Lesional Epilepsy

Lesional epilepsy is characterized by an epileptogenic
(epilepsy inducing) structural lesion, which might include a malformation of blood vessels, a tumor or an area of abnormal brain tissue. The surgical approach depends on the correlation or link between the EEG and brain scan findings.  Well defined lesions in non-vital brain tissue can be completely removed, with the post-operative seizure-free rate reaching as high as 70% to 90%.  In some cases however, the microscopic abnormal brain cells extend beyond the MRI-defined lesion (e.g. cortical dysplasia), and this might result in surgical failure.  Long duration of epilepsy suggests the possibility of a more-widely-distributed epileptogenic area or network, and intracranial (below the skull directly onto the brain tissue) electrodes can be used to more accurately define the abnormal area.