Crockett here; In case you are curious, TENS is an acronym for transcutaneous electrical nerve stimulation. The periodic trickles of electrical stimulation, which can be programmed to your liking, distract the brain from the pain signals it is receiving from the same area of the body. This helps in at least two ways: (1) It reduces the perceived strength of the pain signals to the brain; and, (2) It interrupts the cycle of muscle tension that can be triggered by pain, and cause other secondary problems.
A friend on this site had a TENS unit that had not been effective for her, and she offered it to me to use when my stenosis was most severe. It was wonderfully effective. I have since had a bilateral laminectomy, cages inserted between L4 and L5, and between L5 and S1. These three vertebrae have also been fused. My surgery was just three weeks ago, and I am now more free of back pain than I have been in 15 or 20 years. Now I am using the TENS unit on my right hip, which is just about worn out. My pain is like a prairie dog. Eradicate it in one area, and it pops up somewhere else!