We reviewed the records of consecutive patients aged >10 years with drug‐resistant focal epilepsy who underwent evaluations for epilepsy surgery between March 2010 and December 2019 at the NHO Shizuoka Institute of Epilepsy and Neurological Disorders in Japan. We included patients who had undergone resective surgery and excluded those who had undergone palliative surgery (such as corpus callosotomy and vagus nerve stimulation) or surgery that was performed across the cerebral lobes. A total of 370 patients who had undergone epilepsy surgery were identified. Patients who achieved a favorable seizure outcome at least 2 years after surgery (Engel class I) were included. A total of 240 patients satisfied the above criteria and were included in this retrospective study. We divided the patients with surgically defined EZ into three groups: EZ on frontal lobe, temporal lobe, and posterior cortex (parietal or occipital lobe). We defined extra‐FLE as EZ on temporal lobe and posterior cortex, and extra‐TLE as EZ on frontal lobe and posterior cortex.
All patients underwent presurgical evaluation including long‐term video‐electroencephalogram (EEG) monitoring, 1.5 or 3 Tesla magnetic resonance imaging (MRI), and single‐photon emission computed tomography (SPECT) and/or [18F] fluorodeoxyglucose positron emission tomography. Long‐term video‐EEG monitoring was performed using the EEG‐1000 instrument (Nihon Kohden), and the standard 10–20 system of electrode placement was used in all cases. T1 and T2 or sphenoidal electrodes were added when necessary. In some patients, the Wada test or a functional MRI was undergone to determine the dominant hemisphere for language/speech functions. Additional intracranial electrode was conducted to determine the EZ and the extent of resection when the EZ could not be sufficiently identified and/or in the absence of a clear lesion on MRI after estimating the EZ based on the above evaluations.
This retrospective study was reviewed and approved by the Ethics Committee of the NHO Shizuoka Institute of Epilepsy and Neurological Disorders (2021–28).
All patients underwent presurgical evaluation including long‐term video‐electroencephalogram (EEG) monitoring, 1.5 or 3 Tesla magnetic resonance imaging (MRI), and single‐photon emission computed tomography (SPECT) and/or [18F] fluorodeoxyglucose positron emission tomography. Long‐term video‐EEG monitoring was performed using the EEG‐1000 instrument (Nihon Kohden), and the standard 10–20 system of electrode placement was used in all cases. T1 and T2 or sphenoidal electrodes were added when necessary. In some patients, the Wada test or a functional MRI was undergone to determine the dominant hemisphere for language/speech functions. Additional intracranial electrode was conducted to determine the EZ and the extent of resection when the EZ could not be sufficiently identified and/or in the absence of a clear lesion on MRI after estimating the EZ based on the above evaluations.
This retrospective study was reviewed and approved by the Ethics Committee of the NHO Shizuoka Institute of Epilepsy and Neurological Disorders (2021–28).
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