Jeff Elias, M.D., (left) and Nathan Fountain, M.D., talk with an 11-year-old patient being evaluated and monitoried at UVa's F.E. Dreifuss Comprehensive Epilepsy Program to determine if he is a candidate for surgical resection.

October 13, 2003 -- Sharon Weeks remembers once living her life "always waiting for the next seizure." Just two years ago, Weeks experienced as many as seven seizures a day, so she couldn’t work or drive. Weeks turned to the F.E. Dreifuss Comprehensive Epilepsy Program at UVa Health System, where she was diagnosed with a type of epilepsy suitable for epilepsy surgery. Today, nearly one year since the operation, Weeks is seizure-free.

Nathan B. Fountain, M.D., associate professor of neurology and the program’s director, explains that while Weeks’ case may seem miraculous, recent advances in diagnostic testing, imaging and surgical techniques are safer and more readily available, enabling physicians to identify and remove the source of epilepsy in some patients, essentially curing them.

"Epilepsy is any neurological disease characterized by the spontaneous recurrence of seizures," explains Fountain. Seizures are abnormal bursts of electrical activity in the brain, which may affect a person’s movements, sensations or awareness for a short time. Correctly diagnosing the site of seizure origin can be complex, but is critical to determining appropriate treatment.

Surgery Only Hope for Some

The most commonly performed epilepsy resection surgery is anterior temporal lobectomy (ATL), which involves removing approximately 4 to 5 cm of the temporal lobe (box). At UVa, approximately 74 percent of patients are essentially seizure-free after ATL surgery, and the risk of stroke or other serious complication is less than 1 percent.

Most seizures can be effectively controlled by medication. But one-third of epilepsy patients have intractable epilepsy for which alternative therapies, including surgery, are the only hope for eliminating or reducing the frequency or severity of their seizures. "Intractable is defined as having had seizures for more than one year and having failed adequate trials of two appropriate antiepileptic drugs (AEDs) at the maximum tolerated doses," explains Fountain.

People with intractable, focal-onset seizures are candidates for resection. "Resective surgery removes the site of seizure origin and is the only curative epilepsy therapy yet available," says Fountain, who advises that all people with intractable epilepsy seek surgical evaluation. "Sometimes a seizure’s clinical presentation is misleading, suggesting that its onset is generalized when actually it is focal, and potentially suitable for resective surgery."

Presurgical Evaluation

Inpatient presurgical evaluation is a two- or three-phase process. Simultaneous video and EEG monitoring from the scalp, also called extracranial monitoring, is the most important phase-1 evaluation method. Electrodes attached to the patient’s head record brain waves during and between seizures. "Extracranial monitoring substantiates that the spells in question are actually seizures and reveals the seizure type and probable site of origin," says Fountain, noting that it usually takes several days to capture enough seizures to make a correct diagnosis.

Other phase-1 diagnostic tests include high-resolution MRI, which can detect structural brain diseases such as lesions or scar tissue; positron emission tomography (PET) scan, which may reveal the site of seizure onset by measuring metabolism of glucose and oxygen in the suspected area of origin; and ictal and interictal single-photon emitted computed tomography (SPECT) scans, which may reveal blood flow alterations at the seizure origin site. Neuropsychological testing uses both standardized memory and I.Q. tests and individualized psychological assessment to look for areas of focal deficit.

If phase-1 evaluation pinpoints the seizure origin site, the patient is eligible for resective surgery. If the focal area is not determined, however, or if diagnostic results conflict, the patient may proceed to phase-2 evaluation, which involves intracranial EEG monitoring. Assisted by stereotactic guidance, surgeons position electrodes on the brain surface or into brain tissue to further monitor the seizures and identify their focus.

Temporal Lobe Surgery

"Any area of the brain is a candidate for resection, but the vast majority of patients have temporal lobe epilepsy, in which the seizure arises in the mesial temporal lobe at a small scar, visible only by high-resolution MRI," says Fountain.

Temporal lobe epilepsy occasionally requires invasive monitoring. However, patients with extratemporal seizures typically require more invasive evaluation with intracranial electrodes to pinpoint the site of resection and possibly to map out functional areas to be avoided during resection. Jeffrey Elias, M.D., assistant professor of neurosurgery, may perform the surgery with the patient awake when important brain functions, such as the motor and speech areas, need to be mapped and localized precisely.

"For any temporal lobe surgery, a Wada test is performed to determine whether the patient’s memory and language functions are located in the left or right hemisphere and whether or not the other temporal lobe can support memory after surgery," explains Elias.

Removal of Seizure Focus

Phase three involves removal of the seizure focus. The most commonly performed surgery, anterior temporal lobectomy (ATL), involves removing approximately 4 to 5 cm of the temporal lobe. Explains Elias: "A small incision is made behind the hairline, from which we can remove the anterior tip of the temporal lobe and access the seizure focus deep within the brain. Resecting the seizure focus is the riskiest part, because it is located directly beside the brain stem."

"Approximately 74 percent of patients are essentially seizure-free after undergoing ATL, and the risk of stroke or other serious complication is less than 1 percent," says Fountain. "For those patients who are not seizure-free, about half improve and half stay the same." Patients typically remain on AEDs for up to two years following surgery and have a yearly follow-up. Although extratemporal surgery is more complex, favorable success rates make it an attractive therapy option.

Patients must go through the Comprehensive Epilepsy Program to be considered for surgical treatment. Fountain notes that the program’s emphasis on a multidisciplinary, systematic approach to diagnosing and treating epilepsy, particularly for cases of intractable epilepsy, make it one of a handful of highly specialized epilepsy centers nationwide.

If you have a patient with epilepsy who might be a candidate for evaluation at the F.E. Dreifuss Comprehensive Epilepsy Program, call 434-924-5401.