Aw Becky, that just stinks! I certainly know the feeling; aargggh! Is it too soon for you to have another epidural injection in the spine? If not, I think I'd go for it. Also, have you ever considered Radio-Frequency Ablation? I'm sure you have but thought it might be worth mentioning. One note of interest that may only pertain to me, my gait peculiarities with the knee and my back; any sort of backless foot wear will set off my back pain. Sad, but true. Like most here, I like sandals and flip-flops and clogs, but...the knee and the back seem to conspire against that idea. If it try, they'll both let me know in no uncertain terms; pffft.
I know you've tried just about everything under the sun to get a decent night's sleep, but have you tried Melatonin or SleepyTime tea? I found it helpful many years ago when I had shoulder surgery and just couldn't get comfortable in bed. It wasn't foolproof, but it did help on most nights.
Sending some very strong, special brew "Sleeping Pixie Dust," your way tonight. Nemo had a hand in making this batch and he can fall asleep while standing!