Quantitative sensory measures distinguish office workers with varying levels of neck pain and disability
From: Pain. 2008 Jul 15;137(2):257-65. Epub 2007 Oct 25
This study was undertaken to investigate any relationship between sensory features and neck pain in female office workers using quantitative sensory measures to better understand neck pain in this group. Office workers who used a visual display monitor for more than four hours per day with varying levels of neck pain and disability were eligible for inclusion. There were 85 participants categorized according to their scores on the neck disability index: 33 with no pain (neck disability index less than 8); 38 with mild levels of pain and disability (neck disability index 9-29); 14 with moderate levels of pain (neck disability index 30). A fourth group of women without neck pain (n=22) who did not work formed the control group. Measures included: thermal pain thresholds over the posterior cervical spine; pressure pain thresholds over the posterior neck, trapezius, levator scapulae and tibialis anterior muscles, and the median nerve trunk; sensitivity to vibrotactile stimulus over areas of the hand innervated by the median, ulnar and radial nerves; sympathetic vasoconstrictor response. All tests were conducted bilaterally. ANCOVA models were used to determine group differences between the means for each sensory measure. Office workers with greater self-reported neck pain demonstrated hyperalgesia to thermal stimuli over the neck, hyperalgesia to pressure stimulation over several sites tested; hypoaesthesia to vibration stimulation but no changes in the sympathetic vasoconstrictor response. There is evidence of multiple peripheral nerve dysfunction with widespread sensitivity most likely due to altered central nociceptive processing initiated and sustained by nociceptive input from the periphery.
Reorganization of the motor cortex is associated with postural control deficits in recurrent low back pain
From: Brain. 2008 Aug;131(Pt 8):2161-71. Epub 2008 Jul 18
Many people with recurrent low back pain have deficits in postural control of the trunk muscles and this may contribute to the recurrence of pain episodes. However, the neural changes that underlie these motor deficits remain unclear. As the motor cortex contributes to control of postural adjustments, the current study investigated the excitability and organization of the motor cortical inputs to the trunk muscles in 11 individuals with and without recurrent low back pain. EMG activity of the deep abdominal muscle, transversus abdominis, was recorded bilaterally using intramuscular fine wire electrodes. Postural control was assessed as onset of transversus abdominis EMG during single rapid arm flexion and extension tasks. Motor thresholds for transcranial magnetic stimulation were determined for responses contralateral and ipsilateral to the stimulated cortex. In addition, responses of transversus abdominis to transcranial magnetic stimulation over the contralateral cortex were mapped during voluntary contractions at 10% of maximum. Motor thresholds and map parameters, centre of gravity and volume, were compared between healthy and low back pain groups. The centre of gravity of the motor cortical map of transversus abdominis in the healthy group was approximately 2 cm anterior and lateral to the vertex, but was more posterior and lateral in the low back pain group. The location of the centre of gravity and the map volume were correlated with onset of transversus abdominis EMG during rapid arm movements. Furthermore, the motor thresholds needed to evoke ipsilateral responses was lower in the low back pain group, but only on the less excitable hemisphere. These findings provide preliminary evidence of reorganization of trunk muscle representation at the motor cortex in individuals with recurrent low back pain, and suggest this reorganization is associated with deficits in postural control.
