Neck Solutions Blog

Lumbar disc degeneration and genetic factors are the main risk factors for low back pain in women: the UK Twin Spine Study

From: Ann Rheum Dis. 2011 Jun 6. [Epub ahead of print]

Low back pain is a common musculoskeletal condition in all ages worldwide and in Europe in particular. The lifetime prevalence of non-specific low back pain may reach 80%, with the annual prevalence ranging between 25% and 60% in different ethnic groups. Radiological features of low back pain is a common musculoskeletal condition in all ages worldwide and in Europe in particular. The lifetime prevalence of non-specific low back pain may reach 80%, with the annual prevalence ranging between 25% and 60% in different ethnic groups. Radiological features of lumbar disc degeneration are almost universal in adults, and have been proposed repeatedly as one of the main causes of low back pain. Although an association has been demonstrated, the individual risk factors for low back pain remain unclear and universal consensus regarding the extent of lumbar disc degeneration and low back pain association is lacking. The lack of standardized clinical criteria and radiological definitions has further hampered the undertaking of well-executed epidemiological studies. More sensitive imaging modalities, such as MRI, have fallen in cost and become more widely available and are paving the way for new, large-scale epidemiological studies of lumbar disc degeneration.

Obesity, smoking and occupation have been reported to be associated with prevalent low back pain, although the quantitative effect of the majority of them has been found to be negligible—even insignificant. On the other hand, several studies have consistently suggested the presence of a major genetic component underlying variation of low back pain, although data remain scarce.

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The prevalence of MRI-defined spinal pathoanatomies and their association with Modic changes in individuals seeking care for low back pain.

From: Eur Spine J. 2011 May 5. [Epub ahead of print]

Low back pain is common condition; 6–10% of cases may become chronic and result in major disability, high medical expenses, and lost productivity. Low back pain may originate from many spinal structures, but degenerative processes in the intervertebral discs seem to be among the most common causes. Because of its ability to detect disc and subchondral bone marrow signal changes, magnetic resonance imaging (MRI) has emerged as the imaging study of choice for LBP and has significantly advanced the evaluation of degenerative disc disease. Signal intensity changes in the vertebral bone marrow adjacent to the endplates are common MR imaging observation.

Vertebral endplate (Modic) changes are bone marrow and endplate lesions visible in MRI. They are shown to be associated with degenerative intervertebral disc disease. Three different types have been described. Type I lesions are assumed to indicate an ongoing active degenerative process. Type II lesions are thought to manifest a more stable and chronic degeneration and reflect fatty replacement of the adjacent marrow . Type III lesions are associated with subchondral bone sclerosis.

Modic Type 1 changes are generally associated with inflammation or neovascularity mediated by pro-inflammatory cytokines. This would account for lower back pain and asymptomatic patients exhibiting Modic Type 1 changes are very rare. Type I changes are associated with fissuring of the cartilaginous endplate and increased vascularity within the subchondral bone on histologic examination, and correspond to vertebral body edema.

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What are the reliable radiological indicators of lumbar segmental instability?

From: J Bone Joint Surg Br. 2011 May;93-B(5):650-657.

Intervertebral instability of the lumbar spine is thought to be a possible pathomechanical mechanism underlying low back pain and sciatica and is often an important factor in determining surgical indication for spinal fusion and decompression.

The spine is made up of segments, described as “motion segments,” consisting of two vertebrae and the interconnecting soft tissue. Spinal stability is defined as the ability for the vertebrae to maintain their relationship and limit their relative displacements during physiologic postures and loads. The requirement of stability is essential to the spinal column to prevent premature mechanical and biologic deterioration of its components. It is also fundamental to protect the spinal cord and nerve roots and to minimize energy expenditure.

One important mechanical function of the lumbar spine is to support the upper body by transmitting compressive and shearing forces to the lower body during the performance of everyday activities. To enable the successful transmission of these forces, mechanical stability of the spinal system must be
ensured.

Stability of the lumbar spine as a whole is maintained by the cooperation of discs, joints, ligaments, and muscles. Degenerative processes in the disc and facet joints affect the stability of the motion segment.

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Menopause causes vertebral endplate degeneration and decrease in nutrient diffusion to the intervertebral discs

From: Med Hypotheses. 2011 Mar 25. [Epub ahead of print]

Lumbar spine disc degeneration is a common musculoskeletal condition and increases with age. Disc degeneration can progress to disc herniation, spinal canal stenosis, facet joint arthrosis and degenerative spondylolisthesis. It is not fully understood what factors initiate and influence the progression of disc degeneration. There is however, general agreement that spinal mechanical stress accelerates the development of disc degeneration and increases the likelihood of disc herniation. Increasing evidence suggests that hormones may also influence the severity of disc degeneration.

The vasculature in the outer annulus of the disc supplies only the periphery of the disc so that nutrition to the bulk of the disc, including all the inner annulus and nucleus pulposus, is derived from the vertebral epiphyseal end arteries where nutrients diffuse across the cartilaginous endplate to reach the disc. In this regard the vertebral endplate plays an important role in disc nutrition. Compromise of diffusion of nutrients to the disc cells may play a large part in the progression or even initiation of disc degeneration. Increasing evidence suggests that estrogen deficiency also influence the severity of disc degeneration in post-menopausal females. Structural disorganization of the vertebral endplate occurs with disc degeneration, with the most common endplate changes observed clinically being Schmorl’s node. Schmorl’s node is more commonly seen in post-menopausal women than younger women. Osteosclerosis, osteonecrosis and fibrosis associated with Schmorl’s nodes can impede nutrient diffusion into the disc as well as removal of metabolites from the disc.

In this article, the authors hypothesize that menopause negatively affects vertebral endplate quality and induces endplate degeneration. This endplate degeneration decreases nutrients diffusion from vertebral body into discs, and also impedes removal of metabolites, leads to further disc degeneration. To confirm their hypothesis, a cross-sectional post-contrast MRI study can be performed in pre menopausal and post menopausal women. If the hypothesis is confirmed, then low dose hormone replacement treatment may retard disc degeneration in post menopausal women and thereby limit the consequences associated with disc degeneration such as low back pain.