Surgical Treatment Options for Epilepsy

The Pediatric Epilepsy Program at C.S. Mott Children’s Hospital offers the full spectrum of surgical options, including implantation of neurostimulation devices, disconnection of certain parts of the brain, and removal or ablation of brain tissue causing seizures. With this wide range of treatment options and major advancements in neurodiagnostic procedures and technologies, surgery is no longer reserved only for those with a single, well-defined seizure focus. Surgical therapies can now be considered for children with poorly defined epileptogenic zones, multifocal epilepsy, seizures arising from deep structures in the brain, and even generalized epilepsy. In short, most people with epilepsy who continue to have seizures despite treatment can be evaluated for surgical treatment options.

Additionally, the minimum age at which various surgical treatments can be considered has been steadily decreasing. This is an important trend because surgery earlier in life has the potential to prevent more days of seizures and other negative impacts of epilepsy than surgery later in life. Early surgery can also take advantage of increased brain plasticity in childhood. Brain plasticity refers to the brain’s ability to reorganize itself in response to the changes that may occur as a result of surgery. Overall, if your child needs epilepsy surgery, the earlier they are evaluated, the better we can help.

Getting Started

If your child’s seizures are not fully controlled after two medication trials, this is generally referred to as drug-resistant, refractory, or intractable epilepsy. While it is still possible to attain complete seizure freedom through continued medication trials, research has shown that the chances of seizure freedom are significantly higher if other epilepsy treatments are also used. This includes ketogenic dietary therapies and surgical treatments.

The first step is to talk with your neurologist about these options and the potential risks and benefits of each for your child. This discussion then continues with an epileptologist who specializes in epilepsy surgery. If you decide to further explore surgical therapies, we will refer you to our Epilepsy Surgery Clinic. Here you will meet with a team that includes epileptologists, a neurosurgeon and a social worker to discuss your goals and available options. In development of a presurgical evaluation plan, the team will consider these and other factors:

  • Your child’s current seizure control and quality of life
  • Existing neuroimaging and EEG data
  • Your child’s epilepsy syndrome or type of epilepsy
  • Your child’s age and weight
  • Your child’s mental health and cognitive functioning
  • Other health conditions that may impact or be impacted by surgery
  • Your level of risk tolerance
  • Your family, social, and environmental supports and barriers
  • Your child’s ability to participate in certain presurgical tests and procedures

This initial discussion often helps to narrow down the treatment options to consider and the presurgical tests and procedures your child will need. After this appointment, you may end up not pursuing surgery any further, you may decide to try vagus nerve stimulation (which does not require extensive presurgical evaluation), or you may start scheduling the various tests and procedures involved in presurgical evaluation.

Presurgical Evaluation

Based on your Epilepsy Surgery Clinic appointment, our team puts together a presurgical evaluation plan that typically involves multiple diagnostic tests and procedures that will take place over several months. Guided by your goals, and what the team already knows about your child’s epilepsy, the plan will include a series of possible tests in a particular sequence. After each test, our team will have more information about the nature of your child’s epilepsy and will decide which additional tests are needed. Our goal is to obtain precise information on where the seizures are coming from and how various surgical options might impact functioning. We try to reach this goal using as few tests as possible. The following are some of the tests your child may need (not every child needs every test):

Tests that are almost always needed

  • Video EEG monitoring – admission to the hospital, usually for 1 – 7 days, to record your child’s typical seizures and identify where they are coming from
  • Epilepsy Protocol Brain MRI – imaging test that looks for structural abnormalities often known to cause seizures
  • Neuropsychological testing – a full day of testing to assess cognitive abilities like memory, attention, language and intelligence; results can provide clues as to where seizures are starting, as well as a baseline measure to compare with testing done after surgery
  • Speech and language evaluation – tests similar to neuropsychological evaluation that focus specifically on speech and language

Tests that are often needed

  • SPECT Scan (Single Photon Emission Computed Tomography) – an imaging test, combined with video EEG monitoring, that shows how blood flow in the brain is affected during and between seizures
  • PET Scan (Positron Emission Tomography) – an imaging test that looks at the brain’s metabolism of glucose; areas of the brain where seizures start often have slower metabolism

Tests that are sometimes needed

  • MEG Scan (Magnetoencephalography) – a test that helps identify where seizures are starting by measuring the magnetic fields created by the brain’s electrical activity; often combined with EEG and MRI to create a detailed map of brain structure and activity
  • Functional MRI – a special type of MRI that looks for areas of increased blood flow in the brain that show up when your child is asked to perform certain tasks; this helps identify which parts of the brain control which functions
  • Wada Test – a test where one side of the brain is put to sleep while an EEG is recorded; your child performs tasks to assess language and memory, and the test shows which side of the brain controls these functions
  • Intracranial EEG Monitoring and Stereotactic EEG (SEEG) – surgical procedures done to find out exactly where seizures are starting and map important functions like speech and movement; the surgery can either involve placing a grid or strips of electrodes on the surface of the brain or inserting depth electrodes into the brain (SEEG); your child is monitored until functions are mapped and enough seizures are recorded, and then a second surgery is done to remove the electrodes

Surgical Treatment Options

During the presurgical evaluation process, your child’s case will be presented and discussed at our Refractory Epilepsy Conference. During this meeting, a large multidisciplinary team, including both pediatric and adult providers, discusses your child’s epilepsy and overall health, test results and possible surgical options. In some cases, consensus will be reached about one or more specific treatment options to discuss with your family. In other cases, additional testing is recommended, and the case may be re-presented after those results are obtained. The team includes epileptologists, neurosurgeons, nurse practitioners, neuropsychologists, speech language pathologists, neuroradiologists, social workers, and others. Together, the team carefully considers and discusses available data to arrive upon their recommendations – all with the health and safety of your child in mind.

