Authors: Zachary Lee Hickman, MD; Steven Hernandez, BS; Eddie Fakhouri, BS; G. Oliver; Gary Jean, BS; Lea Alali; Thomas DiChiara, BS; Jueria Rahman; Konstantinos Margetis, MD, PhD; Zachary Hickman, MD (New York, NY)

Introduction: Complicated mild TBI (mTBI) is defined as GCS 13-15 with a head CT demonstrating a traumatic intracranial lesion (hemorrhage/contusion/edema) or depressed skull fracture. Studies investigating the necessity/efficacy of seizure prophylaxis following complicated mTBI to prevent post-traumatic seizures (PTS) are limited and guidelines for antiepileptic drug (AED) administration in these patients are lacking. We examined PTS incidence following complicated mTBI in patients that either received, or did not receive, seizure prophylaxis. Methods: A Level 1 trauma center database was retrospectively reviewed to identify consecutive subjects aged 15+ years that presented with complicated mTBI between Apr-Dec 2016. Exclusion criteria included a history of seizures; prior or penetrating TBI; neurological decline to GCS<13; need for invasive neurosurgical intervention. Demographic data was collected and prophylactic AED administration information was obtained, including AED type/dose/duration. Medical records were queried to determine the incidence of early/late PTS from in-hospital events and on follow-up. Data was analyzed using unpaired Student’s t, Fisher’s exact, or Chi square tests, as appropriate. Results: 86 consecutive complicated mTBI patients (mean age 58.7+/-2.3y, 62% male, mean GCS 14.8+/-0.1) were included in our cohort. 79.1% of patients received prophylactic AEDs, median AED duration was 8 days (range 1-98). There were no in-hospital PTS (0/86, 0%). For patients with 7+ days follow-up (n=62), the incidence of early PTS was 1.9% (1/52) in the AED group and 10.0% (1/10) in the no AED group (P=0.30). There were 3 late PTS in both the AED/no AED groups (4.4% versus 16.7%) (P=0.10). Overall PTS incidence was 8.1% (7/86). Conclusion: No patients in our cohort had an immediate PTS during their initial hospital visit. The early PTS rate was low (3.2%), but there was a non-trivial incidence of late PTS (8.1%). The incidence of both early/late PTS trended lower in patients that received prophylactic AEDs immediately after injury.