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.
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 couldnt 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.
B. Fountain, M.D., associate professor of neurology and the programs
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
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 persons
movements, sensations or awareness for a short time. Correctly diagnosing
the site of seizure origin can be complex, but is critical to determining
Only Hope for Some
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.
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.
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 seizures clinical presentation
is misleading, suggesting that its onset is generalized when actually
it is focal, and potentially suitable for resective surgery."
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 patients 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.
Surgery: Evidence-Based Medicine
Surgery: Evidence-Based Medicine
Nathan Fountain, M.D., believes that lack of physician understanding
is the biggest barrier to people with intractable epilepsy
investigating surgical treatment. Says Fountain, "Many
neurologists dont realize that the efficacy of epilepsy
surgery has been proven." A landmark trial * conducted
in 2001 compared epilepsy surgery to treatment with antiepileptic
drugs (AEDs). The study followed 80 patients with temporal
lobe epilepsy. Half were immediately evaluated for surgery,
of which 36 went on for resective surgery.
other half continued AEDs. One year later, 58 percent of the
40 patients randomized to be evaluated for surgery were free
from disabling seizures compared to 8 percent of the 40 patients
who were not evaluated.
study demonstrates that not only is surgery effective, but
that the evaluation is effective," says Fountain, who
advises that people with intractable epilepsy seek evaluation
early in the course of their disease. "The mean duration
of epilepsy before surgery is approximately 20 years,"
he says, "which is unfortunate given the debilitating
psychosocial issues that commonly accompany this chronic disease."
He adds that resective surgery is highly cost-effective.
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.
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.
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.
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.
any temporal lobe surgery, a Wada test is performed to determine
whether the patients 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.
of Seizure Focus
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."
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
must go through the Comprehensive Epilepsy Program to be considered
for surgical treatment. Fountain notes that the programs 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,