Selective amygdalohippocampectomy (SAH) is a temporal lobe epilepsy operation designed to remove the amygdala and hippocampal formation while preserving more of the lateral temporal neocortex than a standard anterior temporal lobectomy.
Why target the mesial temporal structures?
In many people with mesial temporal lobe epilepsy—particularly those with hippocampal sclerosis—the seizure network is centred on the hippocampus, amygdala and closely connected mesial structures.
What “selective” means
The operation aims to reach the mesial temporal structures through a limited surgical corridor rather than removing a larger portion of the anterior temporal lobe.
Different approaches include transsylvian, transcortical and subtemporal routes.
Who may be considered?
SAH may be considered when presurgical evaluation strongly supports unilateral mesial temporal onset and the lateral temporal neocortex does not appear to be an essential part of the epileptogenic zone.
SAH versus anterior temporal lobectomy
Both operations are established treatments for selected drug-resistant temporal lobe epilepsy.
A 2024 systematic review and meta-analysis including more than 3,000 people found no overall significant difference in seizure freedom between SAH and anterior temporal lobectomy, although outcomes varied by surgical approach.
Visual-field deficits
The same meta-analysis found a lower risk of postoperative visual-field deficits with SAH overall compared with anterior temporal lobectomy.
This does not eliminate visual risk, because optic radiations remain close to the operative field.
Memory and naming
Preserving lateral temporal cortex may reduce some cognitive risks, but memory decline can still occur because the hippocampus itself is removed.
Risk depends strongly on hemisphere, pre-existing memory function, language dominance and the health of the opposite temporal lobe.
Left versus right surgery
Dominant-hemisphere surgery often carries greater risk to verbal memory and naming, while non-dominant surgery may affect visual or spatial aspects of memory.
Individual organisation varies substantially.
Long-term cognitive outcomes
A 2026 long-term study comparing anterior temporal lobectomy and SAH found different memory trajectories over ten years, reinforcing that cognitive outcome cannot be reduced to a simple claim that one procedure always preserves memory better.
Why SAH is not always appropriate
If seizure onset extends into the temporal pole, lateral temporal cortex or a broader network, a selective operation may leave epileptogenic tissue behind.
The surgical approach must follow the seizure network rather than a preference for smaller surgery.
Risks
Risks include bleeding, infection, stroke, memory decline, naming difficulty, visual-field loss and psychiatric change.
The central point
SAH is a selective mesial temporal operation, not a universally “safer version” of temporal lobectomy. It is appropriate only when the presurgical evidence supports a predominantly mesial temporal epileptogenic network.
Related reading
Temporal Lobe Epilepsy →
Hippocampal Sclerosis →
Anterior Temporal Lobectomy →
Sources
- Anterior temporal lobectomy versus selective amygdalohippocampectomy — 2024 systematic review and meta-analysis
- ATL and SAH complications across Europe — 2025 review, meta-analysis and Delphi consensus
- Ten-year cognitive outcomes after temporal lobe epilepsy surgery — 2026
Evidence checked: September 2026.