET analyzer with 10% asymmetry and subtraction ictal SPECT coregistered with MRI(SISCOM) and wide resections of the cortex based on the EcoG findings might be necessary to better localize the site of extratemporal epilepsy and to reduce postoperative complications.