Neck Solutions

Sitting with ischial and back supports

Sitting with adjustable ischial and back supports: biomechanical changes

From: Spine. 2003 Jun 1;28(11):1113-21

Low back pain is acute or chronic pain involving the lumbosacral, buttock, and/or thigh. Discogenic low back pain is aggravated by the sitting position, which is necessary in many occupations and daily activities. About 100 million workdays are lost annually in the United States due to low back pain. Despite improved knowledge and health care resources for spinal pathology, chronic disability resulting from nonspecific low back pain is rising exponentially. Although the causes of discogenic low back pain are multifactorial and complex, sitting postures could increase stresses within the disc and contribute to disc degeneration and pain. Two major occupational risk factors are static muscle load and flexed curvature of the lumbar spine; both are involved in seated work tasks.

During sitting, the head, arm and trunk weight is carried mainly by the ischial tuberosities and surrounding tissues. High pressure at the tuberosities is closely associated with high load to the spine. A significant mechanical spine loading is associated with low back pain resulting from trunk muscle coactivation. Ischial and lower back interface pressure vary with different sitting postures and body positioning. Repositioning of the lumbar support to redistribute the interface pressure and load is essential in preventing low back pain associated with inappropriate sitting in a working environment. Therefore, a device that decreases the sitting pressure and load carried by the ischial tuberosity may decrease forces within the disc and associated degeneration and pain.

Physiologic lumbar lordosis in the standing position ranges from 40° to 60°, with the lordosis occurring mainly at S1-L5 and L4-L5, and with the sacral inclination ranging from 30° to 40°. Compared to standing or lying supine, sitting could cause the pelvis to rotate posteriorly, resulting in decreased sacral inclination and lumbar lordosis and increased forces at the discs. A number of investigators have reported interaction between low back pain and biomechanical changes such as decreased lumbar lordosis, malalignment of lumbar curvature, and narrowing of disc spaces. Williams et al reported that use of a lumbar roll that increased lumbar lordosis reduced low back pain, and the chair backrest also helps increase the lumbar lordosis and decrease intradiscal pressure.

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Musculoskeletal discomfort at work predicts low back, neck and shoulder pain

Does musculoskeletal discomfort at work predict future musculoskeletal pain?

From: Ergonomics. 2008 May;51(5):637-48

The objective of this prospective cohort study was to evaluate if peak or cumulative musculoskeletal discomfort may predict future low back, neck or shoulder pain among symptom free workers. At baseline, discomfort per body region was rated on a 10 point scale six times during a working day. Questionnaires on pain were sent out three times during follow-up. Peak discomfort was defined as a discomfort level of 2 at least once during a day; cumulative discomfort was defined as the sum of discomfort during the day. Reference workers reported a rating of zero at each measurement.

Peak discomfort was a predictor of low back pain (relative risk (RR) 1.79), neck pain (RR 2.56), right or left shoulder pain (RR 1.91 and 1.90). Cumulative discomfort predicted neck pain (RR 2.35), right or left shoulder pain (RR 2.45 and 1.64). These results suggest that both peak and cumulative discomfort could predict future musculoskeletal pain.

Electromyography for assessment of pain in low back muscles

Electromyography for Assessment of Pain in Low Back Muscles

From: Phys Ther. 2008 Aug 8; [Epub ahead of print]

Pain is currently evaluated with “subjective” methods (eg, patient self-report). This study aimed to test whether fatigue indexes are able to accurately discriminate between subjects with and subjects without low back pain. Sixty subjects separated into 2 groups-a group with low back pain (n=30) and a group without low back pain (n=0)-participated in this study. Electromyographic (EMG) and force data were obtained during a muscle fatigue test. The same test was repeated to monitor recovery. Linear regression analysis was used to obtain fatigue indexes. Subjects with pain produced significantly lower force values than those without pain. The use of fatigue indexes and force values permitted accurate classification in 89.5% of cases. The results confirm that subjects with pain show early myoelectrical manifestations of muscle fatigue and that EMG can be a useful tool in the evaluation of low back pain.

Magnetic Resonance Imaging for the assessment of degenerative disc disease of the lumbar spine

Advances in Magnetic Resonance Imaging for the assessment of degenerative disc disease of the lumbar spine

From: Semin Spine Surg. 2007 June; 19(2): 65–71

The intervertebral disc is characterized by a tension-resisting annulus fibrosus, and a compression-resisting nucleus pulposus composed largely of proteoglycan. Both the annulus and the nucleus function in concert to provide the disc with mechanical stability. Early disc degeneration begins in the nucleus with proteoglycan depletion. Quantitative MRI techniques have been developed to non-invasively quantify the earliest degenerative changes that occur within the disc. Our ability to identify and quantify these early biochemical changes will provide a better understanding of the pathophysiology of disc degeneration and facilitate the study of interventions that aim to halt or reverse the degenerative process.

