Axial Neck Loading Linked to Sports-Related Spine Injury
High peak linear and rotational acceleration of the head results in cervical spine injury
FRIDAY, July 22 (HealthDay News) -- Sports-related cervical spine injuries can be produced by an axial loading of the neck, with the impact causing high peak linear and rotational acceleration of the head, according to a letter published in the July 21 issue of the New England Journal of Medicine.
Steven P. Broglio, Ph.D., from the University of Michigan in Ann Arbor, and colleagues examined the in vivo biomechanical data on a cervical spine fracture in a male athlete, while he performed a head-down tackling maneuver during football. Peak linear and rotational acceleration of the head were measured using the Gadd severity index (GSI) and head injury criteria (HIC). Computed tomography (CT) scan and magnetic resonance imaging (MRI) were performed.
The investigators found the brain CT scan to be normal. However, the CT scan of the cervical spine revealed a fracture of the left facet of C6 at the inferior articulating process that extended into the laminar junction. MRI showed left-sided joint effusion and muscle edema at C6 and C7. The peak linear acceleration was 114×g (g-force, or 9.8 m per second squared) and rotational acceleration was 3318 radians per second squared. Compared to other athletes, the impact resulting in cervical fracture produced a substantially higher GSI score (812 versus 289.1) and HIC score (487 versus 187.4), probably due to longer duration of impact. A stable left C6 facet fracture with no neurologic sequelae showed complete healing on a 12-week follow-up CT scan.
"The mechanism of injury is consistent with sports-related spine injuries produced by an axial loading of the neck that results from the combined force of the head impact and the inertial loading from the torso," the authors write.
One author disclosed a financial interest in the instruments (HIT System, Sideline Response System [Riddell Inc.]) that were used to collect the biomechanical data reported in this study.