てんかん外科手術における術前シミュレーション

Preoperative Simulation in Epilepsy Surgery

Point

・難治性てんかんに対して根治的手術を計画する場合，まずは脳波，MRI，核医学検査，脳磁図などの非侵襲的検査の結果から焦点を推定する．

・焦点局在がある程度まで絞り込めたが不十分な場合や，重要機能領域と重なる場合には，頭蓋内脳波検査や皮質機能マッピングを経て根治的手術が行われる．

・焦点をできる限り十分に切除すること，正常脳機能を損なわないことの両方を意識した術前シミュレーションが重要である．

　In patients with intractable epilepsy, seizure focus resection can yield favorable seizure outcomes. First, the localization of the seizure focus is estimated by noninvasive methods such as magnetic resonance imaging（MRI）, video-electroencephalography（EEG）monitoring, nuclear medicine examinations, magnetoencephalography, and neuropsychological tests. A subgroup of patients may require additional information obtained from the intracranial EEG. There are two major methods for intracranial EEG: intracranial EEG with subdural grid electrodes（SDG）and stereotactic electroencephalography. If the estimated seizure focus overlaps with the eloquent area in noninvasive studies, the margin and extent of the resection are determined by the results of intracranial EEG and functional mapping by electrical cortical stimulation. Herein, we present a case of lobe epilepsy with subtle MRI lesions in the superior temporal sulcus of the language-dominant hemisphere. The results of the SDG and functional mapping showed that the seizure onset zone overlapped with the language area. Resection of the middle and inferior temporal gyri and multiple transections of the language area resulted in Engel IIB seizure outcomes. In such cases, a thorough preoperative simulation is required to determine the best resection margin for seizure control and functional preservation．