The first step in deciding whether someone should have epilepsy surgery is to make sure that the seizures are medically refractory, or uncontrollable with antiepileptic drugs.
Most patients with difficult-to-control seizures have been treated with two or more drugs in separate trials and in various combinations, and have been treated unsuccessfully for at least 2 years. If the seizures are frequent, relatively short trials of medications can reveal the failure of medical therapy. If the seizures are infrequent, a longer trial of medication is needed to determine that the therapy is ineffective. Therefore, it is important for epilepsy surgery candidates to have a complete record of the antiepileptic drugs that have been tried, including the maximal dosages, blood drug levels, and adverse effects. When the seizures are associated with a blood vessel malformation, benign tumor, or other structural lesion, the proof that the seizures cannot be controlled by drugs is less important in considering epilepsy surgery than it is for other patients.
After a patient’s seizures are confirmed to be medically refractory, a series of pre-operative diagnostic tests are performed to identify the area of the brain from which the seizures arise and the areas that control vital functions such as language, memory, movement, and sensation. Doctors hope to find that the seizures arise from an area that is not vital for intellectual or other important functions. Some areas of the brain can be removed without any observable or measurable changes in intellect, personality, or mood. The removal of other areas may be associated with slight deterioration or, in some cases, actual improvement in memory or other vital functions.
Many potential surgical candidates select the risks and benefits of surgery over the disadvantage and medication burden which accompanies refractory seizures. Over the past three decades, important strides have been made in developing new technologies and surgical techniques that have made surgical intervention both safe and effective.