A potential therapeutic role of unilateral anterior thalamic deep brain stimulation in epileptic spasms: A case report.

OBJECTIVE: Deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) is an established palliative therapy for drug-resistant focal epilepsy; however, its efficacy for epileptic spasms (ES) and the clinical utility of unilateral stimulation remain unclear. To address these issues, we report a case of drug-resistant focal epilepsy with ES treated with unilateral ANT-DBS. CASE: An 18-year-old right-handed male with focal cortical dysplasia type I had long-standing drug-resistant epilepsy. Despite multiple resective and palliative surgeries-including right frontal disconnection, corpus callosotomy, right anterior temporal lobectomy, and vagus nerve stimulation-daily ES, weekly focal impaired consciousness seizures (FIC), and monthly focal-to-bilateral tonic-clonic seizures (FBTC) persisted. Presurgical evaluation suggested an epileptic focus in the left temporal lobe for FIC/FBTC. ANT-DBS was planned for seizure alleviation. Lead implantation on the right side was considered unfavorable because of marked postsurgical atrophy. Therefore, unilateral ANT-DBS lead implantation on the left side was performed. RESULTS: After implantation, ES frequency transiently decreased (median 0.46 seizures/day) but later increased during follow-up. Stimulation was initiated on postoperative day 22. After the stimulation amplitude reached ≥2.0 mA (postoperative day 92), the median spasm frequency decreased again to 0.31/day, lower than the preoperative baseline of 0.75/day (58.1% reduction; p = 0.012). FIC frequency also decreased from 0.21/day to 0.09/day (60.0% reduction; p = 0.121). SIGNIFICANCE: Unilateral ANT-DBS was associated with a clinically meaningful reduction in ES in this highly refractory case, suggesting a potential therapeutic role even when bilateral implantation is not feasible.