Transcutaneous electrical nerve stimulation (TENS) is defined as the application of electrical stimulation to the skin for pain relief. It’s based on the gate-control theory of pain, which proposes that painful impulses pass through a “gate” in the brain. TENS is performed with a portable, battery-powered device that transmits painless electrical current to peripheral nerves or directly to a painful area over relatively large nerve fibers. This treatment effectively alters the patient’s perception of pain by blocking painful stimuli traveling over smaller fibers.

Used for postoperative patients and those with chronic pain, TENS reduces the need for analgesic drugs and may allow the patient to resume normal activities. Typically, a course of TENS treatments lasts 3 to 5 days. Some conditions, such as phantom limb pain, may require continuous stimulation; other conditions, such as a painful arthritic joint, require shorter periods (3 to 4 hours). TENS has also been found to decrease knee pain associated with osteoarthritis. However, recent studies have shown TENS isn’t helpful in patients with chronic lower back pain.¹ (See Current uses of TENS.)

TENS is contraindicated for patients with cardiac pacemakers because it can interfere with pacemaker function. The procedure is also contraindicated for pregnant patients because its effect on the fetus is unknown. It’s also contraindicated in patients with dementia. TENS should be used cautiously in all patients with cardiac disorders. TENS electrodes shouldn’t be placed on the head or neck of patients with vascular or seizure disorders.