Prognostic factors for whiplash associated disorders

Sammanfattning: Disability and chronic pain secondary to low- speed vehicle collisions has been a known condition since the nineteenth century. Today, whiplash-associated disorders (WAD) are the most common personal injuries reported to insurance companies after motor vehicle accidents (MVAs). The prognosis has great variations, spanning from discomfort for a few days to lifelong disability and severe reduction in quality of life. A few well-accepted prognostic factors exist, including high level of pain immediately after the accident, post- traumatic stress and anxiety, and previous history of pain conditions. However, there is no accepted universal pathomechanism and there is a need for additional surveys regarding common characteristics of individuals with poor recovery potential after a whiplash injury. The overall objective of this thesis was to investigate possible risk factors for non- recovery after whiplash trauma. Specifically, we aimed to identify potential associations between non-recovery and involvement of insurance companies, genetic markers, cervical radiological degeneration, and sagittal align- ment. Additionally, we aimed to investigate the effect of an educational video-intervention on the recovery rate. The participants in this thesis are derived from four cohorts. The first cohort comprised individuals aged 18–65 years seeking care at an emergency department (Studies I and III). The second cohort comprised individuals aged 18– 65 years reporting neck pain to insurance companies after an MVA (Studies I and II). The third and fourth cohorts consisted of individuals aged 16–65 years, also recruited from an emergency department after whiplash trauma (Studies IV , V , VI, and VII). In all seven studies of this thesis, inclusion was made by the study team. Information in baseline questionnaires were filled in with regard to demographics and physical and mental health. The patients were followed up with regard to a patient-reported outcome measure (PROM), defined as reported non- recovery or recovery. Secondary outcome measures were level of pain and distress and the Whiplash Disability Questionnaire (WDQ). For Study V, we performed a randomization to either the intervention with the educational video or to a standard information sheet. In the studies included in this thesis, financial compensation from insurance companies, facet joint degeneration, sagittal alignment variables (low thoracic inlet angle (TIA) and Neck Tilt), high level of pain and distress were associated with non-recovery. Further, expectation of poor recovery was a risk factor. No prognostic or therapeutic value was demonstrated for genetic markers (represented by COMT gene haplotypes), the educational video, disc degeneration, or cervical sagittal curvature. This thesis contributes to the general knowledge on those groups of individuals that are at risk of poor prognosis after whiplash trauma. It raises a few new questions regarding prognostic factors. The findings of radiologic profiles being associated with non-recovery must be re-examined in the future, tentatively emphasizing the association between facet joint degeneration and continuous pain.