Session VII - Spine

Correlation of Clinical Findings, Collision Parameters, and Psychological Factors in the Outcome of Whiplash-Associated Disorders

Martinus Richter, MD; Dietmar Otte, MD; Hans-Werner Kuensebeck, MD; Michael Blauth, MD; Christian Krettek, MD, Hannover Medical School, Hannover, Germany

Purpose: Recent debates about whiplash-associated disorders and the late whiplash syndrome in particular have focused on the role of psychosocial factors within a given culture to explain why some collision victims progress from acute to chronic pain, although others do not. In a prospective study, we conducted a clinical and psychological assessment of whiplash victims and technically analyzed the collisions they suffered.

Methods: Restrained automobile occupants presenting to a trauma center with a whiplash-type neck distortion were assessed clinically, including use of a visual analogue scale (VAS 1-10), radiologically, and psychologically with the Short Form 36 (SF36), Everyday Life Quality (EDLQ), and Pain Control Questionnaires (FSR). The collision and its estimated delta V (change in velocity for the occupant's vehicle) were also assessed. For inclusion, the diagnosis "whiplash-type neck distortion" was defined as a soft tissue injury of the neck, Abbreviated Injury Scale (AIS) score 1 (without ligamentous or osseous instability) after a vehicle collision. The subjects also met the diagnostic criteria for grade 1 or 2 whiplash-associated disorder, as defined by the Quebec Task Force. Subjects with multiple trauma beyond soft-tissue injuries, those with loss of consciousness, and those with pre-existing neurological or psychiatric diseases were excluded. The patients were assessed at a 6-month follow-up with the VAS ratings of symptoms, SF36, EDLQ, Depression Scale (CES-D), and Impact of Event Scale (IES).

Results: Of 73 consecutive accident victims, 30 were excluded (10 with loss of consciousness, 6 with pre-existing neurologic or psychiatric disease, 9 with fractures, and 5 with radiographic evidence of ligamentous instability). Forty-three patients (22 men, 21 women) with an average age of 29 years (range, 19 to 72) were initially assessed. Twenty-seven (63%) had been drivers, 10 (23%) were front-seat passengers, and 6 (14%) were rear-seat passengers. Sixteen (37%) were rear-end collisions, 12 (28%) were frontal, 4 (9%) lateral, 1 (2%) was a roll-over, and 10 (23%) involved multiple collisions. The mean delta V was available for 36 of the 43 collisions and was 13.9 (range, 5 to 30) km/h. The most frequent initial symptoms were pain (n = 35, 81%), with an onset time of 1.1 hours (range, 0 to 12) and a VAS score of 4.5 (range, 1 to 8.5), and stiffness (n = 20, 46%), with an onset time of 3.0 hours (range, 0 to 24) and a VAS score of 4.8 (range, 3.1 to 6.7). Thirty-two (74%) of 43 subjects were available for follow-up. The mean duration of symptoms was 28 days (range, 0 to180). No correlation was found between the severity or between the duration of symptoms and the delta V of collision or other collision parameters. Patients with initial pain VAS >5 or those with a duration of symptoms of >28 days showed significant changes in single categories of the SF36, EDLQ, CES-D and IES scores at 6 months. They also had initial psychological profiles that were predictive of these outcomes in decision-tree analysis with CART (Classification and Regression Trees).

Discussion: Although only 32 (74%) of the 43 eligible subjects entered and completed the study to follow-up at 6 months, this group did not differ from those eligible but not recruited or lost to follow-up when comparing demographic and anthropometric data, collision parameters, and psychological scores. They could, therefore, be considered a representative sample. The array of initial symptoms and their severity are typical of whiplash patients in other studies. Psychological factors were found to be more relevant than collision severity or clinical findings in predicting the duration and severity of symptoms in restrained occupants of automobiles with grade 1 or 2 whiplash-associated disorders. The high significance of the psychological factors as predictors despite the small sample size suggests that their effects are large; other factors with less influence will only be detected with larger sample sizes.

Conclusions: Our data reveal that cultural differences do exist in the natural history of whiplash-associated disorders, and that, within a given culture, psychological factors are the best predictors of outcome. Put simply, culture, not crash, is the chief determinant of chronic pain after acute whiplash injury.