Author: Richard H. Adler

A recently published study by researchers in Ontario offers a clinical decision rule for early prediction of long-term whiplash associated disorder following rear end motor vehicle collisions.* It also includes supporting data which quantifies potential risk factors for chronic Whiplash associated disorder. This study has several features which add to its usefulness to those who deal with injury claims from automobile whiplash cases in insurance, medical and legal settings.

First, the authors note that Ontario has a no-fault insurance system which makes recovery of damages for pain and suffering in a traumatic injury claim difficult. This minimizes the risk of error presented by issues relating to compensation and litigation.
Second, the researchers were able to study rear-end collision patients prospectively, beginning shortly after collision. The cohort of 353 patients had been reported on in earlier studies, and consisted of patients presenting to either of the two emergency departments in Kingston, Ontario between October, 1995 and March 31, 1998.** An in-place injury surveillance program ensured comprehensiveness.

Patients were initially contacted within two weeks of injury, and on up to 8 occasions during a two-year follow-up period. For purposes of developing a clinical decision rule, outcome at six months was used. Whiplash associated disorder was defined as the presence of neck pain, upper back pain or shoulder pain (one or more) at six months post accident, with regular or daily frequency, and moderate to severe intensity.

The researchers analyzed data in a number of areas, including:

1. Symptoms reported initially;
2. Intensity and frequency of symptoms;
3. Crash characteristics;
4. Personal characteristics of patients.

RESULTS: RISK FACTOR ANALYSIS

At six months post injury, 35.3% of the patients were experiencing whiplash associated disorder. The authors note:

"...symptoms, as opposed to crash or personal characteristics, were the most consistent predictors of persistent Whiplash associated disorder".

This may indicate a low threshold of collision impact force and property damage for the occurrence of symptoms. It also suggests the absence or presence of whiplash associated disorder injury symptoms is "only modestly" affected by the auto accident circumstances.
In general, the most important risk factors identified through multiple logistical regression analysis were age (over 51) and the number of symptoms initially reported. The early development of certain specific symptoms (upper back pain, upper extremity numbness and weakness, and visual disturbance) was strongly associated with whiplash associated disorder.

The risk of whiplash associated disorder at 6 months increased significantly with increased intensity and frequency of trauma symptoms initially reported. (specifically neck pain, shoulder pain, upper back pain, lower back pain, and upper extremity numbness and weakness).

Personal characteristics of the injured person associated with increased risk of whiplash associated disorder at six months included:

1. Age (51 and over);
2. Time missed from work (as of initial interview);
3. Changes in work or leisure activities (as of initial interview).

DISCUSSION:

The primary purpose of this study was to begin formulation of a clinical decision rule for early identification of patients who are at risk for developing chronic whiplash associated disorder. The model developed involves asking patients, two weeks post collision, a sequence of up to three questions, addressing upper back pain, neck pain, and shoulder pain, respectively. The pattern of responses was found to be reasonably sensitive and "moderately" specific. The authors anticipate further refinement and validation will come from other prospective studies of emergency room patient groups.

This study's data and analysis regarding risk factors for chronic whiplash associated disorder have broad value for those healthcare providers, attorneys, and others who have a sustained interest in the medical-legal issues presented by neck and back injuries. The findings of greater risk for chronic whiplash associated disorder among the aged will confirm the clinical experience of many treating doctors. Early identification of high value risk factors can promote reasonable allocation of resources for diagnostic testing, care and treatment of traumatic personal injuries by insurance companies and care providers.

The study's findings regarding the relatively low predictive value of crash characteristics have major forensic significance for personal injury patients and their attorneys. Washington State trial judges are routinely asked by insurance company attorneys to permit "expert" testimony about statistical probabilities of injury, based on the amount of property damage to the vehicle and other collision characteristics. This study can help to confirm the lack of legal relevance and probative value of such inquiry in specific injury cases, where proof the collision caused traumatic injury which has persisted over the long term can be clouded by the admission of "junk science" testimony and evidence.

The personal injury recovery professional attorneys at Adler Giersch ps stand ready to assist those with neck and back injuries through our offices in Seattle, Bellevue, Everett and Kent.

* Hartling, L., Pickett, W., et al. Derivation of a clinical decision rule for whiplash associated disorders among individuals involved in rear-end collisions. Acc Anal & Prev 2001; 34: 531-539.

** Brison, R.J., Hartling, L., et al. A prospective study of acceleration-extension injuries following rear-end motor vehicle collisions. J Musc Pain 2000; 8: 97-113.