...is that people talk about the discs that leak being painful.

My understanding of the procedure is that the dye injection causes discs to bulge, and that if they are already pinching a nerve, that nerve is compressed MORE than before.

The part about that which puzzles me is that if the disc "leaks" the dye, it can not really expand as a result of added mass, and can therefore not compress a nerve more than previously.

Is the dye itself painful, when it contacts the nerves outside of the disc (hence, the free dye from the "leaks" causes pain by contact)?

my understanding (and I could be wrong) is that no matter how bad the leak, it still cant leak out as fast as its injected as has to work its way though the nulceus and annulus to the tear first - so it will still bulge when injected.

seems to me the tear would bulge even more during the injection as it would have to open up a bit more than usual to let the dye out, but this is just guesswork on my part. hopefully someone who knows for sure will post.

When the radiologist told me to wait till the pain was a "10" for him to stop injecting I thought it would be a while-it was like going from 0-90MPH-the ten hit that fast. They also inject lidocane for the pain but that takes a few minutes to work so they take a brief break between discs-they let you prepare mentally for the next one. My l3/L4 was only about a "3" on the pain scale so I thought the other two wouldn't be so bad-I was wrong! The lidocane DOES hit tho and you do move on to the CT scan. My radiologist gave me hydrocodone also as soon as it was over. The dye goes in faster than it can leak out.-MIchelle