Patients with epilepsy should first be treated with antiepileptic drugs. Surgery should be considered only if drug therapy fails or is unsatisfactory, i.e., if the patient has “refractory epilepsy”. What are the criteria for “failure of drug therapy” and “unsatisfactory outcome”? It is generally accepted that patients who have been taking two or more appropriate antiepileptic drugs for more than two years and still have at least one seizure per month are considered to have refractory epilepsy. However, clinical data show that some types of epilepsy, such as temporal lobe epilepsy, secondary epilepsy due to traumatic brain injury, encephalitis, etc., are usually difficult to control with medication. In other words, these types of epilepsy can be characterized as refractory epilepsy when the diagnosis is established and there is no need to wait for two years.