What is transcutaneous electrical nerve stimulation (tens)?

Transcutaneous electrical nerve stimulation (TENS) is a therapy that uses mild electrical current to treat pain.

Current is delivered through small pieces of material that conduct electricity (electrodes). These are placed on the skin near the source of pain. When the current is delivered, some people experience less pain. This may be because electricity from the electrodes stimulates the nerves in an affected area and sends signals to the brain that "scramble" normal pain signals. Another theory is that the electrical stimulation of the nerve may help the body to produce natural painkillers called endorphins, which may block the perception of pain.