Records of people using electricity to numb pain date back to around 2500 BC. Of course, electricity had yet to be identified, but Roman physician Scribonius Largus, Emperor Claudius’s personal physician, noted that standing on electric eels and electric fish could relieve some pain symptoms.
It may be no surprise that Benjamin Franklin was also a proponent of the health benefits of electricity. As a scientist, Franklin was active in the medical world of the 1700s, when medicine was administered at home by servants and guided by almanacs, including Franklin’s own Poor Richard’s Almanac. His medical commentary covered a wide variety of subjects, including electrical treatments for paralysis, headaches and other ailments. As demonstrated by Franklin’s own experiments involving lightning, electrical shock produces twitching and contraction of muscles. It was believed that sending a charge through affected limbs might regenerate muscle and restore movement. Centuries later, experimentation with electricity as a pain management therapy has continued. The precursor to the modern TENS unit was patented in the United States in 1974, and the therapy remains a noninvasive option for chronic and acute pain.
WHAT is TENS?
TENS (transcutaneous electrical nerve stimulation) is a noninvasive, drug-free method of pain relief used to treat a wide variety of muscle and joint problems, among other acute and chronic pain symptoms.
TENS devices — used in hospitals, clinics or at home — use electrical impulses to stimulate the nerve endings at or near the site of pain, diminishing the pain and replacing it with a vibrating, tingling sensation. The idea is for the electrical current produced by a TENS unit to stimulate the nerves therapeutically and non-invasively. Battery-operated units are generally connected to the skin using electrodes and modulate pulse width, frequency and intensity.
TENS is often part of an integrative approach to pain management. When prescribed by a pain specialist, an in-office trial period allows providers and patients to determine if TENS offers the intended relief. Alternatively, physicians may write a prescription for a TENS unit “under the trial of a physical therapist,” so a patient and a physical therapist can arrange an in-depth education and trial session before using TENS.
Typically, TENS electrodes are placed and tested for approximately 30 minutes, turning them on and off at intervals, but the length can vary depending on patient needs. Pain often is relieved only while the treatment is under way, but the relief may last longer.
Where the electrodes are placed depends on the type and location of your pain. Covering or surrounding the painful area with the electrodes is meant to soothe muscle pain, spasms or painful joints, as in arthritis. Alternatively, the electrodes may be placed in such a way to “capture” the pain of a surgical incision, or electrodes may be put between an injured nerve and the brain. In some cases, TENS is used in conjunction with acupuncture.
Patricia Emerson suffers from reflex sympathetic dystrophy (RSD), a condition with typical symptoms that include pain, tenderness and swelling of an extremity associated with varying degrees of sweating, warmth and/or coolness, flushing, discoloration and shiny skin. Emerson uses a home TENS device and rates the pain relief it provides as a 9 out of 10.
“I twisted my ankle at work, and after six months of injections I still had compressed nerves in the left side of my ankle. I tried everything from pain medications to a spinal stimulator, until finally I tried TENS. It was the best decision I could have made,” says Emerson. “I would advise anybody who suffers from nerve related pain to ask their health care professional about it. I’m using it in combination with medication, but it has helped me step back from the meds — and believe me, I would much rather be doing this than taking something for the pain.”
TENS, PART of an INTEGRATED PAIN-RELIEF APPROACH
Doctors and researchers still cannot pinpoint the exact reason for TENS’ effectiveness. Most explain that electrical stimulation of the nerves blocks the pain sensation and triggers the release of the body’s natural painkillers, or endorphins.
David Rosenfeld, MD, board certified in both anesthesiology and pain medicine and currently practicing with Interventional Spine & Pain Management, considers TENS to be part of a bigger picture of treatment. “In my experience, there is limited and in – consistent evidence to support the use of TENS as an isolated intervention in the management of chronic lower back pain. In my mind, TENS is most useful as part of a multi-disciplinary rehabilitation approach,” says Dr. Rosenfeld. “For acute pain (other than postoperative), I think TENS is still seen as experimental and is often not covered by insurance companies.”
Dr. Rosenfeld believes the best candidates for TENS are those seeking relief from chronic and intractable pain and for management of post-surgical pain. Sherril Smith has used TENS treatment for post-surgical pain.
“I have post-mastectomy nerve damage and have had varying levels of pain since the surgery in 2006. I have tried many different treatments for the pain, mainly Neurontin (gabapentin),” says Smith.
“While TENS works the best, nothing works very well. It did help in the beginning, but it doesn’t seem to be as effective now. I am wondering if my body got accustomed to it, thus making it not as effective.”
TENS: PROS and CONS
According to Dr. Rosenfeld, “The contraindications of using electrical stimulation include patients with pacemakers, blood-borne cancer, epilepsy and pregnancy. Electrical stimulation should not be placed over the carotid sinus, across the heart or temples, and it should not be used for undiagnosed pain.” On the plus side, he adds, “Electrical stimulation provides immediate effect to pain and is non-invasive, non-addictive or habit forming. It is a cost-effective way to treat pain without side effects. And as long as the pads are placed correctly, I think a TENS unit is one of the safest methods to treat pain.”
Patient opinions on its effectiveness may vary. Smith says she considers the TENS unit a bother to wear, but RSD patient Emerson swears by it.
“I’m able to mow my lawn now. I just attach it to my ankle and secure the wires with a cut off sock, and I experience no pain. It’s been wonderful,” Emerson says.
Regarding home use, Dr. Rosenfeld emphasizes thorough evaluation and proper placement of electrodes. “Without proper education on the use of a TENS unit, injury can occur. Despite the ready availability of venders who can supply a TENS unit to a patient, I feel that they should only be given out after evaluation by a health care provider and should not be made available to the general public,” he says.
Emerson agrees. “Using a TENS unit is not a no-brainer. Even after four years, I have to constantly adjust it to get the results I need. Of course, the provider at the pain center was very informative in teaching me how to use it. I think that’s really important so people don’t get frustrated.”
If you have uncontrolled pain, it’s important to talk to your physician about adding TENS to your pain management plan.