Physiotherapist Chris Worsfold talks to Spinal Surgery News about identifying and managing risk factors for poor recovery following whiplash injury
There are scores of animal, human cadaver and computer simulation studies that have identified the cervical spine facet joints [1,2], intervertebral discs and ligaments [3–5], muscles [6–8], dorsal root ganglia [9,10] and vertebral artery [11,12] as being susceptible to injury during the whiplash mechanism, with the majority of the experimental evidence implicating the facet joint – and most probably the facet joint capsule – as a primary cause of symptoms following whiplash injury. Clinical studies demonstrating significant pain relief in chronic neck pain cohorts following nerve blocks or radiofrequency neurotomy lend support to this view [13]. The experimental evidence is compelling for facet joint injury following whiplash.
In vivo studies of pathology following whiplash injury are historically poorly represented in the literature [14], and they have not been without their critics [15]. In a high-quality study, Freeman and colleagues [16] demonstrated “substantial neuroradiographic differences” in the frequency of cerebellar tonsillar ectopia (CTE or Chiari malformation) between 1195 subjects with neck pain, with and without a recent history of motor vehicle-related crash trauma. Indeed, the authors concluded by criticising prior research on psychosocial causes of chronic pain following whiplash for failing to account for a possible neuropathologic basis for the symptoms. A recent investigation within 48 hours of the injury and using a turbo STIR sequence on a sample of subjects – a proportion demonstrating no objective signs (i.e. Quebec Grade I) – documented occult fractures and bone contusions of vertebral bodies and strains, tears, haematomas and perimuscular fluid in muscle [17] (see Table 1).
Muscle damage has also been demonstrated in the acute stage of injury using diagnostic ultrasound scanning [18] (Figure 1) and there has been anecdotal surgical evidence of muscle rupture, facet joint capsule rupture and ligament sprain [19].
Figure 1: Cervical spine ultrasound. Image courtesy of Donal McNally and Mandy Roshier, University of Nottingham
In the absence of Chiari-type symptoms (a history of whiplash injury and persisting suboccipital headache in combination with headache worsened by cough or bilateral sensory or motor deficits in the upper extremities [16]), many people with high levels of pain and disability will have no precise injury identified that can be linked to the symptoms using currently available technology. Indeed, the majority of the injuries arising from cadaver and animal models cannot be identified by clinically available diagnostic modalities. The prospect of imaging devices with higher resolution may provide a link betwe