Long-term treatment of chronic orofacial, pudendal, and central neuropathic limb pain with repetitive transcranial magnetic stimulation of the motor cortex.

ABSTRACT

OBJECTIVE: To assess the long-term analgesic effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) of the motor cortex in patients with chronic pain syndrome. METHODS: The study included 57 patients (orofacial pain, n = 26, pudendal neuralgia, n = 18, and neuropathic limb pain, n = 13) with an "induction phase" of 12 daily rTMS sessions for 3 weeks, followed by a "maintenance phase" of bi-monthly sessions for the next five months. RESULTS: All pain measures significantly decreased from baseline to the end of the induction phase. Analgesic response, defined as pain intensity decrease ≥ 30% compared to baseline, was observed in 39 patients (68%), who could be differentiated from non-responders from the 7th rTMS session. At the end of the maintenance phase (D180), 27 patients (47%) were still responders. Anxio-depressive symptoms and quality of life also improved. The analgesic response at the end of the induction phase was associated with lower pain score at baseline, and the response at the end of the maintenance phase was associated with lower anxio-depressive score at baseline. CONCLUSION: The analgesic efficacy of motor cortex rTMS can be maintained in the long term in various chronic pain conditions. Patients with high pain level and severe anxio-depressive symptoms may have a less favorable profile to respond to the procedure. SIGNIFICANCE: The overall impact of rTMS treatment on daily life requires a multidimensional evaluation that goes beyond the analgesic effect that can be achieved.