Acute Whiplash: Clinical and Finite Element Analysis

Study Design: A prospective 1-year study of whiplash patients presenting with either isolated neck pain (WADI/II), or neck pain with neurological signs/or symptoms (WADIII). Objective: We hypothesize that WADI/II and WADIII are distinct entities with significant differences in clinical presentation, pathoanatomy, and prognosis. Summary of Background Data: Whiplash associated disorders (WAD) are disparate and can range from mild neck pain (WADI/II), to insults associated with neurologic sequellae (WADIII), and even fracture/dislocations (WADIV). To date, literature considers post whiplash syndrome a single clinical and pathologic entity along a spectrum with escalating grades of severity (WADI-IV). However, a diverse pathogenesis may underlie the different grades of WAD, and these distinctive pathoanatomies may better portray the prognosis of these entities. Methods: Thirty one subjects were divided into a WADI/II control group and a WADIII study group. All subjects underwent H&P, radiographic evaluations, and clinical outcome measures (collected at 3, 6, and 12 months). A finite element analysis (FEA) technology (SCOSIA©) was used to predict stresses within the neuraxis. Statistical analysis was performed (Student T-test, Wilcoxon Signed-Rank test) with significance set at p=0.05. Results: At presentation, WADI/II group demonstrated better neurologic assessments, functional performances, and higher quality-of-life measurements in comparison to WADIII cohort. Yet VAS scores were comparable between the two groups. At final follow-up, both groups reported improvements in neurologic status and disability symptoms. However, functional recovery and quality-of-life measures significantly improved in WADIII, and conversely deteriorated in WADI/II. Additionally, WADI/II also portrayed notable worsening of pain symptoms. Litigation claims were comparable between the two groups. FEA predicted higher stress within the neuraxis of WADIII, most notably in subjects with preexisting stenosis and odontoid retroflexion. Conclusion: WADI/II and WADIII are distinct entities with different pathoanatomy and outcomes. Musculoskeletal injury precipitates WADI/II pain symptoms while neuronal stretching leads to WADIII neurologic injuries. Notably, most of the neurologic injuries in WADIII are recoverable.