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Myelography involves the injection of a contrast dye into the spinal canal in order to enhance x-ray or computed tomography (CT) imaging of the spine. Myelograms are typically used to diagnose a variety of spinal problems including nerve injury, herniated discs, low back pain, and spinal tumors in patients who are unable obtain a magnetic resonance imaging (MRI) of the spine, which is considered the ideal test for these conditions. A lumbar spine myelogram is depicted below.
In performing a myelogram, the patient is positioned on his/her side and asked to flex the neck and bring the knees up to his/her chest (in a fetal position). Alternatively, the patient may be asked to sit with his/her head and shoulders forward flexed forward. The skin around the lower back is prepared using an antiseptic solution and a local anesthetic (numbing medication) is injected. A long and thin needle, called a spinal needle, is then inserted through the skin and deeper tissues, and between two lower lumbar vertebrae into the space that contains the cerebrospinal fluid (CSF). At this point, a small amont of contrast material is injected into the CSF followed by acquisition of x-rays or CT images.
In rare instances, some patients may be allergic to the contrast material that is injected into the CSF or certain medications that the patient is taking may make the contrast unsafe to receive. Therefore, patients should discuss their medical history, medications, and any other concerns with their physician and radiologist prior to receiving the injection.
Contact between the spinal needle and a nerve during injection of the contrast material into the CSF can result in painful sensations in the leg during the procedure. This is harmless and patients can be warned about it in advance to minimize their anxiety if it should occur.
Serious complications of a properly performed procedure are extremely rare, and include infections, bleeding around the spine, and trauma to nerves resulting in weakness or loss of sensation.
