The Role of Cutaneous Magnetic Stimulation in Failed Back Syndrome

Abstract

Failed back surgery syndrome (FBSS) represents a distinct subpopulation of patients with refractory and disabling pain symptoms. Traditional treatment options of drugs and surgery have limited success. Constant application of permanent static magnets with 20-mm penetration has statistically reduced neuropathic pain in carpal tunnel syndrome and diabetic peripheral neuropathy. The aim of this study was to determine the efficacy of simultaneous permanent magnetic exposure to the back and feet (350 gauss and 450 gauss, respectively) over a 2-month period for the treatment of neuropathic pain compared to similar sham devices. This was a randomized, placebo-controlled trial of 17 patients with FBSS at two sites. Etiology for FBSS included herniated disks, spinal stenosis, epidural fibrosis, spinal instability, spondylolisthesis, and fusion failure. Baseline Visual Analog Scores (VAS 0-10) of neuropathic pain and sleep disturbance were compared at 1- and 2-month intervals for statistical changes. Sixteen patients completed this 2-month study. One patient dropped out during the first month. There was no statistical reduction in VAS scores for neuropathic pain or sleep. There were no safety issues. Simultaneous and constant exposure of weak, permanent magnets to the feet and back were ineffective in reducing neuropathic pain. Static magnetic fields need to penetrate 5 to 7 cm to address neuropathic pain from FBSS. Unfortunately, information regarding field decay from the surface of the magnet is rarely supplied by the vendors of such devices.