The role of tissue damage in whiplash-associated disorders: discussion paper 1.

STUDY
DESIGN: Nonsystematic review of cervical spine lesions in whiplash-associated disorders (WAD).
OBJECTIVE: To describe whiplash injury models in terms of basic and clinical science, to summarize what can and cannot be explained by injury models, and to highlight future research areas to better understand the role of tissue damage in WAD. SUMMARY OF BACKGROUND DATA: The frequent lack of detectable tissue damage has raised questions about whether tissue damage is necessary for WAD and what role it plays in the clinical context of WAD.
METHODS: Nonsystematic review.
RESULTS: Lesions of various tissues have been documented by numerous investigations conducted in animals, cadavers, healthy volunteers, and patients. Most lesions are undetected by imaging techniques. For zygapophysial (facet) joints, lesions have been predicted by bioengineering studies and validated through animal studies; for zygapophysial joint pain, a valid diagnostic test and a proven treatment are available. Lesions of dorsal root ganglia, discs, ligaments, muscles, and vertebral artery have been documented in biomechanical and autopsy studies, but no valid diagnostic test is available to assess their clinical relevance. The proportion of WAD patients in whom a persistent lesion is the major determinant of ongoing symptoms is unknown. Psychosocial factors, stress reactions, and generalized hyperalgesia have also been shown to predict WAD outcomes.
CONCLUSION: There is evidence supporting a lesion-based model in WAD. Lack of macroscopically identifiable tissue damage does not rule out the presence of painful lesions. The best available evidence concerns zygapophysial joint pain. The clinical relevance of other lesions needs to be addressed by future research.