Analysis of head impact exposure and brain microstructure response in a season-long application of a jugular vein compression collar: a prospective, neuroimaging investigation in American football

Abstract

BackgroundHistorical approaches to protect the brain from outside the skull (eg, helmets and mouthpieces) have been ineffective in reducing internal injury to the brain that arises from energy absorption during sports-related collisions. We aimed to evaluate the effects of a neck collar, which applies gentle bilateral jugular vein compression, resulting in cerebral venous engorgement to reduce head impact energy absorption during collision. Specifically, we investigated the effect of collar wearing during head impact exposure on brain microstructure integrity following a competitive high school American football season.MethodsA prospective longitudinal controlled trial was employed to evaluate the effects of collar wearing (n=32) relative to controls (CTRL; n=30) during one competitive football season (age: 17.04±0.67 years). Impact exposure was collected using helmet sensors and white matter (WM) integrity was quantified based on diffusion tensor imaging (DTI) serving as the primary outcome.ResultsWith similar overall g-forces and total head impact exposure experienced in the two study groups during the season (p>0.05), significant preseason to postseason changes in mean diffusivity, axial diffusivity and radial diffusivity in the WM integrity were noted in the CTRL group (corrected p<0.05) but not in the collar group (p>0.05). The CTRL group demonstrated significantly larger preseason to postseason DTI change in multiple WM regions compared with the collar group (corrected p<0.05).DiscussionReduced WM diffusivity alteration was noted in participants wearing a neck collar after a season of competitive football. Collar wearing may have provided a protective effect against brain microstructural changes after repetitive head impacts.Trial registration numberNCT02696200.

Effect of Internal Jugular Vein Compression on Intracranial Hemorrhage in a Porcine Controlled Cortical Impact Model

“…This novel prophylaxis through venous engorgement is intriguing in its capacity to address the multiple different mechanisms of TBI on microscopic (diffuse axonal injury) and macroscopic (hemorrhage) level that lead to morbidity and mortality. 4,5,12,13 Due to the absence of acceleration injury in the CCI model, our results contest an additional mechanism elucidated by IJV compression besides slosh mitigation through venous structural alterations. A quantitative mathematical model of the complex venous network is a substantial technical challenge and is beyond the scope of this paper; however, studies of simpler geometries and loading conditions have reported that increased internal pressure, volume, and diameter increases load bearing capacity in cylindrical fluid-filled vessels.…”

“…IJV compression and, presumably its effect on brain turgor, size, and resultant slosh mitigation, has been shown in pre-clinical and clinical studies to significantly reduce microstructural axonal damage from concussive impacts and acceleration forces. 12,13,22,23 This appealing approach as a prophylactic measure to TBI can only be considered for therapeutic use if mild venous congestion is shown to not intensify hemorrhagic injury. In this experiment, we have demonstrated that IJV compression prior to injury did not increase the propensity for hemorrhagic extension; and more significantly, actually reduced hemorrhage (both subarachnoid and intraparenchymal hemorrhage) in the porcine CCI model.…”

White matter alterations over the course of two consecutive high‐school football seasons and the effect of a jugular compression collar: A preliminary longitudinal diffusion tensor imaging study

“…The effects of cumulative head impacts on young athletes over their entire careers are still unknown. Emerging neuroimaging investigations have generated evidence that suggests that the brain network may be affected, both structurally and functionally, during one season of contact sports, even with only nonclinical, subconcussive head impacts being tracked [Bahrami et al, ; Bazarian et al, ; Davenport et al, ; Lao et al, ; Koerte et al, ; Merchant‐Borna et al, ; Myer et al, ; Yuan et al, in press). When taken in aggregate over the career of the athlete, repetitive SCI could potentially increase the risk of season (or career) ending injuries, neurological impairments, and WM alterations [Bahrami et al, ; Myer et al, ].…”

“…Even in later adolescence, WM connectivity supporting executive control of behavior is still immature. Therefore, any compromise in WM integrity in youth or adolescence may have significant developmental implications [Asato et al, ; Bahrami et al, ; Davenport et al, ; Merchant‐Borna et al, ; Myer et al, ; Steinberg, ; ).…”

Red Blood Cell Response to Blast Levels of Force Impartations Into Freely Moveable Fluid Surfaces Inside a Closed Container

“…Two clinical studies [6,7] have used a jugular compression collar to reduce cranial slosh. They both demonstrated marked protective effects in high school athletes during competitive fullcontact play with exposure to impacts resulting in accelerations up to 200 g. Initial animal studies also lent support to the physiology of using a small jugular compressive collar in rats by providing an 83% protective effect when the animals were exposed to a 900 x g impact model [8].…”