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The Best in FOAM Education

  • Facundo Gonzalez, MD

The Utility and Usefulness of TENS Units

A 58 year old male ex-firefighter presents for acute on chronic back pain for the past six years. However, this is his third or fourth episode of acute severe pain in recent weeks. He reports that he cannot walk or sleep.

A 35 year old female presents for severe lower back pain. Last week she picked up her 50 lb dog and heard a crack and popping sound. Pain was tolerable until today.

Both patients denied significant trauma, IV drug use, saddle anesthesia, urinary retention, or fecal/urine incontinence. They deny prolonged corticosteroid use and history of cancer. They deny other systemic or associated symptoms.

Both patients presented back to back on the same shift.

Physical Exam:

  • Paraspinal tenderness bilateral or unilateral at any level (cervical, thoracic, sacral, but usually lumbar)

  • No rash or ecchymosis

  • No motor or sensory deficit

  • Otherwise unremarkable


  • Acute muscle spasm

  • Disc herniation

  • Sciatica pain

  • Cauda equina syndrome

  • Shingles

ED Workup/Management:

  • Pain control (TENS Unit)

  • Ibuprofen, Acetaminophen, Valium

  • Reassurance, education

  • Proper close follow up

Final Dx:

  • Lower back muscle spasm


  • Discharge home with OTC Ibuprofen, +/- muscle relaxant

  • TENS unit recommendations, +/- warm compresses


  • On initial presentation both patients received TENS units, while the rest of their medications were ordered. With the TENS unit alone, the patients were able to find a more comfortable positions on the stretcher. One patient reported that “it took the edge off.”

  • Both patients were ultimately discharged with their pain under control and with close follow up with the Pain Clinic and the Neuro Spine clinic.


  • Lower back pain is one of the top 5 presenting symptoms in the ED

  • 25% of patient who present with back pain will have another episode within a year

  • With the opioid crisis, other means of treating pain are imperative

  • Small ED study in 2018 – 83% functional improvement with TENS unit

  • 2 out of hospital EMS studies (2006,2007) – showed decrease pain sensation with the use of TENS unit.

Transcutaneous electrical nerve stimulation (TENS)

Using mini sticky pads which deliver electrical impulses with variant degrees of intensity [Top left and right dial] with manual control over the Pulse width (Micro-second) [Left center dial] and Pulse rate (Hz) [Right center dial]

The middle switch controls the mode. Which contains the following options:

  • BURST: Fixed frequency, with fixed burst rate, adjustable pulse width

  • MODULATION: Pulse rate goes down and up over 8 seconds

  • NORMAL: Continuous stimulation at whatever setting you chose

Place pads on both sides of the tender. Turn on the device and start adjusting the dials as you show the patient what each one does. Let the patient find the right settings. It should not be painful, but soothing. TENS unit are not Electric Muscle Stimulators (EMS). They are not meant to elicit muscle contractions. However at max levels it may elicit a contraction, but it is not indicated.

There is no specific data on which mode to use for each type of pain. However for acute pain BURST mode will provide burst of stimulation alleviating acute muscle spasms.

The last switch located in the middle at the bottom is the duration of the therapy. Start with 30 minutes on one mode and then switch to another or keep the same if adequate response.

Take Away #1

Next time you encounter an acute back pain or neck pain, try a TENS unit. Let the patient find the right settings.

Take Away #2

Know that back pain is a very common ED chief complaint and avoiding opioid use is key.

Take Away #3

Start with a BURST mode 30 mins. If not proper response try NORMAL mode for next 30 mins.


Facundo Gonzalez, MD is a current first year resident at Stony Brook Emergency Medicine.


  • Effectiveness of Transcutaneous Electrical Nerve Stimulation for Treatment of Hyperalgesia and Pain. Curr Rheumatol Rep. 2008 Dec; 10(6): 492–499. doi: 10.1007/s11926-008-0080-z

  • Prevalence & Management Practices for Patients Presenting to the Emergency Department with Low Back Pain.Buxton: Nunn M, Edwards J, Hayden JA, Kiberd J, Magee K. Poster presented at International Back and Neck Pain Forum; 2016.

  • Transcutaneous electrical nerve stimulation: an effective treatment for pain caused by renal colic in emergency care.

  • Mora B, Giorni E, Dobrovits M, Barker R, Lang T, Gore C, Kober A

  • J Urol. 2006 May; 175(5):1737-41; discussion 1741.

  • Transcutaneous Electrical Nerve Stimulation (TENS) in the Emergency Department for Pain Relief: A Preliminary Study of Feasibility and Efficacy. West J Emerg Med. 2018 Sep; 19(5):872-876. doi:10.5811/westjem.2018.7.38447. Epub 2018 Aug 9.

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