Whiplash - INKling: evidence base for clinical practice

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Spitzer, MD, a professor at McGill University in Quebec, one of the first studies related to the scientific approach to the assessment and management of activity-related spinal disorders including cervical disorders. Spitzer, who has chaired several Canadian task forces on various medical issues such as spinal disorders and the periodic health examination, also presided over another task force study, published in the April 15, issue of Spine dealing precisely with the issue of whiplash-associated disorders.

The authors of the study added that diagnostic criteria and nomenclature used in WAD are confusing and not standardized, a major barrier to a better understanding of the condition. What they came up with was a set of clinical guidelines, even though task force authors admitted that they would have preferred to make firm recommendations based on research findings of good quality in the available literature.

Unfortunately, the virtual absence of such evidence made it necessary to develop these clinical guidelines from a consensus of the knowledge of experts in many clinical fields who served as members of the task force. He added that the report was significant in that it presented a classification of different levels of whiplash, along with the recommendation that specialists MD, PT, OT and others with knowledge of the Quebec task force on WAD be added to multidisciplinary evaluation teams so that clients will, hopefully, have a decreased chance of developing a chronic condition because they were seen early enough by such WAD specialists.

Belanger indicated that continuing education courses are being scheduled around the province of Quebec to train health professionals in the applications recommended by the Quebec task force report on WAD that show the most promise in heading off chronic conditions. Industries in other countries are finding interest in the subject, as well. The restraint is designed to simply snap forward during a collision to minimize head movement.

Stress on the neck and spine is supposed to be significantly reduced, giving greater protection against one of the most common injuries sustained in road accidents. Olson suggests that in this country, general insurers address the problem by not paying for WAD treatment, leaving that particular area of injury to automobile insurance, which has its own set of parameters. He noted that in his own practice of treating people with WAD he does not rely on passive modalities, even in the case of acute injury.

Instead, he treats these clients in a similar way he would treat an athlete who sustained a hamstring pull running track. Featured September 5, 0. December 17, 0. The extensive spread of referred pain is strongly suggestive for central hyper-excitability, possibly involving disinhibitory processes and expansion of receptive fields.

Augmented central nociceptive processing may occur anywhere along the neural pathways and the location of the hyper-excitability cannot be determined from these studies. Nevertheless, some studies have utilized the nociceptive withdrawal reflex to analyze spinal cord hyper-excitability. Patients with chronic WAD displayed lower reflex thresholds than healthy subjects. It is important to recognize that central hypersensitivity is not specific to whiplash, but has been observed in different chronic pain syndromes, such as endometriosis, 13 fibromyalgia, 14 osteoarthritis, 15 tension-type headache, 16 , 17 temporomandibular joint pain, 18 and post-mastectomy pain.

Recent data demonstrate that sensory disturbances observed in chronic WAD are in fact present soon after the injury. In the acute phase post-injury up to 4 weeks , local cervical mechanical hyperalgesia decreased pressure pain thresholds is found in both individuals with lower and higher levels of pain and disability, 20 , 21 but this resolves quickly in those with good and fair recovery. In contrast to local hyperalgesia, which occurs irrespective of pain and disability levels, the presence of generalized hyperalgesia has been shown to be more apparent in those individuals reporting higher pain and disability 21 and subsequent poor recovery.

Importantly some of the sensory phenomena demonstrate capacity to predict individuals at risk of poor recovery. In particular, the early presence of cold hyperalgesia is emerging as a consistent prognostic factor.

Initial studies demonstrated that in addition to initial moderate pain, decreased neck movement, older age, and post-traumatic stress symptoms, cold hyperalgesia predicted higher levels of pain and disability at both 6 months and 2—3 years post-injury. In summary, current evidence would suggest that some central nervous system nociceptive processes are augmented from soon after injury in those individuals who do not recover but develop chronic moderate to severe pain and disability. The reasons as to why this group manifests more profound changes in pain processes are not clear but there are numerous possibilities including but not limited to: The most optimal way to modulate these processes is yet unknown.

In addition to subjecting soft tissues to a biomechanical strain, an MVC event is also an acute stressor which activates physiological stress response systems. In recent times, models have been put forward that link stress system responses 28 and sympathetic nervous system activation 32 and the various physiological changes seen in WAD including both sensory and motor manifestations.

