**7. Current surgical challenges and the future**

Despite the advances in technology and surgical technique, control of seizure in the best centers ranges between 15 and 75% and has no changed for the last three decades [75]. Mechanism of epileptogenesis may involve epileptic network rather than a single focus. Using the depth electrodes, independent ictal onset with same semiology from the hippocampus, entorhinal cortex, and amygdala in the same patient with medial temporal lobe epilepsy can be detected. It is known that unidentified epileptogenic source happens in 50% of patients treated surgically [23].

It is known that 10–15 years after surgery, seizure control declines with only 15–50% remaining seizure free [8].

In cases of more than one pathology, such as MTLS, migratory disorder, or tumor, seizure is usually not controlled unless sources resection is addressed [76].

Neuropsychological tests demonstrated cognitive deficit in most patients without tumors or cavernomas [77]. Epileptogenic network is partially supported by Microanalysis (elevation of glutamate levels in epileptogenic region and greater increase after ictal onset, 7 T-MR spectroscopy detecting the mitochondrial function in cortico-subcortical area) and electrophysiological connectivity [24].

Open-loop device for constant stimulation of the anterior thalami (not approved by FDA) could control the epileptogenic site and the lesional area, reducing the seizure in less than 50% of patients in a clinical trial [78].

For better understanding of the epileptogenic network, we need bioelectric integrated telemetered intracranial monitoring. The next advances will need a molecular biosensor with wireless transmission of critical data. Medicine and surgery are not able to control seizure in all epileptic patients yet.

The new surgical roadmap comprises enhancing research, through collaboration, bioinformatics, information scientist biomedical informatics, and information technology.
