Effects of Repetitive Transcranial Magnetic Stimulation in the Treatment of Phantom Limb Pain in Landmine Victims: ANTARES

Phantom Limb Pain (PLP) is a neuropathic chronic syndrome, characterized by a painful sensation in a body part that has been amputated. The incidence of phantom limb pain is between 50-80% of all amputees, however, additional risk factors as psychological trauma, blood loss, and infection increases its incidence after a traumatic amputation in landmine victims. Satisfactory management is often difficult to achieve and different clinical trials with medical and surgical measures have yielded unsatisfactory results. The response rate with pharmacologic treatment is around 30% using conventional medication as opiates and N-methyl-D-aspartate (NMDA) receptor antagonists, which is not significantly different from response rates with placebo. Recent case series have shown that repetitive Transcranial Magnetic Stimulation (rTMS) of the motor cortex can display an effectiveness that goes from 52% to 88% in the treatment of some refractory neurogenic pain cases which is quite superior to conventional management. However, the use of this type of treatment has not been studied in patients with phantom limb pain secondary to landmine injuries. The main objective of this trial is to evaluate the efficacy and safety of rTMS in the treatment of phantom limb pain in landmine victims. A double blind randomized placebo-controlled clinical trial, including 54 landmine victims with PLP will be performed. At the time of enrollment, a complete medical evaluation will be performed and those patients who meet the inclusion criteria will be randomly assigned to one of two groups, to receive rTMS in series of 20 trains of 6 s in duration (54-s intertrain interval) at a stimulation rate of 10 Hz (1200 pulses) and an intensity of 90% rest motor threshold using an \"active\" coil or a \"sham\" coil. Sessions will be administered 5 days a week (Monday to Friday) during two consecutive weeks. The stimulation will be directed to the primary motor cortex contralateral to the amputated limb. Response will be evaluated by measuring the pain intensity at baseline and after each session using a visual analog scale. These measurements will be repeated 2 weeks after the end of the treatment scheme, in order to determine the duration of the analgesic effect of rTMS