DON'T GIVE UP! I have been going through this with my 8 year old boxer Bondi since november- she was screaming in pain, and then couldnt walk at all. Her back legs were completely paralysed. We took her to vets thinking the worst, to have her PTS- and vet suggested it could be a FCE (fibrocatilagenous embolism / spinal stroke) We were refered to a specialist neurologist,who suspected an herniated disc. bondi after afew weeks being on drugs (painkillers, valium, steroids and various other anti-inflamatories) started to get better. However, she would get better and then worse again. I had previously decided not to do the myelogram (inject dye into spine and do xray/scans) due to the risk associated and the cost and the fact that she was improving with drugs, but after nearly 2 months of ups and downs, she went down hill again and I decided to do it just before xmas. Vet suggested a CT myelogram- but it turned out that they only had to do a regular CT scan to see what was wrong ($1600). She had a massive infection in her spine and also multiple lesions compressing on her spinal cord. She is now on antibiotics for a minimum of 12 weeks to kill the infection, also on strict crate rest, painkillers and we have taken her off the steroids so she can fight infection (and also because she was loosing too much condition on steroids- she was 30kg, got down to 22kg). Since she has been off the steroids she was regained condition and now weighs 25.5kg. She is improving everyday, and can actually walk and get up on her own now, although she is still quite wobbly on her feet. It is going to be a long recovery process- parts of her spine have been eaten away, so we need to wait for the infection to clear up before the bone can start to become fiberous again and regrow. She has spondylosis in her spine aswell, so her spine might re-calcify quicker than dogs without spondylosis. Then hopefully and compression on the spine will be relieved and she will be able to gain more function back. The nerves are the slowest part in the body to heal though- so it will be a long road ahead- 6months + and she will probably never walk the same again, but we are confident she will be able to get around on her own again and enjoy a normal life again :) She is so happy again now, but there have been many days through this horrible time when she wasn't and I have considered PTS- I'm sooo glad I didnt now!
If vet suggests a myelogram, don't delay like I did.
Goodluck and keep us posted.