A Proposed Injury Threshold for Mild Traumatic Brain Injury

Abstract

Traumatic brain injuries constitute a significant portion of injury resulting from automotive collisions, motorcycle crashes, and sports collisions. Brain injuries not only represent a serious trauma for those involved but also place an enormous burden on society, often exacting a heavy economical, social, and emotional price. Development of intervention strategies to prevent or minimize these injuries requires a complete understanding of injury mechanisms, response and tolerance level. In this study, an attempt is made to delineate actual injury causation and establish a meaningful injury criterion through the use of the actual field accident data. Twenty-four head-to-head field collisions that occurred in professional football games were duplicated using a validated finite element human head model. The injury predictors and injury levels were analyzed based on resulting brain tissue responses and were correlated with the site and occurrence of mild traumatic brain injury (MTBI). Predictions indicated that the shear stress around the brainstem region could be an injury predictor for concussion. Statistical analyses were performed to establish the new brain injury tolerance level.

Characterization of persistent concussive syndrome using injury reconstruction and finite element modelling

“…show results consistent with previous research (Table 5) (Zhang et al, 2004;Kleiven 2007;Willinger and Baumgartner 2003). This data set of PCS reconstructions were characterized by a large variance in resultant metrics, with large magnitude brain stress and strain responses, far larger than would be expected based on previous concussion literature (King et al, 2003;Zhang et al, 2004).…”

“…Cerebrum maximum principal strain responses for the PCS cases. Suggested ranges of concussion from the literature represented by black dotted lines (Zhang et al, 2004;Kleiven, 2007), ranges of TBI represented by red dotted lines (Doorly, 2007;. (Zhang et al, 2004;Willinger and Baumgartner, 2003;Kleiven, 2007), ranges of TBI represented by red dotted lines (Doorly, 2007;.…”

“…The collisions were also caused by impacts to non-compliant surfaces, but generally at lower velocities (under 3.8 m/s). Of all the cases there were five that resulted in magnitudes of stress and strain that were less than those expected for concussion (cases 2,3,17,18, and 20) (King et al, 2003;Zhang et al, 2004). The varied nature of the impact conditions in these cases suggest that it is possible that pure biomechanics of impact may not be fully descriptive of the risk for these individual cases and perhaps they had a susceptibility to incurring a concussive or PCS injury.…”

“…The significant impact PCS has on patients dictates the need to better understand the metrics that characterize the risk and severity of this brain injury. Brain injury reconstruction research has proposed peak linear and rotational acceleration and stress and strain parameters to characterize severity of injuries for those patients who experience transient concussive symptoms (King et al, 2003;Zhang et al, 2004;Kleiven, 2007), but no investigation has studied patients with PCS.…”

“…What is certain is that PCS, like other brain injuries, occurs through some form of injurious stress or strain applied to the brain tissue (Holbourn, 1943;Ommaya and Gennarelli, 1974;King et al, 2003;Kleiven, 2007;Post and Hoshizaki, 2012). This injurious loading can occur through contact (Wilinger and Baumgartner, 2003;Zhang et al, 2004;Kleiven, 2007), or through non-contact loading (Gennarelli et al, 1971;Ommaya and Genarelli, 1974). From a biomechanical perspective, brain injury, be it transient concussion or PCS, is likely linked to the characteristics of the event that caused the injury .…”