Epilepsy Surgery: When Is It Necessary?

Patients referred to a neurologist for surgical treatment are not necessarily going to undergo surgery. They must first go through weeks of pre-surgical evaluations, and the appropriate surgical method must be discussed. Following this process, it may be determined that the patient is not a suitable candidate and that alternative treatment plans should be made.

What Is Epilepsy Surgery and When Is It Applied?

Before deciding on surgical treatment, it must be demonstrated that the patient's seizures are resistant to medical therapy. For this reason, patients must have used medication for at least 2 years. At least 2–3 appropriate antiepileptic drugs must be tried individually and in combination, at adequate doses and for sufficient durations. These medications must be incrementally increased until seizures are controlled or until unacceptable dose-related side effects develop. In patients whose seizures are caused by a structural abnormality in the brain — such as a tumour or vascular anomaly — the decision for surgical treatment may be made earlier. Both drug resistance and surgical success rates are higher in these cases. The longer seizures have remained uncontrolled, the lower the likelihood of successful seizure control after surgery and the higher the risk of psychosocial complications.

Types and Processes of Epilepsy Surgery

There are two main types of epilepsy surgery. The first, and preferred, approach is the removal of the epileptic focus itself (resective surgery). The second involves cutting the seizure propagation pathways to reduce the spread, frequency, and severity of seizures (functional surgery, palliative surgery).

Resective surgical techniques aimed at the complete elimination of seizures are applied to patients with partial-onset seizures — that is, seizures that begin from a specific focus. As mentioned above, these are patients who have been proven drug-resistant after using an adequate number of medications at appropriate doses and for sufficient durations, and whose quality of life is significantly impaired. If the epileptic focus is located on one side of the brain and in a relatively safe area — meaning that important cognitive functions such as motor ability, memory, speech, and vision will not be impaired after surgery — the surgical approach should be determined without undue delay. This decision can only be made following pre-surgical evaluations. Prior to surgery, a multidisciplinary team consisting of neurologists, neurosurgeons, radiologists, neuropsychologists, and psychiatrists conducts a series of tests to determine whether the patient is suitable for this type of surgery.

The success of resective surgery depends on patient selection, the type of epilepsy, the location of the epileptic focus, and the pre-surgical investigations. The patient continues to take medication for 1–2 years after the operation. If seizures no longer occur, the medications are gradually tapered and discontinued.

Palliative (functional) epilepsy surgery is performed in patients who are not candidates for resective surgery, with the aim of cutting the seizure propagation pathways — thereby isolating the epileptic focus from the rest of the brain and preventing seizure spread. It is used for treatment-resistant secondarily generalised seizures and for atonic seizures, characterised by sudden drop attacks.

Vagus Nerve Stimulation (VNS — Vagal Nerve Stimulator)

Vagus Nerve Stimulation (VNS), developed in recent years and known colloquially as "pacemaker" therapy, is also a functional surgical method. It works by sending electrical current to the brain via the vagus nerve, which runs along the left side of the neck. In a minor operation, an electrode is connected to the vagus nerve and the battery is placed in a pocket created beneath the skin of the left chest. The battery operates automatically, sending very small electrical impulses to the brain at very short intervals according to the programmed settings. It is an easy method to apply and, as with other functional surgical procedures, is used to achieve seizure control.

Deep Brain Stimulation (DBS) for epilepsy targets the anterior nucleus of the thalamus (ANT), which is part of the network involved in the generation and propagation of seizures in the brain. Leads bilaterally implanted in the ANT provide controlled electrical stimulation to modulate the network. The long-term safety and efficacy of DBS therapy for epilepsy was established over a 7-year follow-up period in the "SANTE" (Stimulation of the Anterior Nucleus of the Thalamus in Epilepsy) randomised controlled clinical trial.

Recovery and Rehabilitation After Epilepsy Surgery

The recovery process following epilepsy surgery varies from patient to patient, but is generally assessed in several stages. In the early post-operative period, headache, fatigue, and transient neurological symptoms may occur. The patient is closely monitored during this phase. In the following weeks, seizure frequency is observed, and antiepileptic medication is generally not discontinued immediately but tapered gradually. The rehabilitation process may involve a multidisciplinary approach, including physiotherapy, psychological support, and speech therapy where necessary. Individual planning is important to help patients reintegrate into daily life and return to work and social activities. Regular follow-up and teamwork determine the success of this process.

Risks and Success Rates of Epilepsy Surgery

As with any surgical intervention, epilepsy surgery carries certain risks. These include infection, haemorrhage, and temporary or permanent neurological deficits (affecting speech, memory, and motor skills). However, in carefully selected cases, these risks are quite low. Surgical success varies depending on the type of epilepsy, the location of the seizure focus, and the brain region being operated on. In temporal lobe resections — one of the most commonly performed operations — the seizure-freedom rate is approximately 60–80%. Risks are minimised through detailed neurological assessments, imaging, and testing.

What Are the Alternatives to Surgical Treatment?

For patients who are not suitable for surgery or who do not wish to undergo an operation, several alternative treatment options exist. Foremost among these is vagus nerve stimulation (VNS), in which a device implanted in the chest wall sends regular impulses to the brain to reduce seizure frequency. Another option is deep brain stimulation (DBS), which is particularly preferred in cases of refractory epilepsy. Additionally, dietary therapies such as the ketogenic diet may contribute to seizure control in some patients. None of these methods may yield results as definitive as surgery, but in appropriate patients they can provide a meaningful improvement in quality of life.