Before a patient can be considered for surgical treatment he has to undergo extensive preoperative evaluation.
The goals for Epilepsy surgery are:
- Establish the diagnosis of epileptic seizures
- Define the electro-clinical syndrome
- Delineate the lesion(s) responsible for the seizures
- Evaluate the past antiepileptic drug (AED) treatments and make sure that an adequate medical treatment had been provided..
- Select ideal surgical candidates with optimal electro-clinico-radiologic correlation
- Ensure that the surgery will not result in disabling neuropsychological deficits.
The main aim of presurgical evaluation in patients with intractable epilepsy is the identification of the cortical area capable of generating seizures and whose removal or disconnection will result in seizure freedom. This area is called the epileptogenic zone. Different diagnostic tools are being used by epileptologist to identify epileptogenic zone.
The current diagnostic techniques used in the definition of these cortical zones for epilepsy surgery are video electroencephalography (EEG) monitoring, magnetic resonance imaging (MRI), ictal single photon emission computerized tomography (SPECT) and positron emission tomography (PET). A detailed neuropsychological evaluation is an indispensable tool for prognosis of neuropsychological deficits after surgery and may significantly influence the final decision about epilepsy surgery.