After years of not issuing guidance on the use of transcutaneous electrical nerve stimulation (TENS) to treat lower back pain, Tricare is officially excluding the machines from coverage, effective June 1. Tricare officials said they decided to stop letting the program's contractors decide whether TENS was medically necessary after studies by the American College of Physicians, along with the Defense Department and Department of Veterans Affairs, found "insufficient evidence" that the treatment is effective in treating acute, subacute and chronic lower-back pain. Read more on Military.com.