671: HEAD INJURY DEPTH AND FUNCTIONAL OUTCOMES IN PEDIATRIC TRAUMATIC BRAIN INJURY

Abstract

Introduction: The centripetal theory of traumatic brain injury (TBI) posits that an inertial mechanism (rotational acceleration and deceleration) injures the brain in an outward-in fashion, where mild injuries affect only the superficial brain and severe injuries affect the deep, subcortical structures of the brain. Neurologic symptoms progressively worsen as depth of injury increases. Depth of brain lesion has been proposed as a potential prediction tool for functional outcome in older children and adolescents, but there is a paucity of data connecting depth of injury and outcome in young children. We hypothesized that functional outcome at hospital discharge will worsen as greatest depth of injury increases in children < 3. Methods: Retrospective chart review including patients < 3 years of age admitted to a tertiary children’s hospital PICU or Intermediate Care Unit between 2015 - 2020 with acute TBI. Patients were divided into 4 cohorts based on greatest depth of injury visible on initial neuroimaging: scalp/skull/epidural vs. subdural/subarachnoid vs. cortical brain vs. subcortical brain injury. Baseline and hospital discharge Functional Status Score (FSS) (score 6-30) and Pediatric Cerebral Performance Category (PCPC) (score 1-5) were assigned. Results: A total of 170 patients were included (scalp/skull/epidural, n=54; subdural/subarachnoid, n=76; cortical brain, n=17; subcortical brain, n=23). Median age was 6 months. Sixty percent of patients were male. Nine patients died, 1 with a cortical injury and 8 with subcortical injuries. Total length of stay (LOS), PICU LOS, and ventilator days all increased as depth of injury increased (p< 0.001). All patients had a normal baseline FSS of 6 and a PCPC of 1. As depth of injury increased from superficial to deepest, patients were more likely to have functional deficits at discharge (FSS: 4% vs. 7% vs. 38% vs. 73%, p< 0.001; PCPC: 2% vs. 8% vs. 44% vs. 73%, p< 0.001). Patients with subcortical injuries had significantly higher median FSS (10, IQR 6.5-13, p< 0.001) and PCPC (2, IQR 1.5-3.5, p< 0.001) at discharge. Conclusions: Functional outcomes at hospital discharge worsen as greatest depth of injury increases in children < 3 with acute TBI, supporting the potential use of depth of brain injury as a prediction tool for functional outcome in this population.