Myelography
The myelography or myelography is an imaging procedure in which a contrast medium in which the spinal cord (Greek Myelon ) containing fluidized channel (also called medullar channel) is injected, and then an X-ray exposure is performed.
Before the development of computed tomography (CT) and magnetic resonance imaging (MRI), known as “large-scale radiology”, it was difficult to assess herniated discs and other masses in the spinal canal. Myelography offers an option for further diagnostics. A special cannula is inserted between the vertebral arches of the third and fourth lumbar vertebrae ( lumbar puncture ), which extends into the dural sac (liquor space). The position is correct if spinal fluid drips from the cannula.
With the availability of modern, non-invasive MRT and CT imaging techniques, the importance of myelography in human medicine has decreased. However, myelography still has its indication for special issues in neurosurgery and when CT or MRI cannot be performed . In principle, myelography was primarily used to diagnose masses in the spinal canal. During the evaluation, attention should be paid to contrast medium breaks and gaps. In veterinary medicine , myelography still plays a major role due to the limited availability of MRI and CT.
In the case of spinal root compression syndromes , the advantage of dynamic imaging can be used in a myelography to detect filling defects in the so-called root pockets. Myelography is therefore used preoperatively to clarify unanswered questions if an MRI or CT scan cannot be performed or cannot be performed without artifacts (e.g. in the case of scoliosis ).
After administration of contrast medium and myelography, a CT can also be made in order to obtain additional layer images with administration of contrast medium.
Complications
The first contrast media available to the French pathologist and radiologist Jean Athanase Sicard (1872–1929) for the first myelographies around 1922 had an oily base and could not be absorbed by the body. Much more stressful than introducing the contrast agent was to remove the oily liquid through the puncture cannula that was still in place at the end of the examination. In many cases this did not work completely, a few drops remained in the lowest area of the dural sac and caused scarring. Today, however, resorbable contrast media are used, with which this problem no longer occurs.
Any procedure that penetrates the intact skin can lead to an infection . Pus pathogens in the spinal canal represent a very serious problem; purulent meningitis can lead to death. Fortunately, these catastrophes are extremely rare.
Quite often, however, spinal fluid is lost after puncturing the dural sac. The cerebrospinal fluid , which looks like water, drains through the hole that has formed, creating a negative pressure inside the skull. The result is severe headache ( post-puncture headache ).
literature
- SB. Peterman: Postmyelography headache: a review . In: Radiology , 1996 Sep, 200 (3), pp. 765-770. Review. PMID 8756929
Web links
Individual evidence
- ↑ Axel Karenberg : Neuroradiology. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 1046.
