Bilateral invasive electroencephalography in patients with tuberous sclerosis complex: a path to surgery?

Area of Science:

• Pediatric Neurology
• Epileptology
• Neurosurgery

Background:

• Children with tuberous sclerosis complex (TSC) often present with epilepsy characterized by multiple tubers on MRI and non-localizing EEG findings.
• Non-lateralizable epilepsy in TSC poses challenges for surgical planning due to difficulties in identifying the epileptogenic zone.
• Frequent seizures and polypharmacy in pediatric epilepsy carry significant long-term risks.

Purpose of the Study:

• To evaluate the utility of bilateral intracranial EEG in lateralizing the epileptogenic zone in children with TSC and non-lateralizable epilepsy.
• To assess the safety and efficacy of identifying resectable seizure foci using invasive monitoring.
• To correlate intracranial EEG findings with surgical outcomes in this patient population.

Main Methods:

• Retrospective analysis of 62 children with TSC evaluated between January 1, 1998, and June 30, 2008.
• Focus on 20 pediatric patients who underwent bilateral intracranial EEG for non-lateralizable epilepsy.
• Review of presurgical testing, intracranial EEG data, surgical interventions, and patient outcomes (Engel classification).

Main Results:

• Bilateral intracranial EEG identified a resectable epileptogenic zone in 14 of 20 patients.
• Five patients had nonresectable zones; one underwent callosotomy.
• Seizure outcome was Engel Class I or II in 8 of 14 patients who underwent resection, with a mean follow-up of 25 months.

Conclusions:

• Bilateral intracranial EEG is a valuable tool for identifying potential resectable seizure foci in TSC epilepsy with non-lateralizable findings.
• Despite challenges in resection for some, significant seizure improvement (Engel Class I or II) was achieved in 8 patients.
• Invasive monitoring via bilateral intracranial EEG is a safe and effective method for localizing the ictal onset zone in complex pediatric epilepsy cases.