Abstracts

Rationale: The benefit of resective epilepsy surgery (RES) in adults with pharmacoresistant epilepsy is well established; however, most outcome studies have focused on young or middle aged adults. Approximately 25% of patients with epilepsy are age 60 or older, yet the largest case series reporting surgical outcome following RES in this population includes only 12 patients (J Neurosurg. 2016 Apr;124(4):945-51). This indicates grave underutilization of RES in older adults, historically due to concerns re: comorbid conditions and poor outcomes. The objective of current study was to investigate outcomes in a large cohort of older adults with epilepsy who underwent RES. Methods: This retrospective, IRB-approved study included patients aged 60 or older who underwent epilepsy surgery at Cleveland Clinic between 01/01/00 to 06/30/15. Only patients with at least 1 year of post-surgical follow-up were included in final analysis (n = 51). For comparative purposes, a younger cohort (aged 26-45; n=50) who underwent RES during the same time period was also selected. To account for potential differences in co-morbidities, the Charlson Comorbidity Index was calculated. The two age cohorts were compared on demographic and seizure variables as well as post-surgical outcomes using chi-squares, student t-tests, or repeated measures ANOVAs. Cognitive outcome was also examined among a subset of patients in the study. Results: Sixty-six older patients underwent RES during the study period, representing 2.8% of all RES completed over that time. Fourteen patients were excluded from further analyses because of inadequate follow-up (n=14), and one patient passed away post-RES related to a cardiac emergency. This resulted in a final sample size of 51 (see Table). Older adults were an average of 65 years old (SD=4.2) at the time of surgery. Not surprisingly, they had a significantly longer duration of epilepsy than the younger cohort (28 yrs versus 18 yrs) and a much higher Charlson Comorbidity Index (.92 versus .22). Despite these differences, their seizure outcomes were similar to the younger cohort (80% versus 68% Engel I outcome at last follow-up) with the same rate of postoperative complications. Unfortunately, longer term seizure outcomes (>3 years) were not available for as many older patients as for those in the younger cohort. It is also interesting to note that older patients were less likely to have negative or bilateral MRI findings or to undergo invasive EEG monitoring prior to resection, suggesting that older patients who undergo RES may have less complex epilepsy than their younger counterparts. A subset of patients (older=25 and younger=32) with well-matched baseline variables completed comprehensive neuropsychological evaluations before and after RES. Postoperative naming decline was more common among older patients; outcome on other cognitive measures was similar between groups. Conclusions: We present the largest and most comprehensive analysis of postoperative outcome following RES in patients 60 or older. They constitute a small minority of RES cases despite the higher prevalence of epilepsy in this age group. Results suggest that older patients have comparable outcomes to younger adults, without increased complications, despite significantly higher comorbidities and longer duration of epilepsy. Future studies will be needed to confirm these findings with longer follow-ups in samples better matched in terms of case complexity. With the rapidly growing elderly population, future research should also seek to identify factors that may limit access to RES among elders with pharmacoresistant epilepsy. Funding: No funding was received in support of this abstract.