**4. Epilepsy surgery for drug resistance epilepsy**

The decision of surgical intervention is usually made in a consensus agreement among the discipline which carry out the investigation in a multi-disciplinary patient management conference in each epilepsy surgery centre. Basically it is a rational estimation of the precision of the epileptogenic zone (thus the success rate of seizure cure) and the risk benefit analysis of the potential post-operative risk.

In general, the outcome will be more favorable for lesional epileptic syndrome with concordance of investigation results and neuropsychological proof of "absence" of important cognitive function within the resected areas. On the contrary, the lack of concordance, the presence of important function in the pathological substrate will preclude the surgical feasibility. Besides the disease factor, there are also patient factors like seizure frequency, duration of illness, comorbidity that will govern the prognostication [50].

Conventionally, the operative outcome will be categorized in four classes according to Engel's classification [51] (**Table 3**).


The rationale is to have complete resection of the epileptogenic zone. Broadly there are three types of epilepsy surgery


## **5. Long-term outcome after epilepsy surgery**

Epilepsy surgery for temporal lobe epilepsy is usually recommended because of promising result. One study including 80 patients with temporal lobe epilepsy showed that the cumulative proportion of patients who were free of seizures impairing awareness was 58% in the surgical group and 8% in the medical group [56]. The Early Randomized Surgical Epilepsy Trial (ERSET) included 38 patients with mesial temporal lobe epilepsy and showed that zero of 23 participants in the medical group and 11 of 15 in the surgical group were seizure free during year 2 of follow-up [57]. Another study including more than 3000 patients from Germany concluded that the number of non-lesional patients and the need for intracranial recordings increased, and more than 50% of evaluated patients did not undergo surgery [58].
