Neck Solutions Blog

Healing of a painful intervertebral disc should not be confused with reversing disc degeneration: Implications for physical therapies for discogenic back pain.

Clin Biomech (Bristol, Avon). 2010 Aug 23. [Epub ahead of print]

Much is known about intervertebral disc degeneration, but little effort has been made to relate this information to the clinical problem of discogenic back pain, and how it might be treated. The authors re-interpret the scientific literature in order to provide a rationale for physical therapy treatments for discogenic back pain.

Intervertebral discs deteriorate over many years, from the nucleus outwards, to an extent that is influenced by genetic inheritance and metabolite transport. Age-related deterioration can be accelerated by physical disruption, which leads to disc “degeneration” or prolapse. Degeneration most often affects the lower lumbar discs, which are loaded most severely, and it is often painful because nerves in the peripheral anulus or vertebral endplate can be sensitised by inflammatory-like changes arising from contact with blood or displaced nucleus pulposus. Surgically-removed human discs show an active inflammatory process proceeding from the outside-in, and animal studies confirm that effective healing occurs only in the outer anulus and endplate, where cell density and metabolite transport are greatest. Healing of the disc periphery has the potential to relieve discogenic pain, by re-establishing a physical barrier between nucleus pulposus and nerves, and reducing inflammation.

Physical therapies should aim to promote healing in the disc periphery, by stimulating cells, boosting metabolite transport, and preventing adhesions and re-injury. Such an approach has the potential to accelerate pain relief in the disc periphery, even if it fails to reverse age-related degenerative changes in the nucleus.

Low back pain may be caused by disturbed pain regulation: a cross-sectional study in low back pain patients using tender point examination

From: Eur J Pain. 2010 May;14(5):514-22

Widespread pain has negative influence on outcome in low back pain patients. Tender point examination is a standardized examination method to estimate diffuse tenderness. To assess diffuse tenderness by means of a standardized tender point examination and to analyse for associations between the number of tender points and spinal structural changes as well as psycho-social factors.

Patients sick-listed 3-16 weeks due to low back pain with or without sciatica completed a questionnaire and went through a clinical low back examination and tender point examination. Of 326 patients 111 had verified nerve root affection and 215 had non-specific low back pain with or without radiating pain. Disc height reductions were estimated on lateral X-rays.

Multivariate logistic regression analysis showed that more than 8 tender points were strongly negatively associated with disc degeneration, and verified nerve root affection and were positively associated with number of years since first episode of low back pain. Furthermore, more than 8 tender points were positively associated with widespread pain, female sex and bodily distress. With all patients included, bodily distress and the number of tender points were positively associated with the intensity of low back pain, but disc degeneration was only positively associated with low back pain in patients with less than 6 tender points.

The pain in patients with diffuse tenderness was rarely related to disc degeneration or nerve root affection, rather it may be caused by disturbed pain regulation.

Restoration of disc height through non-invasive spinal decompression is associated with dec reased discogenic low back pain: a retrospective cohort study.

BMC Musculoskelet Disord. 2010 Jul 8;11(1):155.

An estimated 80% of the population will suffer from low back pain at some point of their lives. Low back pain is the number one factor limiting activity in patients less that 45 years old, the second most frequent reason for doctor’s visits, and the third most common cause for surgical procedures. In addition to imposing upon patients’ quality of life, low back pain is of significant socioeconomic relevance because it may lead to a temporary loss of productivity, enormous medical and indirect costs, or even permanent disability.

While the management of persistent low back pain remains hotly debated, the traditional approach has been non-surgical treatment with analgesia supplemented by physiotherapy. Given the limited efficacy of these modalities, there are also a number of alternative interventions such as massage, spinal manipulation, exercises, acupuncture, back school and cognitive behavioral therapy. The two most common diseases involving chronic low back pain are discogenic low back pain, responsible for 39% of cases, and disc herniation, accounting for just less than 30% of low back pain incidence. These incidence frequencies are supported by the current data that most closely link the clinical pathology of discogenic low back pain and disc herniation to the anatomical structure of the intervertebral disc. Thus, another treatment option is motorized decompression, a technique designed to lessen pressure on the discs, vertically expand the intervertebral space, and restore disc height. However, systematic reviews to date were unable to find sufficient evidence in the literature to support the use of this modality. A subsequent chart review of 94 patients suggests that motorized non-surgical spinal decompression may be effective in reducing chronic low back pain. Furthermore, preliminary data from a prospective cohort study in patients with chronic low back pain reported a median pain score reduction from 7 to 0 (on a 11-point verbal rating scale) following a 6-week nonsurgical spinal decompression treatment protocol.

The goal of this study was therefore to determine if changes in low back pain, as measured on a verbal rating scale, before and after a 6-week treatment period with motorized non-surgical spinal decompression, correlate with changes in lumbar disc height, as measured on computed tomography scans.

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Magnetic resonance imaging and stadiometric assessment of the lumbar discs after sitting and chair-care decompression exercise: a pilot study

From: Spine J. 2010 Apr;10(4):297-305. Epub 2010 Feb 26

Sitting is associated with loss of the lumbar lordosis, intervertebral disc compression, and height loss, possibly increasing the risk of lower back pain. With a trend toward more sitting jobs worldwide, practical strategies for preventing lumbar flattening and potentially associated low back pain are important. The purpose of this study was to determine the feasibility of using upright magnetic resonance imaging (MRI) and stadiometry to measure changes in height and configuration of the lumbar spine before and after normal sitting and a sitting unloading exercise intervention.

