SGEM#483: Electricity – TENS Units for Treating Back Pain

Reference: Otterness et al. The Use of TENS for the Treatment of Back Pain in the Emergency Department: A Randomized Controlled Trial. AEM Aug 2025

Date: August 22, 2025

Guest Skeptic: Dr. Lauren Westafer is an Assistant Professor in the Department of Emergency Medicine at the University of Massachusetts Medical School, Baystate. She is the co-founder of FOAMcast and a researcher in pulmonary embolism and implementation science.  Dr. Westafer serves as the research methodology editor for Annals of Emergency Medicine.
Case: A 44-year-old man presents to the emergency department (ED) with low back pain after bending to pick up his child. He has pain in his left lower back that is worse when he moves. He has no fever, chills, weakness, or numbness. He has well-controlled hypertension and no history of recent antibiotic use or drug use. The patient has no midline tenderness, is without neurological deficit, and has no red flag features on history and physical exam. He took 500 mg of acetaminophen a few times without significant relief.
Background: Back pain is one of the most common reasons patients seek ED care, with an estimated 2.5 million ED visits for back pain each year. After dangerous diagnoses such as spinal epidural abscess, cord compression, and ruptured abdominal aortic aneurysm have been excluded, the next challenge for emergency clinicians is analgesia to improve the patient’s pain and mobility.
Unfortunately, there are numerous causes of musculoskeletal low back pain, rendering a single treatment course inconsistently effective for all-comers. Many pharmacological and non-pharmacological therapies have been tried with limited efficacy. 

Acetaminophen (Williams et al Lancet 2014)
Muscle relaxants (Friedman et al JAMA 2015)
NSAIDs (Machado et al Ann Rheum Dis 2017)
Steroids (Balakrishnamoorthy et al Emerg Med J 2014)
Benzodiazepines (Friedman et al Ann Emerg Med 2017)
Cognitive Behavioral Therapy and mindfulness (Cherkin et al JAMA 2016)
Chiropractic (Paige et al JAMA 2017)
Physical therapy (Paolucci et al J Pain Research 2018)
Acupuncture (Colquhoun and Novella Anesthesia and Analgesia 2013)

One treatment that can be very effective but comes with very real potential harms is opioids. The American College of Emergency Physicians (ACEP) has addressed the issue of opioid use in patients being discharged home after an acute episode of pain. They give a Level C Recommendation saying:

Do not routinely prescribe, or knowingly cause to be co-prescribed, a simultaneous course of opioids and benzodiazepines (as well as other muscle relaxants/sedative-hypnotics) for treatment of an acute episode of pain in patients discharged from the emergency department (Consensus recommendation). 

Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacological modality that administers low-intensity electrical stimulation to inhibit nociceptive pain signals. The efficacy of TENS devices in acute low back pain is uncertain.

Clinical Question: Is transcutaneous electrical nerve stimulation (TENS) more effective at relieving back pain than sham TENS?

Reference: Otterness et al. The Use of TENS for the Treatment of Back Pain in the Emergency Department: A Randomized Controlled Trial. AEM Aug 2025

Population: Adult ED patients (≥18 yr) with thoracic or lumbar back pain of at least moderate severity when research assistants were present (Mon–Fri, 8a–8p).

Exclusions: Patients with suspected spinal cord injury or infectious etiology, fractures, hemodynamic instability, allergy to standard analgesics, pacemakers, and those with skin conditions precluding TENS application were excluded.

Intervention: Two cutaneous TENS adhesive pads above and below the point of maximal tenderness with TENS unit set at a point just below the pain threshold and gradually increased for up to 30 minutes.
Comparison: Sham TENS pads applied but no electrical current.