Epilepsy & Seizure Surgical Procedures
Prior to surgical treatment, most patients undergo several stages of evaluation, which include:
- Pre-surgical Evaluation: At this point, many relatively safe and easy tests are performed. Tests may include routine EEGs, MRI, and PET scans. A critical part of the evaluation is video-EEG monitoring, which actually records seizures. It is performed in the hospital setting.
- Neuropsychological Evaluation: Another essential step, this evaluation can usually be done on an outpatient basis.
- Wada Test: This outpatient exam tests the brain for speech and memory function.
- Intracranial Electrode Evaluation: While not necessary for all patients, this more invasive evaluation involves the surgical placement of electrodes to further localize the site of seizure activity.
If testing determines that the seizure focus can be safely removed, surgery is scheduled. Recordings take place in the operating room to confirm the location of the seizure activity.
While the initial treatment for seizure disorders is medication, some patients are unable to control or stop seizures through these methods. In these cases, surgery may be an option. The goal of epilepsy surgery is to improve seizure control but, in many cases, these procedures can completely stop seizures. Specific epilepsy surgeries include:
- Lobectomies: Used to treat partial seizure disorders. This procedure involves removing tissue from the frontal, temporal, parietal, or occipital lobe. Only that small part of the brain that is thought to be damaged and causing seizures is removed. Some parts can be removed safely but since each lobe of the brain performs specific functions minor deficits may occur. It is important for the patient to completely understand the possible deficits that may result from surgery in that area.
- Hemispherectomy: Used to treat partial seizure disorders and occasionally for certain generalized seizure problems. This procedure is usually performed on children with severe, frequent seizures. Of all the surgical procedures, hemispherectomy has the highest success rate in stopping seizures.
- Corpus Callosotomy: Used in the treatment of generalized seizures such as generalized tonic clonic seizures and also atonic seizures commonly called “drop seizures”. This procedure involves disconnecting the fibers between the two halves (hemispheres) of the brain. This procedure is not a cure for epilepsy. However, it may stop or significantly limit the number of “drop seizures” and decrease the chance of injuries commonly caused by these attacks.
As with any surgery, certain risks must be considered when contemplating epilepsy surgery. It is important for patients to discuss these with their doctors before considering this treatment option.
Vagal Nerve Stimulation
The vagal nerve stimulator has been approved by the FDA for use in patients with partial seizure disorders. This device, similar to a pacemaker, is surgically implanted in the patient’s chest wall. Electrodes leading from the device are wrapped around the vagus nerve on the left side of the neck. The vagus nerve is a large nerve in the neck with many connections that lead into the brain.
Stimulating the vagus nerve in the neck has been shown to “break up” seizures actually coming from the brain. After surgery, the patient comes back to the physician’s office to have the stimulator programmed on the computer. The settings on the computer can be changed periodically to deliver a timed stimulus to the vagal nerve to help control seizures.
The side effects most commonly reported with this device are a tingling sensation in the neck and mild hoarseness of the voice during stimulation. These side effects may subside over time. Although this device does not work for everyone, it may offer improved seizure control to some patients without the sedating side effects that medications can cause. You can learn more about Vagal Nerve Stimulation at Cyberonics.