Lasting Freedom from Seizures
Less than five percent of epilepsy patients can expect freedom from seizures through medication after they’ve tried a few unsuccessful anti-seizure drugs. By contrast, surgery for many types of epilepsy can help well over 70 percent of those patients achieve complete seizure freedom—and even more will be either seizure-free or significantly improved. Yet, surgery is under-utilized.
At WVU’s Epilepsy Center, we’ve found that patients suffer with medically intractable (difficult to control) seizures for 24 years before they have surgery, which is typical of national figures. But for most patients, we can determine if their epilepsy is difficult to treat within just a few years of seizure onset and through trials of two or three standard anti-seizure drugs.
Patients with persisting and disabling seizures have less chance for a long and healthy life. However, according to one large study (Sperling et al. JAMA. 1996), patients who become seizure-free as a result of surgery reduce their risk of death and injury to that of the general population. Timely surgical intervention for intractable epilepsy can save lives as well as improve the quality of life.
On average, over 52 surgical procedures for epilepsy are performed per year. Average breakdown:
- 32 craniotomies for epilepsy
- 12 vagus nerve stimulators
- 8 intracranial electrode placements
There are two goals for surgery in treating epilepsy:
GOAL OF THE CURE — Procedures that remove epileptogenic tissue. This surgery seeks to completely eliminate seizures.
GOAL OF PALLIATION — Procedures that interrupt nerve pathways of seizures. The goal of palliation (which means relief) is to decrease the frequency and severity of seizures.
Goal of the Cure
Lesionectomy — Many patients with recurring seizures have small lesions that clearly cause the seizures. A lesionectomy removes those lesions and usually has excellent results.
Temporal lobe surgery — The majority of surgeries involve the temporal lobe of the brain. In a study of our patients, 73 percent were seizure free after temporal lobe surgery, and 96 percent were either seizure free or significantly improved.
Extra-temporal lobe surgery — Surgery for extra-temporal lobe epilepsy is less common than temporal lobe surgery. If no definite lesion is identified, the success rates may not be as high. Despite this, the opportunity for seizure freedom through surgery far exceeds the chance of stopping seizures with medicine alone.
Hemispherectomy — This procedure is most commonly performed in children with severe and widespread epilepsies. Functional hemispherectomy is one of the most successful surgical procedures for treating widespread and catastrophic epilepsy, with the majority of patients able to realize seizure freedom.
Goal of Palliation (relief)
Corpus callosotomy — Sectioning of the corpus callosum may be beneficial for partial seizures. In addition, uncontrolled generalized seizures, especially “drop attacks,” have an excellent chance of being eliminated with this surgery. Anterior 2/3 callosotomy is usually sufficient to stop drop attacks and the most violent generalized convulsions.
Multiple subpial transections (MSTs) — While the most effective treatment for partial seizures has been removal of the seizure focus (location), this is not an appropriate option when that region of the brain performs functions such as speech or sensorimotor tasks. In MST, the surgeon makes parallel cuts through the cortex to permanently disrupt neural networks that may be causing seizure activity.
Vagus Nerve Stimulation — VNS can be used for patients with partial or generalized seizures and who have no opportunity for a curative surgery. The vagus nerve stimulator is implanted under the skin of the chest. A wire from the device runs under the skin and is attached to the vagus nerve in the left side of the neck. The device electrically stimulates the vagus nerve periodically at a rate that is adjustable. The surgery usually requires no overnight stay. With VNS, approximately half of patients can expect a 50 percent or greater reduction in seizure frequency.