Abstracts

Rationale: Hippocampal abnormalities (HA) may coexist with malformations of cortical development (MCD), constituting dual pathology. This study aimed to explore the rate of epilepsy surgery and post-surgical outcome in patients with solely MCD compared to those with "dual pathology". Methods: We identified 228 patients (120w/108m) aged 2-75 years (mean 29.5 years) with MCD and epilepsy. MCD without HA were seen in 149/228 (65%) of patients (group I). HA were identified in 79/228 (35%) patients (group II). All patients were clinically examined, underwent EEG and MRI. Results: In group I, 66/149 (44%) patients underwent presurgical assessment, 33/66 (50%) - underwent epilepsy surgery for refractory seizures and 17/33 (51%) have been seizure free for more than 12 months following surgery (Engel, Ia; Wieser,1a). The spectrum of MCD in patients of group I, who underwent surgery, was the following: dysplastic tumours - 17, focal cortical dysplasia - 12, tuberous sclerosis - 4. The majority of these MCD (26/33, 79%) was located in temporal lobe. Surgery types in group I were the following: Lesionectomy (sparing the mesial temporal structures) -15/33 patients, standard resection of anterior two-third of temporal lobe (including the mesial temporal structures) - in 9/33 and modified resection of temporal lobe (including the mesial temporal structures) - in 9/33 patients. In group I, seizure freedom correlated neither with performed surgery type nor MCD type. In group II, 31/79 (39%) patients underwent presurgical assessment, yet only 7/31 (23%) had epilepsy surgery and 6/7 (86%) have been seizure free for more than 12 months following surgery (Engel, Ia; Wieser, 1a). In group II, 3/7 patients underwent resection of anterior two-third of temporal lobe (including mesial temporal structures); other 2/7 patients - hemispherotomy, 1/7 - resection of anterior two-third of temporal lobe (including mesial temporal structures) with parieto-occipital disconnection and 1/7 - selective amygdalohippocampectomy. Conclusions: Recognition of dual pathology is important for the presurgical evaluation of patients with pharmacoresistant seizures as meticulously selected patients may have a favourable outcome following epilepsy surgery.