From the Guidelines
Transcutaneous Electrical Nerve Stimulation (TENS) units are recommended for pain management, with a usage duration of 20-30 minutes per session, up to several times daily as needed, starting with low-intensity settings (below 10 mA) and gradually increasing to a comfortable level. The most recent and highest quality study, 1, provides moderate-certainty evidence that TENS reduces pain at less than 2 hours compared with placebo.
Key Considerations for TENS Usage
- Electrode pads should be placed either directly over the painful area, along the nerve pathway supplying the painful region, or at specific acupuncture points.
- For acute pain, higher frequencies (80-120 Hz) with shorter pulse durations are recommended, while chronic pain often responds better to lower frequencies (2-10 Hz) with longer pulse durations.
- TENS works by stimulating sensory nerves to block pain signals (gate control theory) and by triggering the release of endorphins, the body's natural painkillers.
- Before use, ensure the skin is clean and free of oils, and never place electrodes over broken skin, the front of the neck, eyes, or directly over the spine.
Important Contraindications
- TENS should not be used by pregnant women (especially in the abdominal/pelvic regions), people with epilepsy, those with pacemakers or other implanted electrical devices, or over areas with decreased sensation.
- As noted in 1, TENS reduced pain at 1 to 7 days compared with placebo, with a weighted mean difference of −1.18 cm, providing further support for its use in pain management.
Additional Guidance
- It is essential to follow the manufacturer's instructions for the specific TENS unit being used and to consult with a healthcare professional if there are any concerns or questions about its use.
- The evidence from 1 and 1 highlights the importance of considering TENS as a nonpharmacologic treatment option for pain management, particularly for patients who may not respond to or tolerate pharmacologic treatments.
From the Research
Recommended Usage and Dosage for TENS Units
- The recommended usage and dosage for Transcutaneous Electrical Nerve Stimulation (TENS) units for pain management vary depending on the type of pain and individual patient needs 2, 3, 4, 5, 6.
- Conventional TENS is typically used as the first instance, with the purpose of selectively activating large diameter non-noxious afferents to reduce nociceptor cell activity and sensitization at a segmental level in the central nervous system 2.
- The stimulation intensity is critical to therapeutic success, and patients may need to administer TENS throughout the day to achieve optimal pain relief 2, 5.
- The evidence suggests that TENS may be beneficial as an adjunct to pharmacotherapy for acute pain, although systematic reviews are conflicting 2, 3.
- For chronic pain, TENS may be beneficial, but the evidence is limited by methodological limitations and small sample sizes 4, 5, 6.
Types of TENS Techniques
- Conventional TENS: used to selectively activate large diameter non-noxious afferents to reduce nociceptor cell activity and sensitization at a segmental level in the central nervous system 2.
- Acupuncture-like TENS: uses a different stimulation pattern to activate specific nerve fibers and produce analgesia 2.
- Intense TENS: uses a higher intensity stimulation to produce a stronger analgesic effect 2.