Transcutaneous Electrical Nerve Stimulation for Pain Control
Transcutaneous Electrical Nerve Stimulation (TENS) for Pain Control
Main Author: Dr. Kyle Zenk | Support Author: Lori Sandberg, PT, MS
The Transcutaneous Electrical Nerve Stimulation (TENS) is a reliable, non-invasive method for managing both acute and chronic pain; recently, the FDA granted clearance for the TensWave Pain Relief device.
This article delves into the workings of TENS, exploring its mechanisms, applications, and potential benefits. We’ll uncover how this technology is used by physical therapists to effectively alleviate discomfort through carefully targeted electrical impulses. From understanding its basic principles to exploring its use in diverse pain conditions, this comprehensive guide will empower you to make informed decisions about TENS as a pain management option.
Table of Contents
- Transcutaneous Electrical Nerve Stimulation for Pain Control
- What is TENS?
- Is TENS Pain Treatment Effective?
- What Should I Expect When Trying TENS Treatment?
- Contraindications for Transcutaneous Electrical Nerve Stimulation
- SUMMARY: TENS Treatment for Pain
What is TENS?
Transcutaneous electrical nerve stimulation (TENS) is a form of non-medication and non-invasive pain management that has been used for over 50 years to manage both acute and chronic pain conditions. TENS units are safe, cheap, and available without a prescription. They work by delivering pulses of electric energy through pads placed on the skin near the sources of pain.
How does TENS work?
The electrical energy delivered by a TENS unit helps to inhibit pain signals from reaching the brain and stimulate the release of endorphins, or natural pain killers, to decrease nervous system excitability and pain. This process utilizes the same pathways that are used when you massage a hurt or sore muscle to reduce the discomfort. [1]
TENS works through several peripheral and central mechanisms to reduce hyperalgesia. At the peripheral level, TENS activates either large-diameter, low-threshold, non-noxious afferents (A-β) or small-diameter, high-threshold peripheral afferents (A-δ) to unlock the cascade of postulated mechanisms. This targeted stimulation reduces pain by lessening nociceptor activity and reducing unwanted pain sensations.
TENS devices typically allow for customization of its use including the intensity of the energy delivered, frequency of the waveforms to impact certain pain conditions, and the duration of the sessions. This allows for modifications at home to effectively treat their symptoms following guidance by a healthcare professional. People can adjust the frequency to impact pain as needed.
Example TENS frequency settings to impact pain:
Strength:
- 2-10 Hz for chronic pain.
- 35-50 Hz for muscle stimulation.
- 80-120 Hz for recent-onset pain.
TENS unit use typically varies in session time; below are general recommendations. [2]
Session length:
- Acute pain: Less than 20 minutes 1 time per day.
- Chronic pain: 20-30 minutes 1 time per day.
TENS units set at higher intensities causing gentle muscle contractions have been shown to increase local blood flow and further reduce pain. [3]
TENS units are typically battery powered and use wires that attach to pads placed on the skin to deliver electrical energy to the body. Each pad has an adhesive backing to allow it to stick to the skin. The skin should be cleaned with water or an alcohol wipe prior to placing the pads to allow better adhesive and minimize possible skin irritation. Each pad should be placed at least 1 inch apart from one another to help avoid skin irritation and discomfort during treatment.
What Pain Conditions Can TENS Treat?
TENS units can treat a wide variety of pain conditions including, but not limited to the following list.
- Jaw pain.
- TMJ disc displacements (jaw clicking, popping, jaw locking)
- Post-surgical pain.
- Neuropathic or nerve related pain.
- Headaches.
- Neck pain (herniated discs).
- Headaches.
- Arthritis.
- Sports injuries.
- Tendonitis.
- Menstrual pain and labor-related pain.
- Fibromyalgia. [1]
However, individuals who are taking opioid medications for current pain relief may note decreased effectiveness of TENS unit use due to the impact by these medications on the central nervous system. [2]
Twin Cities’ Minnesota Head and Neck Pain Clinic may recommend TENS treatment when conventional treatment such as manual therapy or exercises are providing limited impact on a patient’s symptoms. This can be with highly irritable or chronic pain, where we need an additional tool to break the pain cycle. Our goal is to provide relief to allow our other interventions to become more comfortable and effective for the patient.
New “TensWave” technology for management of debilitating pain
The FDA granted clearance to the “TensWave” pain relief device September 2023. “Zynex Medical has received 510(k) clearance from the US Food and Drug Administration (FDA) for its electrotherapy device, TensWave,” according to Phalguni Deswal”. The FDA clears Zynex’s TensWave device for pain management article states that this device is designed to be a portable, and user-friendly aiming to alleviate pain without medication.
The device’s portable and user-friendly features make it easy to integrate into patients’ daily routines.
Is TENS Pain Treatment Effective?
