Evaluation & Surgery for Epilepsy

When a patient has “epilepsy,” this means that the patient has repeated seizures. A seizure is a burst of abnormal electrical activity in the brain (Figure 1). Seizures can cause a wide variety of symptoms depending on where the seizure is happening in the brain.

Figure 1 (Courtesy of WedMD)
Figure 1

Seizures can be small, also termed “partial,” or big, also termed “generalized.” A partial seizure may or may not involve loss of consciousness and generally starts on one side of the brain. Patients may experience difficulty with speech, odd sensations like feeling “disconnected” or “spaced out,” and/or shaking/numbness/weakness on one side of the body. A generalized seizure involves both sides of the brain and may manifest as sudden loss of consciousness with shaking of the both arms and legs. The patient may fall down and become unresponsive or confused for several minutes afterwards.

Many patients with epilepsy are treated successfully with medication only. As long as the patient takes his or her medication(s) regularly as prescribed by the physician, seizures do not occur. Unfortunately up to 30% of patients will continue to have seizures even when taking multiple medications. This group of patients has seizures that are unresponsive or only partially responsive to medication--It is this group of patients who may need surgery to control seizures.

The first step in determining if surgery can help a patient’s seizures is to do an extensive work-up. This work-up may involve the following:

  • Evaluation by a neurologist, a neurosurgeon, and a neuropsychologist
  • Neuroimaging with a CT scan, an MRI scan, and/or a PET scan of the brain
  • Evaluation with an outpatient EEG (electroencephalogram) to determine where in the brain the seizures are starting, also called the “seizure focus”
  • Evaluation with an inpatient video EEG (VEEG), which involves a 2-5 day hospital stay, if the “seizure focus” is not clear or is not identified on the outpatient EEG

There are many surgical options for seizures depending on the type and location of seizure activity. If there is abnormal tissue in the brain that is causing seizures, then this tissue can be resected with open brain surgery or destroyed using Visualase laser therapy to decrease seizures. One common example of this is “mesial temporal sclerosis,” during which seizures come from a diseased area called the hippocampus in the temporal lobe of the brain.

If seizures are coming from several different areas of the brain and/or areas that cannot be resected or destroyed, then the patient may be appropriate for electrical therapy. Electrical therapies include vagal nerve stimulation (VNS) (Figure 2) , thalamic deep brain stimulation (DBS), and responsive neurostimulation (RNS) (Figure 3)

Figure 2 (Courtesy of Cyberonics) Vagal Nerve Stimulator:
Figure 1

Figure 3 (Courtesy of NeuroPace, Inc.) Responsive Neurostimulator:
Figure 1

The general concept of these “pacemaker-like” therapies is that pulsed electricity into the brain decreases the overall excitability of the brain, making it less likely to produce seizures. Seizures are unlikely to stop completely with electrical therapies but can significant reduce in frequency and severity.

Learn more with this PowerPoint presentation courtesy of WebMD.