Bipolar Permanent Magnets for the Treatment of Chronic Low Back Pain: A Pilot Study.

Collacott EA, Zimmerman JT, White DW, Rindone JP (Bio-Electro-Magnetics Institute, Reno, Nev; Veterans Affairs Medical Center, Prescott, Ariz), JAMA. 2000;283:1322-1325.

The purpose of this study was to examine the effectiveness of a bipolar magnet on chronic low back pain (LBP). The authors described LBP as both costly and disabling to American society, citing prevalence reports ranging from 15% to 45%. According to the authors, over 5 million Americans currently have LBP at an estimated annual direct cost of $15 billion. The high cost and morbidity associated with this condition is partly responsible for patients seeking out alternative forms of less risky treatment. Given a renewed public interest in alternative therapies, the use of permanent magnets to treat LBP has risen substantially. The authors noted that, to date, only 4 reports have been published regarding magnet use for pain, and only 1 of these reports was double blinded and randomized.

This study was designed as a randomized, double-blind, placebo-controlled, crossover pilot study. Twenty subjects (19 men, 1 woman) fulfilling the inclusion criteria (LBP of at least 6 months duration and imaging studies consistent with spondylosis) were included in this study. These general criteria allowed for several types of low back pathology to be seen in this study, including disk herniation, radiculopathy, ankylosing spondylitis, and fibromyalgia. The researchers thought that spondylitic changes in the "3 joint complex" were primarily responsible for pain in all of the cases included in this investigation. The outcomes selected by the authors included a 10-cm visual analog scale (VAS) with verbal anchors of "none" and "severe" at either end, the McGill Pain Questionnaire, and an active range of motion (AROM) measurement of lumbosacral flexion/extension using a 2-inclinometer method.

The study protocol consisted of patients wearing either a sham or real magnet for 6 hours a day 3 days a week for 1 week. The following week was designated as a "wash-out" week. The next week patients wore the opposite magnet from the first week (real or sham magnet). All participants were exposed to a total of 18 treatment hours for both the real and sham devices. The real magnet, which was applied to the lumbar area of each study participant, had a gauss rating of approximately 300 and utilized a multiple-triangle magnetic field configuration. The magnets were held in place using an abdominal binder, and the patients were explicitly instructed not to move the magnet location. Participants were also asked not to alter their usual medication pattern.

The variables VAS and AROM were analyzed before and after treatment using a repeated measures ANOVA and paired t test respectively. The before and after Pain Rating Index portion of the McGill Pain Questionnaire was analyzed using the Wilcoxon signed-rank test. The results showed no statistically significant differences between real and sham treatment outcome measures.

The authors concluded that the application of permanent bipolar magnets to patients with chronic LBP did not demonstrate any significant changes in the outcomes measured. They noted, however, that the study did have limitations. A relatively small and unbalanced (male to female) sample group and greater magnet strength and treatment time, among others, were all mentioned as possible critical variables that could be manipulated in future studies of therapeutic bio-magnets.

Tiziano Marovino, PT Preferred Spine, Sports and Occupational Medicine Allen Park, Mich