The Influence of Posture and Loading on Interfacet Spacing: An Investigation Using Magnetic Resonance Imaging on Porcine Spinal Units
From: Spine. 2008 Sep 15;33(20):E728-E734
Axial rotation has frequently been identified as a risk factor for the development of low back injury in epidemiological investigations. However, the mechanism responsible for this increased risk has not been directly quantified. Increased axial rotation motion is used clinically to indicate instability and has been implicated as a potential cause of low back pain. Recently, it has been demonstrated that larger axial twist angles can be achieved when coupled with forward flexion in vivo. The range of twist motion permitted in the spine has been calculated as a function of the distance between the articulating surfaces of the facets using kinematic data and computed tomography reconstructions, but the tracking of the facet joint in coupled postures has not been reported in detail. Whether the reason epidemiological studies identify axial twist as a risk factor for low back pain is due to a shift in the load distribution from the facet joint to the intervertebral disc or other spinal tissues has not been determined. Using finite element modeling, it was reported that the primary factor in determining the relative effectiveness of the facet joints in resisting rotation was the amount of interfacet spacing. Changes in facet joint spacing in different postures could lead to errors in diagnosis and subsequent treatments prescribed when magnetic imaging technologies are used to diagnose spinal instability. Can posture or loading history cause a difference in the mechanics of the spine? This question is relevant to address concepts such as instability, spine mechanics, and injury mechanisms, and can be explored using an in vitro approach combined with current medical imaging technologies. In vitro investigations permit the necessary control and accessibility necessary to examine the facet joint behavior when the spine is in coupled postures. Therefore, quantifying the effect of posture and loading history on interfacet spacing would provide important information in helping to resolve some of these issues.
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Initial Investigation of the Relation between Extended Computer Use and Temporomandibular Joint Disorders
From: J Can Dent Assoc. 2008 Sep;74(7):643
To determine if temporomandibular joint disorders (tmj) are associated with extended computer use. People with chronic pain and extensive computer use were recruited by means of a newspaper advertisement. Those who responded to the ad were asked to complete an online survey, which included questions on computer use, medical history, pain symptoms, lifestyle and mood. Ninety-two people completed the online survey, but none of them responded to all questions in the survey. Of the 88 respondents who reported their sex, 49 (56%) were female. Most of the respondents had used computers for more than 5 hours per day for more than 5 years, and most believed that their pain was linked to computer use. The great majority had pain in the neck (73/89 [82%]) or shoulder (67/89 [75%]), but many (40/91 [44%]) also had symptoms of TMJ. About half of the participants reported poor sleep and fatigue, and many linked their pain to negative effects on lifestyle and poor quality of life. Two multiple regressions, with duration of pain as the dependent variable, were carried out, one using the entire sample of respondents who had completed the necessary sections of the survey (n = 91) and the other using the subset of people with symptoms suggestive of TMJ (n = 40). Duration of computer use was associated with duration of pain in both analyses, but 6 other independent variables (injury or arthritis, hours of daily computer use, stress, position of computer screen relative to the eyes, sex, and age) were without effect. In these regression analyses, the intercept was close to 0 years, which suggests that the pain began at about the same time as computer use.
This web-based survey provides the first evidence that chronic pain in jaw muscles and other symptoms of TMJ are associated with long-term, heavy use of computers. However, the great majority of people with these symptoms probably also suffer from pain in the shoulder and neck.
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Prevalence of cervical spondylosis and musculoskeletal symptoms among coolies in a city of Bangladesh
From: J Occup Health. 2006 Jan;48(1):69-73
Cervical spondylosis is a common degenerative condition of the cervical spine in the general population in the 50–60 yr age group. The etiology of cervical spondylosis is associated with the aging process, and is closely related to the intrinsic axial load imposed by the weight of the cranium lifelong. Some occupational positions may demand repeated or prolonged flexion, extension or extreme bending of the neck. These may lead to degenerative changes in the cervical spine. Occupation related degenerative change in the cervical spine has recently been included in the disease register of occupational diseases in Germany. Cervical
spondylosis usually produces intermittent neck pain in middle-aged and elderly patients. The degenerative changes in the cervical spine, in advanced stages, can cause compression of the spinal cord. Cervical spondylosis, at present, is the most common cause of loss of position and vibratory sense.