Degenerative disc disease of the intervertebral disc is the most common cause of back-related disability among North American adults. This sometimes debilitating condition affects nearly 12 million people in the United States, and may generate direct and indirect costs exceeding 50 billion dollars annually in health-related expenditures. The radiographic evaluation of patients with degenerative disc disease often begins with plain film radiography and a standard T1- and T2-weighted MRI to assess for structural changes within the nucleus and annulus indicative of disc degeneration including a loss of T2-weighted MRI signal, loss of disc height, disc bulge or herniation, posterior element arthrosis, stenosis, and potential vertebral body compromise. While standard MRI is able to detect these later stage developments, it is not able to provide a quantitative measure of the early changes that characterize early degenerative disc disease. This limitation has led to the search for quantitative, non-invasive measures to evaluate the earliest changes involved in the initiation of the degenerative cascade. Such an imaging tool will be important for the evaluation of the patients with early degenerative disc disease, and also in the assessment of disc regenerative or restorative technologies that aim to halt or reverse the degenerative process.

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Satisfaction with low back pain care

Satisfaction with low back pain care

From: Spine J. 2008 May-Jun;8(3):510-21. Epub 2007 May 25

By using a unique, prospective study of occupational back pain claims, they examined health care satisfaction by provider type and its effect on return to work. They estimated satisfaction differentials by provider type, decomposing overall satisfaction into two components: bedside manner and effectiveness of care. They also examined how health care satisfaction affects the duration of jobless claims. The Arizona State University Healthy Back Study is a prospective study of work related back pain; 1,831 workers completed a baseline interview, with follow-up interviews at 1 month, 6 months, and 1 year. The Arizona State University Healthy Back Study merged demographic and claim characteristics from the workers’ compensation claim files with self-reported severity measures, measures of satisfaction, and postonset employment from worker interviews.

Overall and detailed satisfaction with treatment and workers’ compensation claim duration. They performed a nonparametric descriptive analysis of satisfaction by provider type and used multivariate regressions to decompose overall satisfaction into component parts. The duration analysis links differentials in health care satisfaction to differences in claim durations. Workers treated by surgeons, chiropractors (DCs), or physical therapists are more satisfied with their health care than those treated by MDs. Workers are more concerned with the effectiveness of care than with the bedside manner of their provider. A one standard deviation improvement in satisfaction with the health care provider reduces claim duration by about 25%.

Subendplate microcirculation disturbance in intervertebral disc degeneration

Subendplate microcirculation disturbance directly contributes to intervertebral disc degeneration

From: Zhonghua Wai Ke Za Zhi. 2008 Feb 1;46(3):213-6 Article in Chinese

To build subendplate microcirculation disturbance animal model and to investigate the potential pathogenesis of intervertebral disc degeneration. Twenty four New Zealand white rabbits were divided into treatment group (Group A) and control group (Group B). In Group A, animals received endotoxin and corticosteroid application to build subendplate microcirculation disturbance animal model, validated by microthrombus staining. In Group B, animals were given no drug, but standard feeding. After 3 month, the extent of intervertebral disc degeneration was evaluated by the water content, biochemistry analysis, and morphology. Subendplate microthrombus staining confirmed the exist of microcirculation disturbance.

The water content and biochemistry components content of disc in Group A were lower than those of disc in Group B, and intervertebral disc degeneration was observed in morphology. Subendplate microcirculation disturbance can directly contribute to intervertebral disc degeneration, the nutrients diffusion barrier is the potential pathogenesis of intervertebral disc degeneration.

Caveolin-1 stress induced premature senescence in intervertebral disc degeneration

Caveolin-1 expression and stress induced premature senescence in human intervertebral disc degeneration

From: Arthritis Res Ther. 2008 Aug 5;10(4):R87 [Epub ahead of print]

Chronic and debilitating low back pain is a common condition and a huge economic burden. Many cases are attributed to age related degeneration of the intervertebral disc, however, age related degeneration appears to occur at an accelerated rate in some individuals. We have previously demonstrated biomarkers of cellular senescence within the human intervertebral disc and suggested a role for senescence in intervertebral disc degeneration. Senescence occurs with ageing, but can also occur prematurely in response to stress. We hypothesised that stress induced premature senescence occurs within the intervertebral disc and here we have investigated the expression and production of caveolin-1, a protein that has been shown previously to be upregulated in stress induced premature senescence.

Caveolin-1 gene expression in human nucleus pulposus cells was assessed by conventional and quantitative real-time PCR and caveolin-1 protein expression examined within human intervertebral discs using immunohistochemistry. Correlation between caveolin-1 and p16INK4a biomarker of cellular senescence gene expression was investigated using quantitative real-time PCR.

