Reproducibility and Characterization of Head Kinematics During a Large Animal Acceleration Model of Traumatic Brain Injury

Abstract

Acceleration parameters have been utilized for the last six decades to investigate pathology in both human and animal models of traumatic brain injury (TBI), design safety equipment, and develop injury thresholds. Previous large animal models have quantified acceleration from impulsive loading forces (i.e., machine/object kinematics) rather than directly measuring head kinematics. No study has evaluated the reproducibility of head kinematics in large animal models. Nine (five males) sexually mature Yucatan swine were exposed to head rotation at a targeted peak angular velocity of 250 rad/s in the coronal plane. The results indicated that the measured peak angular velocity of the skull was 51% of the impulsive load, was experienced over 91% longer duration, and was multi- rather than uni-planar. These findings were replicated in a second experiment with a smaller cohort (N = 4). The reproducibility of skull kinematics data was mostly within acceptable ranges based on published industry standards, although the coefficients of variation (8.9% for peak angular velocity or 12.3% for duration) were higher than the impulsive loading parameters produced by the machine (1.1 vs. 2.5%, respectively). Immunohistochemical markers of diffuse axonal injury and blood–brain barrier breach were not associated with variation in either skull or machine kinematics, suggesting that the observed levels of variance in skull kinematics may not be biologically meaningful with the current sample sizes. The findings highlight the reproducibility of a large animal acceleration model of TBI and the importance of direct measurements of skull kinematics to determine the magnitude of angular velocity, refine injury criteria, and determine critical thresholds.

17α-Ethinyl estradiol-3-sulfate increases survival and hemodynamic functioning in a large animal model of combined traumatic brain injury and hemorrhagic shock: a randomized control trial

“…A closed-head TBI was initiated via a pneumatic device targeting a rotation of 250 radians/second in the coronal plane [ 32 ] with a subset of animals monitored for actual head kinematics [ 35 ]. Animals were immediately placed in lateral recumbency and subjected to arterial hemorrhage via controlled removal of approximately 40% of estimated total blood volume 161 ± 48.7 s after the TBI.…”

Non-Linear Device Head Coupling and Temporal Delays in Large Animal Acceleration Models of Traumatic Brain Injury

“…Moreover, previous sensor studies also intentionally varied the impulsive load across different head impact models: drop (helmeted and unhelmeted), 26 sled, 16 linear impactors 11 , 25 and captive bolt guns. 1 In contrast, a recent study by our group 18 using the HYGE device established coefficients of variation (COV) that ranged between 1 and 2% for the device and between 8 and 12% for head kinematic parameters, both of which are generally considered to be within the acceptable ranges in terms of reproducibility. 7 , 15 However, results also indicated unexpected large differences in angular velocity between the initial impulsive load as measured at the device (mean peak angular velocity of 250.51 rad/s) and a triaxial sensor mounted to the head (mean peak angular velocity of 130.22 rad/s), with an approximate doubling in temporal duration for head kinematics.…”

“…Dynamic rotational acceleration and deceleration of the head has been recognized as a fundamental aspect of traumatic brain injury (TBI) throughout six decades of experimental work, 18 and represents a common factor across most human injury scenarios (motor vehicle crashes, blast injury, fall, assault, sporting collision, etc .). Head kinematics (i.e., linear/angular velocity and acceleration) have been associated with both diffuse axonal injury and blood brain barrier dysfunction, and are frequently used to design critical injury thresholds in finite element models that span multiple species.…”

“…Specifically, only a handful of large animal studies have utilized head-mounted sensors 1 , 11 , 16 , 18 , 25 , 26 or high-speed video capture 16 , 23 , 24 to quantify head kinematics during acceleration injury (reviewed in Ref. 18 ).…”

“…Specifically, only a handful of large animal studies have utilized head-mounted sensors 1 , 11 , 16 , 18 , 25 , 26 or high-speed video capture 16 , 23 , 24 to quantify head kinematics during acceleration injury (reviewed in Ref. 18 ). Previous cadaver studies have used various methods for mounting sensors to the skull (see Supplemental Table 1), ranging from directly affixing a sensor to the skull 36 to mounting the sensor to the skull through the scalp 37 among other techniques.…”