TENS (Transcutaneous Electrical Nerve Stimulation)
TESTS AND PROCEDURES

TENS (Transcutaneous Electrical Nerve Stimulation)

March 22, 2017

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TENS (Transcutaneous Electrical Nerve Stimulation)

Natural Standard Bottom Line Monograph, Copyright © 2013 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.

Related Terms

  • Related techniques: Acupuncture-like TENS, auricular TENS, CODETRON, electronic muscle stimulators, electroanalgesia, peripheral nerve stimulation, sensory afferent stimulation (SAS), TES (transcutaneous electrical stimulation), TNS (transcutaneous nerve stimulation), TNS (transcutaneous neural stimulation), TENMS, transcutaneous electrical analgesia.

  • Not included in this review: Cerebral TENS, cranial TENS, deep brain stimulation (DBS), epidural stimulation, percutaneous electrical stimulation (PENS), spinal cord stimulation (SCS), subcutaneous nerve stimulation (SCNS), or use of electrical stimulation for muscle toning.

Background

  • Transcutaneous electrical nerve stimulation (TENS) is a non-invasive technique in which a low-voltage electrical current is delivered through wires from a small power unit to electrodes located on the skin. Electrodes are temporarily attached with paste in various patterns, depending on the specific condition and treatment goals. TENS is often used to treat pain, as an alternative or addition to pain medications. Therapy sessions may last from minutes to hours.

  • TENS devices can be set in a wide range of frequencies and intensities, depending on patient preferences, desired sensations, and treatment goals. "Conventional TENS" involves the delivery of high or low frequency electrical current to affected areas. In "acupuncture-like TENS," lower frequencies are used at specific "acupuncture points" or trigger points. TENS may also be applied to locations on the ear ("auricular points"). Epidural stimulation and percutaneous electrical nerve stimulation (PENS), which are not included in this review, are invasive procedures that require penetration of the skin, implantation, or minor surgery.

  • The practice of using electricity for pain control can be traced to 2500 BC and the Egyptian Fifth Dynasty, in which stone carvings depict an electric fish being used to treat pain. During the Socratic era, electrogenic torpedo fish (Scribonius longus) were used to treat arthritis and headache. In the Middle Ages, electrostatic generators were used, and the discovery of the electric battery in the 19th century led to further experimentation.

  • The use of electrical stimuli for pain relief was popularized in the 19th century and became widespread in the 1960s and 1970s using battery power.

Theory

  • TENS has been hypothesized to improve pain in multiple ways. Theories include effects on sensory nerves, interference with sensory-discriminative pathways, stimulation of release of natural chemicals that affect the way pain is perceived and transmitted (for example, encephalins and endorphins), or through increased blood flow in treated areas such as the skin or heart. Recent data suggest pain relief from low and high frequency TENS is mediated by the release of mu or delta-opioids, respectively, in the central nervous system, and reductions in substance P. However, none of these mechanisms has been clearly established in scientific research, and the basis of activity of TENS remains controversial. Theories used traditionally to explain acupuncture have also been offered, citing effects on flow of vital energy. It is also sometimes suggested that TENS may affect the cardiovascular system, increasing heart rate and reducing blood pressure.

  • Many studies of TENS compare the technique to "placebo" techniques in which a TENS-like control box and electrodes may be used without delivering electric current to the patient. However, patients can often tell if no current is delivered, which lessens the quality of these studies. Much of the research on TENS is not well designed or reported.

Scientific Evidence

Uses

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Grade*

Dental procedures

Several small randomized controlled trials in adults and children report pain reduction or reduced need for pain medications during dental procedures with the use of various TENS techniques. These studies provide promising preliminary evidence but do not include clear descriptions of design or results. Therefore, better research is necessary before a strong recommendation can be made.

B

Knee osteoarthritis

Multiple randomized controlled trials have examined the effects of TENS in patients with osteoarthritis of the knee. Overall, the results suggest improvements in knee stiffness and pain, although it is not clear that walking distance or swelling are improved. The available studies have been small without clear descriptions of design or results. Therefore, better research is necessary before a strong recommendation can be made.

