Neck strain in car occupants: the influence of crash-related factors on initial severity

ObjectiveTo examine the relationship between the initial severity of neck strain in car occupants and crash-related factors, in particular, crash severity.Design/participantsThirty-two individuals with neck strain after a car crash, drawn from physiotherapy and general practices in metropolitan Adelaide, were interviewed about their experience and examined by a manipulative physiotherapist. Crash severity was assessed by measurement of damage to the involved vehicles.Main outcome measuresFive measures of neck strain severity were obtained: number of body regions with symptoms, number of positive responses to palpation, cervical range of motion, subject's own rating on an analogue pain scale, and examiner's severity rating. Two measures of crash severity were used: maximum residual deformation, and velocity change of the subject's vehicle.ResultsNeck strain was observed in individuals who were involved in crashes of low severity. Maximum residual deformation of the vehicle was negatively associated with the subject's cervical range of motion and positively associated with the other measures of neck strain severity. For rear impacts, both measures of crash severity were associated with measures of neck strain severity. The group of subjects who were aware of the impending collision had a greater range of cervical spine movement and fewer positive responses to palpation than those who were unaware.ConclusionsInitial severity of neck strain is positively correlated with crash severity. Awareness of the impending collision may have a mitigating effect on injury severity.G.A. Ryan, G.W. Taylor, V.M. Moore and J. Dolini

Vertebral Artery Blood flow Velocity Changes Associated with Cervical Spine rotation: A Meta-Analysis of the Evidence with implications for Professional Practice

Many studies of vertebral artery (VA) blood flow changes related to cervical spine rotation have been published, but the findings are controversial and the evidence unconvincing. Recent Doppler measurements suggest that contralateral VA blood flow is compromised on full rotation in both healthy subjects and patients. More rigorous research is needed, and it was the aim of this study to conduct a meta-analysis of published data to inform professional practice. A systematic literature search, including only Doppler studies of VA blood flow velocity associated with cervical spine rotation in adults, yielded nine reports with published data. Using weighted means of the pooled data, the magnitude of the effect size (Cohen's d) was calculated for differences between patients and subjects, sitting or lying supine for testing, the parts of the VA insonated, and the changes recorded after cervical spine rotation. From this meta-analysis, VA blood flow velocity was found to be compromised more in patients than healthy individuals, on contralateral rotation, with the subject sitting, and more in the intracranial compared to the cervical part of the VA. Possible reasons for these findings are suggested, and it is advised that sustained end-of-range rotation and quick-thrust rotational manipulations be avoided until there is a stronger evidence base for clinical practice