Carrying loads on the head imposes a considerable amount of strain on the axial skeleton. As the cervical spine is the most cranial and actively mobile part of the vertebral column, it may be vulnerable to the stress of weights placed on the head. The practice of carrying heavy loads, weighing 50 to 100 kg on the head is very common in Bangladesh. Coolies use their heads to carry loads, transporting them from one place or vehicle to another. Accordingly, they are at increased risk of developing cervical spondylosis. Manual handling work may also give rise to musculoskeletal symptoms in different body regions. Since we should not ignore this labour force, their health needs attention. In Bangladesh, no research article or report investigating the status of health among the coolies at the workplace is available, and very few studies have been performed in occupational groups about the prevalence of musculoskeletal symptoms or complaints.
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Assessment of Chronic Neck Pain and a Brief Trial of Cervical Strengthening
From: Am J Phys Med Rehabil. 2008 Sep 10; [Epub ahead of print]
Assessment of chronic neck pain and a brief trial of cervical strengthening to determine the relationship among pain, disability, range of motion, isometric strength, and muscle tenderness in persons with chronic nonradicular neck pain and to compare them with healthy controls without neck pain. Cross-sectional study of 30 subjects with and 14 without chronic neck pain. All subjects were administered pain scales, the neck disability index, isometric cervical strength, cervical range of motion, and a quantitated muscle tenderness measure. In addition, an uncontrolled trial of neck strengthening was performed on a subset of 14 subjects with the same outcome variables.
Tenderness correlated with pain, neck disability index, and headache in the pain group, and statistically, significantly differed from the subjects without neck pain. Males were stronger than females. Strength was less in the group with neck pain, but did not reach statistical significance. Range of motion was less in the group with pain. Neither range of motion nor strength correlated with neck disability index or pain scores in the neck pain group. In the strengthening trial, strength in left and right rotation significantly improved. Range of motion, pain, and neck disability index changed in a positive direction, but did not reach statistical significance. Muscle tenderness did not change.
Muscle tenderness and disability (but not range of motion or muscle strength) is closely related to average pain in the previous week in neck pain subjects. Neck flexor muscle strengthening resulted in positive changes in pain, neck disability index, range of motion, and strength, but not tenderness.
Advances in susceptibility genetics of intervertebral degenerative disc disease
From: Int J Biol Sci. 2008 Sep 2;4(5):283-90
The traditional view that the etiology of lumbar disc herniation is primarily due to age, gender, occupation, smoking and exposure to vehicular vibration dominated much of the last century. Recent research indicates that heredity may be largely responsible for the degeneration as well as herniation of intervertebral discs. Since 1998, genetic influences have been confirmed by the identification of several genes forms associated with disc degeneration. These researches are paving the way for a better understanding of the biologic mechanisms. Now, many researchers unanimously agree that lumbar disc herniation appears to be similar to other complex diseases, whose etiology has both environmental and hereditary influence, each with a part of contribution and relative risk. Then addressing the etiological of lumbar disc herniation, it is important to integrate heredity with the environment factors.
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Mechanical traction for mechanical neck disorders:
From: J Rehabil Med. 2006 May;38(3):145-52
Neck disorders are common, disabling to various degrees, and cost. Mechanical traction is often used as part of a comprehensive program in outpatient rehabilitation. The value of this treatment has often been questioned because studies of its usefulness have generally been inconclusive and there are no data on cost-effectiveness. Mechanical traction for the cervical spine involves a tractive force applied to the neck via a mechanical system. This can be applied intermittently or continuously. Indications for this type of intervention include herniated disc, degenerative disc disease and hypomobile facet joints. The physiological effects of such treatment may include separation of vertebral bodies, distraction and gliding of facet joints, widening of the intervertebral foramen, tensing of ligamentous structures, straightening of spinal curves and stretching of spinal musculature. Traction has also been reported to decrease pain by providing muscle relaxation, stimulation of mechanoreceptors and inhibition of reflex muscle guarding. More definitive information about its effect on pain, function and patient satisfaction is needed for specific subgroups of disorders and symptom durations, to guide further clinical practice.
