The problem with sciatica and low back pain is result of bad blood circulation, from low back down to the feet. I have the same problem.What i have tried is to switch between cold and hot treatment of the leg, for 20 min each. But, on low back it shold not be treated with hot, only cold. i use plastic bottle filled with cold/hot water.Between skin and bottle i have some textile....
The result is very good !!!