Resolution of generalized tonic seizures following focal ablative or resective surgery

Focal brain lesions may underlie generalized tonic seizures, as seen in Lennox-Gastaut syndrome, by engaging bilateral neural networks. However, this seizure type is often not considered surgically remediable. Here, we describe the resolution of apparent electroclinically classic generalized tonic seizures in children originating from a unifocal brain lesion following resective or ablative surgery. This study aims to contribute to emerging evidence that prompt removal of a lesion may resolve generalized seizures by ameliorating aberrant network activity.

Boston Children's Hospital's (BCH) epilepsy surgical database was reviewed to identify children with tonic seizures due to a focal brain lesion who remained seizure-free for longer than 1 year following resective or ablative surgery.

Five children were identified, of whom three underwent resective surgery and two laser interstitial thermal therapy (LITT). Age at epilepsy onset varied from 1 month to 7.25 years, and age at first epilepsy surgery ranged from 5.6 to 9.5 years. Lesions were predominantly located in the frontal lobe (n = 3), and focal cortical dysplasia (FCD) was the most common underlying etiology (n = 3), followed by vascular lesions (n = 2). At last follow-up, seizure freedom (Engel Class 1A) ranged between 1.7 and 4.4 years.

This study presents evidence that resection or ablation of a focal cortical lesion can resolve generalized tonic seizures. The findings also lend credence to the hypothesis that heterogeneous brain lesions can underlie shared electroclinical features through engaging similar brain networks. Children with tonic seizures in whom a lesional etiology is presumed should undergo timely surgical evaluation, as removal of a focal lesion may arrest the evolution of a secondary epileptic network and allow for the restoration of normal brain network development.