Jefferson researchers find timing of post-epilepsy surgery seizures predicts outcome

04/11/05

Timing often matters when it comes to epileptic seizures that can occur after surgery designed to stop them. A multicenter study led by researchers at Jefferson Medical College has found that patients who had an initial seizure within the first four months of surgery were less likely to do as well in the long term as those individuals who did not.

"A patient has surgery to remove some brain tissue, hoping to cure his epilepsy, and has a seizure a week or a month or a year later, and wonders, 'What does this mean? Has surgery failed?'" says Daniel H. Parish, a second-year medical student at Jefferson Medical College of Thomas Jefferson University in Philadelphia, who is the lead author of the report. "We wanted to know if the timing of seizures after surgery was related to long-term outcome." He reports the study findings April 13, 2005 at the annual meeting of the American Academy of Neurology in Miami Beach.

Mr. Parish, Michael R. Sperling, M.D., Baldwin Keyes Professor of Neurology at Jefferson Medical College of Thomas Jefferson University and director of the Jefferson Comprehensive Epilepsy Center, and their colleagues at six other medical centers studied 387 patients who had epilepsy surgery, following these patients for an average of 4.4 years. Although about two-thirds of patients experienced at least one seizure some time after surgery, a similar percentage ultimately stopped having seizures.

They broke down patients into five groups: those who had seizures within one month of surgery, one month to four months, four months to one year, one year to three years, and after three years post-surgery, asking if the length of time to the first seizure mattered to the individual's prognosis.

"The evidence shows that having the first seizure within the first four months bodes worse for prognosis," Mr. Parish says.

"If the person had his first seizure in say two months post-surgery, there is a reduced chance he will remain free of seizures for the long term," he says. "If someone doesn't have the first seizure until six months, chances are that person may have a seizure or two, but ultimately will become seizure-free. The longer a person is seizure-free after surgery, the better."

The findings make sense, he says. "If not enough tissue was taken out, it is going to happen sooner rather than later." There is also a known "running down" phenomenon in which in some cases the epileptic brain eventually loses the ability to have seizures.

These results, if confirmed, "May help predict the long-term success of surgery and help the patient's peace of mind," he notes.

"While seizures in the first few months indicate a worse prognosis, many patients still do well in the long run," says Dr. Sperling, noting that experiencing a seizure after surgery doesn't mean that surgery wasn't successful. However, early seizures might prompt physicians to do additional testing and consider further surgery.

"Having seizures after surgery is not the end of the game," Mr. Parish adds.

They plan to further analyze the results, and break down the various types of seizures they found – grand mal or general tonic-clonic and partial tonic seizures – to see if the kind of seizure matters as well to how well patients do.

The study involved seven medical centers participating in the Multicenter Study of Epilepsy Surgery. These include Yale University, the University of Rochester, Columbia University, Montefiore Medical Center, New York University and the Minnesota Comprehensive Epilepsy Program.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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