Ashley Pedler

Magnetic resonance imaging findings of fatty infiltrate in the cervical flexors in chronic whiplash.

Study Design. Retrospective investigation of muscle changes in patients suffering from chronic whiplash-associated disorders (WAD). Objectives. To quantitatively compare the presence of muscle alterations (fatty infiltrate [MFI] and cross-sectional area [CSA]) in the anterior musculature of the cervical spine in a cohort of chronic whiplash patients (WAD II) and healthy control subjects across muscle and cervical segmental level. Summary of Background Data. 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 WAD 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. Methods. Reliable magnetic resonance imaging measures for MFI and CSA were performed for the anterior cervical muscles bilaterally in 109 female subjects (78 WAD, 31 healthy control; 18–45 years, 3 months to 3 years postinjury). The measures were performed on all subjects for the longus capitis and colli and the sternocleidomastoid muscles. Results. The WAD subjects had significantly larger MFI and CSA for the anterior muscles compared to healthy control subjects (all P < 0.0001). In addition, the amount of MFI varied by both cervical level and muscle, with the longus capitis/colli having the largest amount of fatty infiltrates at the C2–C3 level (P < 0.0001). MFI was inversely related to age, self-reported pain/disability, and body mass index but directly proportional to duration of symptoms. Conclusion. There is significantly greater MFI and CSA in the anterior neck muscles, especially in the deeper longus capitis/colli muscles, in subjects with chronic WAD 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 WAD.

The temporal development of fatty infiltrates in the neck muscles following whiplash injury: An association with pain and posttraumatic stress

Background Radiological findings associated with poor recovery following whiplash injury remain elusive. Muscle fatty infiltrates (MFI) in the cervical extensors on magnetic resonance imaging (MRI) in patients with chronic pain have been observed. Their association with specific aspects of pain and psychological factors have yet to be explored longitudinally. Materials and Findings 44 subjects with whiplash injury were enrolled at 4 weeks post-injury and classified at 6 months using scores on the Neck Disability Index as recovered, mild and moderate/severe. A measure for MFI and patient self-report of pain, loss of cervical range of movement and posttraumatic stress disorder (PTSD) were collected at 4 weeks, 3 months and 6 months post-injury. The effects of time and group and the interaction of time by group on MFI were determined. We assessed the mediating effect of posttraumatic stress and cervical range of movement on the longitudinal relationship between initial pain intensity and MFI. There was no difference in MFI across all groups at enrollment. MFI values increased in the moderate/severe group and were significantly higher in comparison to the recovered and mild groups at 3 and 6 months. No differences in MFI values were found between the mild and recovered groups. Initial severity of PTSD symptoms mediated the relationship between pain intensity and MFI at 6 months. Initial ROM loss did not. Conclusions MFI in the cervical extensors occur soon following whiplash injury and suggest the possibility for the occurrence of a more severe injury with subsequent PTSD in patients with persistent symptoms.

Cervical lateral glide increases nociceptive flexion reflex threshold but not pressure or thermal pain thresholds in chronic whiplash associated disorders: A pilot randomised controlled trial

Sensory hypersensitivity indicative of augmented central pain processing is a feature of chronic whiplash associated disorders (WAD). This study investigated the immediate effects of a cervical spine manual therapy (SMT) technique on measures of central hyperexcitability. In a randomised, single blind, clinical trial, 39 participants with chronic WAD were randomly assigned to a cervical SMT (lateral glide) or manual contact intervention. The Neck Disability Index (NDI) and GHQ-28 were administered at baseline. Pressure pain thresholds (PPTs), thermal pain thresholds (TPTs) and Nociceptive Flexion Reflex (NFR) responses (threshold and VAS of pain) were measured pre and post intervention. There was a significantly greater increase in NFR threshold following SMT compared to the manual contact intervention (p = 0.04). PPTs at the cervical spine increased following both SMT (mean +/- SE: 24.1 +/- 7.3%) and manual contact (21 +/- 8.4%) with no difference between interventions. There was no difference between interventions for pain ratings with the NFR test, PPTs at the Median Nerve or Tibialis Anterior, heat or cold TPT. SMT may be effective in reducing spinal hyperexcitability in chronic WAD.

Differential changes in muscle composition exist in traumatic and nontraumatic neck pain

Study Design. A population based cross-sectional study. Objective. To clarify relative constituents of viable muscle in 2-dimensional cross-sectional area (CSA) measures of ventral and dorsal cervical muscles in patients with chronic whiplash-associated disorders (WAD), idiopathic neck pain, and healthy controls. Summary of Background Data. Previous data using T1-weighted magnetic resonance image demonstrated large amounts of neck muscle fat infiltration and increased neck muscle CSA in patients with chronic WAD but not in idiopathic neck pain or healthy controls. Methods. Magnetic resonance images were obtained for 14 cervical muscle regions in 136 females, including 79 with chronic whiplash, 23 with chronic idiopathic neck pain, and 34 healthy controls. Results. Without fat removed, relative CSA of 7 of 14 muscle regions in the participants with chronic WAD was larger, 3 of 14 smaller and 4 of 14 similar to healthy individuals. When T1-weighted signal representing the lipid content of these muscles was removed, 8 of 14 relative muscle CSA in patients with whiplash were similar, 5 of 14 were smaller and only 1 of 14 was larger than those observed in healthy controls. Removal of fat from the relative CSA measurement did not alter findings between participants with idiopathic neck pain and healthy controls. Conclusion. These findings clarify that previous reports of increased relative CSA in patients with chronic whiplash represent cervical muscle pseudohypertrophy. Relative muscle CSA measures reveal atrophy in several muscles in both patients with WAD and idiopathic neck pain, which supports inclusion of muscle conditioning in the total management of these patients. Level of Evidence: 3

