Abstracts

Rationale: Focal Cortical Dysplasia (FCD) represents the most common malformation of cortical development. This term describes a localized abnormality of cortical cyto-architecture characterized by specific histopathologic abnormalities. These abnormalities include the presence of bizarre dysmorphic, immature, giant, and balloon-shaped neurons as well as cortical mantle lamination abnormalities. The association of FCD with epileptogenesis, although not clearly understood, has been well established. Interestingly, 8-12% of medically intractable epilepsy cases are associated with FCD, while in 14-26% of the cases of recently published pediatric epilepsy series FCD was identified as the underlying factor. In our current communication we present our results of a series of pediatric and adult patients, who were surgically treated in our institution for medically refractory epilepsy secondary to FCD of extra-temporal anatomical origin.Methods: In our retrospective analysis 19 patients (7 males and 12 females) with the histologic diagnosis of FCD of extra-temporal anatomic location were included. Their mean age was 27.6 years (range 4- 42 y). The mean duration of epilepsy was 6.8 years in our series (range 2-14 y). Their pre-operative work-up included detailed neurological examination, meticulous evaluation of seizure semiology, neuropsychological evaluation, surface ictal and inter-ictal EEG, video-EEG monitoring, and brain MRI. In selected cases, proton MR Spectroscopy, ictal SPECT and SISCOM studies, PET scan, Magnetic Source Imaging (MSI) and invasive EEG monitoring via depth and/or subdural strip and grid electrodes were also employed for seizure focus/i localization. Lesionectomies of anatomically and/or electrophysiologically abnormal cortical epileptogenic areas was performed by using subpial dissection/aspiration technique. Post-resective intraoperative corticography was performed in all our cases. Engel’s classification system was utilized for postoperative outcome evaluation in our series. The mean follow-up time in our series was 2.7 years (range: 2-5 years, median: 2 years).Results: Preoperative MRI studies revealed structural abnormalities consistent with FCD in 13 patients (68.4%), while in 6 (31.6%) no abnormalities were seen. The anatomic location of the resected epileptogenic foci was frontal in 9 patients (47.4%), fronto-parietal in 3 (15.8%), parietal in 2 (10.5%), and occipital in 5 patients (26.3%). Outcome data were available for 19 patients at the completion of the first year, for 15 patients at the end of the second year, and for 12 at the end of the third year. Our surgical outcome results are summarized in Table 1. Surprisingly, patients with normal preoperative MRI had better outcome (5/6 had class I) compared with those with abnormal preoperative MRI (6/13 had class I).Conclusions: Seizure free outcome was achieved in 57.9% of our patients. However, the number of patients with class I outcome decreased at the end of the second postoperative year. In our cohort, patients with non-lesional preoperative MRI had better outcome.