Ditto, Vicotria. My back injury was from being run over by a car; subsequent surgery; now my dx is "failed back surgery." During the time between injury & surgery, I had not only sciatica, back pain of course, and foot drop. The foot drop is barely noticable now. The pain is excrutiating: keeps me from ADLs, job, etc. But the balance issue: I didn't realise that was from the back injury. As for knees buckling: yes, I've even fallen. Balance: yes, and have fallen as a result of that, too. When I get out of bed in the AM, real hard to make it to the bathroom. I feel your pain...and all your other symptoms..