ATL versus SAH surgery for drug-resistant mesial temporal lobe epilepsy

What was studied

This systematic review and meta-analysis compared two operations for drug-resistant mesial temporal lobe epilepsy: anterior temporal lobectomy (ATL) and selective amygdalohippocampectomy (SAH). Researchers combined 22 studies published from 1996 through 2023, involving 2,482 patients.

They compared seizure freedom, poor seizure outcomes, visual field deficits, and postoperative complications.

What they found

Patients who had SAH had an 8% lower relative chance of postoperative seizure freedom than those who had ATL. SAH also showed a trend toward a higher risk of poor seizure control, but this difference was not statistically significant.

SAH was associated with a 38% lower relative risk of postoperative complications and a 15% lower relative risk of visual field defects measured with Goldmann testing. Overall, ATL was associated with better seizure control, while SAH was associated with fewer visual field deficits and postoperative complications.

Limits of the evidence

This analysis combined results from previous studies. The abstract does not report the included studies' designs, follow-up lengths, individual risk-of-bias ratings, absolute outcome rates, or the specific complications that occurred. Differences in patient selection and anatomy may also affect comparisons. Because only relative risks are provided, the results do not show how many patients were affected in absolute terms or establish that the surgical approach alone caused the differences.

For families and caregivers

The findings suggest a tradeoff: ATL may offer a somewhat better chance of seizure freedom, while SAH may reduce the risks of visual field deficits and other postoperative complications. These group-level findings do not determine which operation is best for a particular person. Decisions should be individualized based on patient selection, anatomy, and the balance between seizure control and surgical risks.

What to watch next

Further studies could clarify long-term seizure, visual, and complication outcomes, including absolute outcome rates and how patient selection and anatomical factors influence results.

Terms in this summary

Mesial temporal lobe epilepsy

Epilepsy in which seizures begin in deep structures of the temporal lobe, often including the hippocampus and amygdala.

Drug-resistant epilepsy

Epilepsy in which seizures continue despite treatment with antiseizure medicines.

Anterior temporal lobectomy (ATL)

An operation that removes part of the anterior temporal lobe and targeted deeper temporal structures.

Selective amygdalohippocampectomy (SAH)

An operation intended to remove the amygdala and hippocampus while preserving more surrounding temporal lobe tissue.

Engel I

An outcome category indicating seizure freedom after epilepsy surgery in this analysis.

Engel III-IV

Outcome categories representing poorer seizure control after surgery.

Relative risk

A comparison of how often an outcome occurs in one group versus another; it does not provide the absolute number of people affected.

Visual field defect

Loss of vision in part of the area a person can see, which can occur after temporal lobe surgery.