Transcutaneous Electrical Nerve Stimulation (TENS) devices produce a gentle electrical stimulation that when applied through pads applied directly to the skin, has a noticeable effect in reducing pain associated with various types of injuries and ailments. Several recent studies have shown efficacy when used for acute pain specific to primary dysmenorrhea, renal colic, lower-extremity pain, and pain associated with spinal cord injury, and was achieved without adverse effects. This study is intended to compare the effects of TENS units on acute back pain on ambulatory patients who are awaiting emergency medical treatment, to uncover if a statistically-significant analgesic effect is noted compared to a placebo device.

With the emerging amount of new data on the treatment specific to acute pain, it is theorized that early TENS application can be an adjunct for acute pain reduction, specifically for patients awaiting treatment in an emergency department triage waiting room. TENS stimulators are advantageous to patients in that they are non-pharmacologic and non-invasive therapy. TENS devices have an excellent safety profile, are associated with very few contraindications, and have negligible side-effects or adverse events: the most common being minor skin irritation. (Sluka and Walsh 2003) Of financial benefit to a hospital considering their implementation, these devices are also inexpensive. In the realm of emergency medicine, which is being scrutinized to reduce opioid prescriptions, measures must be taken to maximize the efficacy of alternative pain-relief adjuncts.

There are significant gaps in the literature which have depicted no significant benefits compared to physical therapy and other modalities. These studies had used variable treatments times and frequencies, which were not solidified in scientific research at the time of their results. The use of these stimulators has been extensively studied, and the evidence to support their use on various conditions has been inconclusive. Early meta-analyses and systematic reviews have noted the data are inconsistent to suggest a mean reduction of pain when assessed on chronic pain. (Brosseau et al. 2002) However, when applied extensively and at regular settings, TENS has shown the presence of tolerance to TENS when used chronically in as few as four days. (Chandran and Sluka, 2003) This study is intended to harness the newest research comparing the most-effective settings and durations of TENS units, and compare the effects of TENS units on acute back pain on ambulatory patients who are awaiting emergency medical treatment.

Inclusion Criteria:

• Presents to the Emergency Department in an ambulatory status
• Has a complaint of traumatic back pain, acute or acute-on-chronic, which is 3 weeks or less in duration.
• Is designated to an Emergency Severity Index Category of 4 or 5.
• Patient must be unfamiliar with TENS use
• Projected wait time of greater than 30 minutes before a visit with an Emergency Department provider is anticipated based on triage category
• Not actively pregnant for female patients

Exclusion Criteria:

• Patient has a history of using TENS in the past
• Patient is actively pregnant
• History of narcotic use or abuse in the last 24 hours
• Patient has a cardiac pacemaker or a neurostimulation-implant device
• Patient is designated to an Emergency Severity Index Category of 1, 2, or 3
• Patient has an open wound, abrasion, skin rash, or tattoo < 6 weeks old where pads will be placed
• Patient has a current history of Low Back Pain 'red flags' (Bilateral radicular symptoms, saddle anesthesia or paresthesia, bladder incontinence, or bowel incontinence) which require immediate attention.

Once the study is completed, the data used for statistical analysis will be void of personally identifiable information. This data will be in electronic form for use in government-approved software, such as Microsoft Office. These documents will be distributed only to the Primary Investigator and the William Beaumont Army Medical Center (WBAMC) Department of Clinical Investigations assistance with statistical analysis or future publishing consideration. All paper documents are to be maintained in accordance with Department of Clinical Investigations policies; study-specific electronic documents will be kept for a minimum of 3 years before deletion. Upon study closure, all personally identifiable information (including the Master Key) will be destroyed or deleted, and a de-identified data set maintained by the WBAMC Emergency Medicine Physician Assistant Residency Program Director for further study as needed. No human biological specimens will be maintained.

3 years, or as determined by the WBAMC Department of Clinical Investigations.

Principal Investigator, WBAMC Department of Clinical Investigations, WBAMC Emergency Medicine Physician Assistant Residency Program Director.

After computer-generated randomization, participants will either receive the active TENS treatment for 30 minutes, or receive the application of TENS pads and wear the device with no electrical stimulation. Both groups will have pre and post visual analogue scores assessed.