TENS units are a safe, effective tool in providing short-term pain relief. They are recommended as a complimentary tool to an established pain reduction or exercise program for the best outcomes. [3] For example, one study showed TENS unit use with a physical therapy exercise program may provide faster and more effective relief for neck and jaw related pain than TENS unit use alone. [5]
The March 18, 2020, Transcutaneous Electrical Nerve Stimulation Reduces Movement-Evoked Pain and Fatigue: A Randomized, Controlled Trial on TENS unit use with patients with fibromyalgia showed 44% of these patients reported at least a 30% reduction in their pain following daily use for one month.
Author Dana L Dailey reported that “After 4 weeks, a greater reduction in movement-evoked pain was reported in the active TENS group versus the placebo TENS group (group mean difference -1.0 [95% confidence interval -1.8, -0.2]; P = 0.008) and versus the no TENS group.”
What Should I Expect When Trying TENS Treatment?
When trying transcutaneous electrical nerve stimulation (TENS) treatment, expect:
- Sensation: To possibly feel a tingling, buzzing, or tapping sensation on your skin. It should not be painful. You can adjust the intensity of the electrical impulses with a dial or knob on the machine.
- Comfort: You can start on a low setting and gradually increase the intensity until the sensation feels strong but comfortable. Our patients report finding it easy to adjust the pattern and speed of the current.
- Skin irritation: Minor redness at the site of the electrode pads is normal and generally quickly fades. However, if you happen to experience any lasting redness or skin irritation, let us know.
In general, patients can expect pain relief during TENS treatment and 1 to 24 hours following a session.
Possible side effects:
Side effects of TENS use may include:
- Nausea.
- Tingling/prickly sensations.
- Skin irritation.
- Muscle twitching.
- Possible increased discomfort at too high of intensities.
Additionally, individuals can become accustomed to the settings if using constant settings over the course of a few days, resulting in decreased pain relief. To help reduce these effects, it is recommended to use a mixed frequency or changing the intensity by as little as 10% every few sessions to maximize effect of TENS treatment. [3]
Contraindications for Transcutaneous Electrical Nerve Stimulation
Although TENS can provide relief for a wide range of individuals, it may not be a suitable treatment for some individuals.
Individuals for whom TENS is not recommended includes the following conditions:
- Pregnant women during early pregnancy.
- Epilepsy.
- Pacemakers or other electrical/metal implants.
- Deep vein thrombosis (blood clot)
- Heart arrhythmias such as atrial fibrillation.
Furthermore, the pad should not be placed over known tumors, close to transdermal drug delivery systems, over the eyes, on the front of the neck, directly on open wounds, or on areas that have impaired sensation. Additionally, do not use in or near water, driving, or operating heavy machinery. [6]
SUMMARY: TENS Treatment for Pain
Overall, TENS units are a safe, cheap, effective, and readily available form of pain relief for a wide variety of conditions. Although short-term, the pain relief these units provide have allowed countless individuals to experience life with less pain on their own schedule. Consult with a healthcare professional such as a physician, pain specialist, or physical therapist to ensure safe and effective usage.
About the Main Author
Dr. Kyle Zenk is a physical therapist with a focus treating orofacial pain, cervical dysfunctions, and temporomandibular disorders (TMD). TENS is onw treatment options he uses to improve function and help his patients reduce pain signals in the brain.
About the Support Author
Lori Sandberg, PT, MS received her Master of Science degree in physical therapy from the University of Minnesota. In addition, she completed additional training in temporomandibular disorders and orofacial pain.
Resources:
[1] Mark L. Johnson, et al., “Efficacy and safety of transcutaneous electrical nerve stimulation (TENS) for acute and chronic pain in adults: a systematic review and meta-analysis of 381 studies (the meta-TENS study),” Feb 2022, https://pubmed.ncbi.nlm.nih.gov/35144946/
[2] Dac Teoli, et al., “Transcutaneous Electrical Nerve Stimulation,” Mar 2024, https://www.ncbi.nlm.nih.gov/books/NBK537188/
[3] Carol G T Vance, et al., “Using TENS for Pain Control: Update on the State of the Evidence,” Sep 2022, https://pubmed.ncbi.nlm.nih.gov/36295493/
[4] Sai Madhuri Nemani, et al., “Evaluation of the effect of different kinds of treatment modalities for temporomandibular joint pain and its relevance to chronic cervical pain: A randomized controlled trial,” Jun 2024, https://pubmed.ncbi.nlm.nih.gov/38650337/
[5] Martimbianco, A, et al., “Transcutaneous electrical nerve stimulation (TENS) for chronic neck pain,” Dec 2019, https://pubmed.ncbi.nlm.nih.gov/31830313/
[6] UIHC, “Transcutaneous electrical nerve stimulator (TENS),”Jan 2019, https://uihc.org/health-topics/transcutaneous-electrical-nerve-stimulator-tens