There is some evidence available indicating that autonomic disturbances are present in chronic WAD. Impaired peripheral vasoconstrictor responses have been demonstrated in both acute and chronic whiplash 6 but the relationship of these changes to the clinical presentation of whiplash or outcomes following injury is not clear. Autonomic nervous system dysfunction has been found to be present in other painful musculoskeletal conditions such as chronic low back pain, 34 fibromyalgia, 35 and cervicobrachialgia. COMT is the primary enzyme that degrades catecholamines, including adrenaline, noradrenaline, and dopamine.

Variants of the COMT gene have been associated with experimental pain sensitivity 39 and with vulnerability to both chronic pain 39 and anxiety disorders. These individuals also estimated that they would take longer to recover both physically and emotionally. In summary, investigation of stress system responses and their role in both non-recovery and the clinical presentation of WAD is in its infancy. Nevertheless, due to the traumatic nature of its onset, this may be an important factor to be considered in this condition.

There has also been a substantial body of research investigating the motor, muscle, and sensorimotor changes in individuals following whiplash injury. Changes include loss of movement, 42 altered muscle recruitment patterns 43 , morphological changes in neck muscles, 44 disturbed eye movement control, 45 , 46 loss of balance and joint repositioning errors, 47 , 48 and decreased muscle strength 49 with most of these changes being identified in the early acute post-injury stage as well as in individuals with chronic WAD.

It should be noted that many of these movement and motor disturbances are not unique to whiplash-related neck pain but are also found to be present in individuals with non-traumatic neck pain of insidious onset, 43 , 50 thus it could be extrapolated that they are not involved in the initiation and maintenance of whiplash-related pain and disability, rather are a sequelae of as yet unexplained nociceptive processes.

The exception to this is recent interesting findings of magnetic resonance imaging muscle data. Structural muscle changes in the form of fatty infiltration in the neck muscles of females with chronic WAD have been identified. However, before definitive conclusions can be drawn regarding the importance of these quantifiable muscle changes, an improved understanding of the underlying mechanisms for alterations in paraspinal muscle structure and function as well as their contribution to the development and maintenance of painful signs and symptoms is required.

Few measures of motor or muscle function have demonstrated the capacity to predict poor recovery following injury. Decreased cervical range of movement is the physical factor most commonly investigated for its predictive capacity.

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An earlier review found only limited evidence for the prognostic capacity of this factor 54 and this is supported by more recent reviews where the general consensus is that this factor is not a strong predictor of poor recovery. Most of the documented motor deficits movement loss and altered neuromuscular control seem to be present in whiplash-injured individuals irrespective of reported pain and disability levels and rate or level of recovery.

This is not to say that management approaches directed at improving motor dysfunction should not be provided to patients with whiplash. Rather the identification of motor deficits alone may not equip the clinician with useful information to either gauge prognosis or potential responsiveness to physical interventions. The psychological presentation of whiplash can be as equally diverse as the physical presentation, with some individuals showing marked distress and others seeming resilient to the injury.

Depressive symptoms are also a common feature of acute whiplash injury 65 and may be associated with prior mental health problems and poorer general health, 65 , as well as poor post-injury adjustment. Different psychological factors may be involved in the etiology and development of chronic whiplash pain when compared to other painful musculoskeletal conditions. The sudden, traumatic onset could also lead to stronger somatic beliefs and related fears regarding recovery.

The effect of the psychological stress surrounding the crash itself as opposed to or in addition to distress about neck pain complaints may have a significant influence on outcome. A recent prospective cohort study of participants identified three distinct trajectories for post-traumatic stress measured using the PTSD diagnostic scale. However, such management approaches are often not provided to people with whiplash.

Introduction

While potential processes have been outlined in this paper as separate entities, it is clear that there will be interactions and relationships between these processes. To date this has not been well explored but is an important area for future research. However, there are data available to suggest associations between these factors. Similar results have been found in acute WAD, where cold pain threshold and catastrophisation show moderate correlations.

However, they do not support the assumption that psychological factors are the only or main factors responsible for central hyper-excitability in whiplash patients. In particular, spinal cord hyper-excitability appears to not be affected, at least significantly, by psychological factors.

