Surgery for Epilepsy

A summary of the consensus panel's report. Increasing numbers of patients, including many children, are being referred for surgery. Improved technology has made it possible to identify more accurately where seizures originate in the brain, and advances in surgical techniques have made operations safer. As a result, some investigators believe that 2000 to 5000 new patients in the United States may be candidates for surgery each year, compared with the present annual rate of about 500. There are several reasons to consider surgery for the treatment of uncontrolled seizures. Repeated seizures can result in progressive cerebral degeneration and handicap. Also, the long-term use of antiepileptic drugs is costly and can have toxic effects. For patients facing a lifetime of ineffective therapy, social and intellectual development and job performance may be compromised. Yet surgery has risks and costs that must be considered. Current data suggest that three categories of seizures may be ameliorated by surgery: partial seizures of temporal or extratemporal origin, secondarily generalized seizures (attacks that begin locally and spread to both sides of the brain) and unilateral, multifocal epilepsy associated with infantile hemiplegia. As a first step, patients with these types of seizures should be referred to a neurologist or specialized epilepsy centre for further evaluation. Before surgery is considered the neurologic evaluation should confirm the following: a diagnosis of epilepsy, including seizure type and syndrome, and a defined metabolic or structural cause. The patient should have had a reasonable trial of the appropriate drugs, with adequate monitoring of compliance and side effects. Patient and family should receive detailed information about the seizure disorder, drug treatments and their side effects, and alternative treatments such as surgery. If evaluation and treatment by a neurologist show that drug therapy is unlikely to result in further benefit the patient should be referred to an epilepsy centre to be evaluated specifically for surgery. Coexisting disorders may affect the decision to operate. Specialized epilepsy centres should have the following personnel: neurologists, neurosurgeons, neuropsychologists and others with training in and experience of epilepsy. Neurodiagnostic equipment should also be available. In all cases electroencephalography and magnetic resonance imaging should be used to identify and exclude other forms of neurologic disease. It is not yet clear when it is necessary to use more extensive tests, such as surface electroencephalography during seizures, invasive intracranial electrode recording, positron-emission tomography or single-photon-emission computed tomography. A program should be developed to assess the value of these tests. It is recommended that data from major epilepsy centres be combined to clarify many unanswered questions about the use of these and other diagnostic methods.