Update on epilepsy surgery A randomized, controlled trial of surgery for temporal-lobe epilepsy A landmark study in epilepsy surgery was recently published in the New England Journal of Medicine. Wiebe et al. 1 completed a randomized, controlled trial validating the utility of temporal lobe surgery for intractable temporal lobe epilepsy of mesial onset. Eighty patients were randomly assigned to receive either surgical or medical treatment for temporal lobe epilepsy. The results were that 58% of the surgery group and 8% of the medical group were seizure-free at 1 year. Additionally, the surgery group had better quality of life. Of note, there was one death in the study and this occurred in the medical group. Epilepsy surgeons have known for years the dramatic impact in seizure control and quality of life resulting from the surgical treatment of epilepsy and been frustrated at the lack of enthusiasm among some members of the epilepsy community for this safe and effective therapy. It is interesting to note that the convincing results achieved by Wiebe et al. were obtained using an intention to treat paradigm. Patients were randomly assigned to either surgical or medical treatment prior to video-EEG monitoring and MRI. As a result, 4 patients in the surgery group were felt not to be good candidates for surgery and did not undergo surgery. Hence, the 58% number underestimates the efficacy of temporal lobectomy. In addition, the authors performed a standard temporal lobe resection, which included an extensive lateral neocortical resection and a variable resection of the anterior hippocampus ranging from 1.0-4.0 cm. It is well-known from depth electrodes studies and re-operations for failed epilepsy surgery that the posterior hippocampus may be the cause of epilepsy in a fraction of patients 2, 3. In fact, there has already been a randomized, prospective blinded study showing that the results from a complete hippocampectomy are superior to a partial hippocampectomy 4. Again, had the authors performed a more extensive hippocampal resection, their rate of seizure cure may have been even higher. For there reasons, it is important to emphasize to the readers that the 58% cure rate reported by Wiebe et al. is an underestimation of the potential cure rate if patients are selected for surgery after a more extensive work-up including video-EEG monitoring, MRI, WADA testing and PET scanning and if a more extensive hippocampectomy is performed. Cure rates approaching 80-90% have been reported for carefully selected patients 5. Wiebe S, Blume WT, Girvin JP, Eliasziw M. A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med 2001; 345:311-318. Spencer DD, Spencer SS, Mattson RH, Novelly RA, Williamson PD. Access to to the posterior temporal lobe structures in the surgical treatment of temporal lobe epilepsy. Neurosurgery 1984; 15:667-671. Germano IM, Poulin N, Olivier A. Reoperation for recurrent temporal lobe epilepsy. J Neurosurg 1994; 81:31-36. Wyler AR, Hermann BP, Somes G. Extent of medial temporal resection on outcome from anterior temporal lobectomy: a randomized prospective study [see comments]. Neurosurgery 1995; 37:982-90. Engel JJ. Surgery for seizures. N Engl J Med 1996; 334:647-52. Theodore H. Schwartz, M.D. Director, Center for Epilepsy Surgery Department of Neurological Surgery Weill Cornell Medical College New York Presbyterian Hospital 525 East 68th St., Box #99 New York, N.Y. 10021 Tel: (212) 746-5620 Fax: (212) 746-5592 schwarh@med.cornell.edu