Account Options

The relationships between sensory changes and post-traumatic stress symptoms have also been explored. Using trajectory modeling analyses, distinct trajectories or clinical pathways for both pain and disability and post-traumatic stress were identified. Additionally dual analyses revealed that the developmental trajectories of pain and disability and PTSD were mostly in synchrony. Recent findings have also illustrated a relationship between symptoms of post-traumatic stress and physical characteristics of WAD.

Physical measures of hyperalgesia cold and mechanical predicted both a moderate to severe post-traumatic stress symptom trajectory as well as a more severe pain-related disability trajectory 26 indicating relationships between the physical and psychological manifestations of acute to chronic WAD.

Current post-traumatic stress symptoms have also been shown to be associated with less activity later in the same day in chronic WAD. Thus data are emerging to show that the physical and psychological processes associated with WAD not only co-exist but are also inter-related. Further research is required to clarify this understanding.

The results of more thorough investigation along the lines outlined above may provide direction as to the high priority factors to target. For example, should stress responses be targeted or nociceptive peripheral and central processes or psychological processes or a combination of these factors? This is not clear as yet. As discussed in this paper, there is growing evidence of both complex biological and psychological manifestations of WAD and these factors likely contribute to the significant chronicity rate and recalcitrance to treatment associated with this condition.

There is still much work to be done. It remains unknown as to whether or not these processes can be modulated and if modulation will lead to improved outcomes. National Center for Biotechnology Information , U. J Man Manip Ther. Author information Copyright and License information Disclaimer. This article has been cited by other articles in PMC. Abstract The aim of this paper was to review the physical and psychological processes associated with whiplash-associated disorders.

Introduction Whiplash-associated disorders WADs are a common, disabling, and costly condition that occur usually as a consequence of a motor vehicle crash MVC. Stress System Responses In addition to subjecting soft tissues to a biomechanical strain, an MVC event is also an acute stressor which activates physiological stress response systems. Changes in the Muscle and Motor Function There has also been a substantial body of research investigating the motor, muscle, and sensorimotor changes in individuals following whiplash injury.

Psychological Presentation of WAD The psychological presentation of whiplash can be as equally diverse as the physical presentation, with some individuals showing marked distress and others seeming resilient to the injury. Relationships between Physical and Psychological Features of WAD While potential processes have been outlined in this paper as separate entities, it is clear that there will be interactions and relationships between these processes.

Conclusions As discussed in this paper, there is growing evidence of both complex biological and psychological manifestations of WAD and these factors likely contribute to the significant chronicity rate and recalcitrance to treatment associated with this condition. Course and prognostic factors for neck pain in whiplash-associated disorders WAD.

Canada Sets Guidelines for Whiplash

Results of the bone and joint decade — task force on neck pain and its associated disorders. Eur Spine J ; 17 Suppl 1: A prospective cohort study of health outcomes following whiplash associated disorders in an Australian population. Inj Prev ; Physical and psychological predictors of outcome following whiplash injury maintain predictive capacity at long term follow-up.

The anatomy and biomechanics of acute and chronic whiplash injury. Traffic Inj Prev ; Muscular hyperalgesia and referred pain in chronic whiplash syndrome. Sensory hypersensitivity occurs soon after whiplash injury and is associated with poor recovery. Sheather-Reid R, Cohen M. Psychophysical evidence for a neuropathic component of chronic neck pain. The late whiplash syndrome: Eur J Pain ; 6: Curatolo M, Sterling M. Pain-processing mechanisms in whiplash associated disorders: Sterling M, Kenardy J, editors.

Evidence for spinal cord hypersensitivity in chronic pain after whiplash injury and in fibromyalgia. Psychological factors are related to some sensory pain thresholds but not nociceptive flexion reflex threshold in chronic whiplash. Clin J Pain ; Differential development of sensory hypersensitivity and a measure of spinal cord hyperexcitability following whiplash injury.

Whiplash-associated disorder: musculoskeletal pain and related clinical findings

Endometriosis is associated with central sensitization: J Pain ; 4: J Rheumatol ; Osteoarthritis and its association with muscle hyperalgesia: Decreased pain detection and tolerance thresholds in chronic tension-type headache. Arch Neurol ; Central hyperexcitability as measured with nociceptive flexor reflex threshold in chronic musculoskeletal pain: Hypersensitivity to mechanical and intra-articular electrical stimuli in persons with painful temporomandibular joints. J Dental Res ;

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