[Effect of epilepsy surgery based on magnetic resonance imaging (MRI) classification]

We prospectively analyzed the effect of surgical procedures in epilepsy patients, except for those with mesial temporal lobe epilepsy. Twenty patients with a mean age of 26 years (range 3 to 58 years, 10 male and 10 female) underwent the surgical procedures. These patients were divided into 3 groups according to MRI findings, as follows; group A (localized type): localized lesions such as angiomas or benign tumors, group B (widespread type): widespread lesions such as regional encephalitis or stroke, visible on anatomical neuroimaging, and group C (cryptic type): no lesion visible on anatomical neuroimaging. Following surgery, 11 (85%) of the 13 patients in group A were seizure-free, one showed worthwhile improvement, and one, whose lesion was not removed totally, was unchanged. In group B, two patients (50%) were seizure-free and 2 (50%) showed worthwhile improvement. All the patients in group C showed worthwhile improvement. Lesionectomy, cortical excision, multiple subpial transection (MST) or a combination of these procedures were effective in groups A and B. Patients in group C had a chance to obtain worthwhile improvement by corpus callosotomy or cortical excision. Intracranial EEG recording provides useful information for epilepsy surgery in intractable cases.