TENS Efficacy on Acute Back Pain in an Emergency Department Triage

The Use of Transcutaneous Electrical Nerve Stimulation on the Efficacy of Acute Back Pain Within an Emergency Department Triage: A Randomized Trial

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.

Using a sample population in a military treatment facility emergency department, this prospective, randomized controlled trial utilized forty-six total participants evenly divided to both a active and placebo group, were used to determine the efficacy of Transcutaneous Electrical Nerve Stimulation (TENS) on acute back pain of ambulatory patients presenting for emergent care.

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.

After all necessary data collection forms are obtained, a pre-VAS score will be obtained. The participant will point to the area of maximum subjective pain, and then four TENS pads will be applied directly around the point of maximal pain that was determined by the patient, located at least 3 centimeters but no more than 6 centimeters from the area in a square or frame-like placement. While the device is off, it will be set at the following settings: The selector switch will be set to 'Milli' or milliamperes, and the frequency dial will be rotated to 100 Hertz. The participant will be instructed to rotate both dials in a clockwise direction if more intensity is desired, or counter-clockwise if less intensity is desired. The participant will wear the device and pads for a 30-minute duration; upon completion, post-VAS scores and a patient satisfaction survey will be obtained.

After all necessary data collection forms are obtained, a pre-VAS score will be obtained. The participant will point to the area of maximum subjective pain, and then four TENS pads will be applied directly around the point of maximal pain that was determined by the patient, located at least 3 centimeters but no more than 6 centimeters from the area in a square or frame-like placement. However, no electrical stimulation will be provided. The participant will also wear the device and pads for a 30-minute duration; upon completion, post-VAS scores and a patient satisfaction survey will be obtained.

Enrolled participants will have baseline Visual Analogue Scores (VAS) pain scale scores assessed, consisting of a 0 to 100 unit scale, with instruction to locate their level of pain on the scale of 0 being "No pain at all," 50 being "Moderate Pain," and 100 being "Worst pain imaginable," and will be compared to score on the same scale after treatment.

Using an assessment questionnaire of patient satisfaction, with nominal and ordinal results measured for statistical significance: Do you feel that early intervention with this device increases your satisfaction as a patient? If given the opportunity, would you like to continue to use this device while waiting? If you were to guess, do you think you were part of the treatment group or the no-treatment group? On a scale of 1 through 10, with 1 being "completely dissatisfied" and 10 being "completely satisfied," how satisfied are you with being provided this 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.

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

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