Forgot this part (sorry, brain hasn't been working too great)...I do think that in your case they should at least confirm that it is not the spinal cord injury! Hopefully the new MRI will be able to do that!
I'm sorry you are dealing with a flare. I don't really have an answer since I'm in kinda the same position myself...MS but no spinal injury. Just had a flare where my left leg is just kinda useless...hard to explain. I did solumedrol, but havent really seen any improvement and have been wondering when to call the neuro back. But I wanted to say you aren't alone and I look forward to seeing what others have to say :-)
Bright Blessings,
April