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Stereo-Electro-Encephalo-Graphy SEEG With Robotic Assistance in the Presurgical Evaluation of Medical Refractory Epilepsy: A Technical Note
Published on: June 13, 2016
Stereoelectroencephalography and surgical outcome in polymicrogyria-related epilepsy: A multicentric study
Louis Georges Maillard1,2,3, Laura Tassi4, Fabrice Bartolomei5,6
1Research Center for Automatic Control of Nancy (CRAN), University of Lorraine, CNRS, UMR 7039, Vandoeuvre, France.
Objective:
We aimed to (1) assess the concordance between various polymicrogyria (PMG) types and the associated epileptogenic zone (EZ), as defined by stereoelectroencephalography (SEEG), and (2) determine the postsurgical seizure outcome in PMG-related drug-resistant epilepsy.
Methods:
We retrospectively analyzed 58 cases: 49 had SEEG and 39 corticectomy or hemispherotomy.
Results:
Mean age at SEEG or surgery was 28.3 years (range, 2-50). PMG was bilateral in 9 (16%) patients and unilateral in 49, including 17 (29%) unilobar, 12 (21%) multilobar, 15 (26%) perisylvian, and only 5 (9%) hemispheric. Twenty-eight (48%) patients additionally had schizencephaly, heterotopia, or focal cortical dysplasia. The SEEG-determined EZ was fully concordant with the PMG in only 8 (16%) cases, partially concordant in 74%, and discordant in 10%. The EZ included remote cortical areas in 21 (43%) cases and was primarily localized in those in 5 (10%), all related to the mesial temporal structures. All but 1 PMG patient with corticectomy or hemispherotomy had a unilateral PMG. At last follow-up (mean, 4.6 years; range, 1-16), 28 (72%) patients remained seizure free. Shorter epilepsy duration to surgery was an independent predictor of seizure freedom.
Interpretation:
PMG-related drug-resistant epilepsy warrants a comprehensive presurgical evaluation, including SEEG investigations in most cases, given that the EZ may only partially overlap with the PMG or include solely remote cortical areas. Seizure freedom is feasible in a large proportion of patients. PMG extent should not deter from exploring the possibility of epilepsy surgery. Our data support the early consideration of epilepsy surgery in this patient group. Ann Neurol 2017;82:781-794.
Insights
Polymicrogyria (PMG)-related epilepsy surgery can lead to seizure freedom in many patients. Comprehensive evaluation is crucial as the epileptogenic zone may not fully align with PMG findings.
Area of Science:
- Neurology
- Neurosurgery
- Epileptology
Background:
- Polymicrogyria (PMG) is a cortical malformation associated with drug-resistant epilepsy.
- Understanding the relationship between PMG and the epileptogenic zone (EZ) is critical for surgical planning.
Purpose of the Study:
- To assess the concordance between polymicrogyria (PMG) types and the epileptogenic zone (EZ) identified by stereoelectroencephalography (SEEG).
- To determine postsurgical seizure outcomes in patients with PMG-related drug-resistant epilepsy.
Main Methods:
- Retrospective analysis of 58 patients with PMG and drug-resistant epilepsy.
- 49 patients underwent SEEG, and 39 had resections (corticectomy or hemispherotomy).
Main Results:
- The epileptogenic zone (EZ) showed only partial concordance with polymicrogyria (PMG) in 74% of cases.
- 72% of patients achieved seizure freedom after surgery, with shorter epilepsy duration predicting better outcomes.
- PMG extent did not preclude successful epilepsy surgery.
Conclusions:
- Comprehensive presurgical evaluation, including SEEG, is vital for PMG-related epilepsy due to potential EZ-PMG discordance.
- Epilepsy surgery offers a high chance of seizure freedom in PMG patients.
- Early consideration of epilepsy surgery is supported for this patient group.
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