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.
While the efficacy of this sort of approach is not traditionally as satisfying as focal epilepsy surgery, it is a useful tool in certain populations of children with epilepsy. In general, about a third of the patients who have a vagus nerve stimulator placed experience a significant reduction in seizure frequency and severity, and medication regimens can be significantly decreased. The natural appeal of such an approach, as any parent can imagine, is that the procedure is reversible: the stimulator (but not the wires) can be removed if the treatment is not effective, with no significant long term consequences.
Optimizing targets and parameters for neurostimulation to control epilepsy will be the focus of our research efforts to offer even safer and more attractive options to treat epilepsy in the future.•
In the previous case, a child underwent a focal resection before undergoing a corpus callosotomy. In this case, of a 19-year-old with autism and severe developmental delays, the procedures were reversed. She was initially diagnosed with infantile spasms as a baby. (Infantile spasms are a severe form of epilepsy occurring in infants 3-9 months old.) She went on to fail many different medications and became increasingly distant, with loss of her limited language and previously acquired skills. After she was accepted in a residential setting, she began to experience disabling drop attacks, causing her to wear a helmet. After a video EEG and MRI, it was determined that a corpus callosotomy was indicated. She underwent the procedure and her drop attacks stopped but she began to exhibit partial or focal seizures, with her head turning to the right, speech arrest and staring. She was reevaluated and the video EEG showed focal onset of her complex partial seizures. Grids and strips were implanted on the right side of her brain, seizure onset and epilpetogenic zone were delineated, and a right frontal disconnection was performed. Although she underwent four surgeries in total (including placement of a vagal nerve stimulator) and remains on medication, the family and the personnel at her school report increased language, better eye contact and a happier young woman, with a big decrease in seizure frequency and severity.
As with all surgical procedures, epilepsy surgery carries with it a small risk of infection as well as bleeding. The length of recovery varies from person to person but most children and young people recover quickly, spending 1-3 weeks in the hospital and resuming their usual activities within a month of hospital discharge. Again, the most important thing to remember is that epilepsy surgery is a safe and efficacious treatment for refractory patients. It is appropriate even in the setting of severe developmental delays, widespread areas of abnormality and neurocutaneous syndromes. Results must be measured in improvement in quality of life and not just in seizure freedom. The courageous children and parents who embark upon this strategy in search of a better quality of life, independence, and freedom from disabling seizures and their medications must be cared for by a team of trained and experienced professionals, with careful deliberation and testing both before, during, and after the procedure.
WebMD Feature from “Exceptional Parent” Magazine