B

Anesthesia (pain relief during surgery)

Auricular TENS is sometimes used in Europe to reduce the need for anesthesia during surgical procedures. There is not enough reliable evidence to draw a firm conclusion in this area.

C

Alzheimer's disease

Preliminary research suggests that TENS may benefit some symptoms of Alzheimer's disease, including mood, memory, and cycles of daily rest and activity. Additional human study is necessary before a firm conclusion can be drawn.

C

Angina (chest pain)

Several small, brief studies report benefits of TENS on angina pectoris pain. However, most studies were conducted during the late 1980s and early 1990s, and were not well designed or reported. New drugs for heart disease have been developed since these studies were conducted, and people with heart disease or chest pain are advised to seek immediate medical attention from a licensed physician.

C

Ankylosing spondylitis

There is not enough reliable evidence to draw a firm conclusion in this area.

C

Back pain

The effects of TENS or acupuncture-like TENS on low back pain remain controversial, and multiple controlled trials have been published in this area. Studies have not been consistent in the type of TENS techniques used (location, intensity, frequency, duration) or in definitions of back pain, and most trials have not been well designed or reported. Published meta-analyses have grouped some of these studies together to try to determine whether this technique is effective, but have also yielded inconsistent results, with some authors reporting overall benefits, and others finding no clear advantage over placebo. Better-designed research is needed before a firm conclusion can be reached.

C

Burn pain

There is not enough reliable evidence to draw a firm conclusion in this area.

C

Cancer pain

There is not enough reliable evidence to draw a firm conclusion in this area.

C

Chronic pain

The effect of TENS on chronic pain of various causes and locations remains controversial, and multiple controlled trials have been published in this area. Although numerous studies report benefits, studies have overall been small, poorly designed, and without clear descriptions of results. Better-designed research is needed before a firm conclusion can be reached.

C

Dysmenorrhea (painful menstruation)

TENS has been examined for the treatment of dysmenorrhea in several small studies. Research in this area suggests that the use of TENS may reduce short-term discomfort and need for pain medications. However, the available trials do not clearly describe study designs or results. Most outcomes are not measured using validated scales. Overall, blinding, randomization, dropouts, and statistical analysis are not well described. Sample sizes are small. Therefore, the research in this area remains indeterminate.

C

Headache

Preliminary controlled trials suggest that TENS may have some benefits in patients with migraine or chronic headache. Additional well-designed research is necessary before a firm conclusion can be reached in this area.

C

Hemiplegia / hemiparesis

There is not enough reliable evidence to draw a firm conclusion in this area.

C

Labor pain

The effect of TENS on labor pain remains controversial, and multiple controlled trials have been published in this area. Although some research reports small benefits, including reduced need for pain medications, studies have overall been small, poorly designed, and without clear descriptions of results. Better-designed research is needed before a firm conclusion can be reached. It is not clear if passage of electricity using TENS has harmful effects on the fetus.

C

Local anesthesia during gallstone lithotripsy

TENS has been tested for its effects on pain control during lithotripsy (a technique used to break up gallstones). Currently, there is not enough reliable evidence to draw a firm conclusion in this area.

C

Facial pain / trigeminal neuralgia

Several studies report benefits of TENS in patients with chronic facial pain of various causes. However, these trials have been small without clear descriptions of design or results. Therefore, additional research is needed before a firm conclusion can be drawn in this area.

C

Myofascial pain

There is preliminary data that high frequency/high intensity TENS may benefit myofascial pain. However, currently there is insufficient evidence from well-designed controlled trials to support this use.

C

Nausea/vomiting of pregnancy

There is not enough reliable evidence to draw a firm conclusion in this area.

C

Neck and shoulder pain

There is not enough reliable evidence to draw a firm conclusion in this area.

C

Pain from broken bones / acute trauma

There is not enough reliable evidence to draw a firm conclusion in this area.

C

Peripheral neuropathy

Several case reports and a small number of controlled trials report improvements in pain symptoms in people with peripheral neuropathy or nerve damage. However, these studies have not been well designed or reported, and additional research is needed before a firm conclusion can be drawn about effectiveness.

