Abstracts

Rationale: Nonlesional extratemporal seizures are challenging to plan respective epilepsy surgery. Surgical outcomes have been reported to be worse than those for temporal lobe epilepsy. The aim of this study was to evaluate the overall surgical outcomes of nonlesional extratemporal epilepsy and to determine the usefulness of SISCOM (Subtraction Ictal SPECT Co-registered to MRI) in the prediction of successful postsurgical outcome. Methods: From January 2007 to April 2010 at Samsung Epilepsy Clinic in Samsung Medical Hospital, 25patients with nonlesional extratemporal lobe seizures (17 female) were enrolled who had undergone comprehensive presurgical evaluation and subsequent intracranial EEG monitoring for epilepsy surgery (a postoperative period of ≥ 1 year). Their clinical data including SISCOM analysis were all reviewed and postsurgical outcome was determined using Engel classification. Results: Mean age at surgery was 26.8 years, mean disease duration before surgery was 13.7 years, and mean follow up was 35.9 months. There were 12 Frontal lobe epilepsy, 6 Temporo-parietal lobe epilepsy, 4 Parietal lobe epilepsy, and 3 Occipital lobe epilepsy. In 12 cases, hyperperfused areas in SISCOM were congruent to surgical resection margin, and were noncongruent in 13 cases. Hypometabolic areas in FDG-PET were congruent in 11, and were non congruent in 14 cases. Post surgically 10 (40%) were seizure free (Engel class 1A), and 14 (60%) were not seizure free. Pathology was all focal cortical dysplasia. Seizure free outcome was predicted 6 of 11 (54.5%) in congruent SISCOM, but only 4 out of 11 (36.4% ) in noncongruent SISCOM. Conclusions: Our results suggest that seizure free surgical outcome were seen in 40% of cases in nonlesional extratemporal epilepsy. It seems that SISCOM analysis is helpful to replace limited role of MRI as image study for nonlesional extratemporal epilepsy.