Epilepsy surgery, by definition is the removal of an area of brain with the aim of alleviating seizures. In order to proceed, evaluation needs to be undertaken to determine whether seizure onset can be localized to one area, and whether that area is functionally silent. In the majority, the aim is to alleviate seizures with no deterioration in function.
There are no current randomized studies in children demonstrating the superiority of surgery over medical treatment for this group of patients. However, many nonrandomized studies strongly suggest that epilepsy surgery may produce seizure freedom in a substantial number of nonidiopathic focal epilepsy (NIFE) cases, regardless of age or cause. The evidence base now suggests that 40%–80% will become seizure free. This figure is dependent on underlying pathology (less likely in developmental malformations and cryptogenic cases) and extent of resection. Therefore, surgery is now established in the routine management of children with presumed lesional focal epilepsy, and criteria for referral and evaluation for pediatric epilepsy surgery have been recently proposed.1
SURGERY IN CHILDREN NOT ONLY AIMS AT SEIZURE ALLEVIATION
Children should not be referred for surgery as a "last resort." The rate of cognitive and behavioral comorbidity associated with early onset of epilepsy is high, and early cessation of seizures likely leads to improved neurobehavioral outcome. The concept of "epileptic encephalopathy" implies ongoing cognitive impairment as a result of underlying epileptic activity and may be potentially reversible. Longitudinal data on cognitive outcome are lacking due to the absence of standardized assessments over the lifespan and lack of a control group.
There is some evidence of stable postoperative intelligence quotient (IQ) suggesting at least an unchanged developmental trajectory that may be related to duration of epilepsy rather than ultimate seizure outcome. Brain plasticity and relocalization of function are additional factors that are influenced by age and type of surgery.
SURGERY IN CHILDREN IS NOT THE VERY LAST OPTION
There is no minimal age for surgical referral. All children under the age of 5 years with a definitive magnetic resonance imaging (MRI) lesion are potential surgical candidates. Should seizure control be achieved with medication a conservative wait period is indicated. Children older than the age of 5 years with a definitive lesion may be left to determine response to anticonvulsants but failure of two medications in children with apparent focal seizures should be prompt referral for assessment. Delayed surgical referral depends on adequacy of neurodevelopmental progress. As a rule, all children suffering from pharmacoresistant focal epilepsy should be evaluated at a specialized epilepsy center if they exhibit behavioral and cognitive dysfunction.
The number of antiepileptic drugs (AEDs) utilized and duration of the epilepsy are of strict importance in the decision to perform epilepsy surgery in adults for epilepsy. In contrast, the pediatric evaluation is influenced by a variety of additional factors such ...