Ever wondered why someone is hurt worse in a car wreck than someone in a similar-type wreck? It’s a good question, and one that has been extensively researched, which shows a number of different variables contribute to chronic (long-term) injury risk in a collision.
What follows is a summary of this research. These test results have been published, presented at scientific conferences, and subjected to peer review. The following risk factors have been identified, and there are likely others:
Gender:
Per-Olof Bylund & Ulf Bjornstig, Sick Leave & Disability Pension Among Passenger Car Occupants Injured in Urban Traffic 23(9) Spine 1023, 1024 (1998).
Women predominately are among those having cervical strain injuries following rear-impact collisions, and take sick leave for longer periods.
Clinical ligamentous instability:
Jack E. Wilberger & Joseph C. Maroon, Occult posttraumatic cervical ligamentous instability 3(2) Journal of Spinal Disorders 156, 160 (1990).
When horizontal displacement exceeds 1.5 mm, and/or angular displacement is greater than five (5) degrees on either lateral or flexion/extension films, the possibility of significant ligamentous injury should be considered in acute trauma patients. If there is marked limitation in spine motion, then the flexion/extension films should be rechecked at an appropriate interval in order to avoid a permanent problem.
Presence of a tow bar:
The presence of a tow-bar on a vehicle struck from the rear increases the risk of long-term consequences of neck injuries by 22%, but does not affect the risk of short-term consequences.
Early onset of symptoms and/or more severe initial symptoms:
Delayed recovery of whiplash injuries were primary related to the severity of initial injury, as measured by symptoms of radicular irritation and intensity of initial neck pain.
Greater cognitive impairment:
A significant predictor of a poor recovery from a whiplash injury is the intensity of the initial reaction to a more severe injury, which includes sleep disturbances.
Greater number of initial symptoms:
A. Watkinson, M.F. Gargan & G.C. Bannister, Prognostic factors in soft tissue injuries of the cervical spine 22(4) Injury 307, 307-09 (1991).
In a follow up study of whiplash injury victims 10.8 years (on average) following a collision, no patient fully recovered who initially had more than just neck pain.
Past history of neck pain or headache:
Previous history of head trauma or pre-traumatic headache were predictive of delayed recovery at 6 and 12 months following a whiplash injury.
Initial degenerative changes seen on radiographs (x-rays):
A. Watkinson, M.F. Gargan & G.C. Bannister, Prognostic factors in soft tissue injuries of the cervical spine 22(4) Injury 307, 308 (1991).
In a follow up study of whiplash injury victims, patients with initial degenerative changes on radiographs (x-rays) have more symptoms after 2 years than those with normal radiographs at the time of injury, and no patient with severe symptoms had a normal cervical spine radiograph (x-ray) 10 years following a collision.
C. Maimaris, M.R. Barnes & M.J. Allen, ‘Whiplash injuries’ of the neck: a retrospective study 19(5) Injury 393, 395 (1988).
In a study designed to observe the natural progression of whiplash injuries and to identify useful prognosis factors, the authors found 33% of patients with whiplash injuries were symptomatic two years after a collision, and pre-existing degenerative changes as well as positive radiographic findings in the neck strongly indicated a poor prognosis.
Age:
Age is a significant variable in predicting the outcome of a whiplash injury at 6 and 12 months.
With so many different variables, it is impossible to determine an injury threshold whereby nobody can be hurt because the permutations of these different risk factors could be in the thousands or tens of thousands. It is difficult to deny the more of these risk factors one is subjected to at the time of a collision, the more likely they are to be hurt, i.e., Murphy’s law.
