Hemispherectomy reportedly produces remarkable results in terms of seizure outcome and quality of life for medically intractable hemispheric epilepsy in children. We reviewed the neuroradiologic findings, pathologic findings, epilepsy characteristics, and clinical long-term outcomes in pediatric patients following a hemispheric disconnection. We retrospectively studied 12 children (8 males) who underwent a hemispherectomy at Asan Medical Center between 1997 and 2005. Clinical, EEG, neuroradiological, and surgical data were collected. Long-term outcomes for seizure, motor functions, and cognitive functions were evaluated at a mean follow-up of 12.7 years (range, 7.6-16.2 years) after surgery. The mean age at epilepsy onset was 3.0 years (range, 0-7.6 years). The following epilepsy syndromes were identified in our cohort: focal symptomatic epilepsy (n=8), West syndrome (n=3), and Rasmussen's syndrome (n=1). Postoperative histopathology of our study patients revealed malformation of cortical development (n=7), encephalomalacia as a sequela of infarction or trauma (n=3), Sturge-Weber syndrome (n=1), and Rasmussen's encephalitis (n=1). The mean age at surgery was 6.5 years (range, 0.8-12.3 years). Anatomical or functional hemispherectomy was performed in 8 patients, and hemispherotomy was performed in 4 patients. Eight of our 12 children (66.7%) were seizure-free, but 3 patients with perioperative complications showed persistent seizure. Although all patients had preoperative hemiparesis and developmental delay, none had additional motor or cognitive deficits after surgery, and most achieved independent walking and improvement in daily activities. The long-term clinical outcomes of hemispherectomy in children with intractable hemispheric epilepsy are good when careful patient selection and skilled surgical approaches are applied.

Accurate localization of the seizure onset zone is important for better seizure outcomes and preventing deficits following epilepsy surgery. Recent advances in neuroimaging techniques have increased our understanding of the underlying etiology and improved our ability to noninvasively identify the seizure onset zone. Using epilepsy-specific magnetic resonance imaging (MRI) protocols, structural MRI allows better detection of the seizure onset zone, particularly when it is interpreted by experienced neuroradiologists. Ultra-high-field imaging and postprocessing analysis with automated machine learning algorithms can detect subtle structural abnormalities in MRI-negative patients. Tractography derived from diffusion tensor imaging can delineate white matter connections associated with epilepsy or eloquent function, thus, preventing deficits after epilepsy surgery. Arterial spin-labeling perfusion MRI, simultaneous electroencephalography (EEG)-functional MRI (fMRI), and magnetoencephalography (MEG) are noinvasive imaging modalities that can be used to localize the epileptogenic foci and assist in planning epilepsy surgery with positron emission tomography, ictal single-photon emission computed tomography, and intracranial EEG monitoring. MEG and fMRI can localize and lateralize the area of the cortex that is essential for language, motor, and memory function and identify its relationship with planned surgical resection sites to reduce the risk of neurological impairments. These advanced structural and functional imaging modalities can be combined with postprocessing methods to better understand the epileptic network and obtain valuable clinical information for predicting long-term outcomes in pediatric epilepsy.

Ann Indian Acad Neurol, Official Journal of Indian Academy of Neurology