Relationship between pressure pain thresholds and pain ratings in patients with whiplash-associated disorders

ObjectivesIncreased sensitivity to pressure is commonly associated with painful musculoskeletal conditions, including whiplash-associated disorders (WADs). Pressure pain thresholds (PPTs) close to the site of presumed tissue damage are thought to represent the degree of peripheral nociceptive sensitization. PPTs over healthy tissue, away from the site of injury, are a marker of central nervous system hyperexcitability. There is uncertainty, however, as to what extent does the sensitization of the nociceptive system, whether peripheral or central, contribute to the ongoing, habitual pain experienced by people with WAD. MethodsOne hundred patients with WAD were assessed within 4 weeks of their accident and followed after 3 months; 24-hour average neck pain score, PPTs at the cervical spine and tibialis anterior, demographic factors, and psychological measures were collected. ResultsCervical PPT and neck pain score were significantly, but weakly correlated (r=−0.20 to −0.33). There was no significant correlation between tibialis anterior PPT and pain score at any time point (r=−0.01 to −0.21). Regression analyses indicated a strong influence of generalized psychological distress and fear avoidance on the relationship between PPT and pain report. DiscussionThe competing explanations for these findings are that either PPTs provide a poor marker of peripheral and central sensitivity or that these processes are only weakly related to the day-to-day pain experienced by patients with WAD. The latter explanation is supported by the confounding effect of psychological factors on pain score.

Evidence of Spinal Cord Hyperexcitability as Measured With Nociceptive Flexion Reflex (NFR) Threshold in Chronic Lateral Epicondylalgia With or Without a Positive Neurodynamic Test

UNLABELLED There is emerging evidence of altered pain signal processing as a likely underlying mechanism in chronic lateral epicondylalgia (LE), yet this remains to be assessed. Furthermore, it has been proposed that neurodynamic tests reflect nociceptive withdrawal responses. Therefore, the objective was to improve our understanding of spinal cord excitability as measured by nociceptive flexion reflex (NFR) threshold in chronic LE with and without a positive neurodynamic test. NFR threshold, pain-free grip, and pressure pain threshold were measured in 30 LE participants and 31 healthy controls. Test of neural tissue involvement (using upper limb neural tension, radial bias) was used to differentiate LE participants with or without a positive neurodynamic test. There were significant differences in NFR threshold between the control and LE with or without a positive neurodynamic test (F[2,54] = 5.68, P = .006), after adjusting for age, sex, pain rating at NFR threshold, and reflex size (NFR interval peak z score). The mean differences (95% confidence interval) in NFR threshold between the control and LE with or without a positive neurodynamic test were 3.74 mA (.637, 6.84) and 3.38 mA (.0245, 6.74) respectively. PERSPECTIVE The results suggest evidence of spinal cord hyperexcitability, particularly sensory hypersensitivity, in LE with or without a positive neurodynamic test. Our data appear to support the hypothesis that continued peripheral afferent stimulation results in facilitation of nociceptive pathways in this patient population.

Assessing fear-avoidance beliefs in patients with whiplash-associated disorders: a comparison of 2 measures.

ObjectivesTo examine the development of fear avoidance behaviours following whiplash injury using two different measures of fear avoidance, the Pictorial Fear of Activities Scale-Cervical (PFActS-C), and the Tampa Scale of Kinesiophobia (TSK-17). Secondarily we assessed the capacity of these measures to predict recovery status at long term follow up and initial cervical range of movement (ROM). MethodsNinety-eight patients with acute WAD were recruited and completed measures of pain and disability (NDI), fear avoidance beliefs and cervical ROM at baseline (<4 weeks), 3 and 6 months post injury. Participants were grouped based on NDI scores at 6 months follow up as either recovered (NDI <10), mild (NDI 10-28) or moderate/severe (NDI⩽30). ResultsRepeated measures, linear mixed model analysis showed a significant main effect for time and group for both TSK-17 and PFActS-C scores (P⩽0.001). On both measures the moderate/severe group scored significantly higher than the mild and recovered groups. TSK-17 scores, age and initial pain intensity at baseline significantly predicted NDI scores at 6 months (P=0.002). PFActS-C scores, age and initial pain intensity at baseline significantly predicted initial cervical extension and rotation ROM (P=0.001). DiscussionFear avoidance beliefs and behaviours develop quickly following whiplash injury and influence both the initial physical presentation and long term outcome of patients with WAD. The PFActS-C may provide a measure of fear of movement which is more specific to the cervical spine in patients with WAD in comparison to the TSK-17.

