People with severe epilepsy who undergo brain surgery have markedly fewer disabling seizures during the following year than those relying on medication do, a study finds.
Epilepsy patients become candidates for surgery when the effectiveness of their epilepsy medication diminishes greatly. Roughly 400,000 to 600,000 people in the United States have reached such a state, known as intractable epilepsy. The patients usually endure this chronic condition for decades before being referred for surgery, says study coauthor Samuel Wiebe, a neuroscientist at the University of Western Ontario in London, Ont.
At the university’s London Health Sciences Centre, Wiebe and his colleagues randomly assigned 40 patients with intractable epilepsy to undergo surgery and continue receiving epilepsy medication. Forty others got medicine only.
Four of those slated for surgery either refused or were excluded for medical reasons. Of the 36 who had surgery, 23 had no disabling seizures during the following year, and 15 remained free of all seizures during that time. In comparison, only three people in the medication-only group remained free of disabling seizures during the year, and only one remained free of all seizures, the team reports in the Aug. 2 New England Journal of Medicine.
A disabling seizure causes the patient to lose awareness of his or her surroundings. During these attacks, patients may have convulsions or assume a motionless stare, sometimes handling objects over and over, smacking their lips, or even undressing unwittingly, Wiebe says. Lesser seizures, which patients detect without loss of control over their bodies, include such sensations as nausea, strange fear, and déj vu, as well as a false perception of smells.
In these patients, seizures result from damage to the brain area called the cerebral temporal lobe. Electrical impulses generated by the trouble spot send aberrant signals that cause nerve cells to misfire.
Before performing epilepsy surgery, physicians conduct tests to determine whether the side of the brain opposite the spot that causes epilepsy is compensating for the damaged area. Only then do surgeons remove the damaged part.
Since the temporal lobe has roles in learning, memory, olfactory perception, and choosing thoughts to express, the surgery carries risks, Wiebe says. Some people find it hard to learn and retain new information after the operation, he says. In his study, 2 of the 36 surgery patients encountered memory problems.
The new study is the first randomized trial comparing surgery with medication for intractable epilepsy, says neurologist Jerome Engel Jr. of the University of California, Los Angeles. To validate the finding, scientists need to do a large, multi-center trial of patients with intractable epilepsy.
People with uncontrolled epilepsy can’t drive and often don’t marry or develop social skills necessary for a normal life, Engel says. Surgery might change this pattern for young people. Within 2 years after physicians establish that medications don’t alleviate a person’s seizures, that patient should become a candidate for surgery–before his or her life is permanently affected, Engel says.
Although every year in the United States roughly 3,000 people with severe epilepsy undergo brain surgery to alleviate seizures, tens of thousands either are never offered the procedure or refuse it, Engel estimates.
“What’s amazing is the number of operations that aren’t done,” Wiebe says.
Physicians have shied away from surgery because of its invasive nature and initial expense. However, if surgery eliminates seizures and the need for expensive medication, the money saved exceeds the cost of the surgical procedure within a decade, he says.