Epilepsy surgery: an evidence summary

The Medical Advisory Secretariat, the predecessor of Health Quality Ontario, published an evidence-based analysis on functional brain imaging. This analysis highlighted the low uptake of epilepsy surgery in Ontario and internationally.

The objective of this analysis was to review the effectiveness of epilepsy surgery at reducing seizure frequency, as well as the safety of epilepsy surgery.

The literature search included studies published between January 1995 and March 2012. Search terms included epilepsy, surgery, resection, safety, and complications.

Studies were eligible for inclusion if they included at least 20 patients undergoing surgery; had a comparison group of patients with epilepsy who were not undergoing surgery; and reported follow-up periods of at least 1 year. Outcomes of interest included seizure frequency and complications associated with surgery.

Six systematic reviews reported pooled seizure-free rates that ranged from 43% to 75%. Two randomized controlled trials compared the effectiveness of epilepsy surgery with no surgery in patients with drug-refractory epilepsy. Both trials reported significant improvements in the seizure frequency in the surgery group compared with the nonsurgery group. Eight retrospective cohort studies reported on the safety of epilepsy surgery. Of the 2,725 patients included in these studies, there were 3 deaths reportedly related to surgery. Other complications included hemiparesis, infection, and visual field defects. The studies had long follow-up periods ranging from a mean of 2 to 7 years.

The most recent randomized controlled trial was stopped early due to slow enrolment rates. Thus results need to be interpreted with caution.

There is high quality evidence that epilepsy surgery is effective at reducing seizure frequency. Two randomized controlled trials compared surgery to no surgery in patients with drug-refractory epilepsy. Both demonstrated significant reductions in seizure frequency. There are some complications associated with epilepsy surgery. In the published literature identified, we observed a 0.1% mortality rate associated with the surgery.