Sorry to hear about your complicated post-op course. The best test for you would be an MRI of the spine to evaluate the blood/shadows. The difference should be picked up without any problems by an experienced spine neuroradiologist. Also, it can tell the staging and amount of the blood, meaning if it's new or old, significant hemorrhage or simply postop changes that everyone has. The MRI would also help with looking at the pedicle screws, because if they're pushing on your cord or the nerves - it has to be readjusted without question.
Unfortunately, I'm not quite sure what you mean when you say "acanthocytosis" which actually refers to a condition of the blood that describes different sized red blood cells. I wonder if you're mis-spelling something else. ALso, the 4th disc of what part of the spine??? There's the cervical which is in the neck, thoracic-midback, and lumbar-which is lower back. If the problem is in the lumbar region, then definitely you can have symptoms from that. Otherwise, I would be alittle surpised if you were having mainly leg symptoms from a neck problem. Get the MRI and talk to your surgeon again. If they are unwilling to change anything, go for a second opinion with another surgeon or neurologist. An EMG may also be helpful to see where the pain is coming from.
Best of luck.