The Geography of Fatty Infiltrates Within the Cervical Multifidus and Semispinalis Cervicis in Individuals With Chronic Whiplash-Associated Disorders

STUDY DESIGN Cross-sectional. OBJECTIVES To quantify the magnitude and distribution of muscle fat infiltration (MFI) within the cervical multifidus and semispinalis cervicis muscles in participants with chronic whiplash-associated disorders (WADs) compared to those who have fully recovered from a whiplash injury and healthy controls. BACKGROUND Previous research has established the presence of increased MFI throughout the cervical extensor muscles of individuals with WAD when compared to healthy controls. These changes appear to be greater in the deepest muscles (eg, multifidus and semispinalis cervicis) than in the more superficial muscles. A detailed analysis of the distribution of MFI within these deep extensor muscles in chronic WAD, recovered, and control groups would provide a foundation for further investigation of specific mechanisms, etiologies, and targets for treatments. METHODS Fifteen participants (WAD, n = 5; recovered, n = 5; and control, n = 5) were studied using a 3-D fat-water separation magnetic resonance imaging sequence. Bilateral measures of cervical multifidus and semispinalis cervicis MFI in 4 quartiles (1 [medial] to 4 [lateral]) at cervical levels C3 through C7 were included in the analysis. Intrarater and interrater reliability were established. A mixed-model analysis was performed to control for covariates, identify interaction effects, and compare MFI distribution between groups. RESULTS The limits of agreement confirmed strong intrarater and interrater agreement at all levels (C3-C7). Sex, age, and body mass index were identified as significant covariates for MFI. Significant interactions were found between group and muscle quartile (P<.001) and between muscle quartile and cervical level (P<.001). Pairwise comparisons for intraquartile MFI between groups revealed significantly greater MFI in the WAD group when compared to the recovered group in the first quartile (P<.001), second quartile (P<.001), and third quartile (P = .03). When compared to the control group, the WAD group had significantly greater MFI in the first quartile (P = .002) and the second quartile (P = .045). The control group had significantly higher MFI in comparison to the recovered group in the first quartile (P = .048). CONCLUSION This study provides preliminary data mapping the spatial distribution of MFI in the cervical multifidus and semispinalis cervicis muscles in individuals with chronic WAD, those who have recovered from a whiplash injury, and healthy controls. Muscle fat infiltration is more concentrated in the medial portion of the muscles in all participants. However, the magnitude of MFI in the medial quartiles (1 and 2) is greatest in the chronic WAD group.

Less efficacious conditioned pain modulation and sensory hypersensitivity in chronic whiplash-associated disorders in Singapore.

Objectives:Cultural differences in pain perception exist. Although chronic whiplash-associated disorder (WAD) is well investigated in western countries, little is known about its presentation in Singapore. We studied the neck motion and pain sensitivity in people with chronic WAD in Singapore. Materials and Methods:Thirty chronic WAD participants (>3 mo, Neck Disability Index: 40% [SD 17%]) were age, sex, and ethnicity matched with 30 pain-free controls. All 60 participants underwent the following tests: active neck motion, pain thresholds (pressure, brachial plexus provocation test [BPPT], cold), cold pain tolerance, and conditioned pain modulation (CPM). The test stimulus of contact heat and conditioning stimulus of cold water immersion was used to assess CPM. Data were evaluated to determine differences between WAD and control groups. Results:Active neck motion (F1,29=80.02), pain thresholds of blunt pressure (F1,29=20.84), BPPT (F1,29=54.56), and cold (Z=−4.31) were significantly lower in participants with WAD (P<0.0001). Cold pressor pain tolerance was significantly lower in participants with WAD (Z=−2.89, P=0.02). A less efficacious CPM was also demonstrated in participants with WAD (F1,29=9.20, P=0.03). A combination of BPPT and cold hyperalgesia best predicted the WAD group (sensitivity=96.7%, specificity=96.7%). Discussion:These findings of sensory hypersensitivity and decreased neck motion in Singaporeans with chronic WAD are consistent with physical impairments reported in western populations.

Morphological changes in the cervical muscles of women with chronic whiplash can be modified with exercise-A pilot study

Introduction: In this preliminary study we determined whether MRI markers of cervical muscle degeneration [elevated muscle fatty infiltration (MFI), cross‐sectional area (CSA), and reduced relative muscle CSA (rmCSA)] could be modified with exercise in patients with chronic whiplash. Methods: Five women with chronic whiplash undertook 10 weeks of neck exercise. MRI measures of the cervical multifidus (posterior) and longus capitus/colli (anterior) muscles, neck muscle strength, and self‐reported neck disability were recorded at baseline and at completion of the exercise program. Results: Overall significant increases in CSA and rmCSA were observed for both muscles, but significant reductions in MFI were only evident in the cervical multifidus muscle. These changes coincided with increased muscle strength and reduced neck disability. Conclusions: MRI markers of muscle morphology in individuals with chronic whiplash appear to be modifiable with exercise. Muscle Nerve 52: 772–779, 2015