In one of the largest studies of surgery for epilepsy ever conducted, researchers have found that almost three-quarters of patients who had surgery for intractable epilepsy were still mainly seizure-free ten years after the operation. They also found that being mainly seizure free one year after the operation was a good indicator for remaining seizure-free in the longer term.

Researchers from the Mayo Clinic in Rochester, Minnesota, USA, analysed the cases of 399 patients with focal epilepsy and seizures that were not successfully controlled by medication. These patients had had surgery for their epilepsy between 1988 and 1996. There were 214 females and 185 males. These patients were on average 32 years old at the time of the operation, and had had seizures for an average of 20 years. Fifty-six percent of patients had complex partial seizures, 30% had generalised seizures, 6% had simple partial seizures, and 4% had a combination of seizure types. Evaluation for surgery included EEG studies, MRI and neuropsychological testing. Most patients (93%) had surgery to the temporal lobe.

Dr A Cohen-Gadol and colleagues found that six months following surgery, 81% of patients were totally seizure-free or only had auras or seizures related to withdrawal from medication. Ten years later, 72% of patients followed up remained totally or nearly seizure-free. Importantly, of the patients who were totally or nearly seizure-free one year after the operation, 92% of them remained so ten years later. Only four percent of patients in this study had medical problems due to the operation itself. Patients who continued to have seizures mostly found that their frequency was significantly reduced.

The authors, in their report published in the April issue of Journal of Neurosurgery, said that seizure type and frequency one year after the operation appeared to be a good indicator of how successful the surgery would be in the long term. Other factors that were associated with poor outcome after surgery included being male, having had previous surgery, and having a seizure focus outside the temporal lobe.

These findings show that surgery for epilepsy surgery is very safe and has a high rate of success in a selected group of patients. Not all epilepsies are treatable by surgery, but surgery is probably still under-used. Importantly, seizure freedom one year after the operation appears to be a good indicator of long-term progress.

Find out more here