Abstracts

Rationale:
Our study seeks to evaluate anti-seizure drug (ASD) usage prior to pre-surgical evaluation in drug resistant epilepsy (DRE). DRE has been defined in a consensus proposal as failure of adequate trials of two tolerated, appropriately chosen ASDs (whether as monotherapy or in combination) to achieve sustained seizure freedom. Although the benefits of epilepsy surgery have been clearly demonstrated, surveys on attitudes among neurologists in Europe and North America have revealed inconsistent attitudes regarding its utility. We posited that a substantial number of patients are trialed on more than two ASDs prior to pre-surgical evaluation. This study aims to look at a sample of patients considered for surgery to assess the number of ASD trials prior to surgical consideration. 
Method:
We conducted a retrospective study of all patients with DRE who were evaluated for epilepsy surgery at the Froedtert Comprehensive Epilepsy Center (FCEC) who were presented at the Epilepsy Surgery Conference from 1/1/2017 to 12/31/2018. We abstracted demographic data including the patient’s age at the time of evaluation, age at seizure onset, duration of epilepsy, gender, race, ethnicity, distance from registered home to the FCEC; distance to our center was categorized into three groups: < 15 miles, between 15 and 60 miles, and more than 60 miles.  Additional data were abstracted including the current and previous ASDs, MRI findings, interictal EEG findings, and ictal EEG findings.  Progression to surgery was also abstracted along with additional factors such as the year they were referred to the FCEC, whether they were referred from a primary care provider or a Neurologist, and how many outpatient visits they had with an epileptologist at the FCEC.
Results:
A total of 31 male and 23 female patients met inclusion criteria. The mean number of ASDs trialed at the time of presentation at the Epilepsy Surgery Conference was 5.62 (±3.3; range 1-15).  Nine patients (17%) were tried on only one or two ASDs at the time of their surgical presentation.  A mean of 0.4 ASDs were initiated by epileptologists at our center prior to surgical conference (±1.1; range 0-6).  Distance was significantly associated with an increased number of ASD trials (p=0.015), with patients residing less than 15 miles being tried on 3.7 ASDs compared with 5.8 ASDs for patients between 15 and 60 miles and 6.9 ASDs for those over 60 miles.
Conclusion:
Our study demonstrates that a significant proportion of patients have failed more than two ASDs prior to surgical consideration.  Moreover, in our cohort, the majority of those ASD trials were initiated by physicians prior to evaluation in our center.  While many factors likely contribute to this finding, distance from our comprehensive epilepsy center was a significant factor.  Whether this reflects an issue of access to care (e.g. unable to travel to the center) or a patient-choice factor (e.g. prefer to get care closer to home) is unclear.  These data suggest that delays to surgical evaluation for DRE persist.
Funding:
:None