Brief Research Report A Randomized, Placebo-Controlled Trial of Repetitive Spinal Magnetic Stimulation in Lumbosacral Spondylotic Pain

Objective. Lumbar spondylosis is a degenerative disorder of the spine, whereby pain is a prominent feature that poses therapeutic challenges even after surgical intervention. There are no randomized, placebo-controlled studies utilizing repetitive spinal magnetic stimulation (SMS) in pain associated with lumbar spondylosis. In this study, we utilize SMS technique for patients with this condition in a pilot clinical trial. Methods. We randomized 20 patients into SMS treatment or placebo arms. All patients must have clinical and radiological evidence of lumbar spondy- losis. Patients should present with pain in the lumbar region, localized or radiating down the lower limbs in a radicular distribution. SMS was delivered with a Medtronic R30 repetitive magnetic stimulator (Medtronic Corporation, Skov- lunde, Denmark) connected to a C-B60 figure of eight coil capable of delivering a maximum output of 2 Tesla per pulse. The coil measured 90 mm in each wing and was centered over the surface land- mark corresponding to the cauda equina region. The coil was placed flat over the back with the handle pointing cranially. Each patient on active treatment received 200 trains of five pulses delivered at 10 Hz, at an interval of 5 seconds between each train. "Sham" SMS was delivered with the coil angled ver- tically and one of the wing edges in contact with the stimulation point. Results. All patients tolerated the procedure well and no side effects of SMS were reported. In the treatment arm, SMS had resulted in significant pain reduction immediately and at Day 4 after treat- ment (P < 0.05). In the placebo arm, however, no significant pain reduction was seen immediately and at Day 4 after SMS. SMS in the treatment arm had resulted in mean pain reduction of 62.3% postprocedure and 17.4% at Day 4. The placebo arm only achieved pain reduction of 6.1% postprocedure and 4.5% at Day 4. Discussion. This is the first study to show that a single session of SMS resulted in significant improvement of pain associated with lumbar spondylosis in a randomized, double-blind, placebo- controlled setting. The novel findings support the potential of this technique for future studies pertain- ing to neuropathic pain.