Myelogram  

• What is it?                                        click here for Mylogram Instructions
• Why is it done?
• How is it done?
• What are the limitations?
• What are the risks?

What is it?

A myelogram is a test that helps your doctors look at the nerves and spinal cord in the spine. A myelogram includes injecting dye into the fluid space around the nerves in the spine, taking X-rays and then getting a CT Scan.  This procedure is done on an outpatient basis. 

Why is it done?

The dye used during a myelogram outlines the spinal cord and nerve roots. This helps your doctor determine if there are any unusual indentations or abnormal shapes in the spinal cord. Anything that is pushing into the nerves shows up as an indentation into the spinal sac. This indentation could be from a herniated or bulging disc, a tumor, or an injury to the spinal nerve roots. The myelogram is useful for patients who have metal plates and screws in their spine, which prevents them from having either a CT or MRI scan.

How is it done?

The doctor performs a spinal tap to inject dye into the spinal sac. The dye mixes with the spinal fluid so that it will show up on X-rays. You will be asked to lie on a tilting table while multiple X-rays are taken to show the flow of the dye through the spine. The myelogram is usually combined with a CT scan to get a better view of the spine in cross section and to check the health of the bones and nerves.

What are the limitations?

A myelogram does not show the soft tissues. It shows only the bones and the spinal fluid where the dye has mixed with the fluid.

What are the risks?

Because the myelogram requires a spinal tap, there are risks to be considered. This is one reason that doctors prefer to use "noninvasive" tests first, such as the MRI and CT scan. The risks associated with a spinal tap include meningitis (infection of the spinal fluid), spinal headache, and allergic reaction to the dye. There is also a very small chance that the needle will cause bleeding around the spinal sac. The myelogram requires X-rays, which use radiation. Large doses of radiation can increase the risk of cancer.