Myelography – Treatment, Effect & Risks
Myelographie
Myelography is a radiological diagnostic method to show the space in the spinal canal. Myelography has become less important due to non-invasive diagnostic methods such as computer or magnetic resonance imaging . However, this is often used as an additional diagnostic procedure for specific questions, especially spinal root compression syndromes.
What is myelography?
Myelography is an X-ray contrast medium examination to show the spinal canal or subarachnoid space (spinal liquor space), the spinal cord and the outgoing spinal nerves.
The invasive diagnostic procedure is usually used when there is a suspicion of compression of the myelon (spinal cord) and/or the spinal or spinal cord nerves when other imaging procedures such as computed tomography (CT) or magnetic resonance imaging (MRI) are not sufficient for a detailed diagnosis .
By injecting a contrast medium into the subarachnoid space with subsequent X-rays in different projections or from different perspectives, the space available for the myelon and spinal cord nerves can be visualized.
Function, effect & goals
Various impairments of the spine , which are associated with nerve damage in the spinal cord canal, can justify the indication for a myelography if sufficient information cannot be provided by a CT or MRI.As a rule, these are due to degenerative diseases of the spine, which can cause, for example, spinal canal stenosis (spinal cord canal narrowing) with pressure-related damage to the nerve structures. This manifests itself in pain , sensory disturbances in the legs and arms and lack of strength .
Myelography may also be indicated if there is a suspicion of neuroforamen stenosis (local narrowing of one or more nerve root exit openings). In addition, the diagnostic procedure is often used as a planning aid in the run-up to spinal surgery such as decompression or spondylodesis. The aim of a myelography is the pictorial representation of the space conditions in the spinal cord canal in order to be able to determine and assess the extent and location of potential nerve, vertebral body or intervertebral disc damage.
For this purpose, the blood coagulation values are checked in the run-up to the examination by means of a blood analysis and blood-thinning medication is discontinued to avoid the risk of bleeding. In addition, an X-ray of the spine is often performed before the myelography in order to determine the best possible access to the spinal cord canal for the puncture. Following the local anesthesia of the puncture site, the water-soluble contrast agent (10 to 20 ml) is injected into the area of the lumbar spine using a cannula (lumbar puncture) so that it can be distributed in the dura tube (meningeal tube).
Existing bottlenecks modify the flow of contrast medium and are made visible by the subsequent X-ray images. An X-ray from the front (AP) can use the distribution of the contrast medium to visualize the space in the spinal cord space and the spinal cord nerves through contrast medium cut-outs. Oblique X-rays allow the spinal nerve outlets to be assessed, while lateral images during ante- and retroflexion (forward and backward bending) of the upper body allow conclusions to be drawn about the space conditions in the spinal cord canal.
In addition, a computer tomography can be carried out afterwards (myelo-CT). The combination of contrast medium injection and cross-sectional imaging provides the most detailed information for the assessment and detection of spinal canal narrowing and nerve compression. In order to avoid or minimize the headaches that can occur as a result of the temporary pressure changes in the cerebrospinal fluid (cerebrospinal fluid) as a result of the puncture, a 24-hour bed rest should be observed after the myelography.
Furthermore, a sufficiently high fluid intake should be ensured to quickly compensate for the loss of cerebrospinal fluid. Within the framework of a rare MR myelography (rapid acquisition with relaxation enhancement myelography), water-specific images can also be obtained extremely quickly, which provide information on a displacement of the subarachnoid space, e.g. due to tumors.
Risks, side effects & dangers
As a rule, complications can rarely be observed during myelography . The most common side effect is the temporary headache caused by the loss of cerebrospinal fluid. In addition, an injury to a blood vessel can cause bleeding into the spinal cord canal (epidural hematoma ), which can result in nerve damage.
If the myelography needle (cannula) is misplaced, the outgoing nerves of the spinal cord can be damaged, which can cause pain, sensory disturbances and paralysis . Since myelography is an invasive procedure due to the skin damage caused by the puncture, infection can result from the spread of germs. This can only be superficial or affect deeper structures of the spine such as vertebral bodies, intervertebral discs or spinal cord.
In the worst case, an ascending inflammation of the spinal cord and meninges ( meningitis ) can manifest itself. If the dura (spinal cord skin) does not close on its own, liquor can continuously seep out of the puncture site, which often entails a surgical closure. A myelography can be contraindicated in the presence of hyperthyroidism ( overactive thyroid gland ) due to the iodinated contrast media used.
Hypersensitivity to iodine , which can lead to anaphylactic shock (severe circulatory shock), may also rule out myelography.
Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.