Abstracts

Rationale: Resective surgery is successful in alleviating seizures in a majority of children with intractable epilepsy; developmental pathology being the commonest substrate. While there is considerable experience with surgery for focal cortical dysplasia (FCD) in older children, there is little in the very young. We describe outcomes of children who had resective epilepsy surgery during the first two years of life. Methods: We reviewed patients who underwent epilepsy surgery at Miami Children's Hospital Comprehensive Epilepsy Center between January 1997 and April 2011. We identified 22 patients who had at least one focal resective surgery during the first 2 years of life, and had a pathological diagnosis of FCD. All patients had presurgical evaluation including clinical and developmental assessment, interictal and ictal video-EEG recordings, MRI and intraoperative ECoG. Selected patients had SPECT, PET, functional MRI, chronic subdural recordings, functional mapping, and somatosensory evoked potentials with invasive electrodes. Seven patients underwent reoperation. Seizure outcome following the last operation was analyzed using modified Engel Scale. Results: The mean age at seizure onset was 2.8 months ranging between first day of life-10 months, age at surgery was 10.7 months (1.6-21.7 months). Fourteen patients had abnormal neurological examination and 17 had developmental delay. Eighteen patients had complex partial seizures, one had secondarily generalized seizures resulting in status epilepticus, and 3 had spasms. Localizing and/or lateralizing findings were present in 17/22 interictal, and all ictal EEG. MRI showed lesions compatible with FCD in 18, normal findings in 2, and nonspecific findings in 2. Focal convergent findings were seen in ictal SPECT (15/15), interictal SPECT (5/7), and PET (3/4). Initial surgery included 10 lobar and 12 multilobar resections, second surgery included 3 lobar and 4 multilobar resections, and third surgery included one hemispherectomy. At mean follow-up of 5.5 years, 11 patients were seizure free (50%), 3 patients had >90% reduction in seizure frequency (14%), 4 patients had 50-90% reduction (18%), and 4 had <50% reduction. Postoperative complications included cerebrovascular insult (6), resulting in permanent neurologic deficit (3), infection (2), edema (2), excessive blood loss (1). Histopathology revealed FCD type 2B in 7 patients, type 2A (6), type 1 (5), mild CD (3), and type 4D (1). Favorable outcome was associated with older age at the time of surgery, and longer time from seizure onset to surgery. Seizure free outcome was not associated with abnormal neurological exam, developmental delay, seizure type, presence of lateralizing/localizing features on scalp EEG, lesional MRI, interictal SPECT/PET, performance of subdural implantation, completeness of resection or pathology. Conclusions: Our findings demonstrate that resective surgery in the FCD substrate is successful even in very young children. However, completeness of resection which is a reliable predictor of outcome in older patients cannot be applied to young infants.