I know that my back injury was a different situation (it led to four herniated discs) from what you are dealing with so this may not be helpful. But I carried a TENS unit around for nearly a year as it did 'interrupt' muscle spasms enough that I could get some breathing room and mental distance from them. I later gave it to my brother to help deal with spasms and pain while healing from hip surgery. And it helped him sleep. My unit had a lot of bells and whistles so one could find the cyclicity and intensity that seemed the most comforting, which helped.