Tuesday, May 8, 2012

The Use of a TENS unit

A young woman using a TENS unit. This particular one uses four patches.


  The first Transcutaneous Electrical Nerve Stimulator (TENS)  Unit was patented in the United States in 1974.  The first units were large and fairly expensive, but based on the principle that patients with chronic pain could benefit from low level electrical stimulation of musculature.  Generally TENS is applied at high frequency (>50 Hz) with an intensity below motor contraction (sensory intensity) or low frequency (<10 Hz) with an intensity that produces motor contraction. It attaches to the patient using multiple electrodes and patches.   In the late 1970s and part of the 1980s we saw these given to patients upon physician order, and some of these patients felt they were very helpful. I recall some patients for whom we were able to give less of the narcotic they had been using over time.  This should not be confused with EMS or electro muscle stimulation. This is a different machine, and we are not discussing this within this particular post.   The TENs unit was used in palliative care and in chronic pain patients with some measure of success.  The effects most of us saw were in excess of those anticipated in simple placebo effect.   Over the course of my career, a number of things with regard to TENS changed.    First of all, as electronics  improved,  the units themselves became much smaller, more portable, and much less expensive.  Physicians, chiropractors, and others began to use TENS units for other uses. Some patients find relief from their pain with a TENS unit, and a few find it aggravates theirs.  I have used a TENS unit, while exploring one in a nursing lab, and I found that the sensation for me was very much like having my skin crawl.  This was not a pleasant sensation for me, and it caused me to liberate adrenaline.     The British have been exploring the use of TENS for patients in labor, and for many types of post operative pain.

                  It is important that you have a set of patches for each patient or family member who uses the TENS unit, to avoid cross-contamination.  Fortunately, extra peripherals for each device are relatively inexpensive, so you should keep extras on hand.

TENS unit from LG Medical

      There are a number of different types of patients who must not use a TENS unit.

1). Patients with an internal pacemaker or implanted defibrillator should not use TENS.  It is my personal opinion that persons with chronic cardiac rhythm disturbances should also probably not use TENS, or if they must, they should not use it on their chests or backs, other than perhaps their lumbar- sacral region or legs.
   (Cardiac rhythm disturbances include but are not limited to:  Long QT Syndrome, Brugada Syndrome, Paroxysmal or Chronic Atrial Fibrillation, Supraventricular Tachycardia (SVT) , etc. etc.)

2.)  Pregnant women should not use TENS over the uterus, until labor (when it is likely used on the lumbar-sacral region) because we do not know the effects of TENS on a very young or developing fetus.
3.)  Patients with malignant tumors should not use TENS as studies have demonstrated that mild electrical stimulation may stimulate tumor growth.
4.) TENS should not be used on the neck, the eyes or the head as it has demonstrated negative effects on blood pressure when used in these areas.
5.) TENS units should not be used without physician supervision on anyone with broken skin or rash, or internally without specific direction, physician order, and a special modified machine.
6.) Caution should be employed and a physician should order TENS carefully for patients with epilepsy, in the event that seizures are triggered.
7.)  Long term diabetics with peripheral neuropathy may benefit from the use of TENS but great care must be taken to avoid injury, as they may have diminished sensation in feet, legs, and extremities.
9.) Do not use over metal implants and do not use at home on a patient using any type of an EKG monitor or Holter monitor.
10.) Several references express great reservation in using TENs on those being treated for dementia.  Use with extreme caution for patients with dementia, as they may not be able to detect sensations which may result in damage, or be able to communicate discomfort.

        Despite all the cautions, TENS units may be of great benefit to many patients, who may be able to diminish pain medications they have been taking on a gradual basis under physician supervision.

        As persons interested in medical preparedness, a TENS unit could be an excellent adjunctive piece of equipment.  In emergencies we may not have access to medications for pain other than aspirin, acetaminophen or ibuprofen.  Use of a TENS unit for muscle strain could be very helpful to us.  I am also aware, that although this IS a federally regulated piece of equipment that should only be issued with a prescription, that some of you have found a way to buy one.  In good conscience, I can only recommend that you see a physician now, and get an order for one to aid you with low back or leg pain. It could be very useful to you if, in the future, you found medical access more difficult.  In Canada, it is available only with a prescription.

           How does a TENS unit work ?   Near as physicians can tell us, they theorize that both high and low frequency TENS settings help in the effectiveness of opioid receptors in the brain.  There are also effects on serotonin levels.   TENS works by fooling the central nervous system into believing all is well, and TENS actually also does stimulate the release of positive neurotransmittors.  In short, there is no way of predicting which patients will be aided by this device, and which ones will be simply annoyed by it.
           Still, when faced with a life on medication for some time, or a device in which the patient can adjust the stimulation to low or barely perceptible levels, then the purchase of a TENS unit looks attractive.    Functional and adequate TENS units are available for anywhere between $39.00 and $350.00      Insurance covers most of them with a physician's order, although you might be better off simply putting up the small amount of money needed.   Once you have done an adequate amount of research and have a cogent reason for wanting one, most physicians will write such an order.
         I hope this is helpful to you and any loved ones who need such a device.

Used on s lower back.


These are some reputable US suppliers:




***Readers are responsible to speak with their own physicians and/or nurse practitioners about the selection and  proper use of any TENS unit.  I endorse no particular supplier and no particular machine.  Readers are encouraged to do their own research prior to contacting their physicians about these devices.


tahera said...

Very informative post on the effective use of tens muscle stimulator.

JaneofVirginia said...

Thanks Tahera,
For the right patient it can be effective and can result in a percentage weaning or complete weaning of their pain medication. The message for patients is that it is not a correct modality for everyone.

zahid khan jadoon said...

thanks for sharing your knowledge. i am practicing tens unit from couple of year and i really found the best results

JaneofVirginia said...

Glad a TENS unit has been helpful to you. It really can be of benefit. Vest wishes.