The effects of padded surfaces on the risk for cervical spine injury.
METHODS
This is an in vitro study comparing cervical spine injuries produced in rigid head impacts and in padded head impacts.


OBJECTIVE
To test the hypothesis that deformable impact surfaces pose a greater risk for cervical spine injury than rigid surfaces using a cadaver-based model that includes the effects of the head and torso masses.


BACKGROUND
It is widely assumed that energy-absorbing devices that protect the head from injury also reduce the risk for neck injury. However, this has not been demonstrated in any experimental or epidemiologic study. On the contrary, some studies have shown that padded surfaces have no effect on neck injury risk, and others have suggested that they can increase risk.


METHODS
Experiments were performed on 18 cadaveric cervical spines to test 6 combinations of impact angle and impact surface padding. The impact surface was oriented at -15 degrees (posterior impact), 0 degree (vertex impact), or +15 degrees (anterior impact). The impact surface was either a 3-mm sheet of lubricated Teflon or 5 cm of polyurethane foam.


RESULTS
Impacts onto padded surfaces produced significantly larger neck impulses (P = 0.00023) and a significantly greater frequency of cervical spine injuries than rigid impacts (P = 0.0375). The impact angle was also correlated with injury risk (P < 0.00001).


CONCLUSIONS
These experiments suggest that highly deformable, padded contact surfaces should be used carefully in environments where there is the risk for cervical spine injury. The results also suggest that the orientation of the head, neck, and torso relative to the impact surface is of equal if not greater importance in neck injury risk.
Nightingale
R W
RW
Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.
Richardson
W J
WJ
Myers
B S
BS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D002574:Cervical Vertebrae / Q000293:injuries*; D004867:Equipment Design; D005260:Female; D006260:Head Protective Devices; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D019838:Neck Injuries / Q000209:etiology*