Citation

Jadischke R, Viano DC, McCarthy J, King AI. BMJ Open Sport Exerc. Med. 2018; 4(1): e000362.

Affiliation

Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.

Copyright

(Copyright © 2018, British Association of Sport and Exercise Medicine, Publisher BMJ Publishing Group)

DOI

10.1136/bmjsem-2018-000362

PMID

30364582

PMCID

PMC6196936

Abstract

OBJECTIVES: Most biomechanical research on brain injury focuses on direct blows to the head. There are a few older studies that indicate craniocervical stretch could be a factor in concussion by causing strain in the upper spinal cord and brainstem. The objectives of this study are to assess the biomechanical response and estimate the strain in the upper cervical spine and brainstem from primary impact to the chest in American football.

METHODS: Impact testing was conducted to the chest of a stationary unhelmeted and helmeted anthropomorphic test device (ATD) as well as the laboratory reconstruction of two NFL game collisions resulting in concussion. A finite element (FE) study was also conducted to estimate the elongation of the cervical spine under tensile and flexion loading conditions.

RESULTS: The helmeted ATD had a 40% (t=9.84, p<0.001) increase in neck tensile force and an 8% (t=7.267, p<0.001) increase in neck flexion angle when compared with an unhelmeted ATD. The case studies indicated that the neck tension in the injured players exceeded tolerable levels from volunteer studies. The neck tension was combined with flexion of the head relative to the torso. The FE analysis, combined with a spinal cord coupling ratio, estimated that the strain along the axis of the upper cervical spinal cord and brainstem was 10%-20% for the combined flexion and tension loading in the two cases presented.

CONCLUSION: Strain in the upper spinal cord and brainstem from neck tension is a factor in concussion.

Language: en

Keywords

Hybrid III dummy; brainstem; concussion; football; mTBI; upper neck forces