• Types of Epilepsy Surgery

    A recommendation for your child’s surgery results from a thorough diagnostic evaluation with testing appropriate to the needs of your child. Discussion by the epilepsy surgical team follows every day and every test, with all results reviewed and discussed during the Epilepsy Surgery Conference. Physicians, neuropsychologists, social workers, nursing staff and other medical professionals meet and discuss all of your child’s non-invasive tests to determine whether your child is a candidate for surgical evaluation. If surgery is the best option to treat your child’s epilepsy, consideration must be given to the different types of surgeries that may be appropriate based on your child’s needs.

  • For children who have intractable epileptic “drop attacks” or frequent secondary generalized tonic-clonic seizures, surgical sectioning of the corpus callosum may be beneficial. The corpus callosum is a brain structure that contributes to sharing of information between hemispheres and, consequently, the spread and synchronization of seizure activity as well. With brief but dramatic disruption of normal brain signals that control posture, the child suddenly slumps, falls forward or drops to the ground. “Drop attacks,” caused by myoclonic, tonic or atonic seizures, may result in severe injury to the child. Sectioning the anterior two-thirds or complete corpus callosum stops the spread of seizures from one hemisphere to the other. This procedure has about a 75 percent chance of stopping the “drop” type of epileptic seizure.

    Depth Electrodes
    These electrodes are used to allow for EEG monitoring inside the brain. They are various sized, polyurethane needles that are inserted at specific brain sites using computer and MRI guidance to allow for precise placement in suspected seizure-focus area.

    Subdural Grids
    These light, platinum electrodes on thin, flexible silicon sheets of different sizes are placed on the brain surface by open craniotomy. Location and number / size of grid placement depends on the areas suspected of causing your child’s seizures.

    Subdural Strips
    These strips are used to help determine the hemisphere in which seizures are starting. They are placed through small burr holes, the size of a nickel, in the skull using fluoroscopic guidance. Subdural strips can, additionally, be combined with subdural electrode grids to cover small areas of difficult access.

    Children with severe, intractable epilepsy due to significant brain pathology may be candidates for hemispherectomy or hemispherotomy. This surgery may be recommended when the seizure is widespread or is coming from several different locations in the right or left hemisphere. Half of the brain, either the left or right side, is removed or disconnected from the rest. Surgical removal of the abnormal hemisphere has a 75 percent chance of stopping seizures, and an additional 20 percent of children will have improvement in seizure frequency or severity. Quality of life may be significantly improved.

    If electrodes on the brain surface and subsequent VEEG data and mapping indicate that the seizure area can be located and safely removed, your child may return to the operating room for resection. (To make sure motor, language and memory areas are spared, “mapping” with electrodes, fMRI testing or a  Wada test may be done prior to this decision). During this surgery, the part of the brain cortex responsible for seizure origin is removed. Outcome of resective surgery is individualized for each child, but up to 60 percent of children may have opportunity for complete seizure freedom and additional 10 percent to 20 percent experience meaningful improvement in seizure frequency or severity.

    The vagus nerve stimulator is used as an add-on to medical treatment for partial and generalized seizures, specifically when the child is not obtaining adequate seizure control with drug therapy alone. Using a small stimulator device, implanted just below the child’s left clavicle, and an electrode wire inserted through the neck and attached to the vagus nerve, the VNS acts to stimulate the vagus nerve and exhibit inhibitory effects on the cerebral cortex. The VNS cycles on and off 24 hours a day. A magnet can be “swiped” over the VNS, at the onset or during a seizure, to send an immediate and stronger stimulation of the vagus nerve. Seizures may be reduced significantly in approximately 50 percent to 75 percent of patients. The battery needs replacement after four to 10 years.