Pediatric Epilepsy Surgery (cont.)
Norberto Alvarez, MD
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
In this Article
The corpus callosum is a structure composed of nerve fibers that allows for communication between both sides of the brain. Corpus callosotomy consist of cutting the corpus callosum. In partial callosotomy, one section of the corpus callosum is cut, whereas in total callosotomy the whole length of the corpus callosum is cut. Since the fibers that go from one half of the brain to the other half are cut, the communication between the two halves of the brain is impaired. This is precisely the goal of the callosotomy. By limiting the communication between the two sides of the brain the callosotomy prevents the rapid spreading of the epileptic event from one half of the brain to the other.
The indication for this operation is rather limited, mostly to children who have frequent drop attacks, and at the present time is not frequently performed.
Vagus nerve stimulator (VNS)
The vagus nerve is a nerve that connects the brain with several internal organs such as the lungs, heart, stomach, and other organs. Stimulation of the vagus nerve sends information to the brain. Studies have shown that electrical stimulation of the vagus nerve results in an inhibition of seizure activity. However, the reasons for this improvement are not clear.
The vagus nerve stimulator (VNS) is a device that consists of a wire attached to an electrical stimulator. The wire is wrapped around the left vagus nerve in the neck, and the electrical stimulator is implanted in a pouch under the skin in the upper chest. The stimulator is programmed to send electrical signals continuously. The strength and the frequency of the electrical stimulation is adjusted as needed by professionals with special training in this technique. Additionally, the system has a magnetic hand-held device that can be used by the patient. Patients who can recognize the beginning of their seizures, for example those who have auras, can use this device to activate the system and abort the seizure. Also, since the stimulator can be activated at any time, if needed, it could be useful to shorten long-lasting seizures and also in the prevention of status epilepticus.
VNS seems to be effective in a variety of seizure disorders and epileptic syndromes. It has also proven to be effective in epileptic disorders that are resistant to antiepileptic treatment. Studies show that in many individuals with refractory seizures, VNS significantly reduced seizure activity, and some people have been rendered seizure-free.
VNS is indicated in children with epileptic disorders resistant to medication that are not candidates for surgery.
In the USA, VNS is approved for children older than 12 years of age; however, there is no age limit in the European Union.
What are the risks of VNS implantation?
Potential side effects of VNS implantation are those from general anesthesia, the failure of the implant to work and infection at the implant site. Additionally, stimulation of the vagus nerve may cause hoarseness, coughing, and may even change the heart rate. Because the VNS is implanted outside the skull, there is little possibility of additional neurological damage.
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