Anterior Temporal Lobectomy for Epilepsy

Anterior temporal lobectomy (ATL) is one of the best-established operations for drug-resistant temporal lobe epilepsy. It removes part of the anterior temporal neocortex together with mesial temporal structures such as the amygdala and hippocampus when these form the epileptogenic network.

Who may be considered?

ATL is most commonly considered for unilateral drug-resistant temporal lobe epilepsy when seizure semiology, EEG, MRI and other presurgical data point consistently to one temporal lobe.

Mesial temporal lobe epilepsy

People with unilateral hippocampal sclerosis and concordant electroclinical findings are among the classic surgical candidates.

Other causes include tumours, cortical dysplasia and acquired structural injury.

What is removed?

The exact extent varies by centre and anatomy.

A conventional ATL removes a limited portion of the anterior temporal neocortex and mesial structures. The dominant hemisphere is often treated more conservatively to reduce language risk.

Why remove lateral temporal cortex?

The temporal pole and lateral temporal cortex may participate in the epileptogenic network even when the hippocampus appears to be the major structural abnormality.

This is one reason ATL and selective amygdalohippocampectomy are not interchangeable in every patient.

Seizure outcomes

Modern systematic reviews continue to support ATL as one of the most effective surgical treatments for appropriately selected mesial temporal epilepsy.

A 2025 meta-analysis of multiple surgical strategies reported seizure-freedom rates in the range expected from established temporal surgery, while long-term cohort data show that meaningful seizure control can persist for many years.

Long-term outcomes

A 2026 cohort with mean follow-up around ten years found that more than 60% of people with unilateral hippocampal sclerosis remained seizure-free after ATL.

Outcome was better when ictal EEG and neuropsychological findings were strongly concordant with the operated temporal lobe.

Memory

Memory risk is one of the most important considerations.

Dominant-temporal surgery can cause verbal-memory decline, especially when the resected hippocampus still functions relatively well.

Presurgical neuropsychology, functional imaging and other tests help estimate that risk.

Naming and language

Left temporal surgery can affect naming and word retrieval.

Language organisation must therefore be assessed individually rather than assumed solely from handedness.

Visual-field deficits

The optic radiations pass through the temporal lobe. Injury can cause a contralateral upper-quadrant visual-field defect.

Modern surgical planning aims to reduce this risk.

ATL versus selective amygdalohippocampectomy

A 2024 meta-analysis found no overall significant difference in seizure freedom between ATL and selective amygdalohippocampectomy, although the balance of seizure control and complications varied by operative route.

The choice should follow the individual seizure network and functional anatomy.

ATL versus LITT

Laser ablation is less invasive and can shorten recovery, but recent comparative meta-analyses generally find higher seizure-freedom rates after open temporal resection.

Medication after surgery

Antiseizure medicines are usually continued initially.

Any later reduction is individualised according to seizure outcome, pathology, EEG, risk tolerance and local practice.

The central point

Anterior temporal lobectomy remains a benchmark operation for carefully selected temporal lobe epilepsy because it offers durable seizure control, but the cognitive and visual trade-offs require detailed presurgical assessment.

Sources

Evidence checked: September 2026.