Revision as of 19:58, 19 January 2024

Abstract:

In 2021, the U.S. Food and Drug Administration (FDA), authorized the marketing of the “Q-Collar”, a device worn around the neck that adds an external compressive force to the jugular veins to increase blood volume in the brain. Such a device is worn by athletes in contact sports such as football, and by special forces exposed to blasts, as evidence from clinical studies have indicated its role in mitigating head injuries.¹ The objective of this literature review is to provide an overview of the studies on jugular vein compression collars such as the Q-collar to better understand its role and proven effects in mitigating head injuries, while further encouraging research for its applications.

Introduction:

Traumatic brain injuries occur at alarming rates in the United States. Data from the National Institute of Neurological Disorders and Stroke indicate that an estimated 1.6 to 3.8 million traumatic brain injuries related to sports occur each year.¹ Research on traumatic brain injuries in sports has resulted in advancements in the designs of helmets to better protect the head from impact. However, helmets alone have shown to be ineffective on their own in preventing concussion and long term brain damage.² A jugular vein compression collar is a device that is worn around the neck to apply pressure to the jugular veins in order to reduce blood flow to the brain. Such devices have demonstrated promise in reducing structural brain damage associated with trauma. As they begin to be utilized in conjunction with helmets in the hopes of mitigating brain damage and long term concerns, this review provides information from studies conducted on its use to better understand its applications.

Methods:

The literature search was conducted using the PUBMED database. Articles were searched for using the keywords “Jugular Vein Compression Collar”. Screening for full text articles yielded 25 results. This review included articles discussing jugular vein compression collars in head injuries and sports, while also including animal studies, which resulted in the review of 21 studies in this article.

Discussion:

Jugular vein compression collars (Image 1) have been a topic of interest with regards to traumatic brain injuries. Trauma to the head results in pressure waves that ripple through the fluids of the skull, thus impacting local structures and causing neuronal disruptions. The phenomenon termed “slosh” refers to the destabilization resulting in a fluid wave as a partially filled container, i.e. the skull, is redirected with a force. Jugular vein compression collars provide compression to the jugular veins, resulting in increased intracranial blood volume and pressure, thus reducing the “slosh” effect by reducing compliance in the skull.³ Optic nerve sheath diameter, a direct marker of intracranial pressure, was measured using ultrasound prior to and following application of a jugular vein compression collar. Significant elevations in diameter, indicating increased intracranial pressure, were found following application of the collar.⁴ Intracranial pressure is further raised through elevations in cerebrospinal pressure in the skull following application of the jugular vein compression collar.⁵

The severity of traumatic brain injuries can be characterized by local strain. Micro-damage to local tissue can be demonstrated through inflammatory biomarkers such as phosphorylated tau epitope AT8. Preclinical small animal studies indicate that a jugular vein compression collar results in a significant reduction in these inflammatory biomarkers following head trauma, thus indicating that jugular vein compression collars protect against histopathological changes related to head trauma.^6-7 Such studies have also demonstrated immediate increases in intraocular and intracranial pressure following application of the jugular vein compression collar.⁸

Due to the proposed reduction in micro-damage and histopathological changes to the brain following trauma, jugular vein compression collars have been investigated for their use in contact sports. Many prospective studies were conducted on high school football, soccer, and hockey players, dividing them into groups with collars and control groups without collars. These studies found significant reductions in microstructural brain alterations, improved working memory on standardized tasks, and reduced changes to white matter visualized through MRI in the athlete groups that wore the collar.^9-17

The use of jugular vein compression collars have similarly been investigated for their use to mitigate brain injuries that occur following exposure to blasts. A trial analyzing special forces training groups exposed to blasts divided participants into collar vs. no collar groups. Prior to and following the training exercises, the participants had electroencephalography (EEG) tests. Participants who did not wear the collar were found to have longer periods of laminar electrocortical behavior, a finding associated with pathologies such as seizures.¹⁸ In another trial, special forces were divided into collar and non-collar groups while exposed to blasts in simulation training. Using MRI findings prior to and following the training, it was found that the non-collar group had a significant amount of alteration in white matter.¹⁹ A similar trial made use of fMRI brain activation to assess working memory following a training session with low impact blast simulations. The group without collars had a significant elevation in fMRI brain activation following the training when asked to perform a standardized task, while also indicating an increase in activity in the auditory region compared to the fMRI performed prior to the simulation training. The findings provide initial evidence for the protective effects of jugular vein compression collars on protecting memory functions after blast exposure with possible effects on auditory processing.²⁰ A study exploring jugular vein compression in rats exposed to otoacoustic emissions to simulate blast injuries provides further support for the role of jugular vein compression collars in ameliorating auditory injuries associated with blasts. In the study, rats were divided into collar and non-collar groups. Following exposure to otoacoustic emissions, the rats in the collar group had reduced auditory brainstem response threshold shifts in comparison to the control group. Additionally, the collar group was found to have a greater number of cochlear hair cells following blast injury.²¹ A study with a similar design also found reduced cochlear hair cell loss and further concluded that the jugular vein compression collar significantly reduced tympanic membrane rupture.²²

The use of the jugular vein compression collar also provides a degree of compression on the carotid artery. As such, it influences the baroreceptors in the carotid sinus, and induces an increase in sympathetic activity. This effect of the collar has been studied for its potential in patients with orthostatic hypotension, a condition in which there is a decrease in blood pressure as one assumes a standing position, as it could assist such patients in maintaining blood pressure with postural changes.²³

Conclusion:

The studies analyzing jugular vein compression collars indicate the correlation between collar use and reduced microstructural brain damage. While many studies analyzed the use of the collar over the course of a sports season or simulation training event, further studies analyzing the use of the collar and associated brain imaging and histopathologic findings over a longer time period can provide better insight into the role of jugular vein compression in mitigating traumatic brain injuries.

