What is a Myelogram?

Orthopaedic & Spine Center
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Dr. McFarland with operating lights

Mark W. McFarland, DO

As a spine specialist and surgeon, x-ray and MRI are pretty much the tools of my trade; however, I occasionally need more detail or different detail than they can provide.  That’s when I order a Myelogram.  In this article, I will discuss what a Myelogram is, why it is ordered, what happens during the test and what it tells us.

In medical terminology, the prefix myelo means “of the spinal cord” and gram means “a picture or record”; hence, a picture of the spinal cord.  The use of the suffix “gram” has also become associated with the use of a dye or contrast agent used in an x-ray, CT or MR scan, because of the contrast agent’s ability to highlight or illuminate images for diagnostic purposes.

A myelogram is usually ordered when the MRI scan I’ve ordered doesn’t show me enough detail about the nerve roots and vertebrae of the spine. I may be concerned about a potential bulging or herniated spinal disc, spinal cord compression due to a tumor or spinal stenosis.  A myelogram can give me a better look at arthritis in the spinal joints and may even alert me to an infection of which I was not aware.

Because the contrast agent is injected into the spinal fluid in the intrathecal space, it will spread to illuminate the entire spinal column, the nerves, the roots, and all the vertebrae.  After the injection of the contrast agent is completed under fluoroscopy, which is a special type of x-ray, the patient then gets placed in a CT scanner for another type of x-ray which is taken at high speed and from many different angles.  This almost always gives the Radiologist the images needed for a diagnosis and will also give me the images I may need for surgical intervention down the road.

To prepare for the test, a patient will need to stop taking blood thinners for about 5 days before the procedure, and it may be recommended that you stop any anti-inflammatory medications as well for a period of seven days before your procedure.  You should not have this procedure if you have ever had an allergic reaction to contrast dye, iodine, or shellfish.  Please inform us if you have any food or drug allergies.  Patients should inform us if they are pregnant, have diabetes, have increased intracranial pressure, multiple myeloma, pheochromocytoma, homozygous sickle cell disease or a known thyroid disorder. Typically, no lab work will be required unless the patient has severe liver or kidney disease.

When I send a patient for a myelogram, it is performed by an Interventional Radiologist, usually at an outpatient facility where they have both C-Arm Fluoroscopy and a CT scanner.  You may be advised not to eat or drink anything for 2-6 hours before your test, depending on your physician. However, in the time frame before that, they will want you to be very well hydrated with clear liquids.  You will also have to have someone to drive you home from the myelogram, as it is not recommended that you drive after the procedure.

The myelogram procedure itself takes about an hour.  After your arrival, you will be taken to a procedure room and asked to change into a gown.  You will then be asked to lie upon your stomach on a padded table.  The staff will do everything possible to make you comfortable.  The assisting nurse may administer a sedative by IV to make you calm and drowsy.  Your lower back or cervical area of the neck will be cleansed and draped. 

Your physician will numb the area to be injected with contrast agent with a local anesthetic, which may sting momentarily.  The, the radiologist will insert a needle into the intrathecal space of the spinal canal.  Some spinal fluid will be withdrawn (and sent to the lab for analysis) so there won’t be too much added pressure when the dye goes in.  Next, the radiologist will inject the contrast agent.  The patient may feel some pain, an electric shock sensation and/or pressure running down their arm(s) if their neck is injected or their leg(s) if their lower back is injected.

The contrast fluid will mix with the patient’s spinal fluid and run the length of the spinal column clearly highlighting the vertebral bones and nerve roots.  To aid in the movement of the dye, the patient’s table may be tilted.  All of this will be done under fluoroscopy, a type of live x-ray, so that the radiologist can be very precise with needle placement and ensure that the contrast agent has mixed thoroughly with the spinal fluid up and down the spinal column.  Multiple x-ray images will be taken.

Next, the patient will be taken to the CT scanner to have another type of rapid, multi-view x-ray.  The CT typically only takes about ten minutes to complete.  After completion, the patient will be taken to a recovery area, to fully arouse from sedation and to be observed for a period after their myelogram.  If the patient does well and does not develop serious complications, they will be sent home to recover with a companion to drive them.

Risk and complications are headache – more uncommon are infection, bleeding at the injection site, allergic reaction to the contrast agent, temporary anesthesia to a nerve root or spinal cord, seizures or leaking cerebrospinal fluid.

Headache is the most common complication after a myelogram. It will be recommended that the patient rest lying down with their head elevated at a 30°angle for 24 hours after their myelogram to prevent headaches or to keep them from worsening.  Acetaminophen or NSAIDS can be taken for headache pain.  There can also be soreness at the injection site, which typically resolves in 1-3 days.  The site may be iced intermittently for the first 24 hours, making sure there is a barrier between the skin and the ice pack.  The patient should drink plenty of fluids but avoid alcohol for 24 hours.  You are also advised not to take a bath and/or submerge the injection site in water for 24 hours.  Showers are fine.

The radiologist will read the images, report to me and I will share the results with the patient. Based on the findings, the patient and I can decide upon the best plan of treatment moving forward, whether that be surgery or a more conservative approach.

 

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