Epilepsy Surgery Works

June 16, 2009
Victor Dostrow

In well selected patients with refractory epilepsy, seizure surgery is a safe and effective treatment option. Sadly, it is also much underused.

About three million people in the US have epilepsy. Almost one-third are not well controlled with medications ("refractory"). In well selected patients in this category, seizure surgery is a safe and effective treatment option. Sadly, it is also much underused. Referral to specialized epilepsy centers for evaluation far lags the cohort of potentially eligible patients. General neurologists and primary care providers are often not well informed about the surgical options for epilepsy treatment.

Also, large scale outcomes data are somewhat sparse. A number of trials have been done, but methodologic differences make generalizing the conclusions difficult. A previous meta-analysis showed that 55% of patients with temporal lobe epilepsy refractory to medications are seizure free two years after surgery. This analysis did not, however, clearly determine the benefit of surgery per se. Another limiting factor: Most studies comparing surgical to nonsurgical outcomes at a single center were not randomized. Another confounding factor is the possibility of improvement solely with changes in medication regimen: A recent trial showed seizure freedom for over two years in up to 21% of patients with such medication changes.

A recent meta-analysis seeks to address this, at least in part. Schmidt and Stavem performed an analysis attempting to determine the percentage of patients rendered seizure-free by surgery per se, which they term net benefit of surgery. They did literature searches dating back to 1947 and manually searched bibliographies, using a stringent set of criteria. Out of an initial group of 155 references, they selected 20 studies (13%). From these, they distilled out summary statistics and derived relative risk (RR) figures for seizure freedom for surgical v. nonsurgical patients. Detailed subgroup analyses were also done, to control for the heterogeneity of the studies.

They found that surgery conveyed a significant benefit. Looking across all of the studies, 719/1,621 (44%) were seizure free, as opposed to 139/1,113 (12%) of control subjects (RR 4.26; 3.03—5.98). Four studies reported data on patients who were able to stop antiepileptic drugs (AEDs). The aggregated result: 32% in the surgery group v. 6% in the nonsurgical group (RR 4.67; 2.18–10.01). Subgroup analyses did not show any clear differences. Also noteworthy: 12% of patients in the non-surgical cohort were seizure free due to manipulation of AEDs. This is much higher than expected in a group of patients who have had poorly controlled epilepsy for a long time, and presumably have been previously treated with numerous medication regimens.

So, this analysis presents the best available data on long term surgical outcomes in patients with refractory epilepsy compared to non-surgical management. Refractory patients are more than four times as likely to be seizure free with epilepsy surgery than with medical management. And, a smaller data set shows a similar large difference in patients able to stop AEDs after a time. Seizure surgery is an important and effective option for patients with refractory epilepsy. And, some patients who are not candidates for surgery can be improved with changes in AEDs. In light of these results, a more aggressive approach to these patients with a difficult problem is needed.