Research investigations of The Functional Neurosurgery Program focus on a variety of treatments for movement-related disorders, pain, and epilepsy. Many of the therapies available through the Program utilize the stereotactic neurosurgical techniques developed at Stanford.
Functional Neurosurgery staff collaborate with scientists in the Neuro-Muscular Clinic within the Department of Neurology and Neurological Sciences, Stanford's Pain Program, the Epilepsy Program and Biomotion Research Group.
Seizure Disorder, also known as epilepsy, is a symptom of disturbed electrical activity in the brain. The nervous system is electrical, with impulses constantly shuttling between billions of neurons (nerve cells) and the parts of the body involved in various activities both voluntary (such as walking) and involuntary (such as breathing). Nerve cells may malfunction, causing the normally smooth-running pattern of electrical activity to be disrupted. The damaged cells "overload," becoming over-excited and giving off too much electricity. The result of this temporary overload is a seizure that causes some of the body's activities to go awry: there's a sudden loss or disturbance of consciousness often in association with motor activity; there's no pain associated with the seizure and usually no long-term after effects. Those whose epilepsy is controlled by medical treatment may experience no seizures at all.
Callosotomy is a surgical procedure in which the some or all of the corpus callosum is divided. The corpus callosum is the major fiber connection between the two halves of the brain. The procedure is primarily used to treat "drop attacks" seizures. Many centers are using a trial of vagal nerve stimulation before performing callosotomies.
Complex partial seizures and the other forms of epilepsy are resistant to medical therapy. In patients who are not candidates for open, traditional resective surgery, a vagal nerve stimulator may be used. This implanted device, attached to the left vagus nerve, has been shown in multiple studies to reduce the seizure frequency and intensity by 50% or more in 30% of the patients nine months after the onset of stimulation. With additional stimulation (i.e., greater than 18 months), 54% of the patients develop a 50% or better reduction in seizure frequency and intensity. The procedure itself takes approximately one and a half hours, and the patients usually go home the next day. The procedure has a very few risk.
Cortical mapping is a technique used to localize both the region of the brain generating seizures as well as areas that are responsible for thought and movement. There are various ways of mapping the brain. Noninvasive systems like fMRI, PET, MEG, SPECT can give a good starting point for localization of seizures and thought processes. However, the detail and resolution needed to plan a surgical resection often requires direct recording from the surface of the brain. To do this, surgeons will place a grid electrode directly on the surface of the brain and then record in the operating room or close up the surgical site and record for some days with the electrodes in place, a so-called phase II recording.
Deep brain stimulation for epilepsy is currently under investigation. Although a number of early trials show promise, it has not yet developed to the point where it may be considered a viable alternative to traditional medical management. In some patients, chronic electrical stimulation through electrodes implanted deep in the brain can relieve some of the major symptoms of Epilepsy and Parkinson's disease. Based on results from about 30 patients, the FDA recently approved deep brain stimulation (DBS) within the thalamus for relief of tremor of Parkinson's disease and also for non-Parkinsonian "essential tremor."
Epilepsy syndromes are frequently described by their symptoms or by where in the brain they originate.
Temporal lobe epilepsy. Temporal lobe epilepsy, or TLE, is the most common epilepsy syndrome with partial seizures. These seizures are often associated with auras. TLE often begins in childhood. Research has shown that repeated temporal lobe seizures can cause a brain structure called the hippocampus to shrink over time. The hippocampus is important for memory and learning. While it may take years of temporal lobe seizures for measurable hippocampal damage to occur, this finding underlines the need to treat TLE early and as effectively as possible.
Accurate diagnosis of the type of epilepsy a person has is crucial for finding an effective treatment. There are many different ways to treat epilepsy. Currently available treatments can control seizures at least some of the time in about 80 percent of people with epilepsy.
Stanford Comprehensive Epilepsy Center (SCEC)
The Stanford Comprehensive Epilepsy Center (SCEC) uses state-of-the-art methods to diagnose and classify seizures and evaluate patients for medical and surgical treatment of epilepsy. Of course, surgery is only considered after extensive evaluation and assessment of the efficacy of other treatments. But if it is required, our neurosurgery team provides up-to-date, safe, and effective surgical solutions.
Stanford neuroscientists are also developing new and better ways to treat epilepsy. In a pilot study (published in Epilepsia) conducted by a team that includes Dr. Robert Fisher (Stanford Department of Neurology and Neurological Sciences), five patients with intractable partial epilepsy were treated with intermittent electrical stimulation of the anterior nucleus of the thalamus using deep brain stimulation (DBS) electrodes developed by Medtronic, Inc. Four of the patients showed clinically significant reductions in the severity of their seizures, and all the patients tolerated the surgery of stimulation procedure without ill effects. Although these results are preliminary, they indicate that DBS of the anterior nucleus is a promising treatment modality for intractable epilepsy.