It turns out that one of the biggest problems in a spinal injury is the rush of ATP to the injury site which leads to subsequent tissue death of the nerve tissue. The injection of the dye stops that process. I don't pretend to understand all of the science. But having a quadraplegic father-in-law does give one an appreciation for these kinds of medical advances and the incredible impact that they can make.
The fact that it's a dye that I may in fact be using on yarn. Well, life don't get any better than that.