The spine has discs between each vertebral body in the cervical, thoracic, and lumbar spine. These discs are dynamic spacers between the bones and facilitate the motion between segments. The structure of the disc varies between the cervical, thoracic and lumbar levels. The differences in structure lead to different stabilization patterns in each area of the spine. The strongest discs are in the lumbar region and the weakest are in the neck, with the thoracic discs being of moderate strength.
The discs have two components, the outer anulous fibrosus, and inner nucleous pulposus. The outer ring is made of interlaced collagen fibers. The nucleous is a loose fibrous network with a gelatinous acidic mucoprotein. The combination of the outer core and inner gel is to provide the ability to absorb forces between the bones as the body moves. Extreme forces and sudden movements as well as age can damage the disc integrity. The strength and weave of the fibers is the strongest in the lumbar region and the weakest in the cervical region. Lifting and twisting heavy objects is main primary reason a person suffers a low back injury, while whiplash injuries account for the majority of neck problems. Repetitive activities and age can also damage the discs throughout the spine. Damaged discs can bulge, crack and leak, and herniate. The discs injuries can be very painful, and treatment should not be ignored.
Diagnosing Disc Injuries
Studying the spine is done in multiple ways. The simplest is by an X-ray; They can give basic information on the integrity and alignment of the bones, the height of discs, and the presence of degenerative changes. In a young person, X-rays are usually normal, but in the older person they tend to show age related changes. The problem with an X-ray is that it often can identify the area of pain, but it gives very little information about a cause of pain. CT-scans are sophisticated computer enhanced X-rays that give significantly more information about the bony structure of the spine and some limited information about the discs and spinal nerves. An MRI scan can give significant information about the discs, spinal nerves and cord, joints and bones of the spine. Electromyography can map whether the nerves of the spine are functioning properly. Discograms pressurize the disc with contrast and then they are viewed under X-ray or CT scan to determine the integrity of the disc and whether they are painful. Your doctor will determine which method is best for identifying your issue.
Discograms & MRI Scans
Discograms can tell valuable information in the lumbar region, however, in the thoracic and cervical region the data is of questionable value. In the lumbar region, a discogram can help identify whether a disc has internal disruption and if it is painful. If only one disc is painful, a doctor may be able to preform routine surgery to address the problemed disc. That said, multiple painful lumbar discs do poorly with surgical management. Often, MRI scans can give sufficient information such that a discogram is not necessary. In the thoracic region, a discogram would not clarify surgical options since the MRI can provide sufficient information along with physical exam. The nature of the discs in the cervical region makes discograms vary unreliable for useful information.
I typically suggest that a patient undergoes an MRI if they are experiencing back pain, as it provides a comprehensive look into the inner workings of the back. If you are plagued by constant low back, spine or neck pain, stop in for an assessment. We’ll work with you to find a solution to your pain.
Thomas Cohn, MD
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