Epilepsy Surgery

Epilepsy surgery comprises neurosurgical procedures undertaken to control seizures in people with drug-resistant epilepsy, most classically by resecting the region of brain from which seizures arise. Anterior temporal lobectomy, the removal of the anterior part of the temporal lobe, is the prototypical and best-studied operation, but the field also includes other resections, disconnection procedures, and ablative and neuromodulatory approaches.

Definition

Epilepsy surgery is the surgical treatment of drug-resistant epilepsy, typically by resecting or disconnecting the epileptogenic zone — the region of brain whose removal is necessary to abolish seizures — with anterior temporal lobectomy as its classic form.

Scope

This entry orients the reader to the rationale for surgery in drug-resistant epilepsy, the concept of the epileptogenic zone, the prototypical temporal-lobe resection, and the randomized evidence comparing surgery with continued medical therapy. It is a reference-educational overview and does not provide candidate-selection or treatment guidance.

Core questions

• When is surgery considered for epilepsy that does not respond to medication?
• What is the epileptogenic zone and how does its identification guide resection?
• How effective is anterior temporal lobectomy compared with continued medical therapy?
• How do resective approaches relate to disconnection, ablation, and neuromodulation?

Key concepts

• Drug-resistant (medically refractory) epilepsy
• Epileptogenic zone
• Anterior temporal lobectomy
• Presurgical localization
• Seizure freedom as outcome
• Resective versus disconnective procedures

Mechanisms

The therapeutic principle is to identify the epileptogenic zone through presurgical evaluation and then to remove or disconnect it so that seizures can no longer be generated or propagate. In temporal-lobe epilepsy this commonly takes the form of anterior temporal lobectomy with removal of mesial structures. Stereotactic and image-guided methods contribute to localization and to minimally invasive ablative alternatives, linking epilepsy surgery to the broader functional and stereotactic field.

Clinical relevance

For selected patients whose seizures are not controlled by medication, surgery can achieve seizure freedom that medical therapy alone does not, and it is a recognized option in drug-resistant focal epilepsy. This entry describes how the evidence for surgery is established and how the procedures are categorized; it is not guidance for individual treatment decisions.

Evidence & guidelines

Two randomized controlled trials anchor the evidence base. Wiebe et al. (2001) showed that surgery for temporal-lobe epilepsy was superior to continued medical therapy for seizure freedom and quality of life. Engel et al. (2012) found that early surgery in patients with drug-resistant temporal-lobe epilepsy resulted in greater freedom from disabling seizures than continued medical management over the trial period. Detailed indications are set out in specialist guidelines and are not reproduced here.

History

Surgical treatment of epilepsy has nineteenth- and twentieth-century roots in lesion localization and cortical resection, and matured with the development of presurgical evaluation and imaging. Within the stereotactic and functional tradition, image guidance and minimally invasive ablation later supplemented open resection (Gildenberg, 2009), while randomized trials in 2001 and 2012 formalized the comparison with medical therapy.

Seminal works

• wiebe-2001
• engel-2012

Frequently asked questions

Who is considered for epilepsy surgery?

Surgery is generally considered for people with focal epilepsy that remains uncontrolled despite adequate trials of medication, after a specialized presurgical evaluation identifies a resectable seizure-generating region.

What is anterior temporal lobectomy?

It is the prototypical epilepsy operation, in which the anterior part of the temporal lobe (often including mesial structures) is removed to treat drug-resistant temporal-lobe epilepsy.