Surgery: Can this be a cure for Epilepsy?
In the previous two articles, we have discussed patients with intractable epilepsy who have benefited from epilepsy surgery to remove or disconnect the area of the brain that propagates their seizures. Another group of people who may benefit from epilepsy surgery is those who have generalized seizures - seizures where there is no clear onset in the brain. These children may also have severe developmental delays, worsened by years of seizures. These children are the ones who can benefit from corpus callosotomies or vagal nerve stimulators. In patients who suffer from disabling drop attacks (atonic seizures) where the onset of the seizure activity cannot be localized to one area or one hemisphere, another surgical procedure may be used to prevent the spread of the seizure activity. The corpus callosum is divided in a one-stage operation. While seizure freedom is not as common with this form of surgery, as with focal epilepsy surgery, there are several advantages.
At the American Epilepsy Society Meeting in 2008, we presented a series of 22 children who underwent this procedure over the last four years, and showed that all patients have had a significant reduction in seizure frequency, severity, and the ability to decrease seizure medications and their side effects with very minimal morbidity. Moreover, several of these patients have gone on to have more clearly defined epilepsy: what was thought to be generalized epilepsy became clearly focal once the rapid spread from one hemisphere to another across the corpus callosum was interrupted. These children then returned for staged epilepsy surgery, where grids and strips were used to define their epileptogenic zones, and the seizure focus was removed with better seizure control, improvement in cognitive and motor skills, and a brighter future.
Neurostimulation is being used with varying results. Techniques include vagus nerve stimulation. Vagus nerve stimulation is used for cases where a focal lesion or focal epilepsy cannot be established. In this procedure, the stimulator (or pacemaker) is placed in the chest through a small incision near the armpit. A second incision is made in the neck to wrap a wire around the vagus nerve. The entire unit is then periodically programmed to send electrical currents that can minimize the severity and frequency of seizures. A special magnet can be used to send additional electricity to stop seizures when they occur.
An eight-year-old boy had a history of tuberous sclerosis and autism. Tuberous sclerosis is one of the neurocutaneous diseases involving skin, brain, kidney and heart abnormalities in the form of abnormal tubers. These tubers can grow in the brain, causing seizures. Another abnormality commonly found in tuberous sclerosis is giant cell astrocytomas (brain tumors). With these children, it is imperative to decide whether the seizures are focal (and coming from a tuber or the surrounding area) or generalized. This child underwent resection of a tuber that was believed to be causing his seizures, but his seizures then became generalized. A vagal nerve stimulator was placed, and caused some reduction in seizures. After several years, it became apparent that his very frequent yet subtle seizures were rapidly generalizing and causing him to plateau in terms of his acquisition of social and academic skills. He was eating less and less and becoming more and more aggressive. After video EEG monitoring, a corpus callosotomy was performed. His disabling drop attacks have really lessened in frequency and his social and academic skills have soared. His aggressive outbursts have almost disappeared.