C

Phantom limb pain

There is not enough reliable evidence to draw a firm conclusion in this area. Promising preliminary research requires confirmation with better quality studies.

C

Post-herpetic neuralgia

TENS has been used in post-herpetic neuralgia, however there is insufficient evidence from controlled clinical trials upon which to base recommendations.

C

Post-operative ileus

There is conflicting evidence from clinical trials on the effectiveness of TENS in post-operative ileus. Well-designed, large studies are needed before a recommendation can be made.

C

Post-operative nausea / vomiting

There is not enough reliable scientific evidence to firmly conclude if TENS is beneficial in patients with pain after surgery.

C

Post-operative pain

There are multiple controlled studies of TENS for pain following various types of surgery, including abdominal surgery, heart surgery, lung surgery, gynecologic surgery, and orthopedic surgery. Research is inconsistent, with a variety of TENS techniques, patient types, and study designs used. Overall, the quality of available research is poor. Although some studies do report improvements in pain and reduced need for pain medications, a well-designed review in 1996 concluded that there is no clear evidence of benefit. Better quality research is necessary in this area before a strong conclusion can be reached.

C

Post-stroke rehabilitation

Studies of TENS in post-stroke rehabilitation report inconsistent findings, and benefits have not consistently been demonstrated. Additional research is necessary before a clear conclusion can be reached.

C

Rheumatoid arthritis

Preliminary studies of TENS in rheumatoid arthritis report improvements in joint function and pain. However, most research is not well designed or reported, and better studies are necessary before a clear conclusion can be reached.

C

Skin flap ischemia

TENS has been tested for its effects on blood flow to skin flaps used in plastic surgery procedures such as breast reconstruction. Currently, there is not enough reliable evidence to draw a firm conclusion in this area.

C

Skin ulcer

TENS has been evaluated in patients with diabetic foot ulcers and chronic ulcers of other causes. There is not enough reliable evidence to draw a firm conclusion in this area.

C

Spinal cord injury

There have been limited non-controlled trials of TENS in spinal cord injury. Well-designed controlled trials are required to recommend for or against the use of TENS for this indication.

C

Temporomandibular joint pain (TMJ)

There is insufficient reliable evidence to recommend for or against the use of TENS in temporomandibular joint pain.

C

Urinary incontinence / detrusor instability

There is not enough reliable evidence to draw a firm conclusion in this area.

C

*Key to grades:A: Strong scientific evidence for this use; B: Good scientific evidence for this use; C: Unclear scientific evidence for this use; D: Fair scientific evidence against this use (it may not work); F: Strong scientific evidence against this use (it likely does not work).

Tradition/Theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.

  • Achalasia, antiviral, atopic eczema, bursitis, carpal tunnel syndrome, cerebral blood flow enhancement, cognitive function, dementia, depression, dystonia, esophageal spasm, fibromyalgia, fracture pain, Guillain-Barre syndrome, hemophilia, herpes, hip pain, interstitial cystitis, itch, joint pain, labor induction, local anesthesia, menstrual cramps, MPD syndrome, multiple sclerosis, muscle cramps, muscle strains/pain, muscle spasticity, musculoskeletal trauma, nerve damage, osteoarthritis, pancreatitis, calcarea, Raynaud's phenomenon, repetitive strain injuries, sacral pain, schizophrenia, shingles, shoulder subluxation, sickle cell anemia pain, sphincter of Oddi disorders, sports injuries, thrombophlebitis, tinnitus, tremor, utero-placental perfusion enhancement, whiplash.

Safety

Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.

  • TENS is generally reported as well tolerated. Skin irritation and redness are the most common adverse reactions, occurring in up to one-third of patients. Hives, welts, or contact dermatitis/allergic skin reactions may occur with the use of electrodes and electrode paste. Electrical burns may occur with excess use or improper technique. Due to the risk of burns, TENS should be used cautiously in people with decreased sensation, such as with neuropathy.

  • TENS should not be used in patients with implantable devices such as defibrillators, pacemakers, intravenous infusion pumps, or hepatic artery infusion pumps. Electrical shocks or device malfunction may occur.

