Epilepsy surgery: Late seizure recurrence after initial complete seizure freedom

What new insights does the analysis by Petrik et al. provide into late seizure recurrence after initial absolute seizure freedom after surgery?

In patients with focal pharmacorefractory epilepsy, surgery is extremely effective. Usually around two thirds of the patients have a very good outcome and usually it is the best possible approach and markedly better than prolonged or altered drug therapy. So it is really a very good therapeutic alternative for patients with drug-resistant epilepsy. 

The paper clearly showed that there are certain risk factors for late recurrence. However, this does not imply that patients with these risk factors, like young age at onset, bilateral lesions, necessity of functional imaging, should not be operated. Because in most instances the relapses where mild in nature and completeness of the resection is definitely essential. That is something we always expect and this is really confirmed by that paper.

What factors were associated with late relapse, and what was the most important factor for sustained long-term seizure freedom?

The most important factor is certainly complete resection. And there were some factors associated with the risk of a late relapse and that was a very young age of patients – a lot of patients were children and adolescents in that study – then bilateral MRI lesions and if PET performance was done preoperatively, and that shows that these were more complex cases, preoperatively. And we all know that these cases have not that good chance as others to get seizure freedom.

Are late relapsing patients more complex than those with early relapse? What factors could explain the differences between early and late relapse?

In fact, the risk factors for early and late relapses are basically identical. The importance of this work here is that it showed that a postoperative period of two years is too short to almost guarantee sustained seizure freedom. So in fact, this paper tells us that you never can feel totally safe and in fact late relapses are possible, but the risk factors are basically identical.

What impact does this analysis have on routine practice?

I think it is an important paper, but the impact is minor on routine practice. There are no hints to perform preoperative diagnostics differently based on that paper. More complex epilepsy should still undergo epilepsy surgery, if the presurgical data allows that. That is the major information. Still, in case of more complex cases or postoperative acute symptomatic seizures, one should be cautious to withdraw the anti-seizure medication, but we do not do that in those cases any way for years. We are always cautious with those patients, so we would never discontinue anti-seizure medication in those cases.

What are the future aspects arising from this paper? Are there any additional comments?

Well, what we are doing at my centre is that all surgical candidates after epilepsy surgery, we see them again as in-patients and we do a long term video EEG recording again, no matter what they are telling us about the outcome. And I could imagine that in some cases we might find abnormalities in the video EEG that would tell us that these are patients at risk. But this is an ongoing work and nobody in the world, I think, does that systematically. Well, the basic message of the paper is certainly that even after five years or even after ten years, relapses are possible. I just had a phone call with a patient who was seizure free for twelve years I believe, and now he had had a seizure relapse, so he was pretty frustrated of course. But that can happen. It is not very often, but it still can happen.