Abstracts

Rationale: Epilepsy surgery remains significantly underutilized. We recently reported that the number of lobectomies for localized intractable epilepsy in the U.S. has not changed despite the implementation of clear evidence-based guidelines ten years ago supporting early referral for surgery. To better understand why epilepsy surgery continues to be under-utilized, our objective was to carefully examine hospital-related factors related to: 1) where patients are being admitted for the evaluation of epilepsy, 2) rates of utilization for surgery across hospitals, and 3) peri-operative morbidity between hospitals with low vs. high volume of epilepsy surgery. Methods: We performed a population-based cohort study of U.S. hospitals from 1990 to 2008 using the Nationwide Inpatient Sample (NIS), stratifying epilepsy surgery rates and trends as well as perioperative morbidity rates by hospital surgical volume. Results: The number of lobectomies for epilepsy performed at high volume centers (>15 lobectomies/year) significantly decreased from 1990 to 2008 (F = 20.4, p < 0.001), while significantly more procedures were performed at middle volume hospitals (5-15 lobectomies/year) over time (F = 16.1, p < 0.001) (Fig 1A). No time trend was observed for hospitals performing < 5 procedures per year (Fig 1A). However, patients admitted to high volume centers were significantly more likely to receive lobectomy than those at low volume hospitals (RR 1.05, 95% CI 1.03-1.08, p < 0.001) (Fig 1B). Also, the incidence of perioperative adverse events was significantly higher at low volume hospitals (12.9%) than at high volume centers (6.1%) (RR 1.08, 95% CI 1.03-1.07, p < 0.001). Conclusions: Hospital volume is an important predictor of epilepsy surgery utilization and peri-operative morbidity. Patients with refractory epilepsy should be referred to a comprehensive epilepsy treatment center for surgical evaluation by an experienced clinical team.