Mesial Temporal Sclerosis

A 28-year-old woman with a 15-year history of focal impaired-awareness seizures presents with recurrent episodes of epigastric rising aura, déjà vu, and oral automatisms followed by post-ictal confusion. She has failed trials of levetiracetam, lamotrigine, and lacosamide. High-resolution 3T MRI with epilepsy protocol shows the finding marked **A** in the diagram. Which of the following statements best characterizes the pathological substrate underlying her seizure disorder?

A 26-year-old woman with focal impaired-awareness seizures since age 14 presents with a history of a prolonged febrile seizure at 18 months. She experiences a rising epigastric aura, déjà vu, and fear, followed by oroalimentary automatisms and dystonic posturing. Despite adequate therapeutic trials of levetiracetam, lacosamide, and lamotrigine, she continues to have 4–6 seizures per month. MRI brain with dedicated epilepsy protocol shows the structure marked **A** (atrophic T2-hyperintense hippocampus) with loss of internal architecture and temporal horn dilation. Video-EEG telemetry confirms left anterior temporal spikes. Which of the following is the most appropriate definitive management for this patient's drug-resistant mesial temporal lobe epilepsy?