Orthopedic Issues Series: Degenerative Disc Disease – Part 1

This post is the first in a series we will be doing on common orthopedic issues.  In Part 1 of this post, we will discuss the anatomy of the spine and some of the causes of Degenerative Disc Disease (DDD), a common yet misunderstood spinal condition that affects a large portion of the population.   In Part 2 of this post, we will go over some of the symptoms of DDD and some of the methods for treating DDD.

Anatomy

There are thirty-three vertebrae in the vertebral column of the human spine, twenty-four of which articulate and move.  Between each of the vertebrae in the three articulating sections of the spine – the cervical, thoracic, and lumbar spine – there is an intervertebral disc.  Each disc, composed of soft jelly-like center (nucleus pulposus) surrounded by a capsule of connective tissue (annulus fibrosis), provides shock absorption and flexibility within the spine.  There is very little blood flow to this region of the body, and if discs are damaged or deteriorate they cannot regrow or heal themselves.

Causes

Degenerative Disc Disease (DDD) is the breakdown in the size and cushioning of the intervertebral discs, which can lead to chronic pain, weakness, numbness and tingling in extremities, and reduced flexibility in the spine. The name of the condition is actually somewhat of a misnomer – it is not actually a “disease”, but rather a condition that is characterized by the degeneration of the intervertebral discs over time. Because of this, the condition can be confusing to understand.

Reduction in the size and cushioning of your discs is part of the normal process of aging, and magnetic resonance imaging (MRI) studies have shown that almost everyone over the age of 60 has degeneration of their intervertebral discs to some degree.[1]  Not all people with disc degeneration have back pain or other symptoms – in fact, individuals with relatively mild disc degeneration may experience no symptoms whatsoever.

However, age is not the only factor in DDD.  Deterioration of the intervertebral discs can be accelerated and exacerbated by other factors.  The culprit in many severe cases of DDD is stress-related damage in the form of repetitive use, trauma, injury, poor posture, poor movement, and obesity.  Among these, one of the most common factors is repetitive use.

Medical professionals are particularly susceptible to developing DDD due to the static postures that some specialties require in clinical practice, most notably dentists.  For example, the repetitive, static posture of a dentist performing clinical procedures creates compressive forces on the cervical discs due to neck flexion and compressive forces on the lumbar discs due to axial loading (the weight of the body compressing the spine vertically).  When these compressive forces are applied for year after year on a daily basis, the result can be an accelerated deterioration of the intervertebral discs.

For more information on how disability insurers evaluate claims based on Degenerative Disc Disease, see:

A Stiff Upper Lip Can Lead to Getting Stiffed by Your Insurer

Disability Insurance: Who Gets Denied?

Myelopathy: Part 1

Myelopathy: Part 2

[1] http://www.arthritis.org/about-arthritis/types/degenerative-disc-disease/


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