This was a pilot, randomized, double-blind, sham-controlled, parallel-group study assessing the effect of a PEMF treatment device on pain and disability in patients with non-specific LBP complaints (ClinicalTrials.gov identifier: NCT03053375). The work was conducted at the University of Bridgeport’s Chiropractic Clinic and was approved by the Institutional Review Board of the University of Bridgeport, Bridgeport, CT, USA (approval no. 2016-05-03). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.
The inclusion criteria were: LBP intensity ≥ 4/10 in the past week on the numerical rating scale (NRS); diagnosis of a non-specific LBP condition; age 18–75 years; fluency in written and spoken English; for female subjects, be postmenopausal, surgically sterile, abstinent, or agree to practice an effective method of birth control for the duration of the study if sexually active. Exclusion criteria were: LBP intensity ≤ 3/10 on the NRS; diagnosis or suspicion of LBP caused by cancer, infection, inflammatory arthropathy, or other non-specific process; compression fracture; significant structural deformity; current or planned pregnancy; any electrically based implanted devices such as pacemakers defibrillators, spinal cord stimulators, insulin pumps; metallic implants (e.g., surgical fusion constructs, disc replacements) in the low back; status post any lumbosacral spine surgery; severe depression, schizoaffective disorders, or suicidal ideation.
Participants were recruited from the UBCC patient population through informational flyers, posters, and word of mouth among staff clinicians and trainees. We recruited among consecutive patients presenting for their first visit for an LBP complaint. If an individual expressed interest in participating, a member of the study team met with that person to assess eligibility. Those determined to be eligible were given full details about the study and invited to participate. Those who agreed to participate provided written informed consent prior to their involvement in the trial.
Participants were randomized into active device or sham group using computer-generated tables to sequentially assign devices at the time of enrollment. Participants were instructed to self-treat with the device for 30 min, two times per day (8–12 h apart), every day for the first 6 weeks (initial treatment dose). After that, they were instructed to use the device for 30 min, one time per day, 2–3 days per week for the next 6 weeks (maintenance dose). A research assistant called the participants up to three times per week for the first week and then weekly thereafter to monitor for any changes or adverse effects and encourage compliance.
The PEMF device used in this study (MDcure®, Aerotel Ltd., Holon, Israel, and Aerotel Inc. USA, New York, NY, USA) is an FDA Class 1 listed therapeutic device that delivers an extremely low-intensity electromagnetic field (nT; 10−9) at a set of low (range 1–100 Hz) frequencies. Sham devices were externally identical to the active devices, except they were deactivated so that no electromagnetic field energy was generated when the devices were turned on. All other features were indistinguishable from the active units. Neither active nor sham devices generated any vibration, heat, or other tactile stimuli.
Participants in each group continued to receive usual care at their discretion throughout the study. We did not modify the treatment plans of the UBCC clinicians, nor did we restrict subjects from any treatments outside of the clinic. We examined the number of overall visits to the UBCC as a rudimentary measure of healthcare service usage. We did not assess any healthcare received outside of the UBCC clinic.
The primary end point was functional capacity assessed via the Oswestry disability index (ODI). We also measured pain intensity via the NRS. These were assessed at baseline, 6 weeks, and 12 weeks.
Differences in age were assessed using Mann-Whitney, while differences in sex, marital status, and ethnic origin were assessed using chi-square tests. Analysis of the primary end point was conducted on the intent-to-treat population and as a trend of change in pain scores over time, using the Freidman test of repeated measures. Adverse events were summarized by number and type. Level of significance is 5%.