Long-term outcome of epilepsy surgery is favorable for many

August 25, 2003

ST. PAUL, MN - The majority of epilepsy patients who are seizure-free for the first year after surgery will have a favorable long-term outcome, according to a study in the August 26 issue of Neurology, the scientific journal of the American Academy of Neurology.

The study examined 175 patients with intractable epilepsy (when the condition is not relieved by medication) who had surgery that removed a small portion of the brain identified as a region involved in seizure generation, and who were seizure-free for the first year following surgery. Researchers followed up with the patients for an average of more than eight years, and found that 63 percent never relapsed (stayed seizure-free).

"Little is known about seizure recurrence in patients five, 10, or 20 years after surgery, and one year isn't enough to follow up a patient who had surgery," said study author and neurologist Susan S. Spencer, MD, of the Yale University School of Medicine, New Haven, Conn. "The number of patients who didn't relapse in this study was larger than we thought it would be."

Among the 65 patients who relapsed, 51 percent had one or fewer seizures per year. A longer seizure-free period indicated that a relapse would be less severe. The remaining patients had more than one seizure per year, and 10 of these patients, who relapsed within four years of surgery, had more than one seizure per month.

Duration of epilepsy before surgery - rather than age at the onset of epilepsy - was a significant factor in predicting seizure freedom, although all patients had a prolonged duration of epilepsy prior to surgery. The group who remained seizure-free had epilepsy for an average of almost 16 years prior to surgery. The group who relapsed had epilepsy for an average of more than 20 years prior to surgery.

In an editorial published in the same issue of Neurology, Edwin Trevathan, MD, MPH, Director of the Pediatric Epilepsy Center at Washington University in St. Louis, Mo., noted that "so few patients in the study had surgery within the first 10 years of their epilepsy that it is not known whether early surgical therapy increased the odds of seizure freedom."

"Surgery has been considered as the last treatment option for patients with intractable epilepsy, but it is clear that surgery should be considered sooner, especially among patients who have failed to achieve seizure freedom without side effects after treatment with a second anti-epileptic drug," said Trevathan.

Patients who had normal brain tissue surgically removed were more likely to relapse than those with abnormal tissue, and the severity of relapse was greater for them also. Seizure freedom is more likely to happen when the tissue removed from the identified brain region is abnormal, Spencer noted.

Other factors noted for increasing relapse risk during follow-up included reduced or discontinued anti-epileptic drugs, illness, fatigue, stress or excessive alcohol intake. Thirteen percent of the group who relapsed were off all anti-epileptic drugs and were seizure-free for at least two years before their first relapse.

Among the patients who remained seizure-free, 24 percent still had auras (warning feelings of impending seizures) at some point after the surgery.

"The fact that auras occurred so often in this group makes one question whether they are a manifestation of the start of a seizure that has not spread farther in the brain - as usually thought - or whether they might have a different physiological basis, like a memory of seizure activity," said Spencer.

Epilepsy is a neurological disorder where abnormal brain activity results in repeated seizures that may involve muscle spasms, loss of consciousness or changes in behavior. More than 2.3 million Americans and 50 million people worldwide have epilepsy.
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The study received financial support from the Office of Student Research at Yale University School of Medicine.

The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, autism and multiple sclerosis.

For more information about the American Academy of Neurology, visit its web site at www.aan.com.

American Academy of Neurology

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