References:

1.) Commissioner of the FDA authorizes marketing of novel device to help protect athletes' brains during head impacts. U.S. Food and Drug Administration. https://www.fda.gov/news-events/press-announcements/fda-authorizes-marketing-novel-device-help-protect-athletes-brains-during-head-impacts. Accessed January 22, 2023.

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3.) Yeoh TY, Venkatraghavan L, Fisher JA, Meineri M. Internal jugular vein blood flow in the upright position during external compression and increased central venous pressure: an ultrasound study in healthy volunteers. Débit sanguin de la veine jugulaire interne en position debout pendant une compression externe et augmentation de la pression centrale veineuse : une étude échographique auprès de volontaires sains. Can J Anaesth. 2017;64(8):854-859. doi:10.1007/s12630-017-0903-3

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5.) Raphael JH, Chotai R. Effects of the cervical collar on cerebrospinal fluid pressure. Anaesthesia. 1994;49(5):437-439. doi:10.1111/j.1365-2044.1994.tb03482.x

6.) Mannix R, Morriss NJ, Conley GM, et al. Internal Jugular Vein Compression Collar Mitigates Histopathological Alterations after Closed Head Rotational Head Impact in Swine: A Pilot Study. Neuroscience. 2020;437:132-144. doi:10.1016/j.neuroscience.2020.04.009

7.) Turner RC, Naser ZJ, Bailes JE, Smith DW, Fisher JA, Rosen CL. Effect of slosh mitigation on histologic markers of traumatic brain injury: laboratory investigation. J Neurosurg. 2012;117(6):1110-1118. doi:10.3171/2012.8.JNS12358

8.) Smith DW, Bailes JE, Fisher JA, Robles J, Turner RC, Mills JD. Internal jugular vein compression mitigates traumatic axonal injury in a rat model by reducing the intracranial slosh effect. Neurosurgery. 2012;70(3):740-746. doi:10.1227/NEU.0b013e318235b991

9.) Yuan W, Diekfuss JA, Barber Foss KD, et al. High School Sports-Related Concussion and the Effect of a Jugular Vein Compression Collar: A Prospective Longitudinal Investigation of Neuroimaging and Neurofunctional Outcomes. J Neurotrauma. 2021;38(20):2811-2821. doi:10.1089/neu.2021.0141

10.) Yuan W, Leach J, Maloney T, et al. Neck Collar with Mild Jugular Vein Compression Ameliorates Brain Activation Changes during a Working Memory Task after a Season of High School Football. J Neurotrauma. 2017;34(16):2432-2444. doi:10.1089/neu.2016.4834

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13.) Yuan W, Dudley J, Barber Foss KD, et al. Mild Jugular Compression Collar Ameliorated Changes in Brain Activation of Working Memory after One Soccer Season in Female High School Athletes. J Neurotrauma. 2018;35(11):1248-1259. doi:10.1089/neu.2017.5262

14.) Myer GD, Yuan W, Barber Foss KD, et al. 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. Br J Sports Med. 2016;50(20):1276-1285. doi:10.1136/bjsports-2016-096134

15.) Myer GD, Yuan W, Barber Foss KD, et al. The Effects of External Jugular Compression Applied during Head Impact Exposure on Longitudinal Changes in Brain Neuroanatomical and Neurophysiological Biomarkers: A Preliminary Investigation. Front Neurol. 2016;7:74. Published 2016 Jun 6. doi:10.3389/fneur.2016.00074

16.) Yuan W, Barber Foss KD, Thomas S, et al. 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. Hum Brain Mapp. 2018;39(1):491-508. doi:10.1002/hbm.23859

17.) Dudley J, Yuan W, Diekfuss J, et al. Altered Functional and Structural Connectomes in Female High School Soccer Athletes After a Season of Head Impact Exposure and the Effect of a Novel Collar. Brain Connect. 2020;10(6):292-301. doi:10.1089/brain.2019.0729

18.) Bonnette S, Diekfuss JA, Kiefer AW, et al. A jugular vein compression collar prevents alterations of endogenous electrocortical dynamics following blast exposure during special weapons and tactical (SWAT) breacher training. Exp Brain Res. 2018;236(10):2691-2701. doi:10.1007/s00221-018-5328-x

19.) Yuan W, Dudley J, Slutsky-Ganesh AB, et al. White Matter Alteration Following SWAT Explosive Breaching Training and the Moderating Effect of a Neck Collar Device: A DTI and NODDI Study. Mil Med. 2021;186(11-12):1183-1190. doi:10.1093/milmed/usab168

20.) Yuan W, Barber Foss KD, Dudley J, et al. Impact of Low-Level Blast Exposure on Brain Function after a One-Day Tactile Training and the Ameliorating Effect of a Jugular Vein Compression Neck Collar Device. J Neurotrauma. 2019;36(5):721-734. doi:10.1089/neu.2018.5737

21.) Sindelar B, Shinners M, Sherman S, et al. Internal Jugular Vein Compression: A Novel Approach to Mitigate Blast Induced Hearing Injury. Otol Neurotol. 2017;38(4):591-598. doi:10.1097/MAO.0000000000001332

22.) Sindelar B, Shinners M, Sherman S, et al. Reduction in Temporary and Permanent Audiological Injury Through Internal Jugular Vein Compression in a Rodent Blast Injury Model. Otol Neurotol. 2017;38(8):1205-1212. doi:10.1097/MAO.0000000000001500

23.) Joshi H, Hynes LM, Edgell H. Influence of a neck compression collar on cerebrovascular and autonomic function in men and women. PLoS One. 2019;14(12):e0225868. Published 2019 Dec 2. doi:10.1371/journal.pone.0225868