What is Degenerative Disc Disease?
The spinal column is made of many spinal bones (vertebrae) stacked on top of each other. The front part of these bones are connected to each other by intervertebral discs. These discs serve as a flexible cushion and allow for a large range of motion in the spine. The outer portion of these discs is a firm ring of tissue, called the annulus fibrosus (disc wall). Within the center of these discs is a jelly-like substance called the nucleus pulposus. This occurs anywhere in the spine.
A young, healthy disc has an intact disc wall and is filled with jelly-like substance inside with a large amount of water to allow for movement. As we age, these discs dry out and lose some of the water in the center. These discs will become "degenerative", less flexible, lose height, and may cause bone spurs which press on spinal nerves.
Degenerative disc disease is also known as "spondylosis" as the discs wear out. As the discs lose water and wear out, they lead to abnormal alignment of the spinal joints, and osteoarthritis is the result.
Symptoms
The most common symptoms are neck or back pain. Advanced degenerative disc disease may lead to herniated discs or advancement of spinal arthritis. In advanced cases, pain or weakness may occur in the arms or legs.
Diagnosis
All discs will become degenerative over time. A degenerative disc is not necessarily painful, and the majority of these will not cause problems. Because of this, the most important part of the diagnosis is a proper evaluation by a specialist.
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History: Your medical provider should appreciate that your medical history may contribute to your symptoms, which may or may not be related to your symptoms. It is also important to understand the time frame for your symptoms, and what makes the symptoms worse or better. Your provider will also learn all previous treatments you have had, and if they have provided any relief.
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Physical Examination: In addition to a good medical history, a thorough physical examination is the most important part of the diagnosis for any spine-related problem. During the physical examination, your provider may try to reproduce your symptoms, and will assess any long-term nerve damage that may have been caused.
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X-rays: X-rays are often the first step for imaging. Even if other images have been taken, x-rays provide unique information that is not available from other studies.
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MRI: An MRI scanner uses a magnetic field and radio waves that are not harmful to visualize the body in 3D. In most circumstances, it is the best way to see the soft tissues of the body, including nerves, intervertebral discs, and other parts of the spine other than the bones.
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CT or CT Myelogram: A CT scan uses many x-rays to produce a 3D image of the body. It is often the best way to visualize the spinal bones or bone spurs. A "myelogram" involves placement of dye into the spinal canal before a CT scan to better visualize soft tissues. For patients who cannot undergo an MRI, a CT myelogram may be the best way to see spinal nerves.
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Discography: Discography or a "discogram" involves injection of radiographic dye under pressure into the disc(s) under x-ray. The patient is awake for this procedure, and tells the provider whether the discogram reproduces his or her symptoms. The purpose of a "discogram" is to find the cause of pain and determine which disc(s) are causing symptoms. A "control" discogram is usually performed on a healthy disc for comparison. Unfortunately, this procedure has been shown to lead to worsening of disc disease. It also provides little if any information that cannot be obtained from modern MRI scanners. Although some providers still offer discography, Dr. Bjerke does not recommend this for any patient.
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Injections: Nerve blocks or spinal injections may be used to help diagnose the cause of a patient's symptoms. In addition to providing relief, they also provide useful information for your provider to pinpoint the cause of symptoms. If you have an injection, it is important to document how the injection affected your symptoms.
Treatment
Degeneration is a normal part of the aging process. There are several degrees of degenerative disc disease. The first stage involves the loss of water from the intervertebral disc. This will show up as a dark disc on an MRI scan. By itself, this is sometimes called "black disc disease". By itself, this stage has not been shown to benefit from surgery or other intervention. Although some surgeons may offer surgery for this, citing "discogenic back pain," Dr. Bjerke does not believe that surgery has any benefit for this diagnosis.
Advanced degenerative disc disease may lead to collapse of the disc and loss of height. This leads to improper alignment of the remaining spinal joints. This misalignment can lead to spinal arthritis, "degenerative scoliosis," and may cause bone spurs which press on spinal nerves. Surgery may be recommended for advanced degenerative disc disease. The exact surgical plan depends on the individual spinal disease, but may include Lumbar Decompression, Lumbar Fusion, ACDF or Posterior Cervical Fusion.