  • There are isolated case reports of lung atelectasis and edema, paresthesias, pain, and increased hair growth with the use of TENS. Seizures have been reported, and TENS should be used cautiously in people with seizure disorder. Unpleasant sensations at and away from the site of TENS, headache, muscle aches, nausea, agitation, and dizziness have also been reported. It is also sometimes suggested that TENS may affect the cardiovascular system, increasing heart rate and reducing blood pressure.

  • TENS cannot be recommended during pregnancy due to insufficient evidence, and due to a theoretical risk of harm to the fetus. Fetal heart rate may be elevated. Although multiple trials of TENS for pain relief during childbirth have been published, interference with fetal heart monitoring equipment may occur, and this technique should not be used unless under the strict supervision of an experienced licensed healthcare practitioner. Safety of TENS is not established in children.

Author Information

  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

  1. Brosseau L, Milne S, Robinson V, et al. Efficacy of the transcutaneous electrical nerve stimulation for the treatment of chronic low back pain: a meta-analysis. Spine 2002;27(6):596-603. View Abstract

  2. Carroll D, Moore RA, McQuay HJ, et al. Transcutaneous electrical nerve stimulation (tens) for chronic pain (Cochrane review). Cochrane Database of Systemic Reviews 2001;(4.) View Abstract

  3. Chandran P, Sluka KA. Development of opioid tolerance with repeated transcutaneous electrical nerve stimulation administration. Pain 2003;102(1-2):195-201. View Abstract

  4. Gadsby G, Flowerdew M. Nerve stimulation for low back pain--a review. Nurs Stand 1997;11(43):32-33. View Abstract

  5. Ghoname EA, White PF, Ahmed HE, et al. Percutaneous electrical nerve stimulation: an alternative to TENS in the management of sciatica. Pain 1999;83(2):193-199. View Abstract

  6. Hsieh RL, Lee WC. One-shot percutaneous electrical nerve stimulation vs. transcutaneous electrical nerve stimulation for low back pain: comparison of therapeutic effects. Am J Phys Med Rehabil 2002;81(11):838-843. View Abstract

  7. Johansson BB, Haker E, von Arbin M, et al. Acupuncture and transcutaneous nerve stimulation in stroke rehabilitation: a randomized, controlled trial. Stroke 2001;32(3):707-713.

  8. Mannheimer C, Carlsson CA, Vedin A, et al. Transcutaneous electrical nerve stimulation (TENS) in angina pectoris. Pain 1986;26(3):291-300. View Abstract

  9. Milne S, Welch V, Brosseau L, et al. Transcutaneous electrical nerve stimulation (TENS) for chronic low back pain (Cochrane Review). Cochrane Database Syst Rev 2001;2:CD003008. View Abstract

  10. Munhoz RP, Hanajima R, Ashby P, et al. Acute effect of transcutaneous electrical nerve stimulation on tremor. Mov Disord 2003;18(2):191-194. View Abstract

  11. Osiri M, Welch V, V, Brosseau L, et al. Transcutaneous electrical nerve stimulation for knee osteoarthritis (Cochrane Review). Cochrane Database Syst Rev 2000;4:CD002823. View Abstract

  12. Peters EJ, Lavery LA, Armstrong DG, et al. Electric stimulation as an adjunct to heal diabetic foot ulcers: a randomized clinical trial. Arch Phys Med Rehabil 2001;82(6):721-725. View Abstract

  13. Price CIM, Pandyan AD. Electrical stimulation for preventing and treating post-stroke shoulder pain (Cochrane review). Cochrane Database of Systemic Reviews 2001;(4):CD001698. View Abstract

  14. Proctor ML, Smith CA, Farquhar CM, et al. Transcutaneous electrical nerve stimulation and acupuncture for primary dysmenorrhoea. Cochrane Database Syst Rev (last updated 2002-02-28) 2002;(4):CD002123. View Abstract

  15. Zarate E, Mingus M, White PF, et al. The use of transcutaneous acupoint electrical stimulation for preventing nausea and vomiting after laparoscopic surgery. Anesth Analg 2001;92(3):629-635. View Abstract

Copyright © 2013 Natural Standard (www.naturalstandard.com)

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.

Updated:  

March 22, 2017