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.
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Safety Safety definitions
Pregnancy And Lactation: Insufficient available information regarding safety of TENS in pregnancy and lactation; avoid use.
Effectiveness Effectiveness definitions
INSUFFICIENT RELIABLE EVIDENCE TO RATE
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.
Angina. Preliminary clinical research suggests that TENS may benefit angina pectoris pain. However, most studies were conducted during the late 1980s and early 1990s, and were not well designed or reported.
Back pain. Some clinical research, including pooled meta-analysis data, shows that TENS or acupuncture-like TENS may relieve low back pain. Other analyses report no clear advantage of TENS for low back pain over placebo.
Dysmenorrhea. Preliminary clinical research suggests that TENS may reduce short-term discomfort and need for pain medications in dysmenorrhea.
Headache. Preliminary clinical research suggests that TENS may have some benefits in patients with migraine or chronic headache.
Labor pain. Preliminary clinical research suggests that TENS may reduce the need for pain medications during labor. Additionally, it is unclear if passage of electricity using TENS has harmful effects on the fetus.
Myofascial pain. Preliminary clinical research suggests that TENS may reduce myofascial pain.
Osteoarthritis. Some clinical research suggests that using TENS in patients with osteoarthritis of the knee may result in improvements in knee stiffness and pain.
Pain. Preliminary clinical research suggests that TENS may be beneficial for alleviating chronic pain of various causes and locations. For instance, some preliminary clinical research suggests that TENS may help reducing symptoms in patients with chronic facial pain. Also, there is some evidence that TENS may help alleviate acute pain of various causes. Some clinical evidence reports pain reduction or reduced need for pain medications in adults and children during dental procedures with the use of various TENS techniques. Additional clinical research suggests that TENS may improve pain control during lithotripsy.
Peripheral neuropathy. Preliminary clinical research suggests that TENS decreases pain symptoms in people with peripheral neuropathy or nerve damage.
Postoperative ileus. Preliminary clinical research suggests that TENS may improve symptoms of post-operative ileus, other research suggests no effects.
Post-surgical pain. Preliminary clinical research suggests that TENS may decrease pain following various types of surgery, including abdominal surgery, heart surgery, lung surgery, gynecologic surgery, and orthopedic surgery.
Rheumatoid arthritis (RA). Preliminary clinical research suggest that TENS in may improve joint function and pain in rheumatoid arthritis report improvements.
Skin flap ischemia. Preliminary clinical research suggests that TENS may be beneficial for skin flap ischemia after surgery procedures such as breast reconstruction.
Stroke. Preliminary clinical research suggests that TENS may benefit post-stroke rehabilitation, while others show no effects. More evidence is needed to rate transcutaneous electrical nerve stimulation for these uses.
Natural Medicines rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Dosing & administration
Gastrointestinal: There was a case report of nausea.
Neurologic/CNS: There was a case report of seizures, dizziness, and headache.
Dermatologic: There were case reports of paresthesias, hair growth, edema, and pain.
Psychiatric: There was a case report of agitation.
Pulmonary/Respiratory: There was a case report of lung atelectasis after TENS.
General: Generally TENS is generally well tolerated; however there have been cases of both mild and serious adverse effects. Skin irritation and redness are the most common adverse reactions.
Musculoskeletal: There were case reports of muscle aches.
Interactions with pharmaceuticals
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Interactions with diseases
IMPLANTABLE DEFIBRILATORS: There is concern that TENS may interfere with implantable defibrillators and pacemakers. Advise patients with implantable devices to avoid using TENS.
SEIZURES: Seizures have been reported with use of TENS. Avoid TENS in patients with seizure disorders.
Mechanism of action
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, 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.