Indications for epilepsy surgery If systemic medication has failed after medical treatment, patients with epilepsy may consider surgical options such as surgery, vagus nerve stimulation, and deep brain stimulation. The exact method needed depends on many factors, including the patient’s age, seizures and type of epilepsy. Some patients may achieve satisfactory results with treatment, but these methods are not always effective, which is one reason why they are not the preferred approach to epilepsy treatment. In general, surgery is only appropriate for patients who are not well treated with medication, but not all patients who are not well treated with medication can have surgery. For patients who are refractory to medication, surgery should only be performed in cases that are suitable for surgery after a detailed preoperative localization assessment. Epilepsy surgery has been performed for more than 100 years, but it was not until the 1980s that it gained traction. In the past, patients with epilepsy often underwent years or even more than 10 years of failed medication before surgery was considered. The current view is that after failure of standardized treatment with medications, the earlier surgery is performed for patients who are candidates for surgery, the better the surgical outcome. Therefore, the current widely adopted approach is to consider surgery when seizures remain difficult to control after 1 – 2 years of regular treatment with 2 – 3 appropriate antiepileptic drugs. Again, surgery is not the preferred approach for the treatment of epilepsy. For patients who have not previously undergone regular diagnosis and regular medication, it is important to adjust the diagnosis and treatment plan followed by standardized medication and observation for a period of time before making a decision. Effectiveness of epilepsy surgery The effectiveness of epilepsy surgery cannot be generalized because the specific surgical outcome depends on a variety of factors, including the type of epilepsy, age, the presence of lesions in the brain, the presence of important brain functions in the resected area, the surgical approach, and the presence of postoperative complications. In general, some patients with epilepsy, especially those with focal lesions in the brain, have relatively good surgical results. These lesions include: hippocampal sclerosis, benign tumors, vascular malformations, stroke lesions, and traumatic lesions. Usually, all require at least a period of medication after surgery. For patients who have been seizure-free after surgery, it is possible to try to taper off the medication after 2 to 3 years; some patients can eventually get off the medication, while others may need to take it for a long time. Patients who continue to have seizures after surgery must be controlled with medications. Risks of epilepsy surgery As with all surgical procedures, there are some risks associated with epilepsy surgery. First, the patient and family should be well prepared before surgery. Given the complexity of localizing the epileptic lesion, no one can guarantee a good outcome, even after a thorough preoperative evaluation. As with medication, surgery is just another form of treatment and has the potential to fail. In reality, some patients will be completely seizure-free after surgery, most will show some improvement, and a few may show no improvement, or in rare cases, even worse than before surgery. Secondly, the surgery itself carries certain risks, depending on how it is performed, and complications such as bleeding, infection, hemiparesis, aphasia, visual field loss, sensory impairment, and brain nerve damage may occur. Preoperative evaluation of epilepsy surgery The preoperative localization evaluation serves two main purposes: to locate the epileptogenic zone as accurately as possible to facilitate maximum removal of the epileptogenic focus, and to clarify the relationship between the resection site and normal brain function in order to minimize damage to brain function. The preoperative evaluation is a systematic and complex task. At a minimum, it should include seizure symptomatology analysis (long-range video EEG), electrophysiological examination (EEG, magnetoencephalography), structural imaging (CT, MRI scan), functional imaging (SPECT, PET), and neuropsychological testing. After obtaining the above information, a comprehensive analysis is required through a preoperative discussion involving multiple departments to determine issues such as suitability for surgery and the specific surgical plan. Not all patients need all of the above tests, and the doctor needs to choose according to the patient’s specific situation. The intracranial EEG is relative to the extracranial EEG. We usually do scalp EEG. The EEG with butterfly electrodes is an extra-cranial EEG, while the intracranial EEG is an EEG technique with electrodes placed inside the skull for monitoring, which is an interventional and invasive test. Usually, intracranial EEG is considered when the location and extent of the epileptogenic zone cannot be determined by non-invasive localization, or when the resection site may be responsible for important brain functions. The main purpose of intracranial EEG monitoring is twofold: to further clarify the location and extent of the epileptogenic zone and to clarify the relationship between the epileptogenic zone and functional brain areas. First, or undergo craniotomy under anesthesia in the operating room, the exact craniotomy varies from person to person. Some may require only a small hole to be drilled in the skull, while others may require removal of a piece of skull of varying size. Intracranial electrodes are then placed in the selected area of the skull without removing any brain tissue and suturing the wound. Back in the video-EEG monitoring ward, one of the intracranial recording electrodes is connected to the EEG machine and monitored for a long period of time until a sufficient number of seizures are captured. In order to clarify the presence or absence of important functions in the brain area covered by the intracranial electrode, the electrical stimulation of the recording electrode is also attended to during the monitoring period. The procedure of epilepsy surgery Broadly speaking, the surgical approach can be divided into two: resection and dissection. Excision is the most commonly performed procedure, and as the name implies, it is a surgical procedure that removes the epileptic area, including the commonly heard temporal lobectomy, frontal lobectomy, parietal lobectomy, occipital lobectomy, and hemispherectomy. The goal of resection is to bring an end to the seizures. Less commonly, dissection is a procedure that blocks the nerve conduction pathway for seizures, often in a somewhat palliative manner, i.e., the corpus callosotomy or multiple subcallosal transection are both dissection procedures. The exact type of surgery for a given patient depends on the specific type of seizure, the epileptogenic zone, and the localization of functional brain areas. Some patients may require only an excision, others may require only a dissection, and still others may require both an excision and a dissection.