Bruce, I've seen it with my own eyes as well (something the skeptics can't say and hence why they don't believe among other reasons I'm sure ... but that's neither here nor there for this discussion). So, I've seen the same things you have.
From what I gather, along the lines of what Cece said ... as soon as you get proper blood flow, you start to get more "healthy fresh blood" regularly flowing by - which contains more positive nutrients for cell life than the blood that was "trapped" there by CCSVI.
This better oxygenated blood helps the areas that were affected by "MS lesions" heal, repair and do things better than previously.
So when we breathe, we only use 20% of the in-take oxygen to support the life of the body (muscles, cells) ... the rest is breathed out. As the blood flows, even as it makes its way from the arteries (carrying fresh oxygenated blood) to the veins (bringing back used oxygenated blood) ... more oxygen is left for the veins to carry back to the lungs keeping the blood fresher than if it gets trapped by CCSVI.
So that's my explanation. Bad/poorly oxygenated blood gets stuck in CCSVI (which then causes the "degenerative" part of MS over time as it is a continuous cycle UNLESS CCSVI is CORRECTED) ... but when CCSVI is corrected ... better blood flow can rapidly (in some cases) help the areas affected.
Also, after liberation ... did your wife say she could feel her blood flowing better (i.e. did she feel her areas of numbness if she had any, go away ... the same as if your foot fell asleep, and the feeling starts to return. My wife did and I've heard stories from others who say the same) ...
Thus my equation of ...
CCSVI (yes or no) * degree of severity of CCSVI (out of 10) * time = severity of MS
100 * 9 * XXX years = severity of MS
Still seems to hold up! Like I said, I'm pretty good at math ... and so far the equation has worked in several cases (predictably).
and here come the arguments I'm sure ...