DIAGNOSTIC SPINAL TESTS

Myelogram with post-injection CT scan

GENERAL INFORMATION

             Problems in the neck or back  can develop following injury to the spine or as a result of aging, disc degeneration and arthritis.  Herniation of a disc or bone spurs can compress the spinal nerves in the neck or lower back and cause pain to radiate into your arms or legs. This may be associated with numbness or weakness. 

            Symptoms can often be improved simply by time, rest,  and common medications such as aspirin or Advil.   Exercises often under the supervision of a physical therapist may be started and hopefully allow you to return to full activity. If however routine treatments are unsuccessful and your symptoms are intolerable your doctor may recommend further testing to obtain a clear picture of what is causing the pain and to assist in planning further treatment.  

              Routine X-Rays studies are able to produce pictures of the bones of the spine and are often the first test  obtained.  They may be helpful but are limited because they are not  able to show the discs or spinal nerves.  If  more detailed information about the bones in a specific region is required a CT scan may be suggested.  Sometimes it is important to visualize all of the bones in your body.  If this is required a bone scan is indicated.  The special test most commonly used to image the nerves of the the spine is a MRI scan.  Often this is all that is required to understand the problem and plan treatment. Sometimes in more complex problems such as spinal stenosis and especially in people who have undergone previous surgery a myelogram combined with a CT scan is needed.  A discogram is a test sometimes used in patients with long standing back or neck pain to  confirm the site of the pain and plan surgery.    

MYELOGRAMS

             Sometimes a test called a myelogram is needed to visualize the nerves in your spine.  A myelogram involves inserting a small needle into the sac that contains the spinal nerves and injecting an iodine containing contrast material called Omnipaque.  The contrast coats and outlines the nerves and allows them to be seen .  Most often the injection is made in your lower back.  The contrast  can then be moved into the area to be studied  by tipping  the special table upon which you are positioned in different directions.  Often in addition to regular X-Rays a CT-scan is performed within a few hours of the myelogram before the contrast is absorbed.  This gives the added benefit of high resolution and cross-sectional images.

THE PROCEDURE

             In the morning prior  to your  myelogram you should  increase your fluid intake.  You may eat a light meal and take your regular medications.  Plan to arrive one hour prior to the procedure. After registering, a nurse will complete preparations for the procedure.  In the procedure room you will be positioned on the X-Ray table on your stomach.  Your back will be washed and the skin numbed with a  local anesthetic.  The myelogram needle will be inserted and a small amount of spinal fluid will be removed for testing.  Some patients feel a mild pressure in the back when the contrast is injected. This part of the test only takes a few minutes.  Once the injection is complete the needle will be removed and X-Rays will be taken with the table in various positions.

               Almost all patients will then be moved to  the CT-Scan room where additional pictures are taken (see below).  Following the CT-Scan you will be monitored until stable and then discharge instructions are reviewed.  A friend or relative must be with you or available to bring you home.  Driving is prohibited.

 Most patients feel fine and are able to go home the same day.  You will need someone to drive you home.  If you are not ready to go home arrangements will be made to keep you in the hospital overnight.

RISKS and SIDE EFFECTS

 There are  a few potential risks and side effects  which you should understand.  Some patients experience a mild ache in their back several hours after the procedure when the local anesthetic has worn off.  This usually resolves rapidly and can be treated with an ice pack for 15 - 20 minutes and/or  Advil or Tylenol.  Allergic reaction to either the contrast agent ( iodine) or local anesthetic (xylocaine) is very rare.  If you think you may be allergic to either of  these medications you must notify you doctor. Complication from placement of the needle are rare. Infection, bleeding and nerve damage have been reported but are very, very, rare.

Post Myelogram Instructions

             The most common side effect is headache and nausea.  About one out of five patients experience some headache.  Usually it is mild and there are several things you can do to minimize the likelihood  that this will develop.  First, increase your fluid intake both before and after the myelogram.   When you ride home you should either lie down in the back seat with your head on some pillows or recline the passenger seat all the way back.  After you get home you should rest in bed or on a couch with your head elevated on two or more pillows through the night.  The only activity you should engage in is going to the bathroom.  You may eat your usual diet.  In the event that you develop a headache, take Tylenol , aspirin or Advil every 4 hours.  You may  also take prescription pain medication that you may have at home as directed.  Should you become nauseated and experience vomiting during the night, you should remain in bed in a flat position but keep your head elevated with two or three pillows.  If you begin to vomit, it is best to remain in bed with your head elevated and try to drink as much clear liquid as you can tolerate.  If uncontrollable vomiting or severe headache develop during the night, please contact the emergency room at Cooley Dickinson Hospital and ask for further advice.   

            Upon awakening in the morning after your myelogram, please do not jump out of bed  immediately.  Is is advisable that you initially sit up on the side of the bed for 3-5 minutes before you attempt to walk.  If you develop a headache or dizziness or nausea or vomiting, then please lie back in bed with your head elevated.  Continue to take pain medications and drink fluids.  Once you are feeling better, then you can attempt  to get out of bed for a short period of time.   Gradually increase the time that you stay on your feet and rest if symptoms begin to return. If symptoms do not improve over the next day or two contact your doctor for further instructions.    

            Contact your doctor or the emergency  room if you develop signs of infection ( fever or redness at the site of injection), or if you notice a change in the way the nerves in your legs are working (increasing numbness or weakness) or a  change in you bowel or bladder function.

CT- SCANS

 Computerized Tomography (CT) is a test which uses X-Rays to obtain cross sectional images of the spine or area being studied.  It is excellent for showing small problems in bones and in addition can often image disc, nerve, and muscle problems.  In the CT department you will be positioned on your back with a pillow under your knees.  The table will slide into a short donut-shaped tube.  You will be asked to lie still and hold your breathe each time an image is taken.  The CT-scan should take approximately 30 minutes.  No special preparation is needed.

Additional Instructions

 Call your doctor’s office for a follow up appointment in 1-2 weeks.

 Please remember to pick up the Myelogram and CT - Scan  from the hospital and  to bring it with you to that appointment so your doctor can review it with you.