Hi Henry,
Which surgery will you be having or what type .. fusion, ADR, hybrid (mix of both)?
Did you have a discogram? How about a CT scan?
I can't answer any of the questions you asked except to say maybe you have more than one type of problem based on what you mentioned re your disc spaces being blackened and compressed .. do you have facet changes as well that maybe you're getting some relief from that or at least enough to feel a bit better..
Mark (mmglobal) most likely is the person to help you out with some answers.
Anyway good luck.. I remember the days when I could only stand 5 mins or so and then even only 30 (re back probs). Now my back tolerates way more but my feet are problematic
Hope Mark and/or someone else pops in here and gives you some answers! Maria