Abstracts

Patients evaluated for epilepsy surgery usually undergo scalp video-electroencephalographic (VEEG) monitoring to determine the site of onset of their seizures. If this monitoring localizes the site of onset, and especially if there is a concordant other localizing finding (e.g. abnormal MRI), patients go on to resective surgery. If scalp monitoring is not definitive, intracranial monitoring is necessary. If the site of seizure onset has not been laterized, we do this monitoring using subdural strips. In order for patients to decide whether or not to undergo this investigative procedure, they need to know the likelihood of the various recommended next steps such as resective sugery versus medical mangement. We have historically indicated that over 80% of patients went on to surgery. The object of this study was to provide data as to the frequency of various management recommendations after subdural strip VEEG monitoring at our center.
The University of Washington Regional Epilepsy Center Clinical Data Base was searched to identify patients who had undergone subdural strip VEEG monitoring. Each patient is discussed in conference following monitoring and a recommendation is made as to further management. The frequency of recommendations of the various treatments, surgery, medical management, repeat monitoring with a subdural grid to be followed by surgery, vagus nerve stimulator (VNS) were noted.
One hundred and five patients were identified. Following monitoring, surgery was recommended in 50(48%) cases, medical mangement in 18(17%), grid monitoring in 18(17%), and VNS in 3(3%). One patient had no seizure activity and repeat monitoring was recommended, but the patient decline further workup. Three participated in family conferences and one opted for surgery and two for medical management. Additional tests were requested for 12 patients, such as additional imaging or WADA testing before definitive recommendation was made. Five of these were eventually referred for surgery directly, 3 for grids, and 4 to medical mangement. Overall 56 of 105(53%) went to surgery without further monitoring and 21(20%) had a grid inserted before planned definitive surgery. Two did not go on to resective surgery. Twenty-eight(27%) continued with medical management or VNS.
Only 53% of our patients went directly to surgical resection following strip monitoring. Another 20% had monitoring with a grid before resection and two of those did not have definitive surgery. Thus 29% of our patients who had subdural strip VEEG monitoring did not go on to resection. We had unintentionally overstated the likelihood of definitive surgery for our patients after strip monitoring. It is important to provide our patients with accurate figures as to the possible outcomes of their monitoring, so they can make rational decisions as to their further treatment.