The following are the most common surgical therapies that are considered for children with epilepsy:

Neurostimluation Therapies

Also referred to as neuromodulation therapies, there are currently three implantable devices available to treat epilepsy. Each device uses mild electrical stimulation to disrupt the electrical activity that occurs during seizures and gradually change this activity over time. The differences between the devices relate to how and where they are implanted, how and when they provide stimulation, and which parts of the brain they can target.

  • Vagus Nerve Stimulation (VNS) – VNS is the least invasive surgical therapy for epilepsy, as it does not involve any surgery in the brain, and the patient is discharged on the same or next day. A pulse generator is implanted under the skin below the collarbone. This connects to a lead that wraps around the vagus nerve in the neck. The VNS sends stimulation to the brain via the vagus nerve for about 20 – 30 seconds every five minutes or so throughout the day. People with focal, multifocal and generalized epilepsies can potentially benefit from VNS, and extensive presurgical evaluation is not needed. In addition to the ongoing, periodic stimulation, VNS offers on-demand stimulation that can delivered by your child or caregiver using a magnet. There’s also an optional autostimulation feature, where the VNS is triggered by a sudden heartrate increase (a common sign of a seizure).
  • Deep Brain Stimulation (DBS) – Like VNS, DBS provides ongoing, periodic stimulation to the brain without needing to know exactly where the seizure focus is. An additional similarity is that it can be used for children with focal, multifocal and generalized epilepsies. The key differences are that DBS does involve surgery to the brain, and it targets a specific region of the brain called the thalamus. Based on presurgical evaluation, two leads are inserted through small holes in the skull into the specific part of this deep brain structure that is thought to be most involved in the child’s seizures. These leads are connected to a neurostimulator and implanted under the skin in the chest. In addition to periodic stimulation, the device can also deliver on-demand stimulation and record electrical activity in this region of the brain.
  • Responsive Neurostimulation (RNS) – Unlike VNS and DBS, RNS provides direct stimulation to the seizure focus or foci, and it only does so when the early electrical signs of a seizure are detected. It is currently used in focal and multifocal epilepsies; however, Michigan Medicine is a participating site in a clinical trial to study its safety and effectiveness in generalized epilepsies, using thalamic stimulation. With RNS, a neurostimulator device is embedded in the skull, and up to four electrode strips or depth electrodes are implanted at the seizure foci (only two of which can be connected to the neurostimulator). The device constantly records the electrical activity in the targeted areas and delivers stimulation directly to them when seizure or pre-seizure activity is detected. The timing of this stimulation can be adjusted based on analysis of the recordings.

Most people who use neurostimulation therapies do not become seizure free; however, some do, and the majority see significant reduction in seizure frequency. Many also experience reductions in seizure duration, severity or recovery time. Additionally, seizure reduction with these therapies tends to improve over time.  

Disconnection Surgeries

In some cases, surgery can prevent the rapid spread of a seizure through the brain by severing a connection that aids in this spread. In other cases, part of the brain that is causing seizures and functioning poorly can be disconnected from the rest of the brain. There are two main types of disconnection surgeries:

  • Corpus Callosotomy – By cutting all or some of the fibers in a part of the brain called the corpus callosum, which is the main connector between the two sides of the brain, this surgery can be very effective in reducing or eliminating atonic seizures (also known as drop seizures). While other seizure types may also be reduced, most children continue to have some seizures. Avoiding atonic seizures, however, can greatly reduce the risk of injury and improve quality of life.
  • Functional Hemispherectomy – In certain types of epilepsy, one hemisphere of the brain doesn’t work very well, causing weakness or paralysis on one side of the body. If this side of the brain also causes all or most of the child’s seizures, disconnecting this hemisphere from the rest of the brain often eliminates seizures. Cognitive function often improves as well. Some children may experience a temporary worsening of weakness and paralysis on one side, but this rarely persists.

Resection Surgeries

If your child has a single, accessible seizure focus that can be safely removed without affecting important functions, resection surgery may be an option. For many children, resection offers the greatest chance of long-term seizure freedom. The amount of brain tissue removed depends on the location of the seizure focus, how large the network of neurons involved in seizures is, and how precisely the seizure focus has been localized. Typically, but not always, surgeries in the temporal lobe are more likely to result in seizure freedom than those outside of the temporal lobe. Additionally, if a lesion (a specific area of abnormal brain tissue) is present and responsible for your child’s seizures, the chances of seizure freedom after surgery are higher than if no lesion is found.

Laser Interstitial Thermal Therapy (LITT)

Also known as stereotactic laser ablation, LITT is less invasive than resection surgery. Instead of removing a section of skull and cutting into the brain, a small hole is drilled through the skull, and a thin tube with a laser probe is inserted into the brain to reach the seizure focus. Guided in real time by MRI, the laser applies heat to precisely destroy the targeted area of the brain causing seizures. Patients are typically discharged from the hospital in just a day or two. 

All of these surgical therapies come with risks of side effects, changes in brain function and surgical complications. These risks are generally low, but they are important to discuss with your epilepsy care team. It is also important to consider the risks of continued seizures. Careful presurgical evaluation and group discussion by our multidisciplinary epilepsy team helps to minimize risk and maximize post-surgical quality of life.  

Additional Resources

Take the Next Step

Schedule an appointment by calling 734-936-4179.