Epilepsy surgery is undertaken in drug-resistant epilepsy in order to achieve control of seizures and to improve quality of life.
Who Is a Candidate for Surgery?
Approximately 5–10% of patients with epilepsy are candidates for surgery. Detailed investigations are carried out beforehand in order to establish a surgical plan specific to the patient.
Surgical Procedures
The procedures most frequently used in the surgical treatment of epilepsy are summarized below.
- SEEG (Stereoelectroencephalography) — Placement of Depth Electrodes
- Where the seizure focus cannot be localized precisely by EEG, electrodes are placed at predetermined targets using a neuronavigation system.
- Temporal Lobe Resection (Temporal Lobectomy)
- An operation in which the anterior temporal lobe — including the amygdala and the hippocampus — is removed. The temporal lobe is a frequent source of complex partial seizures. Temporal lobectomy is among the commonest operations in epilepsy surgery and yields good results: seizure control in the short and medium term has been reported at around 80% in patients undergoing this procedure.
- Vagus Nerve Stimulation (VNS)
- May be used where the seizure focus cannot be localized clearly, or where there is more than one focus. The vagus nerve lies close to the vessels of the neck; stimulation of this nerve has been reported in the literature to reduce the frequency of seizures.
- Extratemporal Resection
- The region giving rise to the seizures is removed from the frontal, parietal or occipital lobe.
- Resection of a Focal Structural Lesion
- Abnormal or pathological areas within the brain — a tumor, a vascular malformation or cortical dysplasia, for example — are removed. Depending upon the type and site of the pathology, this procedure is highly successful in bringing the seizures under control.
Results
Published data indicate that in approximately 70% of patients who undergo epilepsy surgery, seizures are controlled or their frequency is substantially reduced. Surgery thus improves these patients’ quality of life.
Although some patients continue to require medical treatment indefinitely, the number, frequency and dose of the drugs they take are observed to fall.