Indications for surgical treatment of epilepsy in childhood: a clinical and neurophysiological approach

Resistant epilepsy is defined as the persistence of unacceptable seizures, despite correct drug treatment, or control of seizures at the cost of excessive side effects. About 30% of partial seizures are resistant to treatment; many of them is potentially a candidate for surgical treatment. Selection of patients is based fundamentally on precise identification of the epileptogenic area and on the evaluation that possible removal of that area will not be followed by serious neurological or neuropsychological deficits, or by onset of seizures in another part of the brain. To this end, careful clinical, neurophysiological and functional studies are conducted. Compared with adults, video-electroencephalographic (EEG) study of seizures in childhood is more difficult because of the lack of patient cooperation and, therefore, the lack of every subjective element in the seizures. Furthermore, the criteria for defining drug resistance in childhood are still under discussion, as many epilepsies are age dependent and seizures stop with growth. Despite this, the age at time of surgery has been steadily decreasing, in the conviction that the persistence of intractable partial epilepsy is detrimental to cognitive development and can damage brain areas that are apparently healthy. The clinical and EEG criteria for epilepsies that are secondary to some specific disorders have been defined, e.g. hemimegalencephalia and focal cortical dysplasias often produce epilepsy with onset in the first days of life characterized by partial seizures and subintrant spasms, EEG record of focal or hemispheric burst suppression and drug resistance that can be defined within the first months of life. Prolonged video-EEG monitoring is always necessary to establish congruence between the area in which the seizure originates and the brain lesion evidenced at neuroimaging, Correct monitoring of seizures means close cooperation between neurologist, neurophysiology technician and the patient, if the child is at least 5-6 y old. Absence of cooperation also limits the use of in-depth recording. Neuropsychological assessment of the child can be of great help in defining the area damaged by the epileptogenic site as well as the state of the other brain areas. Close cooperation between neurologist, radiologist, neuropsychologist and brain surgeon is necessary for a case-by-case assessment of indication for surgical treatment.