Neuromodulation therapies for central poststroke pain

Central poststroke pain (CPSP) is one of the most refractory neuropathic pain, and this condition is typically pharmacoresistant. Owing to the refractory nature of CPSP, neuromodulation therapies such as deep brain stimulation (DBS), electrical motor cortex stimulation (EMCS), repetitive transcranial magnetic stimulation (rTMS), and spinal cord stimulation (SCS) have been applied to treating for CPSP. This paper briefly describes profiles of CPSP, and reviews previous reports of each neuromodulation therapy, including our clinical experience. The long–term success rate of DBS of the sensory thalamus or periaqueductal grey matter has been reported to be about 30 % from 92 CPSP cases, while EMCS is most efficient, about 50 % success rate from 142 cases, in the invasive neuromodulation therapies. Recent meta–analyses and therapeutic guidelines reported that high–frequency rTMS of the primary motor cortex was safe and had transient pain relieving effect. rTMS is currently the preferred treatment approach, but must be applied repeatedly for clinical practice. Although SCS was previously believed to be ineffective for CPSP, it can be applied to CPSP because some CPSP cases actually respond to SCS. A greater understanding of the pathophysiology of CPSP and mechanisms of action of neuromodulation therapies could lead more–efficient targets and treatments.