Surgery has become a widely accepted torm of therapy tor medically refractory epilepsy. Epilepsy surgery usually involves resection of an epileptogenic region with the intention of curing the seizures or disconnection of the epileptogenic region from other cerebral areas with the intention of limiting seizure propagation and minimizing the clinical manitestations of the seizures.
The selection of appropriate candidates for resective surgery requires recognition of seizure characteristics, demonstration of a unifocal or uniregional onset of habitual seizures, and determination of the critical functional activity of the tissue. With advanced techniques to define functional cerebral anatomy, the risks of resective surgery can be accurately predicted and neurological deficits avoided. The role of electroencephalography in identifying the epileptogenic area, magnetic resonance imaging in defining structural abnormalities, and single photon emission computed tomography and positron emission tomography in functional localization are reviewed. Based on magnetic resonance imaging findings, three broad groups of patients are defined: those with space-occupying lesions; those with medial temporal lobe epilepsy; and those with nonmedlial temporal, nonlesional epilepsy. The outcome of resective procedures is reviewed in terms of seizure control, neurological deticits, and quality of life. Nonresective surgical options, including corpus callosum section, stereotactic lesions, vagal nerve stimulation, and subpial transection, are also addressed.
Continuing research into the molecular and genetic basis of the epilepsies, made possible in part by analysis of tissue removed from patients undergoing resective procedures, may provide new conceptual surgical and medical applications.
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