P310 Therapeutic use of transcranial magnetic stimulation in pain patients

Background and Aims Repetitive transcranial magnetic stimulation (rTMS) relieves pain. We have used electric field (E-field) navigated rTMS to treatment resistant pain. Here we analyse clinical utility of rTMS, and search clinical factors predicting response. Methods All patients underwent serial rTMS for pain ( n  = 46). The mean age was 45.4 years (range 13–89), 29 women. Their pain diagnoses were: CRPS (19), neuropathic pain (12) and other chronic pain (15). The duration of pain varied between 0.5 and 40 years (median 4.5 years). An E-field navigated NBS-TMS system was applied (Nexstim Ltd, Helsinki, Finland). Intensity and interference of pain were assessed with visual analogue scale (VAS; 0–100 mm) at baseline and after the treatments, and global impression of change was evaluated with GIC scale (−3 to +3). Results There was significant reduction in pain intensity; more prominent and quicker in the interference scores ( P 0.0001 ). 51% of the patients reported positive GIC score. Cohen’s d for effect size was highest for neuropathic pain (0.61 for intensity/0.96 for interference), modest for CRPS (0.45/0.49). Women benefitted better (0.54/0.62) than men (0.33/0.50). Opioid use decreased the effect size to 0.1. Without opioid or benzodiazepine medication, response occurred during the first week, whereas in opioid users, it was delayed up to ten days. Conclusions In addition to neuropathic pain, rTMS is useful for CRPS and fibromyalgia. Diagnosis, sex, and medications influence the results.