patients with re-stenosis considered as controls?

[frodo]

Some time ago there was a thread saying "why not to treat CCSVI just as a treatment for reduction of fatigue?". The main problem for this was that no study with controls was possible (obviously a person knows whether he has got a surgery or not).

But some people get re-stenosis after surgery. Could it be possible to consider this people as a control group?

Maybe if the purpose of the study is well redacted it could. I think that a study named "influence of the venous flow problems in the fatigue of patients with MS" could consider re-stenosed people as controls and settle this issue forever.

What do you think about this? Could this be possible?