Surgical treatment of epilepsy in children with focal cortical dysplasia

OBJECTIVE To elicit the variables affecting the outcome and predicting achievement of long-term seizure-free status. MATERIAL AND METHODS There were 169 children with cortical dysplasia. Preoperative video-EEG and MRI were performed in all patients, invasive EEG - in 14 patients. There were 196 surgeries including 27 redo procedures: corticectomy (n=116), lobectomy (n=46) and various disconnective procedures (n=34). Routine intraoperative ECOG (134 surgeries) was combined with mapping of sensory-motor cortex in 47 cases and corticospinal tract in some patients. A new permanent and not anticipated neurological deficit developed in 5 cases (2.5%). More than 2-year (median - 3 years) follow-up data with repeated video-EEG and MRI are available in 56 cases. Thirty-two (57.2%) children were free of seizures at the last check (Engel IA). We analyzed the correlation between various characteristics (age at manifestation of disease, duration of epilepsy, age at the moment of surgery, seizure type and their electro-clinical pattern, localization and morphological type of cortical dysplasia) and quality of resection (isolation) of epileptic focus. RESULTS Both Type II FCDs and their anatomically complete excision are positive predictors of favorable outcome and achievement of SF-status due to better recognizing during MRI and more complete intraoperative resection (p<0.05). Seizure initiation zone in these malformations is identical to anatomical boundaries of FCD. Residual epileptic activity on immediate post-resection ECOG do not affect the outcome. CONCLUSION Patients with type II FCD, particularly type IIb malformations, are the best candidates for curative surgery, including lesion of brain eloquent areas. Children with type I FCD have much less chances to become free of seizures after focal corticectomy. However, some of them with early onset of catastrophic epilepsies may benefit from larger surgeries using lobectomy or various disconnections.