Epilepsy Surgery

Epilepsy is the second most common cause of mental health disability worldwide, particularly among young adults, and accounts for a significant burden of illness. Approximately 30% to 35%of patients with seizures have drug-resistant epilepsy, defined as failure of two antiepileptic medications given at appropriate doses. Brain resection for medically refractory epilepsy benefits patients by reducing or eliminating their seizure activity, but it is underutilized.Mesial temporal lobe epilepsy is the prototypical surgically remediable epilepsy syndrome. Others include discrete neocortical lesions such as focal cortical dysplasias and diffuse lesions limited to one hemisphere. Excellent outcomes can also be achieved in patients with multiple lesions, for example, tuberous sclerosis when one tuber is the source of seizures. The best prognostic factor for a good outcome is a discrete structural lesion on MRI, in an area that can be safely removed, which conforms to the location of ictal EEG changes and is consistent with seizure semiology. Conversely, the occurrence of generalized tonic– clonic seizures, a normal MRI, extratemporal onset, psychiatric comorbidity, and learning disability reduce the chances.Presurgical evaluation aims to localize the epileptogenic zone (EZ) that must be removed to give seizure freedom through the integration of seizure semiology, EEG, neuropsychological evaluation, and multimodal imaging consist of fMRI, SPECT, PET, DTI, and volumetric MRI.Some resections may be standardized when the EZ is within recognized boundaries, Palliative procedures include disconnection, such as corpus callosotomy, for disabling drop attacks. These may reduce seizure frequency and severity, but very rarely bring seizure freedom.