[Surgery for intractable focal epilepsy in children]

Abstract

Surgery of drug resistant epilepsy in children is a functional surgery which aims at the suppression of the epileptogenic focus. The surgical decision is adopted or rejected as a result of the clinical examination and complementary investigations following a multidisciplinary discussion in which the benefit-risk ratio is being carefully weighed. The objective of the presurgical investigations, dominated by scalp-recorded video-electroencephalography and magnetic resonance imaging, is the localization of the epileptogenic focus. The invasive surgical investigations with intracranial electrode placement are indicated when the limits of a planned resection have to be defined precisely or when the focus is located nearby a functionally eloquent region (sensori-motor and language region). Their identification is possible by means of electrical stimulation. Two methods of exploration are available: The combination of subdural and intracerebral electrode placement through craniotomy and the stereotactic placement of intracerebral depth electrodes (Stereo-EEG). The choice of either of these two methods depends on the child's age and on the topography of the epileptogenic focus. Surgery can be either palliative, with the purpose of reducing the intensity and/or the frequency of a certain seizure type (callosotomy, multiple subpial transsections) or curative, aiming at a suppression of the epileptogenic focus through a resective or a disconnective surgical procedure. We have operated on a population of 148 children and infants between 3 months and 10 years of age during the years 1993 to 2001: In the infant group, dysplastic lesions represented the predominant etiology. In the age group of 3 to 10 years, the underlying pathology was more distributed (dysplastic lesions, epileptogenic tumors, Rasmussen's encephalitis, hypothalamic hamartomas). Extratemporal focal resections required, in the majority of cases, an invasive preoperative exploration and hemispherotomy was frequent in this group (44 p. 100). Sixty-seven percent of the children were seizure-free, with an acceptable morbidity rate, primarily due to shunt placement following hemispherotomy in children with dysplastic lesions. Our preliminary results concerning quality of life and socialization are encouraging and favor surgical treatment at an early stage.