What is Myelography?
Myelography is an imaging examination to find and explain problems of the spinal cord and spinal nerve roots.
It involves putting the tip of a needle into the spinal canal and injecting contrast material (a colorless liquid) into the space around the nerve roots (the subarachnoid space), using X-ray imaging called fluoroscopy. Then a CT scan is done of the part of the spine where a problem is suspected, according to the symptoms and physical diagnosis by the patient’s doctor.
Magnetic resonance imaging (MRI) is often the first imaging test done for problems of the spinal cord and nerve roots. However, some patients may not be eligible for MRI, whether because of an implanted medical device such as a cardiac pacemaker, or severe claustrophobia. Sometimes myelography is done after MRI, when further information is needed.
How should I prepare?
You should inform your physician of all medications being taken and any allergies, especially to iodinated contrast material. Also, inform your doctor about any recent illness or other medical conditions, and any history of epilepsy or seizures. There are some drugs that should be stopped before myelography, including blood thinners, anti-depressants and anti-psychotic medications. You should hydrate well the day before and the day of the procedure, but avoid solid food the morning of the procedure. Women should always inform their physician and X-ray technologist if they are pregnant. You should not drive on the day of the procedure, and should arrange to be in the presence of a responsible adult for 12 hours following the procedure.
How is the procedure performed?
Myelography is usually performed as an outpatient procedure. The radiologist will briefly discuss the procedure and related issues beforehand.
The patient lies face-down on an X-ray table and the radiologist will determine the best place to inject the contrast material, most often in the lower lumbar spine. The skin is cleansed and numbed with a local anesthetic, then the spinal needle is advanced using real-time X-ray imaging (fluoroscopy) to enter the spinal canal in the midline (neither to the left or right). When spinal fluid flows from the needle, the appropriate amount of contrast material is injected and the needle is removed and a bandaid applied.
The table will then be tilted, feet-down for a study of the lumbar spine or head-down for the thoracic or cervical spine. The contrast material is denser than spinal fluid and will flow under gravity to the area of interest, while being monitored by fluoroscopy. Some X-ray images will be taken during this time, followed by computed tomography (CT) imaging.
What will I experience during and after the procedure?
You will feel brief stinging when local anesthetic is injected, and pressure as the spinal needle is inserted. Uncommonly, the needle tip may touch a nerve root, causing a sudden electric feeling in one leg or the other. If so, tell the radiologist which leg so the needle can be redirected. The face-down position can be uncomfortable, particularly when tilted head-down, but you will be asked to be as still as possible. Please inform the radiologist or nurse if you have any difficulty breathing or swallowing.
Headaches, flushing or nausea may rarely follow the contrast injection. A seizure immediately after myelography is a very rare event but may be more frequent in patients with a history of seizures. After the procedure, you will be observed in a recovery area for two to four hours, and will be encouraged to take fluids during this time.
You will need a ride home. Avoid strenuous activity and bending over for the next day. Notify your physician if you experience fever higher than 100.4 F, excessive nausea or vomiting, severe headache longer than 24 hours, neck stiffness or leg numbness, or trouble urinating or moving your bowels.
How will I get the results of this test?
A radiologist will analyze the images, and send a report to your primary care or referring physician who will discuss the results with you.
What are the benefits and risks?
Myelography is a safe alternative when MRI is not possible, or when additional information is required after MRI, to get information and plan treatment for conditions affecting the spinal cord or nerve roots. The use of fluoroscopy and CT does require exposure to radiation, and involves a slight increase of lifetime risk of developing a cancer, but the benefit of getting an accurate diagnosis for an ongoing problem should far outweigh the risk.
Headaches can occur uncommonly, with the characteristic feature that the headache is worse on sitting or standing and better when laying flat. Hydrating with fluid may help, but medications may be needed for more severe headaches. Rarely a special though fairly simple procedure known as a blood patch may be required for long-lasting headache.
Adverse reactions to the contrast material during a myelogram are very uncommon and usually mild, such as rash, itching, sneezing, or anxiety. Seizure is a very rare complication. Other rare complications include bleeding around the nerve roots in the spinal canal, infection, or inflammation of the covering of the spinal cord and roots (meninges). If there is a blockage above the needle puncture site, pressure change within the spinal canal could require an urgent surgery to relieve the blockage.
Radiologyinfo.org for Patients
The radiology information resource for patients. RadiologyInfo.org tells you how various X-ray, CT, MRI, ultrasound, radiation therapy and other procedures are performed. It also addresses what you may experience and how to prepare for the exams. The website contains over 200 procedure, exam and disease descriptions covering diagnostic and interventional radiology, nuclear medicine, radiation therapy and radiation safety and is updated frequently with new information. All material on the RadiologyInfo.org website is reviewed and approved by experts in the field of radiology from the ACR and RSNA, as well as other professional radiology organizations.