This is a hospital-based pilot study involving pre-post assessments in a single group. The sample comprises six asymptomatic hospital employees involved in either general patient care or research writing/data collection. The outcome measures were lumbar total midsagittal cross-sectional intervertebral disc area, vertical height, lordotic angle derived from digitized MRI examinations, and seated body height measured directly with a stadiometer. Midsagittal MRI scans were performed before sitting, after 15 minutes of relaxed sitting (“postsitting”), immediately after seated unloading exercises, and approximately 7 minutes after exercise. Subsequently, seated stadiometry assessments were performed after 10 minutes of supine recumbency, 15 minutes of relaxed sitting, and every 10 seconds after seated unloading exercises until three consecutive height measurements were identical. Digitized midsagittal images were used to derive MRI based outcome measures.

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Effects of Traction on Structural Properties of Degenerated Disc Using an In Vivo Rat-Tail Model

From: Spine (Phila Pa 1976). 2010 May 25. [Epub ahead of print]

An in vivo rat-tail model was adopted to study the structural changes of degenerated intervertebral disc after different traction protocols to investigate the effects of traction with different modes and magnitudes on disc with simulated degeneration.

Traction has been commonly used in clinical practice for treating low back pain. Its effects on disc with degeneration have not been fully investigated. Forty-seven mature rats were used. Continuous static compression of 11 N was applied to the rat caudal 8-9 disc for 2 weeks to simulate disc degeneration. Tractions with different modes (static or intermittent) and magnitudes (1.4 N or 4.2 N) were applied to the degenerated disc for 3 weeks. The disc height was quantified in vivo on days 4, 18, and 39. The treated discs were then harvested for morphologic analysis.

Significant decrease in disc height with degenerative morphologic changes was observed after the application of the static compression. The changes in disc height after the application of traction were found to be magnitude dependent. Continuous decrease in disc height was observed after 4.2-N traction, whereas the disc height maintained after traction of 1.4 N. However, no obvious morphologic change was found in comparison with the degenerated discs without traction.

Although traction was not demonstrated to have restored disc with degeneration, traction with relatively low magnitude was found to have significant beneficial effect in maintaining disc height of degenerated disc, and it might be a potential intervention to slow down the process of degeneration. Future studies of the effects of low-magnitude traction on degenerated disc are recommended.

Association between intervertebral disc degeneration and disturbances of blood supply to the vertebrae.

From: Chin Med J (Engl). 2010 Jan;123(2):239-43

Low back pain is a common public health problem in western industrialized societies and the world as well. Studies indicate that the prevalence rate ranges from 12% to 35%, with around 10% of patients becoming chronically disabled. It also places an enormous economic burden on society. Although the exact cause of low back pain has yet to be defined, intervertebral disc degeneration is considered a major source of it. Since patients with degenerative discs are often asymptomatic, the mechanisms of it are still unclear.

The intervertebral disc lies between the vertebral bodies and links them together. It provides reversible resistance to compressive, rotational, and tensile loads applied to the vertebral column and it also allows the spine to bending, flexion, and torsion. Three major components ensure the properties of the disc: nucleus pulposus, anulus fibrosus, and cartilaginous endplate. Nucleus pulposus represents a centrally located gelatinous homogenous mass (in juvenile discs), anulus fibrosus consists of concentrically organized layers of collagen fibrils, and endplate separates the nucleus pulposus and anulus fibrosus from the adjacent vertebral bone. Any disturbance of the integrity and interplay of one of the three structures can result in a compromised function of the intervertebral disc.

The normal human intervertebral disc in adulthood consists of a large amount of extracellular matrix interspersed by a small number of cells that make up approximately 1% of the total volume. Cells of the disc are made up of at least two phenotypically distinct populations and they are morphologically different; those in the anulus fibrosus and cartilaginous endplate are more elongated and fibroblast-like compared with those of the nucleus pulposus, which are more rounded or oval and chondrocyte-like, sometimes with a capsule around them. These two kinds of cells behave differently, nucleus pulposus cells generally synthesize only type-II collagen in alginate beads, whereas anulus fibrosus cells produce both type-I and type-II collagen.

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Comparison of growth factor and cytokine expression in patients with degenerated disc disease and herniated nucleus pulposus

From: Clinical Biochemistry Volume 42, Issue 15, October 2009, Pages 1504-1511

This study was conducted to investigate the expression of cytokines and growth factors in disc specimens obtained from patients with herniated nucleus pulposus and degenerated disc disease. MRI and Western blot analyses were performed to evaluate the levels of disc degeneration and the expression levels of cytokines and growth factors.

The levels of TNF-alpha and IL-8 were significantly greater in the degenerated disc disease group than in the herniated nucleus pulposus group, but no statistical differences were observed in the expression of IL-1beta, IL-6 and IL-12 between the herniated nucleus pulposus and degenerated disc disease groups. In addition, the expression of TGF beta, VEGF and NGF was significantly higher in the degenerated disc disease group than in the herniated nucleus pulposus group.

The greater levels of cytokine and growth factor expression in the degenerated disc disease group than in the herniated nucleus pulposus explain why discogenic patients usually have more severe back pain than patients with herniated discs.

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