 |
Posterior spinal anatomy
Spine skeletal
Vertebra, lumbar (low back)
Vertebra, thoracic (mid back)
Vertebral column
|
|
myelography; X-ray of lumbosacral spine,
Cervical, lumbar, or thoracic myelography
This X-ray helps
evaluate back injuries and persistent numbness,
low back pain, or
weakness.
-
To detect herniated discs, tumors, injuries,
enlarged blood vessels, and other abnormalities, especially
compression of the spinal cord.
-
To evaluate problems in the spinal cord
before surgery.
-
To detect injuries to the nerve roots
branching off the spinal cord.
-
To detect tumors in the lower part of the
brain
The test is performed in a hospital radiology
department or in the health care provider's office by an X-ray
technician. You will be asked to lie on the X-ray table and assume
various positions. If the X-ray is to determine injury, care will be
taken to prevent further injury. The X-ray machine will be positioned
over the lumbosacral area of the spine. You will be asked to hold your
breath as the picture is taken so that the picture will not be blurry.
Usually 3 to 5 pictures are taken.
Contrast dye injected into the cerebrospinal fluid (which surrounds
the brain and spinal cord) makes it possible to view internal
structures with the help of fluoroscopy, a type of moving X-ray.
A myelogram is an X-ray or
CT
scan of the spine that is performed after dye has been injected into
the spinal fluid. See the document on
lumbar puncture for more information about the dye insertion
portion of this procedure.
-
Local anesthesia is administered at the site
where the spinal needle will be inserted.
-
A long needle is inserted into the spinal
canal, with the help of a fluoroscope, and guided to the
subarachnoid space, between the layers of membrane that surround the
spinal cord.
-
Once the needle is in place, a contrast dye
is injected and X-ray pictures are taken.
-
To move the dye to structures of interest,
you may be slowly titled head down during parts of the test. Care
will be taken to prevent the contrast dye from entering the brain.
| Where It's Done |
Who Does It |
How Long It Takes |
Discomfort/Pain |
|
Hospital imaging suite or radiology
laboratory. |
Doctor. |
45-60 minutes. |
Some discomfort during lumbar puncture and
as table is tilted. |
There is no discomfort associated with the
X-ray. The table may be cold.
Inform the health care provider if you are
pregnant. Remove all jewelry.
The X-ray shows normal structures for the age
of the patient. The doctor examines the X-ray images, called a
myelogram, for signs of abnormalities. Abnormalities can also be
detected by observing the flow of the contrast dye under a
fluoroscope. If the spinal canal is blocked or narrowed, the dye will
not spread evenly or will be blocked, and the contour of the spinal
cord will also be distorted.
There are a number of back problems that the
X-ray will not detect because they
involve the muscles, nerves, and other soft tissues. A
lumbosacral spine CT or
Lumbosacral spine MRI are better options
for soft tissue disorders.
The test will detect abnormalities such as
fractures, dislocations, thinning of the bone (osteoporosis),
and deformities in the curvature of the spine. The test may also
detect bone spurs, disc problems (see
herniated disk), and
degeneration of the vertebrae.
| When
Results Ready |
Special
Equipment |
Risks/Complications |
Average
Cost |
|
A few hours to a few days. |
Fluoroscope and X-ray equipment with a
tilting table, contrast dye, spinal needle, and local
anesthetic. |
Risks associated with radiation,
particularly during pregnancy; seizures; stroke; bleeding;
infection and inflammation; headaches; nausea and vomiting;
allergic reaction from the contrast dye. |
$$ |
There is low radiation exposure. X-rays are
monitored and regulated to provide the minimum amount of radiation
exposure needed to produce the image. Most experts feel that the risk
is low compared with the benefits. Pregnant women and children are
more sensitive to the risks of the X-ray.
Obstruction and abnormalities are easily seen
and well defined on X-rays.
-
Additional diagnostic information may be
obtained from the spinal fluid (see LP testing).
-
It's invasive.
-
It involves exposure to radiation.
-
It cannot be performed in people with severe
curvature of the spine or increased intracranial pressure.
|
