Transcutaneous Electrical Nerve Stimulation - TENS

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TENS is a simple, non-invasive technique, in which electrical currents, generated by a portable stimulating unit, powered by a small 9 volt battery, are passed through the surface of the skin to activate underlying nerves via two or four electrodes. Conductive gel or pre-gelled electrodes are used to decrease resistance across the skin-electrode interface, and the electrodes can be concealed under clothing if necessary.

TENS produces a “strong and comfortable” tingling sensation (electrical paraesthesia) within the painful area and the intensity and quality of electrical paraesthesia (ie pulse intensity, pulse frequency and pulse pattern) can be varied and controlled by the patient according to his/her requirements. TENS has been shown to produce useful analgesic effects in all types of patients suffering from acute or chronic pain and has gained worldwide attention and use.

TENS has many advantages over conventional treatment for pain. It does not require surgical intervention, and unlike analgesic drugs, has no serious adverse affects. It can be used long term and can if necessary be used in conjunction with other analgesics, such as drugs. Not every person responds to TENS treatment, the efficacy is approximately 60%. The reason for non response to TENS by the other 40% is unknown at this point in time.

TENS works in two ways:

Pain Gate Control: High frequency stimulas (15 – 150hz) causes the central nervous system to transmit via the large dia nerve signals that causes “gates” cells in the pain pathways to “switch off” pain transmission.

Endorphine Release: low frequency stimulation 2 – 9 Hz encourages the release of morphine like substances which block pain at receptor sites in the nerve pathways. Studies have shown that endomorphis related pain relief can often last for periods which extend considerably beyond the time stimulas.

Some commonly asked questions and answers:

Q. Does TENS work for all pain conditions, and on all patients?
A. No, there is a significant variation between patients with similar pain conditions. However, it is known that TENS does work in 60 – 70% of cases.
Q. How can I have a better chance of success?
A. Professional diagnosis and recommendation are vital in selecting the correct stimulator and placement of electrodes.
Q. Are there circumstance sin which TENS should not be used?
A. Yes for an un-diagnosed pain, when using a cardiac pacemaker, during the first three months of pregnancy, and other instances listed in our detailed literature.
Q. How long will I have to use a TENS stimulator?
A. Some long term chronic pain sufferers may need to use a stimulator for long periods of time maybe years. Other conditions may only need a short period of treatment.

Fisrt published May 1994 - Skin ‘n’ Bones Connection, issue 2 p7-8.