TENS stands for Transcutaneous Electrical Nerve Stimulation. It is a method of pain relief.
In TENS therapy, electrodes are placed on the skin, either directly over the painful area or more commonly, at key points along the nerve pathway. A small, battery-powered generator emits a milli-amp (one thousandth of an ampere) of electricity through lead wires to the electrodes.
How TENS relieves pain is debated. The sensation produced by the electrical stimulation appears to "override" the pain messages and may stimulate the body to produce its own natural morphine-like substance, which minimizes pain.
In the past two decades, TENS has been used for a wide variety of complaints. TENS has been applied to almost every type of pain, from mildly persistent problems (such as sore muscles) to acute postoperative pain and even in the pain of childbirth. The most common reason for prescribing TENS is for chronic low-back pain.
Whether the electric current squelches pain messages, causes the body to produce pain relieving chemicals of its own, or if TENS merely has a placebo effect, it relieves pain for a number of people who try it.
One of the most compelling reasons for prescribing TENS for pain relief is that this therapy has few side effects. TENS is non-addictive, causes no drowsiness, and can be used indefinitely without the problems associated with prolonged drug use. The most common side effect reported has been skin irritation at the site of the electrode, due to either a sensitivity to the gels and adhesives used, or from burns, caused by extended stimulation. TENS may also cause anxiety and should be used with caution by cardiac pacemaker recipients.
For the geriatric patient, TENS is especially appealing. Older people often have more adverse reactions to medications and nerve blocks. Rehabilitation therapy can be difficult for them, and if they have degenerative diseases (such as arthritis) physical therapy may be even more dangerous.