Hey FT,
I have not undergone the procedure personally but I work at an orthopedic hospital as a radiology technician and have participated in dozens of kyphoplastic surgeries over the past three years. I've talked with quite a few patients who have had the procedure done. Most had an improvement, and many have stated that it provided miraculous relief from their lower back pain. There are some who had had no improvement whatsoever. I don't believe I have met any one who has suffered a worsening of condition after kypho but that doesn't mean it can't happen.
I imagine you have been well briefed by your orthopedic surgeon. He should have given you all the pros an cons. As far as back surgery goes, kyphoplasty is a minimally invasive procedure. They will spend as much time setting up while you are under anesthesia as they will actually performing the kypho itself. Time in and out for most cases is usually about an hour. Rarely more than two. A two level kypho doesn't take too much longer than a single level. Recovery time is much shorter too.
My own observations gleaned from talking with post op patients is that often the success of any type of back surgery is dependent upon the overall condition of the patient in general and their willingness to strictly comply with post op instructions. I can't stress that last part enough as I've seen too many patients who were back in for follow up x-rays who were non-compliant with their Doctor's post op instructions. Being grossly overweight will complicate things too, and few things are as positive towards improving overall health as losing those extra pounds! I could lose 20 or 30 pounds myself!
I hope you are in the majority who have positive results. Good luck with your surgery and may God bless the surgeon's work.
John
Will ask him where to go from here on the 30th. Whatever I do is going to have to wait 16 months 'til I qualify for Medicare. It'll take that long to get out of hock anyway. 
