Papers of the Week

(250 WORDS): Repetitive transcranial magnetic stimulation (rTMS) is a procedure increasingly used to treat patients with central neuropathic pain (CNP), but its efficacy is still under debate.Patients with medically refractory chronic CNP were included in two randomized phases (active/sham), separated by a wash-out period of 8 weeks. Each phase consisted of 4 consecutive rTMS sessions and a final evaluation session, all separated from one another by 3 weeks. High-frequency (20Hz) rTMS was delivered over the primary motor cortex (M1) contralateral to the patient's pain using a neuronavigated robotic system. Patients and clinicians assessing outcomes were blinded to treatment allocation during the trial. The primary outcome measured the percentage of pain relief (%R) from baseline. Secondary outcomes were VAS score, Neuropathic Pain Symptom Inventory (NPSI), analgesic drug consumption and quality of life (EQ-5D).Thirty-six patients performed the entire study with no adverse effects. The analgesic effect for the main criterion (%R) was significantly higher in the active (33.8% CI: [23.88-43.74]) than in the sham phase (13.02% CI:[6.64-19.76]). This was also the case for the secondary outcome VAS (-19.34% CI: [14.31-25.27] vs. -4.83% CI: [1.96-8.18]). No difference was observed for quality of life or analgesic drug consumption. Seventeen patients (47%) were identified as responders but no significant interaction was found between clinical and technical factors considered here and the analgesic response.These results provide strong evidence that 3-weeks spaced high-frequency rTMS of M1 results in a sustained analgesic effect and support the clinical interest of this stimulation paradigm to treat refractory chronic pain.