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TENS Unit: Pain Management for Ankylosing Spondylitis

A TENS unit is a device that some people use as a complementary approach to help manage pain. Complementary approaches are those used alongside or in combination with traditional medicine. TENS stands for transcutaneous electrical nerve stimulation. Typically, TENS units are one of many modalities used by physical therapists who can help patients obtain a unit for home use if it is determined that it might be beneficial.

How does a TENS unit work?

The TENS unit is a battery-powered machine that connects to electrodes which are placed on the skin. Small electrical pulses are delivered through the electrodes, and the intensity of the pulses can be controlled by the user. It’s believed that TENS machines work by changing the way the nerves conduct pain signals. By flooding the nerves with the sensations caused by the TENS unit, the nerves are less able to send signals of pain. The electrical impulses created by the TENS machine are also thought to stimulate the body’s production of endorphins, substances which act as natural pain relievers in the body.1,2

How it may help people with ankylosing spondylitis

People with ankylosing spondylitis (AS) have chronic and sometimes severe pain. Often the earliest symptoms are felt in the sacroiliac (SI) joints, which are located where the hip bones (pelvic bones) meet the base of the spine. This can cause chronic low back pain. Some people also have pain and inflammation in other joints, like the shoulders, ribs, hands or feet. The pain and stiffness caused by AS generally begins gradually, developing slowly over several weeks or month. The pain of AS is diffuse (spread over an area, rather than a specific point), dull, and may be constant and severe, although some people have pain that comes and goes. While the pain may begin on one side of the body, it can progress to both sides or may radiate to nearby areas.3-5

A TENS unit can be used on nearly any part of the body – it is not safe to use the electrodes on the front of the neck or near the eyes. A TENS unit may provide temporary pain relief. However, there is a lack of clinical research to prove its benefits for use in people with AS.2

Benefits of a TENS unit

A TENS unit can be a way for people to take control of their pain, and unlike pain medications, they do not have side effects or have a risk of dependency or addiction. The TENS unit is small and can be worn by clipping it onto a belt or slipping it into a pocket. The electrodes are placed near the area of pain but can be under clothing to provide discrete pain relief.2

Risks of a TENS unit

TENS units are generally safe for most people. However, some people should not use a TENS unit, including:

  • Pregnant people
  • Those with a pacemaker or other metal or electrical implant
  • People with epilepsy
  • People with heart problems

The electrodes of a TENS unit should not be placed on the front of the neck as it can cause spasms or blood pressure to lower. The electrodes should not be placed near the eyes as it can cause injury. Some people are allergic to the adhesive on electrodes, although hypoallergenic electrodes are available.2

As with any complementary approach, it’s important to talk to your doctor about all the methods you are using to manage or relieve your symptoms.

Written by: Emily Downward | Last reviewed: February 2019
  1. Complementary therapies. National Ankylosing Spondylitis Society. Available at https://nass.co.uk/managing-my-as/exercise/complementary-therapies/. Accessed 2/15/19.
  2. Lillis C. What is a TENS unit and does it work? Medical News Today. Available at https://www.medicalnewstoday.com/articles/323632.php. Accessed 2/15/19.
  3. Overview of ankylosing spondylitis. Spondylitis Association of America. Available at https://www.spondylitis.org/Ankylosing-Spondylitis. Accessed 1/21/19.
  4. Ankylosing spondylitis. Genetics Home Reference, National Institutes of Health. Available at https://ghr.nlm.nih.gov/condition/ankylosing-spondylitis. Accessed 1/21/19.
  5. Most common symptoms. Spondylitis Association of America. Available at https://www.spondylitis.org/Ankylosing-Spondylitis/Symptoms. Accessed 1/21/19.