11-5-2008
Myelogram contrast
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Just a quick hopefully helpful correction. The contrast injected for myelography cannot affect the ADR hardware. It is a water-soluble agent that is directly injected into the spinal canal (thecal sac). Unless there has been penetrating trauma causing a tear in the dura, the contrast remains within the dura and is gradually absorbed by the vascular system and excreted by the kidneys. Of course, the myelogram itself does cause a small penetration posteriorly, and there usually is a small amount of contrast leaking along the needle tract which can be seen on the CT done after the myelogram.
The contrast used is for all practical purposes the same agent injected intravenously for CT's of multiple other body parts (chest, abdomen, coronary CT's, etc.) It is also injected during a discogram to confirm that the needle is within the disc. It is gradually absorbed from here, as well.
If someone were to have an injury resulting in an unhealed tear of the dura, they would have possibly multiple other symptoms, spinal headaches being the most common. However, the leak would have to also extend through a ligament in front of the spinal canal and in back of the vertebrae in order to reach the ADR hardware (the posterior longitudinal ligament, not the anterior longitudinal ligament-which is opened for the ADR insertion).
Even then, the contrast agent would simply be gradually absorbed. It would be no more toxic or damaging in this location than it would be when injected into all of the various places it is normally used for other studies. It would essentially be the same as if saline were injected around the ADR hardware.
OK, maybe it wasn't a "quick" correction, but hopefully it was "helpful."
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L5-S1 rupture 11/04, left leg pain for 2 wks.
Regular exercise/pain-free until 2007
L5-S1 degen. disease w/constant pain since 6/07
PT, ESI, SI jt injections, 3-level nerve root inj. x 2
L5-S1 Charite Jan. 19th, no back pain so far
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