Brain Wave Guidance May Improve Seizure Control After Surgery

What was studied

This study looked at adults with cerebral cavernous malformations (CCMs), which are abnormal blood vessel clusters in the brain that are frequently associated with drug-resistant epilepsy. The researchers compared 67 adults at one hospital who had surgery to remove a CCM. Seventeen had surgery guided by intraoperative electrocorticography (ECoG), a brain-wave recording used during the operation, and 50 had standard microsurgical lesionectomy without ECoG.

The main question was whether ECoG-guided surgery was associated with better seizure freedom over time. The researchers also combined results from 7 studies, including their own, for a total of 241 patients, to compare seizure outcomes after ECoG-guided surgery versus surgery without ECoG.

What they found

In this hospital group, seizure freedom was higher in the ECoG-guided group at 24, 30, and 36 months after surgery. However, the ECoG group also had larger resection volumes. When temporal lobectomy cases were removed from the analysis, the better seizure results remained significant only for extratemporal ECoG-guided lesionectomies. In the study's univariate analysis, ECoG use and postsurgical antiseizure medication were significant predictors of seizure freedom. In the combined analysis of 7 studies, patients who had ECoG-guided surgery had better seizure outcomes than those who had lesion removal alone.

Limits of the evidence

This was a retrospective study from a single center, so patients were not randomly assigned to ECoG or non-ECoG surgery. Differences between the groups, including how much tissue was removed, could have affected the results. The ECoG group was small, with only 17 patients. The abstract does not report full details about side effects or whether the groups were otherwise similar before surgery. The meta-analysis combined a limited number of studies, and those studies may have differed in methods and patient selection. Because of this, the study shows an association and does not establish that ECoG itself caused the better seizure outcomes.

For families and caregivers

For families considering epilepsy surgery for a cavernous malformation, this study suggests that using ECoG during surgery may be associated with a better chance of long-term seizure freedom, especially for lesions outside the temporal lobe. But the study does not show for certain that ECoG itself was the reason for better results. Surgical planning may also depend on where the lesion is and how much tissue is removed.

What to watch next

Larger comparative studies that better account for differences between patients and procedures, and that report safety outcomes alongside seizure outcomes, would help clarify the role of ECoG and the effect of resection extent.

Terms in this summary

cerebral cavernous malformation (CCM)

A cluster of abnormal blood vessels in the brain that can be associated with seizures.

drug-resistant epilepsy

Epilepsy that does not come under good control after trying appropriate seizure medicines.

resection

Surgery to remove tissue.

electrocorticography (ECoG)

A recording of brain electrical activity taken directly from the brain surface during surgery.

seizure freedom

Having no seizures for a period of time after treatment.

lesionectomy

Surgery that removes the visible brain lesion.

temporal lobe

A region of the brain that can be involved in some types of epilepsy.

meta-analysis

A study that combines results from several studies to look for an overall pattern.