What is a TENS Machine?
TENS is the abbreviation for transcutaneous (through the skin) electrical nerve stimulation - A medical method of relieving pain without drugs.
TENS equipment consists of a battery operated stimulator (about the size of your palm), lead wires and 2 or more electrodes (pads) which stick to the skin. By adjusting control knobs on the stimulator you are able to start or stop the electrical impulses and you can vary the type and intensity of each electrical impulse.
The electrical current, which produces a mild tingling sensation, travels from the stimulator through the lead wires to the electrodes which are placed near the painful areas. The exact electrode placement may be anywhere along this path, but often 1 pair of electrodes is located either at the pain site or near the spine where the nerve pathway connects to the spinal cord.
A physiotherapist can show you how to correctly place the electrodes and then trial it to see if it works for you.
How does TENS work?
The exact mechanism for TENS is not known, Some scientists believe that the electrical impulses override the pain messages travelling along the nerve pathway to the brain. Others theorise that the current triggers the brain to release its own pain killing chemicals. Recent studies have shown that both these theories are probably involved, plus several others.
How effective is TENS?
TENS has been used to control acute and chronic pain in a wide variety of cases. These include back and neck injuries, pulled muscles, arthritis, migraine headaches, labour and delivery and post-operative recovery.
The success of TENS depends in part on how easily the nerve pathway carrying the painful signals can be identified and how accessible they are for placing the electrodes. Patient attitude and clinical history also play an important part. That is why patients must undergo a thorough examination by a knowledgeable clinician before TENS treatment can begin.
Clinical studies over the years show TENS to be effective in reducing pain among 20% to 40% of patients treated for chronic pain conditions. This success rate is considered to be excellent, since most chronic pain sufferers have already tried a number of drugs and interventions including surgery with little success.
Source: Australian Pain Management Association and Pain Management Unit, Royal Adelaide Hospital