Surgery in epilepsy associated with focal lesions in childhood

Abstract

Surgery in children with epilepsy is a new, evolving field. The important practical issues have been to define strategies for choosing the most suitable candidates, as well as the type and the optimum timing of epilepsy surgery. This study was undertaken to illustrate these points. To identify the factors that correlated with outcome, the authors analyzed a series of 200 children (aged 1–15 years, mean 8.7 years) who underwent surgery at the Hôpital Necker-Enfants Malades between 1981 and 1996. In 171 cases (85.5%) the epilepsy was medically refractory and was associated with focal cortical lesions. Surgery consisted of resection of the lesion without specifically attempting to identify and remove the "epileptogenic area." In the group of children whose seizures were medically refractory, the mean follow-up period was 5.8 years. According to Engel's classification, 71.3% of these children became seizure free (Ia), whereas 82% were in Class I. A multivariate statistical analysis revealed that among all the factors studied, the success of surgery in a patient in whom there was a good clinical-electroencephalogram-imaging correlation, depended on the patients' having undergone a minimally traumatic operation, a complete resection of the lesion, and a short preoperative seizure duration. After the surgical control of epilepsy, behavior disorders were more improved (31% of all patients) than cognitive function (25%). The patient age at onset, duration and frequency of seizures, intractability of the disease to therapy, and seizure characteristics, were correlated with cognitive, behavioral, and academic performance pre- and postoperatively. Multivariate statistical analysis revealed that cognitive dysfunction correlated highly with the duration of epilepsy prior to surgery, whereas behavioral disorders correlated more with seizure frequency. These data must be taken into account when selecting patients for surgical treatment and when deciding the timing of surgery. Early surgical intervention allows for optimum brain development.