Mesial temporal sclerosis (MTS) is the most common surgery performed for epilepsy. The development of stereotactic depth electrode electroencephalography (EEG) and other intracranial recording techniques has increased the number of patients who can benefit from this type of surgery. The experts at Cedars-Sinai do their utmost to ensure that the risk of learning, memory and language disturbance is minimized. Many patients following successful surgery are able to lead normal lives with the ability to drive and be gainfully employed, as well as experience an improved quality of life.
After lobectomy, 65 to 85 percent of patients are seizure free, more than 90 percent significantly improve (infrequent seizures, shorter seizures), and less than 5 percent have no change in seizures. Seizure-free outcomes are most common when a localized abnormality is found, although many patients often continue to use anti-convulsants after surgery.
Over the past two decades there have been developments in the surgical management of patients with neocortical epilepsy. Newer imaging techniques such as high resolution MRI, Ictal SPECT and MEG have allowed physicians to localize or determine the precise origin of seizures in many patients. If studies point to a specific area of the brain, a patient may be considered a surgical candidate. Such patients may require invasive monitoring. After surgery, seizure-free rates in these patients are closer to 40 percent to 50 percent but many patients have been helped by extra-temporal resections, with more than 70 percent experiencing a large reduction in the number and/or intensity of seizures.
Hemispherectomy is a surgery in which one half of the brain is removed. A hemispherectomy is usually performed on young patients with severe hemispheric lesions, or older patients that suffered a large brian injury during childhood, since the other side of the brain can take over the functions from the part of the brain that is removed. Although radical, this operation may be effective in eliminating seizures with relatively low risks.
A corpus callosotomy is less commonly done than other surgical treatments for epilepsy. A corpus callosotomy is performed for drop attacks when patients have mixed seizure disorders or if seizures have many sources or origins. A corpus callosotomy surgically separates the left and right hemispheres and therefore eliminates rapid transmissions from one side of the brain to the other. Most patients undergoing corpus callosotomy have some degree of developmental delay. Corpus callosotomy does not usually stop all types of seizures, but may stop drop attacks that can be very harmful.
Multiple sub-pial transections are performed when seizures originate from the language or motor cortex, or from several areas of the brain. The procedure surgically separates small areas of brain tissue. It is also performed when seizures originate from areas too close to the functional cortex. In many cases, this procedure lessens the severity and frequency of seizures.
Vagus Nerve Stimulation (VNS) is a supplementary treatment for certain types of intractable epilepsy and clinical depression. VNS uses a stimulator that sends electric impulses to the left vagus nerve in the neck via electrodes implanted under the skin. This procedure has proven to be effective in certain patients who have not responded to other treatments. The surgery may be done on an outpatient basis, and the battery also can be changed without requiring a hospital stay.
A responsive neurostimulation device or RNS system is a responsive direct brain stimulation treatment for adults with medically refractory epilepsy. The RNS system utilizes a neurostimulator implanted in the skull with one or two leads implanted in the brain at the focal points of the seizures.