Abstracts

The Value of Intracranial Study in Non-Lesional Focal Epilepsy

Abstract number : 2.25
Submission category : 9. Surgery / 9A. Adult
Year : 2021
Submission ID : 1825992
Source : www.aesnet.org
Presentation date : 12/5/2021 12:00:00 PM
Published date : Nov 22, 2021, 06:51 AM

Authors :
Mauricio Mandel, MD - Yale School of Medicine; Hari Mcgrath - Neurosurgery - Yale School of Medicine; Mani Ratnesh Sandhu - Neurosurgery - Yale School of Medicine; Layton Lamsam - Neurosurgery - Yale School of Medicine; Mycah Pumphrey - Meharry Medical College; Dennis Spencer - Neurosurgery - Yale School of Medicine; Eyiyemisi Damisah - Neurosurgery - Yale School of Medicine

Rationale: The success of epilepsy surgery is directly related to the ability to localize and either resect, disconnect or modulate the epileptogenic focus. Although advances in MRI allow for identification of subtle lesions, a considerable number of patients with epilepsy have no clear lesion on MRI. Our objective was to evaluate the role of intracranial EEG monitoring in the diagnosis and directing the appropriate therapy for non-lesional epilepsy, and to present the outcomes of those patients treated with either neuromodulation or resection.

Methods: Between 2015-2021, 477 patients were presented to the Yale epilepsy surgery program and 175 (36%) had no lesion on MRI. Forty-eight patients were submitted to an intracranial study and/or direct surgical treatment of their epilepsy. Main outcomes assessed were the result of the intracranial study, definitive surgical treatment, and seizure freedom at one-year follow up. Patients who underwent corpus callosotomy were excluded from outcome analysis.

Results: Thirty-six of 48 patients (75%) underwent intracranial EEG study. The other 12 patients (25%) underwent direct surgical therapy,i.e., DBS (4), RNS (1), VNS (3) or callosotomy (4) without intracranial monitoring. Following intracranial study, 18 had resection, 8 RNS, and 7 DBS. Thirty-three patients (69%) were included in the outcome analysis. Fourteen patients (42%) were ILAE 1-2 (excellent outcome), 11 (33.3%) were ILAE 3-4 (good outcome), and 8 (24%) were ILAE 5 (poor outcome). The majority of patients with excellent or a good outcome underwent an intracranial study (92.7% and 83.3% respectively), compared to those which was greater than those patients not studied (41.7%, p = 0.035). Patients with excellent outcomes were also significantly more likely to have had resection or RNS, 77% and 23%, respectively.

Conclusions: We found that intracranial studies guide treatment strategy for the management of non-lesional epilepsy, leading to resection and/or RNS which carries a better chance of seizure freedom compared to direct neuromodulation.

Funding: Please list any funding that was received in support of this abstract.: None.

Surgery