A myelogram (myelography) is utilized to diagnose disorders of the spinal canal and cord, such as nerve compression causing pain and weakness.
The test is usually performed on an outpatient basis at a hospital or other medical facility by a neuroradiologist. Neuroradiology is a sub-specialty of radiology that conducts studies of the central nervous system.
A myelogram requires introduction of radiographic contrast media (dye) into the sac (dura) surrounding the spinal cord and nerves. The patient lies on their stomach during the test. After the skin area has been numbed, the dye is injected into the spinal sac followed by x-rays, CT, or MRI scans. After the images are processed, a neuroradiologist interprets the results and sends a report to the referring physician.
Following the myelogram, the patient is taken to a recovery area where they rest lying down with their head elevated for several hours. Once at home, quiet non-strenuous activities are recommended for 24 hours to allow the puncture site to heal. Plenty of fluids (eg, water, juice) should be consumed to clear the dye from the body.
Certain medical conditions, drugs, or allergies should be discussed with the referring physician prior to the myelogram. Some of these topics are listed below.
- Metallic components such as a pacemaker, aneurysm clip, or other metal implants prohibit the patient from an MRI scan.
- Allergies to an IVP (intravenous pyelography) or other contrast dye should be reported. Adverse reactions include hives, swelling, and difficulty breathing. Fore knowledge of an allergy can often be controlled by pre-medicating.
- Epilepsy or seizure disorder, and if medication is taken to control episodes.
- Angina or kidney disorders.
- Diabetic patients who control their disease with medication need to discuss this with their physician. Certain drugs may need to be discontinued for 48 hours prior to the test.
- Blood thinners may need to be discontinued prior to the test.
- Difficulty lying flat on the stomach or inability to remain still.
- The patient will need someone to drive them home following the test. This should be prearranged in advance of the scheduled test day.
- Leave valuables at home.
- Bring prior relevant x-rays, CT or MRI scan for the neuroradiologist's review.
- Do not eat anything after midnight the night before the myelogram. Some patients experience side effects such as nausea and vomiting. Clear liquids are acceptable.
- Take scheduled medication with clear liquid, unless the referring physician has instructed otherwise (eg, diabetics).
Possible Side Effects
Most patients do not experience any side effects from a myelogram. However, common risks include headache, extremity aches or discomfort, nausea, vomiting, or dizziness, which usually disappear within 24 hours.
Sometimes, persistent side effects (eg, headache) require a blood patch. This is a safe procedure performed by an anesthesiologist sealing the small hole created by the injection of dye into the sac (dura). The anesthesiologist draws some blood from a vein in the arm and injects the blood into the sac (dura, epidural space) - this seals the tiny hole and prevents additional cerebrospinal fluid (CSF) from leaking.
If symptoms persist 48 hours, contact the referring physician and/or medical facility.