A study of ten years of patient outcomes shows that surgery is not only effective, but the preferred treatment for select epilepsy patients. In the most comprehensive study of long-term surgery success rates, Mayo Clinic physicians report that 73 percent of 491 Mayo Clinic patients were either seizure-free or experienced seizures only when medication was discontinued.
The study included epilepsy surgical outcomes between 1988 and 1998. Patient follow-up reports ranged from one to 14 years, with an average length of six years. Results will be presented April 27 at the American Academy of Neurology annual meeting in San Francisco by Gregory Cascino, M.D., chair of the Mayo Clinic Division of Epilepsy, Department of Neurology. The study further shows that if seizures occurred following epilepsy surgery, they usually did so in the first year -- and that this first-year recurrence is a reliable indicator of the procedure’s long-term success. The surgery involves removing the epileptic brain tissue, a procedure called a focal cortical resection.
These findings are welcome news for patients with “intractable partial epilepsy.” Thirty to 40 percent of partial epilepsy patients do not respond to medication, and are therefore diagnosed as suffering from intractable epilepsy. “Partial epilepsy” refers to seizures that originate from a specific region of the brain, rather than from both cerebral hemispheres. Partial epilepsy is the most common seizure disorder, affecting over one million patients in the United States and comprising 90 percent of adult epilepsy cases.
“These data strengthen what we’ve long suspected, that is, that individuals with intractable partial epilepsy should be referred as early as possible in the course of treatment to comprehensive epilepsy centers for consideration of surgery,” says Dr. Cascino.
Significance of the Mayo Clinic Findings
Intractable partial epilepsy has long been regarded as especially disabling. By some estimates, intractable partial epilepsy costs individuals and society $12 billion annually for medical treatment, lost wages, psychosocial disturbances and related medical conditions.
“Most patients with intractable partial seizures that originate in the temporal lobe experience two to four seizures a month,” explains Dr. Cascino. “However, even one seizure per month may radically and negatively affect a person’s quality of life — so any new relief we can offer patients is a real gain. Our data suggest that surgical treatments, in some cases, are more effective in reducing seizure activity than other forms of therapy, and that’s really great news.”
About Partial Epilepsy
Partial epilepsy is characterized by recurrent seizures produced by abnormal excitability and excessive energy discharge of neurons in the brain. These disturbances may be biochemical, and/or consist of structural abnormalities, injuries or growths on the brain. The cause of partial epilepsy is not known.
A patient’s early response to anti-epileptic drug medication is highly predictive of its ultimate success as a treatment. Studies show that if a patient’s seizures are not controlled by drugs within five years of diagnosis, medication likely will not prove successful.
About the Mayo Clinic Study
The Mayo Clinic researchers reviewed long-term outcomes of epilepsy surgery in a large group (491 patients) diagnosed with intractable partial epilepsy and treated at Mayo Clinic Rochester. Previous studies by others have followed small groups of patients for one to two years.
The researchers’ objectives were to identify and evaluate preoperative factors that may play a role in producing the best surgical outcomes. This information will help choose candidates best suited for epilepsy surgery. Statistically, positive surgical outcomes are more likely among women, rather than men, and among patients who’ve not had prior surgeries. The procedure is more successful if the patient has seizures that originate in the temporal lobe of the brain.