Epilepsy and Lesionectomy
What Is a Lesionectomy?
A lesionectomy is an operation to remove a lesion -- a damaged or abnormally functioning area -- in the brain. Brain lesions include tumors, scars from a head injury or infection, abnormal blood vessels, and hematomas (a swollen area filled with blood).
A lesion causes seizures -- also called the seizure focus -- in about 20% to 30% of people with epilepsy that do not improve after taking medication (intractable or refractory epilepsy). It is not known for certain if the lesion itself triggers the seizures, or if the seizures result from irritation to the brain tissue surrounding the lesion. For this reason, surgery may also include the removal of a small rim of brain tissue around the lesion, called lesionectomy plus corticectomy.
Who Is a Candidate for Lesionectomy?
Lesionectomy may be an option for people whose epilepsy is linked to a defined lesion and whose seizures are not controlled by medication. In addition, it must be possible to remove the lesion and surrounding brain tissue without causing damage to areas of the brain responsible for vital functions, such as movement, sensation, language, and memory. There also must be a reasonable chance that the person will benefit from surgery.
What Happens Before a Lesionectomy?
Candidates for lesionectomy undergo an extensive pre-surgery evaluation-including seizure monitoring, electroencephalography (EEG) and magnetic resonance imaging (MRI). These tests help to pinpoint the location of the lesion and confirm that the lesion is the source of the seizures. Another test to assess electrical activity in the brain is EEG-video monitoring, in which video cameras are used to record seizures while the EEG monitors the brain's activity. In some cases, invasive monitoring -- in which electrodes are placed inside the skull over a specific area of the brain -- is also used to further identify the tissue responsible for seizures.