Introduction

Discography is a diagnostic procedure to help identify the source of back or neck pain. Discs are cushions located between the bones that make up your spine. Normally, discs act as shock-absorbers to protect the bones in the spine. Aging or trauma can cause discs to break down, leading to pain. There are many methods for treating disc pain, but if treatments are unsuccessful after a period of time, a discogram may be ordered to determine the exact disc that is creating a problem. From there, a more appropriate treatment plan can be formulated.

Anatomy

Your spine is made up of a series of small bones called vertebrae. The opening in the center of each bone forms the spinal canal. Your spinal cord is located within the protective spinal canal. The spinal cord extends from the brain and is a major part of your nervous system.

The spinal cord does not fill the entire space in the spinal canal. Instead, the spinal cord is surrounded by the epidural space (cavity), which contains fluid, nerves, and blood vessels. Spinal nerves extending from the spinal cord travel out of openings or “tunnels” in the bones (foramina) to exchange nerve signals with your brain about specific parts of your body.

In between each vertebra is an intervertebral disc. The discs are made up of strong connective tissue. Their tough outer layer is called the annulus fibrosus. The annulus fibrosis is composed of many layers. The outermost of its layers contain nerves. The discs gel-like center is called the nucleus pulposus.

The discs and two small joints connect one vertebra to the next. The discs and joints provide support and stability, while allowing movement. The discs also act as a shock-absorbing cushion to protect the vertebrae.

Causes

Discography is not a treatment, but rather a diagnostic tool to identify which disc is causing pain. Discs can become painful for several reasons. Heavy lifting or overloading the spine, repetitive strenuous activities, and using poor body mechanics while lifting can cause the outer layers of the disc (annulus fibrosis) to tear. Sudden pressure from trauma can rupture a disc as well.

The center of the disc (nucleus pulposus) is cushion-like because it is filled with fluid. With age, discs lose water content. The discs become more narrow, less flexible, and less effective as cushions between the vertebrae. Being overweight or a smoker only adds to the problem. For these reasons, herniated discs occur most frequently among middle aged people.

As a disc deteriorates, the outer layer can weaken and tear. A herniated disc occurs when the outer layer ruptures, and its inner content of fluid leak out. Discs heal slowly, during which time new nerve endings may form in the ruptured areas. The leaking fluids can irritate the new nerve endings. Disc fluid contains chemicals. Upon contacting the nerves, a chemical reaction takes place. The nerves become irritated, resulting in pain. If the disc travels into the spinal canal it may put pressure on the spinal cord or spinal nerves. The pressure and chemical reaction results in pain.

Symptoms

Disc problems can cause neck or back pain in the area of the affected disc. You may experience a burning or tingling sensation, as well as numbness, weakness, or shooting pain. Depending on the location of the ruptured disc, your symptoms may spread to your arms or legs.

Diagnosis

A discogram is a diagnostic procedure that is usually performed after nonsurgical treatments have failed. It is common for people to try more than one method of pain relief. If pain continues after several months, a discogram is considered to help pinpoint the exact disc that is causing the problem, in order to formulate a new treatment plan, which may include surgery.

On the day of your procedure, you will be asked not to take any pain medication. You will wear a gown for the procedure. You will be positioned in a way that your doctor can access the affected area of your spine, such as lying on your front. Before the procedure begins, the affected area of your neck or back will be sterilized and numbed with an anesthetic. You may receive relaxation medicine and antibiotics before your procedure.

Your doctor will use a live X-ray image (fluoroscopy) to carefully insert and guide a needle to the outer layer of the suspected disc. A second needle is moved through the first one. The second needle is guided to the center of the disc. If more than one disc is suspected, this process may be repeated on the other discs as well.

After the needle is positioned in the center of the disc, contrast dye is injected. The contrast dye may cause temporary pain. You will be asked to rate your pain and asked if the pain is similar to that of your symptoms. If more than one disc is being tested, this step is completed at each one. The needles are removed following the evaluation.

The second step in discography uses an X-ray to show where the contrast dye has spread. The pattern of dye within the disc can help determine if the disc is abnormal. At this time, a computed tomography (CT) scan may be used to show more detail about the extent of the rupture or tear pattern, as well as the size and shape of the disc.

You will be monitored for about 45 minutes before you can return home. Another person should drive you if you received relaxation medication. Your doctor will prescribe pain medication to ease the temporary pain caused by the procedure. Your doctor will discuss your results with you and present options for future treatment.