Check out this link for information on tDCS:

http://neurotalk.psychcentral.com/thread160980.html

It's a long thread, but I highly recommend reading through all of it. I have found it very inspiring and just started these treatments myself 3 weeks ago and have already seen some improvement. I just changed protocols and am noticing better, more consistent pain relief with this new one...which is very exciting.

It's really great that you are working with a physical therapist who you trust and feel comfortable with. I had a phenominal one this last time I had to go through therapy and she really worked with me to help me achieve my goals. It was a real partnership where I was willing to push through the pain and she was able to give me the progressions of each exercise and worked with me to gradually increase the difficulty of what I was doing. Because of her I was able to make good steady progress. It takes time but I just kept getting better and better and after months and months of getting worse and worse and worse it was so wonderful to go in the opposite direction.

With your back pain...have you noticed sensitivity to touch, color changes (even just a slight reddish mild sunburn look), constant burning, etc? Do you know what sort of things trigger the pain? Is it after you do a lot of activity (if so...any specific activites?) or if you lay or sit in a certain position? I use the lidoderm patches on my back sometimes too.

Also...might be worth a shot...maybe try using the lidoderm patches on your foot again along with one of those disposable heating pads you can get at the pharmacy. I buy the cheap generic versions (not therma-care...too expensive) because you can get 3-4 of them for $5 or less. The lidoderm patches don't help a lot on my ankle but in combination with the heat they are a little more effective for me.

And like I said...definitely try the TENS and see if that helps, as well as the ultrasound at physical therapy. I have a portable TENS unit now and I clip it to my belt, run the wires down the pant leg so they don't catch on anything, and it really helps me keep the pain level manageable through the day. Don't think I could have made the progress I did in physical therapy without it. The ultrasound I got a home unit on amazon.com for about $45 back in December and I have been doing it twice a day after I take a warm bath. By itself it doesn't feel like it makes a big difference in the pain but I have noticed that the effects of the TENS, warm bath, etc last longer since I have been doing the ultrasound therapy.

Take care and if you have any more questions, please ask.