Pediatric epilepsy surgery

Approximately 25% to 35% of patients with epilepsy continue to have seizures even with appropriate drug treatment, a proportion that has remained relatively unchanged for the last 3 decades despite the introduction of several new antiseizure medications.^1,2 Epilepsy surgery offers a better likelihood of seizure freedom in properly selected patients with such drug-resistant epilepsy (DRE). This is particularly important for childhood-onset DRE, which is often associated with adverse long-term developmental and cognitive consequences.³ Evaluation of patients for epilepsy surgery is a stepwise process and requires intracranial EEG monitoring (IEM) in many patients, particularly in those where MRI of the brain does not show a lesion specific enough to guide neurosurgical decisions (MRI-negative).^4,5 The goal of extraoperative IEM is to accurately define the seizure-onset zone, and its anatomical relationships with “eloquent” functional cortical areas.⁴ Although IEM provides crucial information for epilepsy surgery, it is associated with risks of infection, intracranial hemorrhage, and elevated intracranial pressure.⁶ These adverse events are not trivial and have required an additional surgical procedure(s) in up to 3.5% of patients.⁶ Over time, recognition of these adverse events, understanding their mechanisms, and improvements in surgical technique have resulted in increased safety and use of IEM.^6,7 Nevertheless, key questions remain regarding the long-term trends in the utilization of IEM and whether increased use of IEM has resulted in improved safety and efficacy of epilepsy surgery in pediatric DRE.