Surgical treatment for epilepsy has a long and distinguished history.^11,15,33 Trephination was practiced since prehistoric times in many parts of the world, and cauterization, a popular therapy in the European Middle Ages, persisted into the late 19th century. The modern era of epilepsy surgery was inaugurated when surgeons began to operate on “invisible” lesions based on principles of functional cerebral localization developed largely by John Hughlings Jackson.³² Macewen, in 1879,²⁴ and Horsley, in 1886,¹⁹ were the pioneers of this approach. The advent of electroencephalography (EEG) in the first half of the 20th century made it possible for Bailey and Gibbs³ and the Montreal group led by Penfield and Jasper^20,27 to perform epilepsy surgery, predominantly anterior temporal lobectomy, based on electrophysiologic evidence alone. Much of the early neuroscience research that characterized and mapped human cortical function was derived from the work that Penfield and Jasper performed during surgery for epilepsy.²⁷ Nevertheless, surgical treatment was offered to only a few patients. Although this therapeutic modality has gained increasing acceptance in recent years, it remains underutilized today.

Whereas surgical intervention during the early years was constrained by the limited localizing capabilities of available diagnostic tools, initially consisting of seizure semiology and direct observation of defects in the skull and cortex, and later including EEG, pneumoencephalography, and cerebral angiography, the factors that continue to restrict epilepsy surgery today are more sociopolitical. With recent tremendous advances in our ability to accurately delineate structural and functional epileptogenic brain regions and to safely and effectively remove them, there has been a resurgence of interest in epilepsy surgery, and the number of patients undergoing surgical treatment for medically refractory epileptic seizures doubled or tripled worldwide between 1985 and 1990.¹⁶ It has been estimated for the United States that there may be over 100,000 potential surgical candidates, with 5,000 to 10,000 added annually,¹⁸ but only about 2,000 surgical procedures to treat epilepsy were performed in the United States in 1990. The number has not changed appreciably since then, despite a randomized controlled trial of surgery for temporal lobe epilepsy,³⁶ and a Practice Parameter published by the American Academy of Neurology recommending surgery for this condition.¹⁷ This underutilization is typical of other industrialized countries as well and can be attributed in part to (a) the reluctance of third-party payers to provide support for expensive presurgical evaluation, a problem that is currently being addressed by efforts to streamline the diagnostic process where possible, and to conduct studies that demonstrate the cost-effectiveness of surgical intervention over the long run; and (b) inadequate dissemination of information concerning advances in epilepsy surgery to primary care physicians, who too often are not identifying potential candidates and referring them to epilepsy surgery centers in a timely fashion. Furthermore, when patients are referred for epilepsy surgery, it is after an average of 22 years of seizures, often too late for meaningful rehabilitation.^4,14

Underutilization of surgical treatment for epilepsy is steadily being reversed, and surgical intervention is playing an increasingly important role in the epileptologist’s therapeutic armamentarium, as evidenced by the escalating number of conferences, books, and monographs on this subject in recent years.^{2,5,6,7,8,9,10,22,23,26,28,29,31,35,37,38,39,40} This is a direct result of new developments in structural and functional neuroimaging; improvements in other areas of diagnosis, particularly involving EEG and long-term monitoring; and refinements in surgical technique. However, the growth of surgical treatment is also due to a better understanding of the pathophysiology of those epileptic disorders that are amenable to this therapy, which to a large extent has derived directly from basic research conducted on the human brain in epilepsy surgery centers. Consequently, many different surgical procedures are available to treat specific individual epileptic disorders, and a variety of presurgical evaluation protocols can be applied depending on the suspected underlying epileptogenic disturbance and proposed surgical intervention. Therefore, surgical approaches are no longer dependent on the particular experience or biases of the surgical team in each center, nor are they constantly changing, with each new patient seen as a unique problem. Rather, a number of universally accepted strategies have been developed based on data derived from many epilepsy centers worldwide and validated by their results, which can be applied to categories of patients in a well-organized fashion according to predetermined criteria. Furthermore, based on years of cumulative data, reasonably reliable prognoses can be made before the recommendation of surgery, and specific surgically remediable syndromes can be easily identified for which medical prognosis is so poor and surgical prognosis so good that early surgical intervention can be deemed the treatment of choice.¹³