The persistence of persistent changes in the brain that produce seizures is characteristic of epilepsy, and there are severe neurobiological, sociological, and cognitive-psychological consequences. The so-called drug-refractory epilepsy refers to epilepsy and epilepsy syndromes that cannot be terminated with current antiepileptic drugs during the effective treatment period or are clinically proven to be refractory to treatment, and often require surgery. Drug-refractory epilepsy 1. Drug-refractory intractable epilepsy: Drug-refractory intractable epilepsy is defined from a surgical point of view as (1) more than 1 year of d epilepsy. (2) Seizures more than 3-4 times per month. (3) After regular treatment with 2-3 first-line antiepileptic drugs and after the blood drug concentration has reached the effective range, the seizures still cannot be controlled. (4) Patients with frequent seizures that cause severe disability or seriously affect work, study and life. Patients who meet the above conditions should undergo surgery as soon as possible after the first line of antiepileptic drug therapy. 2. Secondary (symptomatic) epilepsy Secondary or so-called symptomatic epilepsy is mostly partial epilepsy or partial secondary generalized seizures, usually with a definite seizure origin, often with progressive development, frequent or tending to severe seizures, interictal patients may develop behavioral disturbances and may lead to developmental delay or mental retardation. Complex partial seizures in medial temporal lobe epilepsy often become difficult to control with medication after adolescence. Seizures can also cause brain damage by creating new foci of epileptogenic brain structures in distant areas. Frequent seizures can also affect the development and growth of the immature brain. Especially with the advent of CT and MRI, PET, SPECT and magnetoencephalography, epileptogenic lesions in the brain can be easily detected by the above-mentioned non-invasive examination methods, and can be surgically removed with better results. 3. Patients whose surgical resection does not cause important functional deficits. It is clinically proven that the following diseases, epilepsy syndromes or epilepsy are the best indications for surgical treatment, and surgery should be actively pursued in such cases. (1) Medial temporal lobe sclerosis or hippocampal sclerosis. (2) Cortical dysplasia or malformation (3) Epilepsy due to benign as well as low-grade tumors (4) Epilepsy due to cavernous hemangioma (5) Epilepsy due to abscess cavity or traumatic scar (6) Pre- and perinatal vascular lesions (7) Eccentric convulsion-hemiparesis-epilepsy syndrome (HHE syndrome) (8) Intractable partial-onset epilepsy due to Rasmussen’s encephalitis (9) Landau-Kleffner syndrome (10) Frequent fall seizures