Neck Solutions Blog

Minimizing the source of nociception and its concurrent effect on sensory hypersensitivity: An exploratory study in chronic whiplash patients

From: BMC Musculoskelet Disord. 2010 Feb 9;11(1):29. [Epub ahead of print]

Cervical spine pain and dysfunction resulting from a motor vehicle collision motor vehicle collision are common patient problems encountered by health care practitioners. Many patients will significantly recover with respect to neck pain and disability within the first six months to one year. Researchers have reported that 32% to 56% of those that have sustained a motor vehicle collision will continue to suffer pain and disability beyond the six month period.

The cervical zygapophyseal joint has been implicated as a source of pain in those with chronic whiplash associated disorders . Studies utilizing controlled, comparative anaesthetic nerve block procedures have reported that the prevalence of cervical zygapophyseal joint pain in those with chronic whiplash associated disorders ranged from 54% to 60%. Biomechanical and neurophysiological studies have provided evidence in support of cervical zygapophyseal joint involvement in motor vehicle collisions.

Research has indicated that the ongoing pain associated with chronic whiplash associated disorders may be due to altered pain processing as evidenced by sensory hypersensitivity at distant sites involving uninjured tissues. Central nervous system hyperexcitability may provide an explanation for the generalized sensory hypersensitivity seen in some patients with chronic whiplash associated disorders. Sensory hypersensitivity is characterized by decreased pain thresholds to mechanical, thermal, and electrical stimuli. The presence of sensory hypersensitivity, in particular cold hyperalgesia, in whiplash patients has been associated with a poor prognosis. The precise mechanisms underlying sensory hypersensitivity are unclear, but peripheral, spinal, and supraspinal mechanisms have been hypothesized.

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A study of the test-retest reliability of the self-perceived general recovery and self-perceived change in neck pain questions in patients with recent whiplash-associated disorders

From: Eur Spine J. 2010 Feb 4. [Epub ahead of print]

The objectives of this study were to determine the test-retest reliability of two self-perceived recovery questions in patients with recent whiplash associated disorders, and to assess whether remembering previous answers influences reliability. The self-perceived general recovery and self-perceived change in neck pain questions were administered to 46 patients with recent whiplash associated disorders 6 weeks after recruitment and again 3-5 days later. At follow-up, the authors’ also asked participants if they remembered their previous answers. The authors’ used the intra-class correlation coefficients (ICC) to measure the reliability of the original ordinal response structure and kappa statistics for dichotomized responses. The ICC [95% confidence intervals (CI)] for the general recovery and for the change in neck pain questions were 0.70 (0.60-0.80) and 0.80 (0.72-0.87), respectively. The kappa statistic (95% CI) for the general recovery question was 0.81 (0.64-0.99) when recovery was defined as “completely better” or “much improved”. The kappa statistic (95% CI) for the change in neck pain question was 0.80 (0.62-0.99) when recovery was defined as “very much better” or “better”. The authors’ analysis suggests that the test-retest reliability may be higher for participants who remembered their previous responses. In conclusion, their results suggest that self-perceived recovery questions have adequate reliability for use in epidemiological research of whiplash associated disorders.

Magnetic Resonance Imaging Findings of Fatty Infiltrate in the Cervical Flexors in Chronic Whiplash

From: Spine (Phila Pa 1976). 2010 Jan 28. [Epub ahead of print]

Retrospective investigation of muscle changes in patients suffering from chronic whiplash associated disorders. The objective was to quantitatively compare the presence of muscle alterations (fatty infiltrate and cross-sectional area) in the anterior musculature of the cervical spine in a cohort of chronic whiplash patients (whiplash associated disorders II) and healthy control subjects across muscle and cervical segmental level.

Magnetic resonance imaging can be regarded as the gold standard for muscle imaging. There is little knowledge about in vivo features of anterior neck muscles in patients suffering from chronic whiplash associated disorders and how muscle structure differs across the factors of muscle, vertebral level, age, self-reported pain and disability, body mass index, and duration of symptoms.

Reliable magnetic resonance imaging measures for fatty infiltrate and cross-sectional area were performed for the anterior cervical muscles bilaterally in 109 female subjects (78 whiplash associated disorders, 31 healthy control; 18-45 years, 3 months to 3 years post injury). The measures were performed on all subjects for the longus capitis and longus colli and the sternocleidomastoid muscles.

The whiplash associated disorders subjects had significantly larger fatty infiltrate and cross-sectional area for the anterior muscles compared to healthy control subjects. In addition, the amount of fatty infiltrate varied by both cervical level and muscle, with the longus capitis and longus colli having the largest amount of fatty infiltrates at the C2-C3 level. Fatty infiltrate was inversely related to age, self-reported pain and disability, and body mass index but directly proportional to duration of symptoms.

There is significantly greater fatty infiltrate and cross-sectional area in the anterior neck muscles, especially in the deeper longus capitis and longus colli muscles, in subjects with chronic whiplash associated disorders when compared to healthy controls. Future studies are required to investigate the relationships between muscular morphometry and symptoms in patients suffering from acute and chronic whiplash associated disorders.

Related Posts:

The clinical presentation of chronic whiplash and the relationship to findings of MRI fatty infiltrates in the cervical extensor musculature: a preliminary investigation

Fatty infiltrate in the cervical extensor muscles is not a feature of chronic, insidious onset neck pain

MRI study of the cross sectional area for the neck extensor musculature in patients with persistent whiplash associated disorders

Related Links: Fatty Infiltration in the Cervical Extensor Muscles in Persistant Whiplash Associated Disorders

Factors associated with recovery expectations following vehicle collision: A population-based study.

From: J Rehabil Med. 2010 Jan;42(1):66-73

Whiplash associated disorders are a common problem, estimated at 300–600 cases per 100,000 population per year in North America and western Europe. They are costly to insurance/medical systems, and may result in long-term disability in the injured person, including increased risk of future neck pain and other health complaints. Clinically, there is uncertainty about how to manage these injuries, and the scale and complexity of the whiplash dilemma makes whiplash injuries an important public health concern. Although many different treatment modalities have been studied, these treatment effects in whiplash associated disorders are modest at best, and frequently short-lived. This suggests that other types of interventions may be required to reduce disability and improve outcomes. As such, researchers and clinicians should focus attention on factors that have demonstrated independent associations with patient recovery.

One already demonstrated and clinically meaningful approach is to focus on patients’ expectations about their own recovery. Studies have consistently shown that, for a wide variety of medical conditions, positive expectations for recovery are positively associated with better clinical outcomes, from increased success of rehabilitation and to reduced levels of post-operative pain. In addition, 2 recent studies have identified recovery expectations as important in whiplash associated disorders recovery. In fact, in a Canadian study, those with whiplash associated disorders having positive expectations recovered more than 3 times faster than those who expected never to get better. A Swedish study found a dose-response relationship between recovery expectations and disability 6 months after the crash. After controlling for severity of physical and mental symptoms, individuals who expected they would not make a full recovery were over 4 times more likely to have a high disability; those who self-rated as having “intermediate” recovery expectations were over two times more likely to have high disability. Both groups were compared to those stating they were very likely to make a full recovery. Given the substantial effect size and independent relationship demonstrated by recovery expectation on recovery in both whiplash associated disorders population studies, assessing patients’ expectations early in the injury experience appears useful, particularly in identifying those who have the greatest concerns regarding their recovery, thus helping reduce the burden of whiplash associated disorders in this vulnerable group. Moreover, such findings lead to the prospect that modifying a persons’ expectation for whiplash associated disorders recovery will speed their actual recovery and thus decrease the burden of impairment and disability.

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