From their previous review, they found limited evidence of no benefit. From this current review, they have 5 additional studies that has started to shift the findings in favour of intermittent traction and revealed moderate evidence of benefit for pain reduction. Their current review includes neck disorder with radicular findings while the past review did not. In this current review, it became evident that intermittent traction should be examined separately. Additional outcomes in the categories of function, disability and patient satisfaction were included in this update, while in the past only pain was assessed. There are no current reviews assessing traction and neck pain. Two older reviews show that either no clear conclusions can be drawn or there was no benefit. Any discordance with respect to intermittent traction finding is due to addition of new studies since their publication. They agree that non-standardization of traction dosage and clinical variables have not been reported clearly. This is consistent with the lumbar traction reviews.
Inconclusive evidence for continuous and intermittent traction exists due to trial methodological quality. Two clinical conclusions may be drawn, one favouring the use of intermittent traction and the other not supporting the use of continuous traction. Attention to research design flaws and description of traction characteristics is needed.
Masticatory muscle activity during maximum voluntary clench in different research diagnostic criteria for temporomandibular disorders (RDC/TMD) groups
From: Man Ther. 2008 Oct;13(5):434-40.
EMG can be used for a deeper understanding of the pathologies of several dysfunctional patients, for instance of those with temporomandibular joint disorders (TMJ). Tmj is a complex disease, and its nature has not been completely understood yet. A large part of tmj patients report pain in the masticatory muscles, and present symptoms and signs of muscular alteration. EMG assessment of their masticatory function is being used for diagnosis, to monitor the progression of the disease, and to measure the effect of treatment. In particular, when used as a diagnostic test to differentiate between patients with tmj and neck disorders, standardized EMG of the masticatory muscles was found to have a sensitivity of 0.86, with a 0.92 specificity.
Among the methods developed for the classification of patients with tmj, the research diagnostic criteria for temporomandibular disorders (research diagnostic criteria for temporomandibular disorders) had been proposed to produce reproducible case definitions, to investigate the time course of the disease, and to assess treatment efficacy. The research diagnostic criteria for temporomandibular disorders uses a two-axis system, taking into consideration physical diagnosis, pain-related disability, and psychological status. The physical findings (axis I) can be coordinated with the assessment of psychological distress and psychosocial dysfunctions associated with orofacial disability (axis II). Axis II considers the pain-related disability and the psychological status (depression, anxiety, vegetative symptoms), with subjective reports of pain intensity, activity limitations, and non-specific physical symptoms.
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Whiplash associated disorders impairment rating: neck disability index score according to severity of MRI findings of ligaments and membranes in the upper cervical spine.
From: J Neurotrauma. 2005 Apr;22(4):466-75
The aim of this study was to explore whether reported pain and functional disability in whiplash associated disorders patients is associated with lesions to specific soft tissue structures in the upper cervical spine, as assessed by MRI. Pre-selected structures for MRI assessment included the alar ligaments, the transverse ligament, the tectorial and the posterior atlanto-occipital membranes. The questionnaire employed was a modification of the Oswestry Low Back Pain Index. It was comprised of ten single items related to pain and activity of daily living. Ninety two whiplash patients and 30 control persons, randomly drawn, were included.
Whiplash associated disorders patients reported significantly more pain and functional disability than the controls, both for total score and each of the ten single items. In the whiplash associated disorders patients, MRI lesions to the alar ligaments showed the most consistent association to the reported pain and disability. Lesions to other structures often occurred in combination with lesions to the alar ligaments. Lesions to the transverse ligament and to the posterior atlanto-occipital membrane also appeared to be related to the neck disability index score, although the association was weaker than for the alar ligament. The disability score increased with increasing number of abnormal (grade 2-3) structures. These results indicate that symptoms and complaints among whiplash associated disorders patients can be linked with structural abnormalities in ligaments and membranes in the upper cervical spine, in particular the alar ligaments.