Caveolin-1 gene and protein expression were demonstrated within the human intervertebral disc for the first time. Nucleus pulposus cells from degenerate discs exhibited elevated levels of caveolin-1 that did not relate to increasing chronological age. A negative correlation was observed between gene expression for caveolin-1 and donor age and no correlation was found between caveolin-1 protein expression and age. A positive correlation was identified between gene expression of caveolin-1 and biomarker of cellular senescence.

Our findings are consistent with a role for caveolin-1 in degenerative rather than age induced changes in the nucleus pulposus. Its expression in intervertebral disc tissue and its association with the senescent phenotype suggests that caveolin-1 and stress induced premature senescence may play a prominent role in the pathogenesis of intervertebral disc degeneration.

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Painful disc lesion in biplanar magnetic resonance imaging and discography

Painful Disc Lesion: Can Modern Biplanar Magnetic Resonance Imaging Replace Discography?

From: J Spinal Disord Tech 2008; 21:430–435

Internal disc disruption’’ is one of the prominent somatic sources of low back pain. MRI is the most common investigation performed to evaluate discogenic pain. Though MRI has advantages of being a sensitive investigation for identifying pathologic anatomy of disc degeneration, its value is limited by its inability to evaluate the physiologic status of the disc. Studies have questioned the specificity of MRI in diagnosing discogenic pain and have reported degenerative changes in 26% to 57% of asymptomatic volunteers. Discography is a useful tool to identify the painful disc responsible for patient’s symptoms. In evaluation of discogenic low back pain there has been a debate as to whether discography should replace MRI. Proponents of discography believe that it is an invaluable tool for identifying the pathologic disc producing pain. Critics believe that discography is an invasive investigation and has no place in modern practice.

Over the last decade there has been a vast improvement in the quality of MR images. Attempts have been made to identify features on MRI scans that would correlate with patient’s symptoms and would potentially eliminate the need for discography. Such features are the vertebral end plate changes described by Modic and the high intensity zone described by Aprill and Bogduk. The implications of these findings have been a subject of controversy.

This is a prospective study aimed at correlating the results of discography with new MRI classification in a consecutive series of patients with disabling low back pain considered for spinal surgery. In addition, we also aimed to compare vertebral end plate changes and high intensity zones seen on MRI with discography findings.

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Lumbar disc degeneration: association between osteophytes, end-plate sclerosis and disc space narrowing

Lumbar disc degeneration: association between osteophytes, end-plate sclerosis and disc space narrowing

From: Annals of the Rheumatic Diseases 2007;66:330-333

Peripheral joint osteoarthritis is characterised radiologically by the presence of osteophytes, subchondral sclerosis and joint space narrowing. Joint space narrowing is due to cartilage loss, whereas both subchondral sclerosis and osteophytes are hypertrophic responses of bone, thought to arise directly either to cartilage loss or to biomechanical stress. The pathophysiology and hence the inter-relationship of these features are however not well understood. Recently, strong associations between the presence of enthesophytes, osteophytes and bone sclerosis at various joint sites have been shown. Partly on the basis of these observations, it has been suggested that some individuals may be more likely to develop bone formation in response to disease occurrence. We looked at a series of lumbar spine radiographs and characterised the severity of the component radiographic features. Although the pathology of disc degeneration differs from peripheral joint osteoarthritis, we hypothesised that if there was a predisposition to develop new bone formation in the form of osteophyte or sclerosis in response to mechanical stress, there would be a strong association between increasing severity of the features of new bone formation. The aim of this study was to determine the strength of the association between increasing severity of osteophytes and end-plate sclerosis, and the association between both these features and disc space narrowing in the lumbar spine.

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The pathogenesis of discogenic low back pain

The pathogenesis of discogenic low back pain

From: J Bone Joint Surg Br. 2005 Jan;87(1):62-7.

Discogenic low back pain is a common cause of disability, but its pathogenesis is poorly understood. We collected 19 specimens of lumbar intervertebral discs from 17 patients with discogenic low back pain during posterior lumbar interbody fusion, 12 from physiologically ageing discs and ten from normal control discs. We investigated the histological features and assessed the immunoreactive activity of neurofilament and neuropeptides such as substance P and vasoactive-intestinal peptide in the nerve fibres. The distinct histological characteristic of the painful disc was the formation of a zone of vascularised granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus along the edges of the fissures. Substance P, neurofilament and vasoactive-intestinal peptide immunoreactive nerve fibres in the painful discs were more extensive than in the control discs. Growth of nerves deep into the annulus fibrosus and nucleus pulposus was observed mainly along the zone of granulation tissue in the painful discs. This suggests that the zone of granulation tissue with extensive innervation along the tears in the posterior part of the painful disc may be responsible for causing the pain of discography and of discogenic low back pain.