Pediatric palliative epilepsy surgery

M. Jeno, B. Zimmerman, S. Shandley, L. Wong-Kisiel, R. Singh, N. McNamara, E. Fedak Romanowski, Z. Grinspan, K. Eschbach, A. Alexander, P. McGoldrick, S. Wolf, S. Nangia, J. Bolton, J. Olaya, D.W. Shrey, S. Karia, C. Karakas, P. Tatachar, A.P. Ostendorf, S. Gedela, P. Javarayee, S. Reddy, C. Manuel, E. Gonzalez-Giraldo, J. Sullivan, J. Coryell, D. Depositario-Cabacar, J.S. Hauptman, D. Samanta, D. Armstrong, M.S. Perry, A. Marashly, M. Ciliberto. Pediatric palliative epilepsy surgery: a report from the Pediatric Epilepsy Research Consortium (PERC) Surgery Database. Pediatric Neurology (2024), doi: https://doi.org/10.1016/j.pediatrneurol.2024.04.028.

Introduction

Epilepsy is common, occurring in 0.5-1.5% of the pediatric US population, with drug-resistant epilepsy (DRE) occurring in nearly one-third of persons with epilepsy under 18 years of age. The International League Against Epilepsy (ILAE) defines DRE as “failure of adequate trials of two tolerated, appropriately chosen and used, antiepileptic drug schedules to achieve sustained seizure freedom”. After two anti-seizure medications (ASMs) have failed, the likelihood that an additional ASM will lead to seizure freedom is around 4-5%. These statistics have not changed despite increasing pharmaceutical options for the treatment of epilepsy over the last 20 years, highlighting the need for other treatment options for DRE. However, surgery continues to be an underutilized therapy, particularly when seizure freedom is not expected.

Definitive (or curative) surgical treatment for epilepsy is determined after identification of a seizure focus, followed by neurosurgical resection, disconnection, or ablation with the goal of achieving seizure freedom. Palliative epilepsy surgeries have a goal other than seizure freedom, including reduction of seizure severity, reduction in seizure frequency, or alleviation of a particular seizure type to improve quality of life. A palliative approach may be indicated when the epileptogenic zone cannot be fully resected due to failure of localization or lateralization, overlap with eloquent cortex, the presence of multiple epileptogenic zones, or the presence of generalized epilepsy. Corpus callosotomy, neuromodulation, and multiple subpial transections are procedures traditionally considered palliative procedures, though any surgical procedure can be considered a palliative treatment based on the preoperative goal of therapy including traditionally definitive procedures such as hemispherotomy, lobectomy, and lesionectomy.

Palliative epilepsy surgery can improve outcomes beyond what is captured with available surgical outcome measures, such as QOL in patients undergoing palliative hemispherotomy. Some palliative surgical procedures also have diagnostic utility that may lead to more definitive surgery later. For example, corpus callosotomy can help lateralize the seizure onset in frontal lobe epilepsies which can be difficult to lateralize on surface EEG. Responsive neurostimulation (RNS) allows long-term limited invasive EEG recording and can potentially lateralize or localize the most active seizure onset zone in suspected multifocal epilepsy leading to more definitive subsequent therapies.

Reducing seizures via epilepsy surgery, even without achieving seizure freedom, can help maximize neurodevelopmental potential and quality of life, as refractory seizures can lead to cognitive decline, impaired social outcomes, and higher risk of sudden unexplained death in epilepsy (SUDEP). This highlights the need to redefine surgical success as it relates to palliative procedures. In this paper, we evaluate the characteristics of children in the US offered palliative pediatric epilepsy surgery using a multicenter database to compare patient selection, evaluation, surgical treatment and outcomes of patients ultimately undergoing palliative epilepsy surgery.