Epilepsy surgery

Author: Marco Beggiato
Date: 26/06/2014



Epilepsy surgery is the name for the different types of brain surgery (also called neurosurgery) that some people with epilepsy have to stop or reduce the number of seizures they have. There are different types of epilepsy surgery. One kind of surgery involves removing the part of the brain that is causing seizures, another kind involves separating the part of the brain that is causing seizures from the rest of the brain.

epilepsy surgery ,November 2013

Why Surgery?

Approximately 60% of all patients with epilepsy suffer from focal epilepsy syndromes. In about 15% of these patients, the seizures are not adequately controlled with anticonvulsive drugs, and such patients are potential candidates for surgical treatment. Around 65% of newly diagnosed epilepsy patients have a good response to antiepileptic drugs (AEDs). However, about 35% of patients have incompletely controlled epilepsy.
Around 70% of people (7 in 10 people) who have surgery find that the surgery stops their seizures and they become seizure-free.

surgery for childhood epilepsy ,March 2014
epilepsy surgery ,November 2013

Presurgical evaluation

A potential surgical candidate must have three main criteria:
-the patient (or his or her parents for young children and patients with intellectual impairment) needs to understand the objective of the presurgical evaluation and to agree on the possibility of a surgical treatment;
-the patient should suffer from disabling seizures despite appropriate medical therapy;
-imaging and electroclinical data should be consistent with the possibility of a surgically remediable epileptic syndrome.
In the majority of surgical candidates, video-EEG monitoring plays an essential, role in the presurgical evaluation, by providing a detailed description of ictal clinical signs and EEG discharge, as well as prolonged interictal recordings.

Ictal EEG also provides valuable latcralizing and localizing information with regard to the ictal onset zone.
Memory and psychological tests are also used to see how memory and lifestyle might be affected after the surgery.

Epilepsy surgery: eligibility criteria and presurgical evaluation ,March 2008
Epilepsy surgery ,November 2013

Surgery in child

Children are not small adults. Epilepsy surgery in children requires a careful approach during presurgical evaluation and surgical approach, as it is different from adults.
-Seizure frequency is high in children when compared to adults.
-Frequent seizures in infants and children is associated with developmental arrest or regression, especially in children younger than 2 years.
-Focal epilepsy in childhood is often associated with age-specific etiologies. Dysplasia is the commonest substrate in children, whereas hippocampal sclerosis is common in adults.
-The presentation of intractable localization-related epilepsy is often heterogeneous in childhood. Pediatric patients with hemispheric or unilateral focal etiologies can have generalized seizures, generalized and multifocal electroencephalography (EEG) patterns, and rapid evolution of electroclinical features.
-The child's brain is capable of significant reorganization of neurologic function after insult and surgery, a unique and complex phenomenon that is critical for surgical planning. For example, interhemispheric language transfer occurs in children operated below the age of 6 years.
Epilepsy surgery is considered in children when:
-epilepsy is refractory, which is defined as inadequate control of seizures despite proper drug therapy with AED or the adequate control of epileptic seizures but with unacceptable side effects.In adults, medical intractability may be considered as failure to respond to at least two anticonvulsant drugs over at least 2 years. These rules may not be appropriate in children and infants with catastrophic-onset epilepsies as seizure frequency may be such that a greater number of drugs are tried over a shorter time. In such cases, there is a need for early surgery for seizure freedom and prevention of developmental delay.
-To be suitable for temporal or extratemporal epilepsy surgery, it should be proven that the seizures arise exclusively from one area of the brain that is functionally silent. Such an area of the brain may be relatively small or large, dependent partly on the underlying pathology and partly on the area of brain involved.

surgery for childhood epilepsy ,March 2014

Main type of epilepsy surgery

The first, and by far the most common, is called resection or resective surgery. In this type, the surgeon removes the area of the brain that causes the patient's seizures. Especially the most common type is called a temporal lobectomy, in which part of the temporal lobe of the brain is removed.

Standard temporal lobectomy for temporal lobe epilepsy, arrows indicate removal of temporal lobe.
The second, less common type of epilepsy surgery interrupts nerve pathways that allow seizures to spread. The term disconnection is sometimes used to describe it. Some examples are the corpus callosotomy and the multiple subpial transection (helpful when seizures begin in areas that are too important to remove).
Disconnection procedures are generally thought of as providing relief, but not a cure.

Corpus Callosotomy, before (A) and after (B) MR Studies (arrow indicates area of callosotomy)

Types of surgeries ,August 2013

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